battery testing
Turbo Mini Forums

I'm sure someone will be able to guide me on this.

I've got a relatively recent battery (approx. 2 years old) which was in the mini when I put it on the road. The battery discharged over the winter and the car needed a jump to get going.

At the weekend, the battery was recharged and now showing approx. 12.something amps (cant quite recall). I put it in the metro to crank it over to get oil pressure but I'm only getting about 5 or 6 seconds before it looses power. I've just being doing some research on the web which suggests I need to check the voltage drop when cranking.

The big question is, can a battery show a respectable standing charge but still need additional charging to provide the appropriate cranking amps or is it pumped? trying to get my head round if I need a new battery or simply put this one on charge for longer

cheers

Rob

If its gone completely discharged its probably goosed Robe.

12. somthing amps or 12. somthing volts?

basically its probably fucked, even a new battery will loose about 30% off is capacity if its flatted out and recharged, if you leave them they really loose capacity.

also check the battery voltage with it disconnected, if its showing much less than 12volts you might have a dead cell (6 cells at 2ish volts each)

if it is still taking a charge leave it until its only drawing a couple of amps, on a boost charger this shouldnt be too long, less than an hour certainly, on a slower charge a few ours should be plenty.

I knew that's what I'd be told; I'm sure I got a 3yr warranty with it but can't find the receipt............

12 something voltage reading was initially taken before I refitted the battery. no amps readings taken; the battery was re-charge for say 4 hours or so initially

Edited by Rob Gavin on 12th Apr, 2016.

Euro have lion 063 battery for £35; might just buy one as i'll need something at some point

Hold off as long as poss, no point buying a new battery for it to sit about and go flat.

also battery wise, I always go for Varta if I can, good strong battery.

I've bought a few Yuasa batteries recently for the 205's, so far so good, they come with a 5 yr guarantee from Halfords for not a great deal of £ with a trade card.

really need to get a trade card. a little impatient as the car is ready for oil pressure and I've no real way of jumping it in its current position

Yuasa are another good battery,

Bosch and Varta are apparently made in the same factory, varta are allegedly a tad better.

As a guide, if a 12V led acid battery only has 12V it's fooked.

Fully charged in good condition it should show 12.7 V, see below

.......................V
100% ............12.7
75% .............12.4
50% .............12.2
25% .............12.0
Discharged ....11.9

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

cheers guys. I've just called my local Halfords to see if I can blag a trade card; not holding out much hope but we'll see what we can do

Got any mates that work at a garage Rob? I just borrowed a load of old invoices for parts off a mate and told them I worked for him, gave me a card there and then

Well i went up to the shed this afternoon and put the battery on charge around 4pm. Voltage at that point was 13.6. Went back up at around 7pm and voltage was up at 14.4.

So after 3 hrs charging, it turned the car over with plugs out for perhaps 10 seconds before it lost the will to live. I blagged the battery out of keiths car which was around 14.3v but, Although it was better, didn't last Long either. This battery has been sitting pretty much all winter in his car so not completely surprised though.

Ended up stretching 2 sets of jumpleads clipped onto the solenoid at the front of the metro (battery is where the passenger seat should be) and jumping off the audi parked outside!

How much fuel is in the Audi though?

In the 13's at last!.. Just

Lol! Filled up yesterday so aroung 3/4 tank. Now if i had some petrol in the metro, i could have had a go at starting it!

I have a 5a CTEC charger maintainer mainly because the battery on the skyline was a 1100A cca agm and my normal charger couldnt charger it
Anyway it is microprocessor controlled it does loads of stuff and one of them is to charger / recondition agm and lead acid batteries
I had a couple new ish ones, same story as yours I left them out and they died this charger fixed them
Its payed for its self imo and it can maintain all year round so leave it on the cars and it just does its job

Yes i moved to the darkside

Instagram @jdm_brett

food for thought brett

I've had the same experience using a modern CTEK charger on a battery that has had some deep cycles. Always gets it back to fully charged and fully working. Well worth the money, and they are much cheaper than they were a few years ago.

Found similar last week. Battery had "good" voltage reading after charge but died after a few seconds under load.

I got a new bosch battery and a smart charger at the same time. Put the duff battery on the smart charger and it did a repair cycle and now appears to be good. I'm blaming my shite cheap charger for the "death" of at least two mini batts and a motorbike batt too!

I've got no idea where my charger came from, never mind how old or good it is. Perhaps time for a replacement, although these smart ones are more expensive than the new battery!

I have a normal £30 battery charger, and a hobby Turnigy 5a charger, mostly for charging my LiPo batteries etc, but I have bought completely dead drill batteries back to life with it for emergency use where the oem charger wouldn't recognise they were attached. Would probably do a car battery too similar to what Brett has. Might be worth getting one of these fancy modern LiPo jump pack/phone charger gizmos. I've fancied one for a while just not got round to buying one because they're not cheap. Most RC car LiPos can discharge at 30-40 C, so with a 5000mAh battery you're looking at a 200amp maximum discharge capacity 😶