My Honda battery seems to let go every 2 years. Any suggestions as to why???🤔

[Pride]

Every couple of years or so my OEM NSX battery just decides to pack up and not crank over and as Kaz witnessed yesterday at Silverstone, it was so flat in fact it barely brought up the dash lights and that was immediately after 3 parade laps and a very long drive getting there.

When parked in my garage I always make sure that the CTek digital pulse charger is plugged into it so ready and maintained for its next outing.

Once again Yeomans will kindly change it under the battery warranty but it's still very mystifying.

Today I put a volt meter across the terminals once removed and it read a low 10.31v
The condition warning light glowed a bright green colour indicating a healthy battery.

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Yet when I used my drop tester it fell instantly into the poor black section, suggesting knackered although still glowing green.

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Any suggestions as as to why this should happen so consistently???

[havoc]

10.3V isn't a healthy battery, regardless of a glowing light.

What alarm have you got fitted?

And what 'accoutrements' have you got that are / may be draining the battery? That turntable below the rear glass, for example - battery or wired-in??? LEDs / Neons / big Subwoofer behind the passenger seat?!?

...and has anyone checked your alternator?


If it's always doing it, and it's always OEM batteries, then one (or more) of:-
- your alternator isn't doing the required job, or is doing so but only partly / intermittently;
- there's something else providing a drain on the battery (alarm / other modification - think there may be a few to choose from), which a 'new' battery can deal with but which after a couple of years becomes too much.
- you've an intermittent short-to-earth, perhaps?
- your CTEK is faulty and not really charging / conditioning?
- ...or someone with better electrical knowledge can come up with another idea?


I would GUESS that if you've got an a-market alarm + LEDs + neons + turntable + ??? all turned on, then the overall draw when driving might be similar to / more than the alternator can provide, which means you could be draining the battery (slightly) while driving - a long journey could undo all the good that the trickle charge has done. A new battery has sufficient peak juice to cope with this, a slightly older battery may not...although I'd expect a CTEK to do better than that...how old is the CTEK?

[goldnsx]

One cell seems to be bad. There are 6 of them. If one quits the job you'll get around 10 V.

Are you sure that the CTEC is connected correctly? I also use a CTEC and these are very good.

What is the charging voltage of the alternator? It should be around 14.5 V.

If all check out fine the only reason I can imagine is that someone said that even battery makers are saving costs and lead which leads to a shorter battery life. >5 years would be good.

[Pride]

Thanks guys, I've sold and used CTEK digital pulse chargers ever since they first came into the country over 15 years ago, the one I use now is the latest version MX5.

I went to Japfest a week ago, no problems, Greenwhich Park to Brighton classic car run the following day, no problems, back in the garage connected to the charger and a week later no battery power.
Here's a pic of the charger I took this morning before removing the battery from the car.

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And yet putting the key into the ignition the dash lights were very dim and it still refused to turn over.
I checked all the connections on the battery and starter motor and they are both tight and clean.

I've double checked for current draw when all turned off and locked and it's milliamps.
The model turntables are AA battery operated so don't apply.

Alternator charges at 14.5volts when above 1500rpm

The battery has a 3 year warranty and I've had at least 4 replaced under warranty over the last 6 or7 years.
They used to cost £55 but in March this year the price jumped up 50% to nearly £90.

The upgraded sound system i put in isn't too excessive in my opinion.:)

I'll be picking up the replacement battery on Saturday under warranty, I'm almost certain it will be fine again for a good few months, at least until another cell drops out and it all starts over again.:(

[goldnsx]

Did you always use the same battery supplier?

[Pride]

Did you always use the same battery supplier?

For years I always fitted a red top Optima, but since closing my car stereo shop down ten years ago now I decided to replace it with the correct Honda NSX battery as it was almost a third the cost at the time.

[goldnsx]

Varta or Banner make batteries.

[Pride]

That's a fair point goldnsx, I might just as well try another make and see what happens over time, nothing to lose I suppose as they will also be under warranty.

Does anyone have a favourite make and type preference for reliability??

I do between 2-3000 miles a year.

What type??
Lead acid, spiral wound, gel cell, recumbent gas..........all I would really like is reliability at the end of the day.

[havoc]

Have you still got an old CTEK - if that is showing the battery fully 'conditioned', yet it's still weak straight after unplugging, that would point to a fault with the charger...but you say it's been happening for the last ~4 batteries which presumably is more than one CTEK in that time...which points back to the alternator, maybe?

