Flat battery

[MattS]

Haven't driven the NSX for about a week and it seems to have a flat battery now. (This happened a few weeks ago too and then I jump-started it from another car and drove it around for an hour or so to charge it).

Thought I would take the battery out to check its condition and either replace it or charge it fully using a charger. Problem is the alarm goes off when I disconnect both or either one of the battery terminals = upset neighbours! Needless to say, the battery is still in the car and uncharged.

Does anyone know how I can remove the battery without triggering the alarm system? The handbook strongly advises against charging the battery while still connected to the car.

Thanks,

Matt

[MattS]

Panic over... Amongst all my NSX stuff that I inherited from the last owner, there is a small key. Lo and behold, this fits a small unlabelled black box in the engine compartment (towards front,driver's side) and when turned anticlockwise turns the alarm off. The immobiliser system still seems to work.

The battery's now out for charging.

I might actually leave the alarm turned off (but the immobiliser on) to see if this prolongs the charge life..

Happy New Year to all,

Matt

[DamianW]

Check the thread "trickle charger for battery". I leave my NSX plugged into an Optimate charger and its yet to fry anything ;) Saves a lot of grief with flat batteries if you don't use it much.

[mcibuk]

i still havn't got round to fitting my Accumate but hope to do so in next week or two.
Damian - with the Optimate can you keep your car "alarmed"? With Accumate on TVR the alarm had to be switched off as the trickle charge (change in voltage) would set off the alarm system.

[DamianW]

i still havn't got round to fitting my Accumate but hope to do so in next week or two.
Damian - with the Optimate can you keep your car "alarmed"? With Accumate on TVR the alarm had to be switched off as the trickle charge (change in voltage) would set off the alarm system.

Yep certainly do. I leave the bonnet on the catch so there's enough gap for the wire to go in and then I lock the car with the remote and it seems happy.

[mcibuk]

Yep certainly do. I leave the bonnet on the catch so there's enough gap for the wire to go in and then I lock the car with the remote and it seems happy.
I need to fit the Accumate and try it! Could be that it works differently than your "Optimate" or that voltage drop is different on NSX than it was on my TVR. Either way i need to know!
Thanks :D

[Bonners]

The battery's now out for charging.

Matt
Matt - is it just a case of removing the spare wheel bracket and then a few bolts to get the battery out? Looks a bit of faff so thought I might just get the car recovered - free anyway - and get my local dealer to charge/swap it out.

Mine appears to be totally dead, although only 1-2 years old, any chance it could be recovered? Foolishly used one of my motorbike trickle chargers and it clearly wasn't up to the job of keeping the battery charged.

[Kaz-kzukNA1]

https://lh3.googleusercontent.com/pw/AM-JKLUCVMSuQWf-S85h8EX3glGDgVBFbco9YARD_9D8_wBjnOvm3OfYh21mW6Ak6B-BGeNz7XmOwcdaid-qVWabrmakyU3WCizYPzG9-Y52hRNNP0CkkeBMIeiNVjD0Tu73AbqbmQ4gM7_jUr4ckjENTYB lqw=w1080-h710-no?authuser=0
Hope MattS won't mind my replying as OP was from Dec 2004, 17-18 years ago.


Don’t know the spec of your NSX but the basic is the same as above diagram unless you have the special model.


The manufacture warranty of the battery tends to be just 1 year.

However, the vendor or the Honda dealer would extend it to few years.

If you have the proof of the purchase, contact the seller and see whether it is still covered by the warranty or not.


If you are using the ordinary lead acid battery, then anything below 11V is less than 50% capacity left.

Anything below 8V while cranking, you won’t be able to start the engine as ECU has minimum required voltage.


If you are using intelligent battery conditioner such as CTEK, Optimate, etc, it has minimum voltage threshold of about 2.0 - 3.0V in order to trigger the conditioning sequences.

If your battery voltage is really low, try connecting another battery in PARALLEL to exceed the minimum voltage requirement to force the re-conditioning process.

