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

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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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....

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Originally Posted by 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....

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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???

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?

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Originally Posted by 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?

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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.

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....

Quote:

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Originally Posted by 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?

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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.

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???

Pulled relays yet??

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Originally Posted by britlude

Pulled relays yet??

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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 :)

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.

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.....

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....

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.

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

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

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

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

what news???

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Originally Posted by britlude

what news???

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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.

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

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

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Originally Posted by britlude

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

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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. 😁

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. :)

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

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. :)

Oh FFS!

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