NSX battery shenannigans

[britlude]

now my car isn't doing daily duty getting me to and from work every day (work moved, and instead of a 7 mile round trip, it's now 50!) the car is having a more relaxed time of it...

however the battery doesn't like it. now this may be a symptom that was concealed with every day use, or the car is sulking, but over the last month or 2 the battery has been weak.

to help, i put it on a ctek trickle charger, to keep things topped up, but after disconnecting after a week, starting the car to move it to the middle of the drive to wash it, and then it not wanting to start again to actually go anywhere, or back to its parking spot, something needed to be done...

battery taken off, checked at a battery specialist, declared suspect, charged, then 2 days later checked.....
https://live.staticflickr.com/65535/52743264158_c76f829640_c.jpg (https://flic.kr/p/2omK1Tq)IMG_20230308_165549 (https://flic.kr/p/2omK1Tq) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

seems 9.96V isn't very good when it was over 12 2 days previous....

so a new battery was ordered in.... meanwhile, it was time to sort the spindly very old terminals...
https://live.staticflickr.com/65535/52743264363_184fbd64e5_c.jpg (https://flic.kr/p/2omK1WX)IMG_20230307_171550 (https://flic.kr/p/2omK1WX) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

https://live.staticflickr.com/65535/52742773381_3521963e4a_c.jpg (https://flic.kr/p/2omGuZK)IMG_20230307_171620 (https://flic.kr/p/2omGuZK) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

yuk... the wires were't much better...
https://live.staticflickr.com/65535/52743028994_f377ca1f78_c.jpg (https://flic.kr/p/2omHNYS)IMG_20230307_171610 (https://flic.kr/p/2omHNYS) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

https://live.staticflickr.com/65535/52742773321_7c85239973_c.jpg (https://flic.kr/p/2omGuYH)IMG_20230307_171856 (https://flic.kr/p/2omGuYH) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

so these had to be sorted.... the earth was easy, buy a new 50mm^2 cable and fit that to my new clamps
https://live.staticflickr.com/65535/52742257642_33d4ddfddf_c.jpg (https://flic.kr/p/2omDRFG)IMG_20230310_123748 (https://flic.kr/p/2omDRFG) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

i bought these clamps as both terminals have 2 wires going to them, but then i realised the smaller wire to the negative could easily reach the chassis mounting... so it was routed there...

the positive terminal was cut off...
https://live.staticflickr.com/65535/52743264198_087799d86f_c.jpg (https://flic.kr/p/2omK1U7)IMG_20230307_172106 (https://flic.kr/p/2omK1U7) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

wires cleaned.... main power cable
https://live.staticflickr.com/65535/52742773176_7afaf1ef4b_c.jpg (https://flic.kr/p/2omGuWd)IMG_20230310_123734 (https://flic.kr/p/2omGuWd) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

fusebox cable
https://live.staticflickr.com/65535/52742257697_006daf7a41_c.jpg (https://flic.kr/p/2omDRGD)IMG_20230310_123740 (https://flic.kr/p/2omDRGD) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

:)

[britlude]

and new ends crimped on.... note, despite researching what the wire sizes were, to get the right terminals, turns out most people don't know what they are talking about, so the main power lead going to the back of the car is 50mm^2 and the power lead going to the fusebox is 25mm^2
https://live.staticflickr.com/65535/52743028559_a15e25b238_c.jpg (https://flic.kr/p/2omHNRn)IMG_20230310_130039 (https://flic.kr/p/2omHNRn) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

then the battery was due to be in... alas when we got to the shop, it hadn't been delivered and we were given the option of a bigger capacity battery.. fortunately we had the battery box with us, and, just like a cat, if it fits it sits! sooo....
https://live.staticflickr.com/65535/52743188840_e893c39112_c.jpg (https://flic.kr/p/2omJCuQ)IMG_20230308_165643 (https://flic.kr/p/2omJCuQ) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

95Ah rather than the 65Ah, and a whole load more CCA (i did later find that a higher capacity one is available in the same form factor, and cheaper, but we were in a physical shop and could actually buy it from a real person, and it was already in the car!)

