PC680 Battery - Tips for Recovering from Deep Discharge

[New Cat]

I left my ignition on and have deeply discharged my fairly recent Odyssey PC680 battery.

After 2 days on the Optimate 3, it has done nothing - only the green light to say it is switched on, none of the other lights come on at all.

I've now attached it to a Hilka 8amp charger on overnight slow charge mode and no signs of life yet.

Any tips? I suspect that I'll have to pay the £90+ stupidity tax and get a new one but if I could recover it that would be great!

Thank you 

[Jonathan Kay]

That's sealed rather than topuppable?

This isn't unusual. And I'd do exactly what you're doing, but get it back on the Optimate as soon as possible to avoid overcharging.

Then you have to work out after that whether it's shot while it's somewhere convenient rather than...

The Clubsport that Powervamp recommend costs a lot less than £90... I've just fitted one.

Jonathan

PS: If it isn't sealed Roger and others might suggest a rejuvenating pill. I'm not convinced, but if you're about to throw it away there's not much to lose.

[Nigel Fox]

Modern chargers seem to contain electronics that prevent them charging very flat batteries.

i would connect it to a vehicle battery via jump leads, then start the engine and charge it from the alternator.

[Nillbymouth]

I've done this several times and my CTEK and Optimate won't touch the battery. To get round it I connect it to a spare battery via jump leads for 30 minutes. The CTEK then charges it with no problems. I'm not sure if this is a dodgy method but it works for me! If there are issues with this then please somebody tell me.

[Jonathan Kay]

I don't know a better approach than that, and it's what I do. But NB post#2.

i would connect it to a vehicle battery via jump leads, then start the engine and charge it from the alternator.

Any reason for preferring that way to using a trickle charger?

Jonathan

[New Cat]

Thanks guys, the Hilka overnight (on slow charge) seems to have done the trick! It was showing as fully charged and the immobiliser light on the car was back to flashing merrily. 

I reconnected it to the Optimate before I left the house (it immediately moved to the "Test" light that wasn't previously illuminating) this morning and may have got away with it...

The PC680 is pretty small, sealed, gel type battery in a dedicated aluminium tray, mounted on its side, so when one breaks, there seem to be few options for replacement.   

[Jonathan Kay]

Well done. 

But I'd still want to know that it isn't on its way to meet its maker.

The PC680 is pretty small, sealed, gel type battery in a dedicated aluminium tray, mounted on its side, so when one breaks, there seem to be few options for replacement.   

Have a look at the Powervamp Clubsport EP. And then there's the Great Lithium Question.

Jonathan

PS: The PC680 isn't a gel type... the G in AGM stands for "glass" or "glass fibre".

[Wodybode]

"To get round it I connect it to a spare battery via jump leads for 30 minutes."

I wouldn't recommend leaving it connected to another battery for half an hour, in fact I'd only do it for at most a minute or two to avoid overheating the plates and possibly buckling them. The jump leads allow an uncontrolled current flow which is not recommended. If you just get enough energy in it to register about 10 volts the smart charger should start to work and charge it. Or do what you did with the older (not smart) charger which will allow charging even if it is not showing any voltage but will limit current flow to whatever the charger is limited to, in your case up to 8 amps. 

The smart charger will self regulate the charge rate so you can leave it connected and don't have to remember to periodically check and disconnect like you have to with the older chargers.

If you know a friendly garage they can put a smart tester on the battery to assess it's condition. It looks like a big multimeter and it injects voltages and loads during it's check and gives an overall condition reading for the battery. It only takes a minute.

[ECR]

Apparently connecting another good battery in SERIeS and charging the 2 will fool smart. Chargers into charging exhausted batteries

[Jonathan Kay]

What sort of charger are you suggesting to use for that? (I wouldn't try it.)

Jonathan

[ECR]

Received wisdom from the net ( perhaps it's in parallel not series)

[Ian B]

Parallel

[New Cat]

Thanks, good tip on trying to find a friendly local garage with a battery condition tester. Its currently on the Optimate 3 in a blaze of green lights so on the face of it looks fine.

[Wodybode]

I've heard, but I don't know how much truth is in it, that if you have an old lead acid battery that has sulphated up and won't hold a charge, you can thermally shock the plates by short circuit testing and rapid charging ie. via jump leads, which can cause the sulphate buildup to break off and drop to the bottom of the battery and the battery becomes good again. 

I must point out though that this would be fraught with danger as the short circuiting can cause the battery to blow up and I suppose hot battery acid in the face might ruin your day. 

[Jonathan Kay]

If you know a friendly garage they can put a smart tester on the battery to assess it's condition. It looks like a big multimeter and it injects voltages and loads during it's check and gives an overall condition reading for the battery. It only takes a minute.

If I had a high-load tester I'd definitely use it for this, but I'm not sure that I'd go elsewhere, and I certainly wouldn't go elsewhere serially in order to detect deterioration as early as possible.

But we all have a high-load testing system already installed. That's why measuring the minimum battery voltage seen during cranking is such a valuable indicator. And following it over time is even more informative.

(There are 1.5 additional reasons for checking this as well. Some ECUs and possibly some other electronic bits aren't happy at low voltages, and if they cease to function transiently while cranking it's very hard to diagnose. (Because most of us don't have an oscilloscope either.) And quite a lot of the (usually implicit) diagnostic approaches to electrical problems rely on there being enough smoke in the system at the time of testing.)

Jonathan