(I don't know enough about the innards of an alternator to comment further, but that's arguably the one common component here)

[Pride]

Have you still got an old CTEK - if that is showing the battery fully 'conditioned', yet it's still weak straight after unplugging, that would point to a fault with the charger...but you say it's been happening for the last ~4 batteries which presumably is more than one CTEK in that time...which points back to the alternator, maybe?

(I don't know enough about the innards of an alternator to comment further, but that's arguably the one common component here)

Cheers for your input Martin, over the years I find CTEK charges do not like being dropped or knocked about particularly when at full working temperature and as I'm pretty clumsy I have had to replace a few in my time.

I have also had to replace the alternator twice. The first time it just stopped charging, so I replaced it with an identical casing style Denso alternator which went up in a huge ploomb of white smoke during a very high revving, spirited drive, that was about 6 years ago, so I decided to buy a second hand origanol on EBay and no such problems since.

I believe the voltage regulator is built in the alternator is it not???

[Hagasan]

As your car likes to talk its head off just ask it what's wrong ��. Apart from that, check good earths, terminal connections on battery etc. Everything else I'd suggest has been mentioned unless your car just doesn't like going "north" ��

[dcnsx]

I had a similar problem with a previous car. New battery that would be flat in two weeks if left standing. It turned out to be a bad connection with a fuse, I took everyone out and put back in problem solved. Although it was an Alfa so there you go...

[goldnsx]

I believe the voltage regulator is built in the alternator is it not???
Yes, it is.

I'd go with a standard Varta or Banner.

Without anything connected a lead battery is between 12.2 (empty) and 12.8 V (full). You can easily check your CTEC by measuring the voltage while it's connected to the battery, it should be 13.5-14.5 V. If you disconnect it and let the battery sit overnight it should have near 12.8 V if it's good. As you have a power ampere tester you can gain even more data. A good battery should not go down below 9 V under 100 ampere.

Your blowing alternators are a little mystery (to me). The regulator could be not working (well not if it's showing 14.5 V above 1500 rpm) or it's cooking the batteries, so they die that way. Unknown to me is also the added stereo system. How much load does it ask from the 12 V system? I could only imagine only if you listen very loud in traffic jam that the battery gets depleted. The alternator only offers full current at 1500 rpm or higher. At ldle with everything switched on (lights, windows defogger etc.) it is not able to deliver that amount of current and gets the extra juice demanded from the battery.

Did you also check for leaking ampere while the car sits? Something around 30 mA is normal in the NSX. The silly clock module draws the most I've heard. If you have a working CTEC connected the parasitic current draw is compensated by the CTEC.

Just as an info: my Odyssey 680 is always tricklecharged by a CTEC and it's in its 13th year now! That's what I call quality. :) I've also power tested it (100 A) and it's still perfect.

[Pride]

Thanks goldnsx, I think I'll try the Odyssey 680, the spec looks fantastic and for just £99 it's now about the same price of the Honda OEM battery with at least double the life expectancy.

http://www.odysseybattery.com/design_advantages.aspx

[goldnsx]

An unknown variable is your stereo upgrade and maybe other faulty sources all mentioned above I'd check out too.

Oh, don't forget to order the additional adapters for a in car installation.

[Pride]

Stereo upgrade is an amplifier with a negligible 25amps max current draw which I never really crank up in any case.

And cheers for the extra battery info.

[NSX100]

I had a similar problem with a previous car. New battery that would be flat in two weeks if left standing. It turned out to be a bad connection with a fuse, I took everyone out and put back in problem solved. Although it was an Alfa so there you go...

Same with me and mine is an NSX.

If I leave it for more than 2 weeks without the CTEK the battery will go flat despite how new is the battery. In almost 10 years I am on my 5th battery. Kaz and others have been all over the car and cannot trace any fault. Or maybe it is intrinsic to NSXs?

[Heineken]

I've made the experience that vehicle batteries tend to be optimized towards typical use. That is being kept fairly well charged, driven every few days, etc.
What I would try is an Optima Yellow. They are gel batteries which are much less sensitive to unusual using patterns (like less charging, low charge level and others), otherwise they are compatible.

My NSX is equipped with the Optima YT R 3,7 YellowTop 48Ah since autumn 2017 (well, not enough for a long time test) and all I've done so far is disconnecting the battery after driving and even though it was not connected to any charger from October to April it started up flawlessly (due to very little self-depletion).

The other Yellow Top is in my Honda Jazz since November 2016 and shows no sign of weakness. The original Honda battery regularly died after about one year due to the auxiliary heating discharging it too much (not really low but a typical car battery is not cycle proof and dies early if recharged too often, instead of keeping it on a steady high charge). In this case the gel type battery offered a big improvement as it's specifically rated as cycle proof.