fits in the hole...
https://live.staticflickr.com/65535/52743028434_a41c780f90_c.jpg (https://flic.kr/p/2omHNPd)IMG_20230310_142003 (https://flic.kr/p/2omHNPd) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

initial startup is a whole lot swifter, and when running i had the best voltmeter i've ever had
https://live.staticflickr.com/65535/52743028419_b9690b916a_c.jpg (https://flic.kr/p/2omHNNX)IMG_20230310_142724 (https://flic.kr/p/2omHNNX) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

i checked the charging system and had 14.6v everywhere and the gauge use to struggle to get to 12.5v

after a run out in an evening tho, it had dropped back to nearer its usual level, and after a run today, including 15mins on a motorway with just the radio on, it was here....
https://live.staticflickr.com/65535/52742772846_f0220d553a_c.jpg (https://flic.kr/p/2omGuQw)IMG_20230312_140947 (https://flic.kr/p/2omGuQw) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

14.3v everywhere... sooooo maybe an alternator issue too? i have one winging its way to me, so i shall find out shortly, no i didn't pay the £996 plus postage amayama want! refurb is fine

[NSX100]

and new ends crimped on.... note, despite researching what the wire sizes were, to get the right terminals, turns out most people don't know what they are talking about, so the main power lead going to the back of the car is 50mm^2 and the power lead going to the fusebox is 25mm^2
https://live.staticflickr.com/65535/52743028559_a15e25b238_c.jpg (https://flic.kr/p/2omHNRn)IMG_20230310_130039 (https://flic.kr/p/2omHNRn) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

then the battery was due to be in... alas when we got to the shop, it hadn't been delivered and we were given the option of a bigger capacity battery.. fortunately we had the battery box with us, and, just like a cat, if it fits it sits! sooo....
https://live.staticflickr.com/65535/52743188840_e893c39112_c.jpg (https://flic.kr/p/2omJCuQ)IMG_20230308_165643 (https://flic.kr/p/2omJCuQ) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

95Ah rather than the 65Ah, and a whole load more CCA (i did later find that a higher capacity one is available in the same form factor, and cheaper, but we were in a physical shop and could actually buy it from a real person, and it was already in the car!)

fits in the hole...
https://live.staticflickr.com/65535/52743028434_a41c780f90_c.jpg (https://flic.kr/p/2omHNPd)IMG_20230310_142003 (https://flic.kr/p/2omHNPd) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

initial startup is a whole lot swifter, and when running i had the best voltmeter i've ever had
https://live.staticflickr.com/65535/52743028419_b9690b916a_c.jpg (https://flic.kr/p/2omHNNX)IMG_20230310_142724 (https://flic.kr/p/2omHNNX) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

i checked the charging system and had 14.6v everywhere and the gauge use to struggle to get to 12.5v

after a run out in an evening tho, it had dropped back to nearer its usual level, and after a run today, including 15mins on a motorway with just the radio on, it was here....
https://live.staticflickr.com/65535/52742772846_f0220d553a_c.jpg (https://flic.kr/p/2omGuQw)IMG_20230312_140947 (https://flic.kr/p/2omGuQw) by JON SUTH (https://www.flickr.com/photos/197052607@N08/), on Flickr

14.3v everywhere... sooooo maybe an alternator issue too? i have one winging its way to me, so i shall find out shortly, no i didn't pay the £996 plus postage amayama want! refurb is fine


I would be very interested to read how others comment on this. I have had my NSX for nearly 14 years and keep it permanently on the CTEK, especially through winter when it is rarely used. The battery, no matter how new (and it is replaced every 3 years or so) has always been troublesome. Without the CTEK, it will discharge in about 2 weeks if unused even in summer. On the other hand the Voltmeter will typically read about 14 and, if used daily, for example on a vacation trip, there is no a problem.

[Nick Graves]

Yes, about a fortnight and starting gets very grunty.

Same with all the 'alarmed' fleet - only the unalarmed S2000 is a bit more durable. Well was; the battery is now ancient. I mean, really ancient.

Had a CTEK connection problem on the 86 and a relatively new battery was killed dead as I didn't realise. Generally, I get a good few years from batteries as the cars are effectively plug-ins.

You have to clean the CTEK plugs quite regularly - the contact area is rather small and oxidises quickly; the charger gets terribly confused.

I've also started to use cheaper batteries - I don't think Panachronic or Youass ones are anywhere near as durable as I thought they once were.

[britlude]

seems the rockauto vendor didn't have one available after all :(

it also seems to be the rarest alternator on the planet.....

found aftermarket repair kits.... not as expensive as the OEM honda stuff, obviously

[Old guy]

The first observation is that once the engine is running the operating voltage of the car is established by the alternator. The battery is just along for the ride and in fact with a little creative fiddling the system will operate fine with the battery removed - restarting will be a problem. Around 14.6 volts would be the typical running voltage. Given the rather crusty condition of your battery cables, I would carefully examine the B+ connection at the alternator, the grounding of the alternator to the engine and the two engine ground straps (transmission and right front head).