If you can't even crank the engine, your battery may need de-sulphating phase but may never be able to recover the full capacity even if when fully charged.


If you know what you are doing, you could connect your battery conditioner at the jump start terminal at the Eng bay without taking the battery off the car.


Just make sure to keep the battery in healthy condition.

If jump start the car, you are forcing the altenator/ACG to work really hard to charge the flat battery while running the engine.

This could lead to new issue of alternator failure as the rectifier and other parts get so hot.


Kaz

[Bonners]

Thanks Kaz, hadn't realised the original post was so old. ;) Mine is a Gen 1 from 94 (I think). No crank and not even any lights. I tried using leads at the weekend and that got power going to car, hazards came on etc. but still not enough to get the car to turn over. It was an Optimate 4 I was using, works fine on the motorbikes but good enough for a car battery?

I did think about towing her with my mower up a hill right beside my house (private road) but you're saying that could cause further problems right?

I'm not the most technical guy but 5 bolts I can manage so I'll take the battery out and see if I can get a local shop to rejuice it. Bigger issue is hoping the old back can bend enough to heave the battery out, doesn't look like the easiest thing to do. Thanks again.

[Old guy]

First off, check the battery cable clamps that connect to the battery posts. Honda clamps suffer abuse poorly and it is not uncommon for over tightening of the clamp to result in damage to the clamp which results in a connection failure and no start condition. After tightening, if you can twist the clamp on the post you are going to have to fix / replace the clamps.

Conventional lead acid batteries are damaged by deep cycling. If the battery has been repeatedly discharged to the point of being flat you have shortened its life and are likely in need of a replacement.


I tried using leads at the weekend and that got power going to car, hazards came on etc. but still not enough to get the car to turn over. It was an Optimate 4 I was using, works fine on the motorbikes but good enough for a car battery?


I am confused by that statement. Did you try to use the Optimate to start the car? That will never work. The Optimate has a current rating of 1 amp and the starter probably draws 80 - 100 amps when cranking a high compression engine like a C30 / C32. If you were just using the Optimate for maintaining the battery that should work fine. If 'using leads' meant using battery jumper cables to connect the battery in another car to the jump start terminals in the engine compartment that should spin the starter motor just fine. If the starter motor failed to spin using jumper cables then you have some other problem.

[Kaz-kzukNA1]

The output current of the Optimate 4 is only 1A when in bulk charging mode so it 'can' handle the so called 'car battery' but just takes ages.
The battery conditioner designed for the higher capacity battery (like car battery) has much higher current rating.

It would be nice if you have multimeter to measure the voltage but if not, probably easier if you just take the battery out and have it charged by someone.

The Optimate 4 can operate as long as your battery can hold above 2V during the safety check phase.

You should be able to tell at which stage the Optimate 4 decided to quit through the indicator.

Do you have security/immobiliser on your NSX?

If the hazard light came on when you connected something, you may have triggered the immobiliser.

After having the battery charged or getting the new one, wear ear plugs and be prepared with the loud siren as soon as you reconnect the battery.

Quickly dis-arm the alarm/immobiliser to stop the siren.

Standard procedure for me so I always have ear plugs nearby while working on the car.


Kaz

[Bonners]

Conventional lead acid batteries are damaged by deep cycling. If the battery has been repeatedly discharged to the point of being flat you have shortened its life and are likely in need of a replacement.

Not repeatedly discharged as battery replaced last year so first time.

If 'using leads' meant using battery jumper cables to connect the battery in another car to the jump start terminals in the engine compartment that should spin the starter motor just fine. If the starter motor failed to spin using jumper cables then you have some other problem.

Sorry, jumper cables yes. I was hopeful here but engine didn't turnover. Perhaps I didn't leave it connected and the donor car running for long enough to get a base charge in the NSX battery? Could I have blown a fuse....or damaged the alternator? I connected to the positive terminal and the spare wheel brace...which got the hazards flashing.

