Charging a battery

[thornz]

Does a car battery charge at idel?
Or do you need to be actively driving it round for it to have any chance of charging?

[escortman]

normally best to rev it above idle

[sergei]

It will charge battery at idle.
Unless your car has an old style generator.

[thornz]

Its on a 91 MR2 so not an ancient car.
How long would you think you would need to leave it running? Had it going for about 30 mins last night, shut it down, and it had enough for the alarm to work properly, but as soon as I tried turning it over, that was teh end of it, sucked all juice out of it and didnt fire.

[sergei]

Its on a 91 MR2 so not an ancient car.
How long would you think you would need to leave it running? Had it going for about 30 mins last night, shut it down, and it had enough for the alarm to work properly, but as soon as I tried turning it over, that was teh end of it, sucked all juice out of it and didnt fire.

Assuming charging current is 5A, for 35Ah completely flat battery ~7Hours (obviously missed out many things but good as guide).
Far better off spending $25 on shitty chargers from warehouse and leave that on overnight.

If you battery went completely flat, and is one of those cheapish wet cells, then it lost ~ half of its capacity already.

[thornz]

Its on a 91 MR2 so not an ancient car.
How long would you think you would need to leave it running? Had it going for about 30 mins last night, shut it down, and it had enough for the alarm to work properly, but as soon as I tried turning it over, that was teh end of it, sucked all juice out of it and didnt fire.

Assuming charging current is 5A, for 35Ah completely flat battery ~7Hours (obviously missed out many things but good as guide).
Far better off spending $25 on shitty chargers from warehouse and leave that on overnight.

If you battery went completely flat, and is one of those cheapish wet cells, then it lost ~ half of its capacity already.

Okay cheers, will get some chargers today, dont fancy leaving it running for that long

It looks a pretty decent AA battery, but then again, I know nothing about batteries, so could be completely wrong on the quality of it.

[postfach]

It looks a pretty decent AA battery

At first I thought but then I realised you meant

[thornz]

It looks a pretty decent AA battery

At first I thought but then I realised you meant

haha

[Mr Revhead]

Golden Power!!!

[Bling]

Okay cheers, will get some chargers today, dont fancy leaving it running for that long

$20 @ k-mart, $30 @ bunnings FYI For a cheap Arlec one, does the trick. Can even borrow mine if you don't think you'll need one again, though with petrol prices, probably better off just heading to K-mart

[B_giB]

Golden what?

[thornz]

Okay cheers, will get some chargers today, dont fancy leaving it running for that long

$20 @ k-mart, $30 @ bunnings FYI For a cheap Arlec one, does the trick. Can even borrow mine if you don't think you'll need one again, though with petrol prices, probably better off just heading to K-mart

Thanks for the offer, but I think I will buy some, have had to borrow some a fwe times before for other cars, so I should stop being a cheapskate and splash out!

[matt dunn]

If the battery is a calcium/calcuim battery,

you could drive non stop from dunedin to Auckland it it wont be charged if it started off too flat.

And they wont charge with a cheap $30 charger either.

they need to be put on a special high voltage charger.

And before you say it's just a normal car battery,

More than 50% of normal car batterise sold today are Calcium/Calcium.

[Bling]

Are you saying a standard battery charger will not charge over 50% of car batteries these days full stop or that if its too flat thats the case?

[Dell'Orto]

Calci/calci batteries do need a special charger, they require a higher rate of charge to keep em happy.

[sergei]

If the battery is a calcium/calcuim battery,

you could drive non stop from dunedin to Auckland it it wont be charged if it started off too flat.

And they wont charge with a cheap $30 charger either.

they need to be put on a special high voltage charger.

And before you say it's just a normal car battery,

More than 50% of normal car batterise sold today are Calcium/Calcium.

They need 14.8V or slightly above to fully charge them. Only gotcha is that they need ~16V to charge them from dead flat and that means not hooking up dead flat battery to 16V, to put is simply, charger needs to ramp up voltage from whatever the battery is at to 16V without exceeding recommended charging current, then drop to ~14.8V.

Most maintenance free batteries will have calcium doping in them. The reason why they started to add calcium in '70 (instead of antimony) is that it stop water loss. Every other aspect of calcium battery apart from maintenance free aspect is worse than lead/antimony battery.

Arlec charger I have puts out just under 15V unloaded so it will be sufficient to float charge the calcium/calcium or calcium/antimony lead-acid battery.

Correct me if I mistaken but by calcium/calcium you mean both lead plates are doped with calcium?

[Bling]

Rather than starting a new thread, i'll ask in here.

I had a battery lose it's charge on me. To be fair, I just haven't used it in a long time. So I chucked it on my Arlec overnight and it was still dead. Took it to be tested and they put it on a better charger and it came back perfectly fine. Though it did take overnight to charge up.

Is it worthwhile buying a better charger than what I have now to cover myself in the future? Do the more expensive one offer better features or just a higher 'rate' to charge with. I have charged up batteries that have drained overnight due to lights left on, without a problem. But if i'm better off with a charger that will cover all situations, then i'd consider buying one.

What chargers do people use and is it worthwhile for me to even look at getting a better one?

[Crucible]

We have a special charger for calcium batteries at work and it normally takes 48hrs/2 days to re-charge.

Try hook the battery up to a car next morning with it being on charge overnight and it will still be flat.

[Bling]

Problem with the Arlec though is that it indicates it's charged I think at the start of a charge. After a short period of time it will drop the charged LED off and you know it's charging. It didn't do that with the battery I had. So I just assumed it was goneburger as that's what the manual says. I wasn't keen to leave it on any longer as it wasn't doing the job from the little I knew.

[iOnic]

http://www.batterydirect.co.nz/battery_chargers.htm

Could help? I'm pretty sure Repco sells that 7 stage automatic charger thing. Brad might know?