Although these use cases don't directly apply to your problem but it would be worth a shot, from my point of view.

[goldnsx]

If I leave it for more than 2 weeks without the CTEK the battery will go flat despite how new is the battery. In almost 10 years I am on my 5th battery.
This is NOT normal.

Years ago (or when the batteries were of good quality) it took about 3 months to deplete a battery of a standard NSX. If you added electronics like theft-alarm things look different. Sometimes an aging relay is powering all the time and draws current when it should not. This is highly likely in an older car.

For all of you with much shorter depleting time please check how much current the car draws from the battery when it's just sitting around (no interior lights on of course). 30 mA is around ok for the NSX in standard form. If it's more try to pull fuses/relays by watching the multimeter. If it drops significantly you're on the right track.

The ADAC found out over the years that the battery makers use less and less lead in their batteries and welcome to "brave new world" shortened the life cycle of their product in general. This is induced by the dictat to lower costs. OK, enough of the conspiracy theory...

My last OEM Honda battery died after 4.5 years (one cell bad), that's ok but I'm usually using Banner or Varta and they're good (as well). What really kills a battery is it's laying around for more than a few days fully empty. 1 month fully depleted and it's shot.

[Kaz-kzukNA1]

All nice/interesting advice so just supplement…

Voltage, capacity, internal resistance, dark current, number of discharge/charge cycle, type of battery, driving mode, driving environment, car storage environment especially the temperature, etc.

The ordinary green/red/black indicator on the battery relies on the specific gravity measurement.
Can't detect increased internal resistance.

Basic/mid range battery conditioner from CTEK, Accumate, etc uses constant current control circuit with voltage sensing.
It does test for the sulfation/sulphation and load test to a certain level but unless you pay extra, it doesn't have enough absorption capacity for heavy load test and thus, can't detect some of the failure modes.
Partially because of the above and the way they use voltage sensing, even if it shows fully charged, your battery will fail cranking the engine.

Internal resistance changes depending on the capacity level so must be tested under the same condition.

Over 12V doesn't mean 100% charged capacity as well as 0.0V doesn't mean 0% empty capacity.
Depending on the type of battery, even just about 11V would mean 0% empty status and fail to crank the engine.

If your battery conditioner has desulfation/desulphation mode, try it after you had flat battery issue and if it is of ordinary lead acid type battery like Honda one.
It may prolong the life of battery if used once a year on low annual mileage car.

With ordinary lead acid battery, even if it happened just once, making it flat will never recover the full capacity. The damage has been done.

If jump starting the car, please pay extra attention to the surge current when removing the cable from the donor car/battery pack.
It could damage your ACG, controllers, etc and on modern cars, even could kill the ECU.

Drive regularly.
My Honda battery is 6 years old and still healthy.
I only connect it to the battery conditioner a few times per year when doing desulfation or top up the charge after doing some electrical testing without running the engine.

In Japan, many car owners tend to replace it every two - three years because of their driving mode/cycle and heatwave during the summer.

Many classic MX-5 owners are reporting battery life of well over 10 years including mine.
It sits inside the boot so away from Eng/Rad and even in the winter, it's in better condition than being exposed to outside atmosphere.


Kaz

[goldnsx]

Doesn't the MX-5 have an AGM battery (like Hawker or Optima) for the pure reason of weight saving? No wonder it lives way longer...:)

[Kaz-kzukNA1]

Bit off-topic but I was told the same and even wrote somewhere on here or on Prime that it's AGM but it's not.
Many MX-5, Miata, Eunos Roadster forums are also stating that it's AGM but....

For the Panasonic battery made in Japan for the NA series, also sold in UK are not AGM.
Mazda UK dealers stopped supplying it for a while but it came back on the market again many years ago.
It travelled all the way from Japan.

I had an opportunity to speak with the battery engineers a while ago and confirmed that it's a sealed gel type with high quality calcium plates.
Expensive but still, very good long life battery.

Kaz

[Pride]

OK, the story so far:

I removed the battery and had Yeomans confirm that it just didn't hold up to a drop test although showing nearly 12v on a volt meter.

I allowed my CTEK charger to fully load it up over night. By the morning my volt meter reading 12.8 volts.

I then reinstalled it after double checking the quality of both live and earth connections and all was good.

Keys into the ignition position, I pressed my Clifford remote control to desengage the immobiliser circuits and I observed instantly that my DRL's were not as bright as usual in my darkened garage along with the ignition lights also not as bright.

