Do I have a dead battery?

Do I have a dead battery?

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rotorwings

Original Poster:

208 posts

124 months

Thursday 10th April 2014
quotequote all
New owner of a 2 year old R300 with very few miles (1250). First Caterham, so I am not sure what is normal.

After starting the car a few times in one morning it barely turns the motor over, and once already the car needed to be jump-started.

I have monitored the standing voltage after a long run and it is 12.6V (basically fully charged), but when starting the car the battery voltage drops to under 8V.

Normally, I would consider all this a problem (especially the voltage drop when starting the car) but I am not sure what is expected from these, quite small, Banner batteries.

Do I need a new one? What voltage are others seeing during engine start-up?

downsman

1,099 posts

155 months

Thursday 10th April 2014
quotequote all
When you say stating the car a few times in one morning, how far did you drive between starts?

The battery has been specified to be light(ish) and doesn't have to drive all the electric motors on a normal car.
However, a 2 litre engine takes some turning over and the battery is going to take a few miles to recharge fully.
The other thing to consider is the immobiliser will drain the battery if the car is left for a few weeks, so it is best to disconnect the battery or use a battery conditioner when not using the car.

rotorwings

Original Poster:

208 posts

124 months

Thursday 10th April 2014
quotequote all
3 - 4 Starts in 10-15km

DCL

1,215 posts

178 months

Thursday 10th April 2014
quotequote all
A regular issue with Caterhams. Although everyone has different opinions, basically, the battery and alternator are as small as you can really get away with on a road car. The small alternator can struggle to charge the battery quickly, and the small battery can be discharged quickly - all very different to average family car. This means care is needed to keep the battery charged and avoiding unnecessary loads. I would recommenced you use a battery conditioner to keep it fully charged when not in use.

My experience of the Duratecs is that they don't charge on idle (do you have a 72mm alternator pully?)so avoid long periods idling. Two years is not old for a battery but if it has been abused it could be beginning to fail. The voltages you quote are on the low side of what I would expect - you should see 13+ volts when you rev it. Have you checked the cells are topped up to the marker?

rotorwings

Original Poster:

208 posts

124 months

Thursday 10th April 2014
quotequote all
Yes, all cells have fluid above the material.

I see 14V when cursing @ 3000rpm, so the alternator is working fine. The battery is 12.6 to 12.7 at rest, so it does charge. But the worrying figure is the 7.5-8V voltage when cranking the engine - even when the battery is fully charged. It seems to not have any 'oomph'. On a normal car I would be inclined to call it dead, but I am not sure what is normal for a Caterham.

rotorwings

Original Poster:

208 posts

124 months

Thursday 10th April 2014
quotequote all
Yes, all cells have fluid above the material.

I see 14V when cruising @ 3000rpm, so the alternator is working fine. The battery is 12.6 to 12.7 at rest, so it does charge. But the worrying figure is the 7.5-8V voltage when cranking the engine - even when the battery is fully charged. It seems to not have any 'oomph'. On a normal car I would be inclined to call it dead, but I am not sure what is normal for a Caterham.

Edited by rotorwings on Friday 11th April 05:36

sjmmarsh

551 posts

219 months

Friday 11th April 2014
quotequote all
The voltage drop sounds normal - mine drops to around 7 volts, but tends to start on the second 'chug', so I wouldn't worry too much. It does sound like the battery is down on its capacity though. - it is worth trying to condition the battery by using a modern charger that discharges and pulse charges the battery.

Do you put the clutch down before turning her over? You aren't turning the gearbox over as well then.

How long does the starter run on yours before it catches?

Steve


rotorwings

Original Poster:

208 posts

124 months

Friday 11th April 2014
quotequote all
sjmmarsh - I think we both might have tired batteries. wink
A voltage drop of nearly 50% seems to be indicate a tired or underspecified battery.
It will turn over a couple of times maybe before starting. Unless it doesn't turn over wink

Yes, I've played with depressing the clutch. It helps.

What are others seeing as a cranking voltage?

Edited by rotorwings on Friday 11th April 10:20

rotorwings

Original Poster:

208 posts

124 months

Saturday 12th April 2014
quotequote all
So, it was definitely the battery!

I picked up a new one this morning and now it starts with real enthusiasm. The lowest voltage I have seen during cranking is 10.1

If anyone is looking for an alternative to the often expensive Banner battery let me know. I got a 'Panther' branded one (also a 53034 and seemingly identical) for 48€ (~£40). Panther are a German company and I don't know if you can get them in the UK, but you can get them delivered from various sources.

But, the car definitely does not charge the battery at idle. Where do I get a smaller alternator pulley to fix this?

Edited by rotorwings on Saturday 12th April 18:52

DCL

1,215 posts

178 months

Sunday 13th April 2014
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SBD can supply a standard size one but if you are regularly going to use the full RPM range then it might not be a good idea as the alternators can fail with prolonged high RPM. There are a few cases of the cooling fins breaking and the windings can go open circuit too. I think it just better to be aware that it doesn't charge on idle and avoid long periods of idling when you can.

sfaulds

653 posts

277 months

Sunday 13th April 2014
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A standard R300 Duratec should charge at idle - what rpm is it idling at?

rotorwings

Original Poster:

208 posts

124 months

Sunday 13th April 2014
quotequote all

It is purely a road car so it rarely gets high into its rev range. A standard pulley should be fine (i think).

It idles at 8-900rpm. Is that normal (sorry, first Caterham)?

sfaulds

653 posts

277 months

Monday 14th April 2014
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I've always run our R300's at about 1100rpm idle hot, and they'll charge fine. Below that they're a pain in the arse when they're cold, and not nice when they're warm. Be aware the adjustment screw gets battered flat over time, so they do need adjusting now and then.