Battery info needed

[RemaL]

I had a gel battery that has not been keeping the charge in my Tiger supercat. So fitted the car batt that was on there before the gel batt went on over 2 years ago. So the car batt has been sitting in the garage for over 2 years not touhced. used a batt tester today to check the charge and seems it's not charging. But the alt light works fine as it always has.

Thinking could the old car batt which is about 4-5 years old be shot? I had kept it on a optimate for a few months over the winter knowing I would be using it this summer

Also if a new battery is needed what suggested cranking amps would be good for the car? it will only be running lights as we have no heater or any other leccy things in the car


cheers

[RemaL]

So no idea on the battery or cranking amps????

[Sam_68]

If your alternator is working, the size of the battery is irrelevant once the car is running; the only issue would be if you did a lot of short trips, so that the energy lost in cranking the engine at start-up never got replaced, but even that is irrelevant if you have it hooked up to an optimate.

Your only worry is therefore how easy the engine is to fire. Some highly-tuned engines can take a lot of juice to crank over (race Crossflows with high compression and no vacuum advance on a standard, ungeared starter being a case in point), but if your engine is reasonably well behaved then the size of the battery isn't that critical.

[singlecoil]

I'd go by what could be reasonably accommodated. If you were really fussy you could try finding out what battery was in the donor car (you haven't told us what engine is in it)

I once started a Lamborghini Countach QV with the battery from a 3 cylinder Subaru, so it really doesn't matter too much.

[RemaL]

oops I have a 2ltr blacktop Zetec from a 06 focus. new and only 600 mils on the clock.

I bought a new battery today with the recommended crancking amps of the focus engine but seems it's now the alternator playing up as it's still not charging

So off to buy a Lucas LRA100 alternator to replace the one that might be broke. shall take it off tomorrow evening to see if anything is loose before buying a new Alt

Edited by RemaL on Tuesday 16th March 19:39

[singlecoil]

If you don't already have one, get a digital multimeter, get the engine running and put the meter across the battery terminals. You should be seeing in the region of 14 volts, showing that the battery is being presented with charging voltage. If not, then obviously it could be the alternator, probably is, but check first for any wiring faults, which are very common on kit cars (poor connections between bullet terminals, badly /incorrectly crimped terminals etc etc etc ). Stop the engine and pull the plug off the alternator and ensure there is continutiy between the terminal to the big wire in the socket, and the positive terminal on the battery. Check the various earths as well.

[RemaL]

checked that already and only getting 12.8 -13.2 V so not charging. But was hoping it would have been the batt first.

hay ho you live and learn

[funwithrevs]

singlecoil said:

I'd go by what could be reasonably accommodated. If you were really fussy you could try finding out what battery was in the donor car (you haven't told us what engine is in it)

I once started a Lamborghini Countach QV with the battery from a 3 cylinder Subaru, so it really doesn't matter too much.

Battery choice only really matters to the life of the battery, not whether it works. Modern batteries are damned good, even a small one can deliver some pretty serious cranking amps so it just comes down to capacity (Ampere-Hours).

A battery requires a regular, partial discharge. If you discharge too deep (battery too small) it will work but the battery will die before its time. If you discharge too shallow (battery too big) then basically lack of use will cause the battery to fail before its time.

So to the OP, best idea is to get the same battery that the donor car used (assuming no mental engine mods) and it sounds like you did just that

[alchilds69]

also worth trying, with the engine running, test tne altenator as before but put a load on it ie headlights and heater on no.2 position. and see if the voltage drops below 13v ish. if it does then replace it or try -

i would of thought if you are still using the ford altenator being from an 06 car. the alternator would be a smart charge altenator. if it is try disconnecting the 3pin multiplug on it. sometimes they revert to a standard altenator and charge normally. ive had this on a few focus's of this age.
good luck

[RemaL]

Well replaced the Alternator last night and now working 100% which is good and ready for the Dyno on Thurs

[RemaL]

Update on this. the recond alt worked for 8-10 weeks and not dead again after just the Dyno and Sotnleigh show or 450 miles.

Ordering a new Brise one today as I am taking the tiger to Le mans next tues

Have fitted a new larger pully as the tiger one supplied might have burnt out the alt due to revving to high.

Not best pleased at the moment

Edited by RemaL on Thursday 3rd June 10:00