When I then went to crank it over the familiar total dimming of all dash lights and DRL's with a faint click from the starter solenoid and nothing else.

Voltmeter still read 12.6 volts when tested.

Just as in the Blackwall tunnel last Sunday I connected my small emergency jump pack across the starter jump posts in the engine bay and hey presto, it cranked over perfectly at the key with full power and fired up instantly.

Any suggestions please???

Ignition switch?
Starter relay or main relay staring to play up?

I've just had a thought.
Should I try connecting my jump pack leads directly across my battery terminals next time in the front compartment???

[britlude]

check the voltage at the batt, then check the voltage at the engine jump point... should be pretty much the same... i'd even suggest (with confirmation from others) to try your load tester at the jump terminals in the engine bay... sounds like there's a resistance between the battery and the heavy current getting to the starter...

there's a duff connection somewhere in the line... any terminals getting hot after cranking?

[britlude]

re-reading... so yeomans confirmed it's duff, and it's still playing up with a new battery, or have you charged your current battery again? just checking, tho the previous still applies!

[goldnsx]

Should I try connecting my jump pack leads directly across my battery terminals next time in the front compartment???
Yes, you should. That way you'll gain the additional info if the wiring from the front to the back is faulty (corroded, missing, whatever).
If if connect the emergency jump pack to the terminals in the engine bay[b] and it cranks right up with full power to the starter AND doing the same to the [b]battery terminals and it doesn't start up you know for sure that the wiring has resistance, most likely at the connections esp. in the front bay. Also watch the voltage gauge in the instrument cluster. What does it read while starting?

[Pride]

re-reading... so yeomans confirmed it's duff, and it's still playing up with a new battery, or have you charged your current battery again? just checking, tho the previous still applies!

Using my snap-on drop tester which convinced Yeomans of it's knackered condition and I know 100% that they changed the battery for a brand new one as I helped remove all the "chicken feed" from it when pulling it out of it's box.

[Pride]

Yes, you should. That way you'll gain the additional info if the wiring from the front to the back is faulty (corroded, missing, whatever).
If if connect the emergency jump pack to the terminals in the engine bay[b] and it cranks right up with full power to the starter AND doing the same to the [B]battery terminals and it doesn't start up you know for sure that the wiring has resistance, most likely at the connections esp. in the front bay. Also watch the voltage gauge in the instrument cluster. What does it read while starting?

Tomorow I will check the voltage drop at front and rear of the car and will try the jump pack on the front terminals, I don't know why I didn't think of trying this earlier today.
Cheers Jon and gold, hopefully that will identify the fault, it's bound to be something obvious I'm sure.

[britlude]

usually a dodgy earth!!!!! :)

[Hagasan]

usually a dodgy earth!!!!! :)

Post #11

[britlude]

Engine end too....... If the jump pack is fine and everything is ok when it's connected in the engine bay......

[britlude]

As I haven't got my manual handy... Where does the loom take its power from? I know there's an extra wire on the positive battery terminal, is that to feed the front fuse box, and the loom gets its power from the engine bay terminals?

[Pride]

As I haven't got my manual handy... Where does the loom take its power from? I know there's an extra wire on the position battery terminal, is that to feed the front fuse box, and the loom gets its powerfrom the engine bay terminals?

That would have been my next question Jon along with can anyone please tell me how many engine bay earth points there are and also where are they sited???

[britlude]

One should be between a front cam cover bolt and bulkhead near coolant bottle mount....

[Pride]

Owing having to watch one of the greatest England victories of all time over the mighty Tunisia I didn't manage to fully check out my starting problem when I got home until 9.30pm

Something I did find out though and I can't understand how this can be is that with my CTEK charger connected to the jump start points in the engine bay, (this is the usual I've always connected my charger when parked in the garage) after disconnecting the charger the battery voltage reads 9.69v even after being on charge for the last 24hrs, so therefore it hasn't been charging the new battery.

Any ideas why that should be as I haven't got a clue???

If I connect my jump starter pack to the engine bay jump terminals I can then crank and start my engine.

I turned off the engine, disconnecting the jump pack I then checked the voltage at the battery terminals which read 9.69v

I then connected the CTEK charger directly to the battery and it's now charging healthily at 12.6v

I will try cranking it over in the morning, hopefully it will crank and start.

Question therefore is???
Is the battery start cable connected straight through directly to the fuse box positive jump terminal or does it go through a fuse or relay system???