[Bonners]

Kaz, yes there is an immobiliser fitted. Lights flashed but thankfully no alarm when I connected her to the donor car/battery. Will be ear plug armed when I reconnect for sure.

As I recall the optimate seemed to show no progress via the lights. I then tried an Oxford trickle charger and it showed the red warning signal. Not even I can get plugging it in wrong so assumed it means battery too discharged to recover

I'm away from home this week but will roll up the sleeves and investigate further at the weekend.

[Old guy]

Kaz, yes there is an immobiliser fitted. Lights flashed but thankfully no alarm when I connected her to the donor car/battery. Will be ear plug armed when I reconnect for sure.

As I recall the optimate seemed to show no progress via the lights. I then tried an Oxford trickle charger and it showed the red warning signal. Not even I can get plugging it in wrong so assumed it means battery too discharged to recover

I'm away from home this week but will roll up the sleeves and investigate further at the weekend.

If you have an immobilizer installed and you didn't even get a click from the starter when you had the jumper cables connected to the other car, I would be suspect that something is up with the immobilizer and it is preventing the starter motor circuit from operating. When you use jumper cables to connect the NSX to another car, try briefly turning the headlights (or the emergency flashers) on the NSX on. They should work fine off of the other car's electrical system. If the headlights won't come on then there is something wrong with the NSX electrical system or you are not doing the jump process correctly. Even with a dead battery, when the NSX is connected to another vehicle you should be able to engage the starter and the motor should run. Once the engine is running, it is theoretically possible to disconnect from the other car and run on just the alternator; but, don't push your luck with that.

If the charger is giving you a warning light I would treat the battery as 'time to recycle'.

[Bonners]

If you have an immobilizer installed and you didn't even get a click from the starter when you had the jumper cables connected to the other car, I would be suspect that something is up with the immobilizer and it is preventing the starter motor circuit from operating. When you use jumper cables to connect the NSX to another car, try briefly turning the headlights (or the emergency flashers) on the NSX on. They should work fine off of the other car's electrical system. If the headlights won't come on then there is something wrong with the NSX electrical system or you are not doing the jump process correctly. Even with a dead battery, when the NSX is connected to another vehicle you should be able to engage the starter and the motor should run. Once the engine is running, it is theoretically possible to disconnect from the other car and run on just the alternator; but, don't push your luck with that.

If the charger is giving you a warning light I would treat the battery as 'time to recycle'.

Gotcha, thanks very much for the help, something to do at the weekend....again.

[Kaz-kzukNA1]

I don't know how good the spare wheel holder/brace is as the GND point when you tried jump starting last time.

In fact, one could accidentally create short circuit by jump starting at the battery especially when the spare wheel holder is in one's way.

Also, seen many NSX with its battery holder bracket in the wrong orientation that the battery positive cable clamp is too close to the metal holder bracket.

The bracket is coated from the factory but by now, most likely peeled off and the metal exposed.

You can't even crank the engine so not directly related but just double check that the 120A fuse inside the same main fuse box in the video/photo below is not blown.

If short circuited or reverse voltage applied, it will blow.






https://youtu.be/ZgYMOkYyAyk

Can you access the Engine (Eng) bay?

In order to prevent the short circuit, there is a proper jump start terminal there on our NSX.

Also, the starter is at the Eng bay so this is the shortest circuit length.

Very old video but provides you with some idea.