Bad grounding connections where the alternator mounts to the engine or the two engine ground strap connections can create a voltage offset because of voltage drop in the ground connections. As a simple test, with the engine running measure the voltage between the large B+ terminal on the alternator and the frame of the alternator. If it measures around 14.6 volts the alternator is probably working just fine. Now measure from the B+ terminal to the a ground point on the chassis (not the engine). If the voltage is significantly less then you have an alternator to engine to chassis grounding problem. If the voltage between the B+ terminal and the alternator frame is significantly less than 14.6 volts then you do likely have an alternator problem. As an observation, in North America parts to rebuild the alternator used to be easily available for a whole lot less than the cost of a new alternator.

If you find yourself with spare time on your hands, a review of the condition of the other significant ground connections on the chassis might be beneficial. Cars in Great Britain do seem to suffer from moisture related corrosion issues much more than where I live.

[Old guy]

I don't know whether these guys will ship to GB; but, they are a good source for rebuild parts. The only part they do not seem to stock is the voltage regulator.


Alternator Rebuild Parts List for 1991-1994 NSX Ref# 31100PR7A02, 31100PR7A03 - ACURA NSX (maniacelectricmotors.com) (https://www.maniacelectricmotors.com/alternator-repair-for-1991-1994-acura-nsx.html)

[britlude]

ta Old Guy.... i did email them monday to ask if they actually had a complete one and how i could get it to the UK... alas no reply....

i have found various sources... all those that claim to have an alternator appear to be mistaken, or just ignoring me, so refurb is planned (it was planned anyway for the original alternator, if i got a recon unit)

i asked a local starter/alternator specialist if they could source the bits for a honda NSX, and he said he was having trouble identifying the car, all he could find was Acura NSX, and asked if it was imported.... seems they are using a US database.....!!!!!

these should be winging their way to me on a convoluted journey, to avoid their frankly ridonkulous $80 shipping charge...

https://alternatorbrush.com/products/alternator-rebuild-kit-for-1991-acura-nsx-13386rk?variant=29361557962786

(https://alternatorbrush.com/products/alternator-rebuild-kit-for-1991-acura-nsx-13386rk?variant=29361557962786https://alternatorbrush.com/products/alternator-rectifier-bridge-diode-assembly-for-1991-acura-nsx-13386rec?variant=29361584046114for)https://alternatorbrush.com/products/alternator-rectifier-bridge-diode-assembly-for-1991-acura-nsx-13386rec?variant=29361584046114

for the early denso CLB16, 110A version..... they list parts for the 120A version but it wan't clear what i needed for the full monty upgrade... still 110A has been fine for the last 31 years...

[paulc]

I got a decent second hand alternator from Christian at ATR, works a treat. Might be worth asking is he has got any more in stock.

[Silver Surfer]

Would a Honda Legend alternator be useful to get parts from?...it's just when you do a SC install...they use a back to front alternator source from a Honda Legend...I seem to remember..


SS

[Hagasan]

I think it's Prelude Kare?

[Nick Graves]

Regendo alternator:

https://www.buycarparts.co.uk/honda/legend-ii-coupe-ka8/4217/10450/alternator HONDA (31100PY3003)

NSX:

https://www.buycarparts.co.uk/honda/nsx-coupe-na/7822/10450/alternator HONDA (31100PH70240)

So, no, probably not...

Remember a Prelude alternator runs backwards - the V6s are clockwise. Don't mount it the right way round.

[NSXGB]

https://www.ebay.co.uk/itm/263678947452?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=glZZaUUBQge&sssrc=2349624&ssuid=zlAOyc5sSUO&var=&widget_ver=artemis&media=COPY

Suggests some cross over parts possible with CRX and Prelude.

Goldtop has a complete engine for sale with ancillaries, he may split the alternator for you?

[Hagasan]

Regendo alternator:

https://www.buycarparts.co.uk/honda/legend-ii-coupe-ka8/4217/10450/alternator HONDA (31100PY3003)

NSX:

https://www.buycarparts.co.uk/honda/nsx-coupe-na/7822/10450/alternator HONDA (31100PH70240)

So, no, probably not...

Remember a Prelude alternator runs backwards - the V6s are clockwise. Don't mount it the right way round.

Yes sorry, I should clarify what I meant.. My meaning was to say that it wasn't a Legend alternator for the Superchargers but actually a Prelude one. Yes it does run in reverse so not suitable in a standard car..