[goldnsx]

I can't answer your question out of my head but it's very unusual to hook up a battery charger in the engine bay. It should connect directly to the battery.
I guess that you have permanent 12V at the jump start terminal in the engine bay fuse box, no relay in between. If you hook it up there AND have a bad connection to the front, sure to have the same problems like the other way round when starting the engine. Dismount all the ground wires (front and back), clean them and fasten them. There's no time argueing more about it, just do it. This is a very common problem on the NSX, esp. when the car is sitting outside or is driven in rain, salt, whatever...There must be resistance at the connections. A high resistance at one point is very bad as it transforms current/power into heat. Please also check how the fat ground wires look like. In some cars the tend to break as they're not sealed while vibration and salt eats them up over time.

Good luck!

[britlude]

chances are there will be a corroded connection either on the main power lead coming thru to the back, or the earth from battery or the engine to the car... if you have a 3v drop between the battery and the engine end....

check the voltage at battery, then check at engine jump points.... if it's not the same check with some long test leads to work out which wire has the resistance in it....

[britlude]

The basic layout from memory is like this

https://farm2.staticflickr.com/1769/41084057900_50e922ddc6_c.jpg (https://flic.kr/p/25Asx4S)IMG_20180619_093157 (https://flic.kr/p/25Asx4S) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr


So the points to check are.....
https://farm1.staticflickr.com/892/41084051160_b122714a63_c.jpg (https://flic.kr/p/25Asv4E)IMG_20180619_092713 (https://flic.kr/p/25Asv4E) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

Numbered.....
https://farm2.staticflickr.com/1825/41084054830_edf2bf65ba_c.jpg (https://flic.kr/p/25Asw9W)IMG_20180619_093139 (https://flic.kr/p/25Asw9W) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

If it works with the jump pack on the rear points, then cable 4-5 connections are ok, try the jump pack black cable to a chassis bolt, like at the end of the cross beam (NOT to somewhere else on the engine or gearbox!) that'll confirm engine earth cable/connections 6-7 is fine.... Then it'll be a case of checking the front cabling and the main power to the rear 3-4... Got some looong jump leads???

[britlude]

And from the ctek charging from the engine bay jump point giving a low charge at the battery, and the car having a regularly low battery , so the alt is doing the same I'd check the engine earth, battery earth and main 12v cable ends..... You have got this wire, or similar in yr engine bay???

https://farm2.staticflickr.com/1762/41995007855_9b24ed8605_c.jpg (https://flic.kr/p/26YXoKz)IMG_20180619_102847 (https://flic.kr/p/26YXoKz) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

between the front cam cover stud and the bulkhead.....

[Pride]

Cheers Jonathan, I really appreciate your help.
Will check tonight.

[Pride]

So, forgoing the footie-fest when I got home I decided to check all the points that you suggested Jonathan, that's after having charged the new Honda battery for 24hrs this time with my old trusty analog charger directly connected to the battery posts in the front.

Now bearing in mind this battery is brand new and it read 12.5v straight out of the box on Sunday and also held rock solid on my drop tester.
Yet when I checked the voltage on getting home today the battery read 10.42v at both the front and rear of the car and the analog charger was making my alarm siren giving a strange, quite squeaking noises while I could hear the charger protesting while still connected and changing.

The Clifford alarm has got non volatile alarm and immobiliser circuits so when in valet mode it's completely by-passed.

I disconnected the charger and tried to crank the engine after turning off the immobiliser, the dash light went completely dimmed out in the crank position and not even enough power to generate a loud clicking noise at the starter, I've never heard or witnessed this before on any car and I've worked on a good few hundred in my time.

Biggest question therefore is why has the battery not charged and actually dropped in charge to 10.42v???
It's as if though something is massively restricting it from being charged or massively discharging it while charging, very odd.

I thought last night that my CTEK MX5 charger had become faulty which is why I connected my old analog charger, but the CTEK is fine as it fully charged my Audi A4 battery in just 2 hours.

I then connected the booster jump pack at the rear and it cranked and started straight away.
I noticed that the short jump pack leads got very hot in the short time it took me to walk around to the near side rear to remove the jump pack terminals.

On its fast cold tick over the alternator kicks out a very healthy 14.58volts.

Any suggestions as I've run out of ideas????

I'm tonight going to remove the battery earth this time before fully charging the battery over night on the CTEK.

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[britlude]

And if you connect the jump pack at the battery end???