https://lh3.googleusercontent.com/RChqXvLanglAOYrJfeHdoUN6Vzs3FEOFOb_SpvgTa5_gWWeu1Y dQgecsveRq19ZvlZIf7aW9aIMxGoaceY7mrpODLKCxlPWcEZ2G JA2o5AOCsgcK3BSH9dXa3XY5peV0r4HVMjIR9fyie7RfLkc2Uc _oil_Zr2qMj6X9Tbn_KeO7Kl4aXer0hwTsBdfxBlDplXN-2YUgcq_k8y4PX4kpvyTx0iTaK0t1fPQmn2DZhQpgLxd6-FryAmy9JpOl2_FB8H-_Nt-GNKow6PKrTfwqz2op2rjl3cfxIBCubQQtu3tXNmUANtaJVFDjq XJtSdyyelZUkx4kcCVRCLY2LKrQAv3W7GgpQkXzFfgdXyZQJVw bG6Q-zzHCSpDZAh0FyE2-W1V6_GPI5GDT5zffXI7q6Q09Lh5aRABbP3e7ONLbuxH6Xb6LnG CT1elAZu_ToJ_dnFV30ZiBR2WgYt7DRYUA2-gf9OB96pcheb1xePJuZDUUyS0MNhjbblzfqET91G-FWieitc0RC15ETX3nerZLa1clXTcq5Hd5sBQUG25pjiMmQU5Zs 0w8WHNXnPcADyebNM-Q3xEt8WlUvYvbtfCTY7XGoRcv3LPfNsR5L7R8rxnykTnvmoewi 4NSCyyHtxs0Tz2YiEMC_HuqS_tM-6xaT5EVFCYrcIB8fzmQ8phAdTNZ1ZvrZgzuIxI8r5JM1x86VXL DVjcxkPm9taoBahMn5no=w800-h600-no?authuser=0

https://lh3.googleusercontent.com/RNoim6capi8J5_J7WyaK1TYrPHzfzH8d5PZFsfvziJFo58KzgK gJpQ6S-LQzXtIz242THjfYPO_9S19dcwdaq39ufRtQfjjloJRvwD9lYhY fpncBAKGIlrNw_axczzWoyzG66BGnPja2x-7IN3U3VLg3xK5wUqbAneLEyBbPoQZ-ugVKl3Dsitk-TDLUPNhMsaYJCosjBIG-vp9Xm4J_8F-F2NwGV9hDQ4imsuTW-6btqMXVwuIO6QamkSZomUWlR5TdKK93JtlBYT5QKcRDP1GlwqD Q0Z24oybAMWIiUn8VJZMHpcjhl8LnhkMXz_BDU2CLxdx45EkHB r4dZKOOa2-PLvUapt2wtIulBF4M7GXxWpH4dyM-5GOmzZHRXXrJ8QsEOQPuEw_ysUZyIJPurEVh5X-x0fzPqH0rgl7md8a4eWuX92P5yhglVioCMDdEIYHwPtXDKztnf S2cWuzeM9annjBSj3L1Skgt_TVONjgSZHoieDsFH-_5Uf3ktmhUqEuGeGXVmArtGOCOmbraVNCmxZV78i2ucwSixseJ hk1ONrU6oX-MJz_dTj7YSLcrRZW1URvtvm8FaRVA-TmyXL95227YvU-zF3RZjlAk0Q8vHR7gvipomwfWvgVEoYRdNe7wBxQX-7frbWrJAGx28srKu2mAynUe9zkouxYIpICNAZIJLMx1hT1suph ZxrIobRNNXbg8N6QLGdSQznHKIcWV=w800-h600-no?authuser=0

