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

[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...

[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?

[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]

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???