The leads are hot as there's a lot of current going thru it.. if they are getting hot without cranking you have a big issue somewhere...

is all the disco lighting connected to the same place, can it be isolated easily.... something is killing the battery, if you disconnect it is there a spark?

next one will be to disconnect the battery, and put a ammeter between the positive and the positive battery clamp and read the 'resting' current....

[Pride]

And if you connect the jump pack at the battery end???

The leads are hot as there's a lot of current going thru it.. if they are getting hot without cranking you have a big issue somewhere...

is all the disco lighting connected to the same place, can it be isolated easily.... something is killing the battery, if you disconnect it is there a spark?

next one will be to disconnect the battery, and put a ammeter between the positive and the positive battery clamp and read the 'resting' current....

I've just tried the jump pack at the battery end and it fires up just as if connected at the rear end and the leads stay cool when just connected without cranking, so that's good.

Leaving the engine running I remove the jump pack, getting back in the car I turn off the engine and immediately try to restart it, all dash lights are much dimmer than normal and in crank position all go out due to lack of power.

I've pulled all the fuses on the various disco led lighting so they're now isolated.

And I've now disconnected both battery terminals and the CTEK is doing it's ting for the night.

In the morning with a fully charged new battery again I will check out the current draw at rest with my ammeter.

To me it's beginning to look more and more like a possible ignition switch, have you ever heard of that causing this sort of problem???

[Hagasan]

I'm wondering if you have a starter solenoid not disengaging properly and possibly shorting to earth and draining the battery. It might explain why the car wouldn't start again. Having said that though, have you checked the battery earth lead to the body for good continuity?

[Pride]

I'm wondering if you have a starter solenoid not disengaging properly and possibly shorting to earth and draining the battery. It might explain why the car wouldn't start again. Having said that though, have you checked the battery earth lead to the body for good continuity?

Thanks Gary, I've actually double and triple checked all the earth points I can find on the car and they all look in solid fine condition.

I've got to say that the starter sounds perfectly normal when spinning the engine over with the jump pack but the battery I installed on Sunday hasn't been able to do that under its own power yet, I will try it in the morning once fully charged again.

[britlude]

so something on the car is discharging the battery then, the current draw sufficient to discharge quicker than a charger can top it up.... if the batt is now disconnected, and it charges fine then its down the putting on an ammeter and pulling fuses to eliminate circuits!!

it use to be the case that the car had to run for about 20 mins to replace the energy taken out the battery to start the car, i'm sure that's reduced now with geared starters etc, but if the batt was flat before you started it with the jump pack, i'm not surprised it didn't restart......


(the leads would be hot on the jump pack after the starting current AND 'whatever is flattening the battery' current!)


ignition switch issues usually mean it doesn't turn over as the 'start' position gets worn and doesn't make a good contact....

[Nick Graves]

I'm wondering if you have a starter solenoid not disengaging properly and possibly shorting to earth and draining the battery. It might explain why the car wouldn't start again. Having said that though, have you checked the battery earth lead to the body for good continuity?

It does sound like a short in the starter motor.

It's got to be a big draw if it's dimming the dash lights after a re-start and the leads are getting hot. Unlikely to be a boom-tastic sound system.

It might even be the alternator, if the bridge rectifier's fried and it's trying to be a starter motor.

[Pride]

OK, the story so far:

I fully charged the battery, 12.6v, engaged the ignition key, disengaged the immobiliser, lights on the dash dimmed down quickly, tried to crank and nothing, not even a click.

I disconnected the earth terminal got out my 12v bulb test light and connected accordingly, it lit up like an inspection lamp.

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So I got out my ammeter, checked the current draw, a huge 2.42amps.

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I then proceeded to disconnect individually the alternator feeds, heated rear window fuse, cigar lighter fuse, electric window fuses and any other fuses which have a heavy draw. The stick light still shining bright after each removal test.

Any ideas please???

[britlude]

Pulled relays yet??

[Pride]

Pulled relays yet??

Yep.
Heated rear window relay, the other relays I touched for any heat build up and listened with my blue-point stethoscope, all silent and cold.
It's at times like this I wish I had your skills Britlude :)

[Pride]

Is there anything behind the bulk head I need to check, I really am struggling to think what could be causing this.

Almost time I think to call in one of my old auto electricians me thinks.

[britlude]

i think you are going to have to pull fuses and relays until you have a pile of them beside the car, be methodical, eliminating circuits until the current drops! there are relays on the bulkhead behind the seats too.... it may get to the point of unplugging ecu's etc, if it can unplug, it'll be unplugged! 3 fuse boxes to play with, plus relays.. take pics before hand just to remind you what goes where!


at least you know why the battery seems to be flat... because it is! now to find out where the drain is.....