https://lh3.googleusercontent.com/mRsMzRWvEzHiyPWIUdZ90ioY48grKn4OOC9LhiBSIzN1wOKOw1 YaPwCcDulaONjPtnYMfFIxAeDj7ZFa3GQVJ_ZferOGvMDM7tA_ 8sOYfqZZNia-hynf8F1XttnwEklKYEQwe2x_c2l2esockEzEb9cTOWDrfIi6uq KHT7sqE_zHVIhc6m956cb3DeasOATOdG9lGO_AV-GJUSV-FoF0MOtOUhYlHXnFL4hD6oC_blkucpU3IDJnh6QXMAmdNuQpRC 1JOAAk6E3UO1oFEF7VIACwxuMWT4fy5akQUc9_71GMw5bO1Wxd 9i2CkcTfPWFfCP2rW2qtXPH5FnfpNXBo7D_R6LKxyQr0TvXmET sAsVBR-JPJmLeQSwcdMS4bJTBOAHtpKtFvvfRMun3GtqeovDs8Nqot-KUPT6UQWaMywpxmeH_bA4oIHK-hUmT1gpOngGqp3Mq-QVu-buwLbL7-CzYI8jMHYySCZ299ZE9Q_N5IYKIDx6yaiZmLmzft6Aa-aGtBso2YFLL6IHW9YiszXEucSR_fJadohee7zRbsMo8Nkfk062 PoE6nIpq6uD_nMnmbl9brH79IYxoS02O1opMuM7AIaY9h6NbL6 KpaIwwmmqUndGWQWVzpSwGB_s8YnYm2pNCXSExxazymdZ6JxZF yXJeEjN94DvkP_0JlbNQIYaZ3F1RHR9Mj5C5ldfvQYW5hucUXA 1kRbNaIrGXCNFIXC=w800-h600-no?authuser=0
You can also use that location for the battery conditioner.

Positive cable at the +B jump start terminal inside the main fuse box and the negative side at the intake manifold.

Depending on the spec of the TH body, the shape of the GND point on the intake manifold is different but you should see negative/minus [ - ] marking nearby.






https://lh3.googleusercontent.com/DkaKc_XuUbqVPshArggPcfMaW-Egn01ctXXshbsV9bJd4pBWIMkraG540y5AWWNbhdbDDU_wsv9_ iQ9FEKAteitOzaWRH97TGrqbTjxyp2F2SDmRttWPYl7EGLF8mC hDNAa7rQaZrxkQyyBAKTsxHyv0G4k9ae0PqcGvKvq-tkgajixUQ6R0z-GtCBWqSP7UzSXvPXcBkHPZC2P2L47rDFE8fpggYzEU874FV88I Q15xIu34aHyPhYLEimQT_5sRdCNihcfqFQCH2k5L3KHOQYsG4L J6qiopLlcPZaOWqET5KLWHO0S0RfGib0-P_TImMQOgvmGgegYHzucEuXAwnw0NiPC3zp2wtDaVv3auRlHOs-AM7fVclpBxy7wWacAYTM9_YHxJoDupaoGytzHAjIGYF0v4OBHl R8oRMosnPTS2tYzWqrZOuHHCPJ8ElsYZnOc51IN1W9LKWTnSXs 7sMPDxvGewyyrba8H2JBkaVYEHXz6RHCP4-4bbGQrX-QdwWUKdtkry5r-Oa9JkQalWq6lYKHLRA2U4igzCgcI2VywkYUt3RJz1ZbY7QHgwh O7Yu7y9lmeijx3f0sNCf1wgcrwLHrIsYjtjh33a1Ut5SwIVWpY LJdv4uq1MlFpaN3DRjAsPGDELkDtIOvCod5soPHNPyFtFtYq1c gxBvAtpSYc1yipOwSCQ2sMp1jRwu7R5xUGmId8n2CgYgTGPfG-k7GYE=w800-h600-no?authuser=0

