924Board.org

[staticsan]

Not sure what the underlying cause was but about six months ago I replaced the battery the car came with (of unknown age) with a brand new battery from the NRMA. However, I discovered a few weeks ago that the alternator was not charging it much of the time, like at idle and especially when the headlights were on! And the NRMA said it was a "calcium" battery that needs a higher charging voltage.

Alternator has now been serviced and the auto-electrician ran a new charging cable. He said it was now charging 13.2V at idle with the fans and headlights on. All good, right?

Well, no. All was fine for a while, including two short-ish trips just two nights ago at night. The alternator warning light never came on, which was a nice change. But this morning it won't start.

The battery is currently measuring 12.35v and this is dropping to about 10v under cranking. Exploring the 'net shows that the charging voltage should be more like 14.2v rather than 13.2v. So. It still hasn't been charging it properly.

Unfortunately, the auto-electrician distrusts Internet forums. How do I convince him that he needs to get a regulator with a higher voltage? Or do I lay out more cash for a non-calcium battery?

Wade.
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'82 British NA - Which I think I've been very lucky with!

[pmcaya2]

There are a number of different batteries that use calcium - yours is probably a maintenance free hybrid. I don't think that charging voltage is the factor in your case. Since it drops 2V overnight, I suspect a bad cell. I would check each cell with a battery hydrometer if possible or return the battery for a traditional lead-acid battery that you can check the electrolyte periodically. Here is a link re: calcium batteries:

http://www.baybat.co.nz/calcium.htm

Good luck - Peter

[Khal]

I stumbled across Battery University while researching Li-Po's. Might be worth a look...
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'80 924 Turbo

[daniel]

Calcium batteries are a deep cycle battery, an expensive choice for a car but should be fine none the less. I use calcium batteries for marine applications and I charge them with 12v's only, no problems at all.
As for you alternator, 13v at idle with maximum electrical load is a good result, dont worry.
My conclusion is that you either have a bad battery or a discharge with the ignition off.
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Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

[staticsan]

It's definitely a "no-maintenence" one, although it does have a vent, so I don't think it's a deep-cycle battery but a hybrid. And two NRMA roadside technicians have now said the voltage on the battery whilst the car is running should be at least 14.2v. And it was fine on Thursday evening after not having driven it since Sunday. Both trips on Thursday were at night.

I have been worried a bit about the clock. Apart from that, the only other current drain is the radiator fans. Normally on mine, they run for about 2-3 minutes after I turn the engine off, then after about 5-10 minutes once convection has moved more coolant around, they come on again for about 5 more minutes. I do have the lower temperature thermoswitch.

The roadside technician also did some rough measurements. A DC clampmeter showed 3-4 amps charging, which he said was low. Starting current was a little over 200A which was fine but he thought the starter was turning slow, suggesting it was underpowered for the task (it's not original).

I'm still going to talk to the auto-electrician Monday morning. It may be the charging problem has damaged the battery.

Wade.
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'82 British NA - Which I think I've been very lucky with!

[pmcaya2]

At this point, I'd swap out a conventional battery from another car to see if your car returns to normal. (200A from your current battery should be able to start a diesel!) - Peter

[pmcaya2]

Also, check your battery and starter ground (or "earth" for those of the English tradition). - Peter

[nickthompson]

200 cranking amps sounds really low to me. I think my v45's battery had around 150. The battery I have in my 924 is rated around 620ish. The Ranger's is rated at 585.

[vatoisimo]

When i had the alt rebuilt, the tech said that the alternator in original configuration would charge at 13.5 volts. So i had him install the updated regulator. It may be that your alternator is like mine.

[staticsan]

The auto-electrician will not budge from the idea that the alternator voltage might need to be higher. However, he did pull the battery and did some tests - under load, it is dropping to 8V. This sounds to me like one cell has died, which means that my charging problems might have damaged it.

Unfortunately, he doesn't carry non-calcium batteries of a low-enough profile for it to fit the 924, so he has lent me a Century Yuasa calcium battery which is one of two brands of calcium batteries he carries. Considering his exact words were that he didn't like the NRMA batteries, this one may be alright, suggesting the NRMA ones are just a little different.

The car has easily survived a road trip to Canberra (return journey is on Monday) and it started fine after I stopped for petrol and later for lunch. However, I haven't needed the headlights on.

I will be going back to him when I have a little more cash (about 2 weeks) to get the starter rebuilt/repaired/replaced. That's when either a) I pay for the other battery, or b) inform him that I had to get the NRMA again and that he now needs to not argue with me (or the NRMA) anymore and to raise the voltage on the regulator.

Wade.
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'82 British NA - Which I think I've been very lucky with!