[britlude]

In the engine bay fuse box you can isolate the feed from the front easily where it bolts into the fusebox... https://flic.kr/p/273daTV

Do it with the battery disconnected first and make sure they are insulated when you reconnect... Seems to be one wire in and 2 out (probably starter and alternator).... At least it should eliminate half the car wiring quite quickly....

[Nick Graves]

I know it's a sod to get to, but have you isolated the starter motor?

I'm wondering if it's that, or the main cable that's broken down.

[Kaz-kzukNA1]

You have multiple issues, charging and draining.
Much easier if having access to your NSX but too many speculations so will just share the past experiences.

By the way, still not clear whether you are really having voltage difference between the front and rear of the car.
When you measured the voltage at the rear (eng bay), where did you use for the GND point?
Also, you mentioned that you are using the CTEK at the jump terminal inside the eng bay.
Nothing wrong with it but where are you using for the GND point?

You mentioned that you checked the battery cable terminal but did you check the crimped section?
I have seen the cable bent and stressed resulting in several wire strands broken off.
If you replaced the cable terminal with aftermarket one, you should double check it.
Also, if you use terminal equipped with power cut off feature, make sure to check the resistance.
Over the years, I have seen increased resistance on some of them.

2.4A of dark current is not huge compared to motor driven devices but obviously, not normal.
As these relays are used at high power circuit, 2.4A may not be enough to generate any noticeable heat in this warm weather.

Don't know whether you have ICE or any modifications to the chassis loom.
If you have, how are you activating the ICE AMP?
If still relying on the speaker relay, pull it out or disable it by the fuse.
Known to stuck close draining the battery.

The a/c blower motor fan relay is famous for getting sticky as well as causing excessive heat due to corrosion at the relay terminals outside of the relay body.
Several NSX in Japan showed melted relay box under the bonnet/hood.
All of the owners didn't drive their NSX regularly.
Keeping the car inside the garage won't prevent this from happening.

If you removed the eng bay cooling fan, disconnected the relay or still using the relay but changed the mounting method, make sure the relay and connector terminals are dry.
You can power up part of the system even without the IG key.

Please remember that these relay box, relay terminal and relay body itself are not water proof.
Even you keep the car inside the garage, condensation will build up at the relay socket terminals.

It's not NSX specific and apply to all cars but if you wash the eng bay, front compartment or use pressure washer for washing the car, take extra care for the electronics connector and components.
They are only good for splash proof and won't survive even the strong stream of garden hose.

Kaz

[goldnsx]

On newer cars Honda used dielectric grease on all connections of the fuse boxes. Might be worth considering...

[ozon02]

Hi Kaaz,
I think that your "adventure" with NSX should find the finale in the form of a book.

[goldnsx]

I might be the first one to buy a copy...

[britlude]

what news???

[Pride]

what news???

Thanks for asking Jon and for everyone's great info and suggestions, I even had a couple of calls from members that don't post to often giving me some good tip and iideas as well as an alternator if required so thanks.

To be honest I've been flat out busy with other stuff going on in my life but as soon as England have finished thrashing Panama 😎 I will then spend a couple of hours trying to pin down the problem but if by then I can't I will then call in my old sparks expert who's at this very moment at the Paul Ricard circuit and about to witness Hamilton race to victory.🏁

So for ever the optimist I should be back on the road sometime next week but I will keep you posted as to its outcome.

[Pride]

Well that's the good old England thrashing prediction out of the way maybe I should now try giving a good old fashioned thrashing to my NSX. :)

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13460

Apologies in advance Kaz if this thought upsets you.:)

[britlude]

any updates, or is the foozball getting in the way???

[Pride]

any updates, or is the foozball getting in the way???

All sorted now thanks Jon but how frustrating, annoying and even embarrassing this eventual cure was.

After all the sodding about with goes along with checking for a big current draw it eventually turns out to be a completely duff brand new out of the box Honda battery.

Due to the fact it came out of a sealed box from the main dealer the last thing on my mind would be to do a drop test on this battery, so psychologically I thought the battery would be 100% perfect.

So after lengthy CTEK digital pulse charges I began to think my charger was faulty but it wasn't.
The ammeter reading of a 4.25amp current draw was in fact 0.425amps as I had the gauge dial set on the wrong setting.