https://lh3.googleusercontent.com/qtdtzhgj4jrQsfmCmK5Ov1pkW-9bpB1l7wzcuzl5u_8uLYBsg4vZUaXrr77Oj4ewRZG7hdZRiGm2 yKbV42kzf577dhxNvEMpLs7H10tCtP8ESpuHna35d8yOeXMD2G Lrzw0vPFoRiq9Bg8qsJwlqff1TnKbAx1qQMghwTrz3eUzeD_LM c-P8DkSi4eaRaTDHwEnydFPHdnURbpMTzWoJGjlbIx_92toi3g6E 30UuoEtOX2GPkI0GtNY4W0aCDOwS1CvQHOugCDx-yejhHgZowbrAKv-Eru3jnAyxF5Ct6NfpNgRAKLHl4wPbA5XowY4ZjOQx5KNgTWUeI rw4S8VrGqI0r_Vwa8IOrv4ub7Ql6GnbkWBUomlFumHwPw1wHUH 2PAl0HRE5l76PESIoRhpEhCfFiWUaYsImoCBbkMFht_7e_k2wz 31p3BbTsV3ReeT--9XQUI30RwRJQHWTJXeg0m5g_Ljpm1Tj0AIKF09B2iWVgqNaYVz H3I1V85WGd5qFfsNyktPiryb8n36J51Cy1ZmLRYjzvRU-hDhvNyF1KomEU2VT32AQ4aX0R8zL7YbzuuAc7RDKNlwrFEWHQd z4ICar6s1jHtZOIqGnfOaCNNslwQ8UEt0SuWieZ40nQMj3m5C8 3MAwkBwswmqHapcvEx4fDxTybEltFTuFVju8VkfgZ7Dw3Ms9iA pvw12_sS57KGPK40BlcC4ToUtcnAvILfEf=w800-h600-no?authuser=0
If not heavily corroded, you can also use the metal tube of the brake booster vacuum line as the GND point.




On my NSX, I wanted the permanent installation for the battery conditioner so wired up in a way to be able to connect at the battery or at the jump start terminal inside the Eng bay.

This will allow me selecting the connection port depending on how I park the car and keep the security/immobiliser armed.

In order to prevent me from moving the car without first disconnecting the battery conditioner, I just cover the shift knob with a glove and big notice board at the steering wheel.




Next time when jump starting, keep eye on the volt gauge.

Turn IGSW into P2 ON, just one position before the cranking.

If the volt gauge doesn't move, you haven't connected the donor electrical power supply properly or you have other issues.

You should see about 12V or above depending on the power source of the jump starter.


Turn IGSW to P3 START (cranking).

Normally, you would see about 10V even during cranking and must hold at least 8V in order to fireup the engine.

If you saw voltage at P2 but no cranking at all (not even slow cranking) at P3, something is preventing the starter circuit.

If slow cranking and no fireup, something is consuming the energy of the donor power source.


Kaz

[Bonners]

Bloody brilliant Kaz, it's precisely an idiots guide that I need to fault find. Thanks so much.

I did find an old thread on the forum that talked about it being better to jump start via the engine bay but then someone said they'd done it many times direct from battery. Given the "proper" way requires me pushing the car out the garage, and back in again if I am unsuccessful, I opted for popping the bonnet (front) instead. I have an inkling a may have popped a fuse tbh. Consumable and easily replaceable I assume? Spare already hidden away in the fuse box by chance?

Another dumb question, a Golf R is man enough as a donor right, or X5 a better option?

[Old guy]

Jumping the car from the jumpstart terminals in the engine compartment is 'better' because it is usually easier. It eliminates the need to remove the spare tire and reach down and try to clip on to the battery terminals. It also has the advantage that if the cable connections at the battery (including the chassis ground) are in bad condition it eliminates that as a factor. If the cable connections in the car are in good condition you can jump start from the battery location without issue.


a Golf R is man enough as a donor right, or X5 a better option?

I assume that refers to the source for jumping the NSX? Either car should suffice as long as they both have the original style battery - i.e. you have not installed some tiny lithium ion battery.

There are a number of fuses that could disable the NSX starter system. These include the big screw in PAL style fuses like shown in Kaz's photo of the engine compartment main fuse box. The #29 50A PAL fuse in the main relay box (up front) will kill the starting system. However, there are other small fuses that can also kill the system. If the car won't start using the jump cables start turning on stuff (headlights etc) to find out what works while it is connected to the other car. That may give you a clue where to start looking.

[Bonners]

Thanks oldguy, will try that if I get that far. Problem #1, opening the bloody fuse box.

It looks like there’s at least 3, perhaps 4 tabs to push in and the one facing the cockpit/firewall, and the one facing across the engine bay (if there is one) look bloody difficult to access. Any tricks or hacks as the kids would say? Thanks.