That was discovered only after pulling relays, fuses disconnecting the alternator and checking earth straps, connections and plenty of frustrated head scratching and cursing as I'd also disconnected all the after market electric kit on the car, i.e. alarm, immobiliser, all the under car and over car lighting, amplifier and all associated audio devices connected to it such as Alpine screen, navigation, Bluetooth and old school iPod adapter which eventually brought it down to a more respectable 0.095amps.

At this point with it still not turning the engine over, reading 11.85v fully charged, the green charge cell glowing brightly I reluctantly decided to do a drop test on it and BINGO!!! A completely factory fresh knackered battery.
On phoning the dealer to tell them this news I was told it was impossible and the battery I'd returned 3 weeks earlier tested OK.
I asked them how they tested it and they said because it was a sealed battery they could only go on the green glow through the battery inspection cell and a voltmeter which read 11.95v after a good charge. I asked if they'd done a drop test on it to which they said the parts department never do. So I told them to try cranking an engine over with it and it wouldn't do a thing.
At that point I said I would be bringing back this faulty battery for a credit note to use on parts as an when required as I had already gone and bought a 5 year warranty YUASA battery and it's now fine.
Moral of the story is never to believe because it's brand new and out of a factory box that it's perfect.
The word frustration doesn't even start to explain my feelings 😡
Here's hoping the England footie team don't play the same against the Croats tonight. 😁

[goldnsx]

Glad, you've sorted that out.

If they're read 11.95V after a full charge they are 'on charge' IMO because it should have been clearly above 12.0 V, 12.8 V or so for a new lead battery if you let the battery sit for a hour after charging. The final voltage of the CTEC still connected doesn't mean anything at all. Recently my friend had it charged by a CTEC which resulted in a green light. But the battery was not able to turn the engine. Of course, you can always charge a dead battery but the green light doesn't mean anything at all in that peculiar case. :)

[Kaz-kzukNA1]

If you had 425mA of dark current, the issue was very likely to be within the system that you disconnected or it's still there but being disturbed by the circuit that you disconnected this time.
Hope it will stay like that and won't hear the same issue in 2 years time….

As mentioned in my earlier post, the green/black/red indicator on the battery case is relying on the specific gravity measurement.
It can't detect increased internal resistance, internal failure, etc.

And because of the design of these basic battery conditioners and the way they use the voltage sensing, even if it shows fully charged, your battery could fail cranking the engine.

Still there are some questions not answered so I have a feeling that you have other issues but for now, glad you are back on the road.


Kaz

[Pride]

And now the mystery of my brand new replacement Honda flat battery has finally been solved.

If you you recall I stated:
"Due to the fact it came out of a sealed box from the main dealer the last thing on my mind would be to do a drop test on this battery, so psychologically I thought the battery would be 100% perfect."

Taking the battery back for a credit note refund to Yeomans Honda yesterday, only because I'd already replaced my battery with a Yuasa battery, I discovered why the so called "new" battery was knackered.

After exchanging the battery four weeks ago under the warranty, Yeomans called me up a couple of weeks later to say that they couldn't find fault with my old battery, I said that was impossible and that they should try connecting it up to a car and try cranking it as they said they didn't have a heavy duty drop tester. I never heard back from them so I assumed they found it faulty after doing so.

The new Honda battery, as you all know if you've ever bought one, comes in a sealed box filled with what I call chicken feed to protect it from being damaged in transit, this stuff gets everywhere including all the crevices in the underside of the battery casing so it was taken into the workshop to be air gunned off, while at the same time my battery was cleaned up with a WD40 soaked cloth.

I'm sure you now know what's coming, yep you guessed it, they gave me back my old battery by mistake, looking brand new after it's thorough sprucing up.

The way that was discovered was that Yeomans pulled out my old battery from their warranty department to explain they couldn't find fault with it and I clamped my Snap-On drop tester across it expecting to see the metre drop instantly into the "black" dead area and to my amazement it held up strong in the Green area lighting up the element like an electric cooker ring.

As a way of an apology from them for mixing up my replacement battery 4 weeks ago Yeomans gave me a £50 credit note to spend on parts when ever I needed but also they gave me the brand new £110 battery to keep as they said they'd disposed of the old box it came in and therefore couldn't take it back into stock.

So even though it gave me a major scratching of my head to resolve what was in the end a simple problem, at least they did this.

SO ON THAT NOTE IF ANYONE NEEDS OR WANTS A BRAND NEW NEVER USED HONDA NSX BATTERY FOR JUST £60 THEN PLEASE JUST PM ME.

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I'm sure this sort of thing only happens to me. :)

[Nick Graves]

Oh FFS!

Let's hope that dark current stays away - you deserve a break!