Battery charging

[DaiRees]

Still a bit nervous about vehicle electrics after owning Peugeots for a combined total of around 17 years

I'm getting the occasion "Battery Low" message and complete refusal of the stop/start system to work (not that that bothers me, if it worked I'd turn it off!). But it's got me thinking about the state of my battery, I do a lot of short trips which obviusly isn't great for the battery. However when I do a longer trip I'd expect the battery to get a good charge and for the stop/start to start functioning again, but even after a few hours of motorway driving it doesn't come back to life and the computer reports that stop/start is unavailable because the battery is charging.

So, especially with the winter approaching, I'd like to use my (Halfrauds fully automatic) battery charger just to give the battery a bit of a boost. I've only ever charged batteries that were removed, or at least disconnected from the vehicle, but I don't really want to disconnect it in case I lose settings all over the place! So the question is, is it safe to charge it while it's still connected? If so I'm guessing +ve to terminal and -ve to chassis earth?

[steve_earwig]

I think the earth thing is for jump leads, probably doesn't matter though.

I'm probably not going to be much help but I was talking to my dad about this recently, he's not keen on hooking a charger up to his battery while it's still connected as they have auto transformers in them so it's actually seeing mains, together with all the transients coming down the line. However I connected my Optimate to all sorts of cars (and bikes) with no issues for 15 years or so (recently replaced it finally expired after charging all the batteries in Goran's shop with a CTEK because Optimates are expensive and have something of a bad rep these days).

Halfords though, not sure I'd trust this without an oscilloscope to see exactly what it's shoving out...

[Doggy]

What about getting one of those standby battery gadgets that plugs into the lighter socket while you disconnect / charge the battery?

(Never tried myself, but I hear they work).

[Welly]

Mmm, your car is 4...approaching 5 years old? my first Volvo Battery lasted about 9 years

My thoughts are to replace the battery as you'll be putting undue stress on the alternator. Everything is crap these days so maybe 4/5 years is 'old' now? don't you have a separate battery for the stop/start bullshit?

There's a lot of mumblings on the friendly* Volvo Forum about alternators crapping out at seemingly low mileages, could be worth checking the Voltage it's chucking out especially when loaded up.

[DaiRees]

Just turned 4 in July

Nah I don't think there's anything wrong with the alternator Welly, they're notorious for the battery needing to be fully charged before the stop/start will work. Imagine the amount of electrical gadgets on this thing that are sucking power from the battery, then I'm doing lots of really short journeys, I'm sure I'm just not giving it enough of a charge. It's not struggling to turn the engine over or anything, and I'm sure the car would tell me persistently if it thought the battery was cream crackered.

And yes there is a 2nd battery to "assist" with the stop start system, my understanding is that it's there to help with the auxiliary systems when the engine's off (a/c fans, lights etc.). I don't believe it's used during "normal" operation.

[DaiRees]

Well the plot thickens, if I said AGM and EFB batteries I bet some of you would know all about them and others would be as bemused as I was.

I've had a look at the battery and although it doesn't say so on the label, googling the part number leads me to believe that it's an AGM (Absorbant Glass Mat) battery. I also found the smaller "assist" battery hiding under the scuttle panel to the left of the main battery, that one's definitely AGM because it says on the top, right next to the FoMoCo logo

And, surprise surprise, it turns out that my Halfrauds battery charger (that's only a few years old) isn't suitable for AGM batteries! So now I'm off to search for a charger suitable for AGM batteries...

[steve_earwig]

I have one of them, it's made by CTEK...

[Welly]

Ha ha you've been FoMoCo'd in yer Volvo.

Should see mine it's littered with Ford labels

I'm sure you'll find a reasonable digital trickle-charger out there and there should be no reason why you can't hook it up 'live' on the car as it were.

If you think about it your alternator must be under constant load when you drive so it's the right way to go in looking after the battery end of things.

[DaiRees]

Yes I agree, I think keeping the battery in good shape will extend it's life considerably, and having recently discovered the price of them that can only be a good thing!!

I've ordered a charger, surprisingly enough a CTEK one Steve. Reading various interweb informations they seem to be the only way to go...

https://www.amazon.co.uk/CTEK-MXS-5-0-T ... ek+mxs+5.0

[steve_earwig]

Ah, the same one I just bought

[OllieNZ]

I deal with AGM batteries on a near daily basis at work, we refer to them as jelly batteries. The best way to find out what you can and can't do with it is see if you can find a manual by the battery manufacturer. Our ones (made by concorde) are able to be charged using either constant potential or constant current. The biggest issue with them is whether or not it's sealed or valve regulated. A sealed one can explode if incorrectly charged where as a valve regulated one will vent.

[Welly]

A sealed one can explode if incorrectly charged where as a valve regulated one will vent.

Seems straight forward enough, where's the nearest mains plug?

[Doggy]

...A sealed one can explode if incorrectly charged where as a valve regulated one will vent hydrogen gas, like the Hindenburg.

FTFY

For our younger readers: http://www.independent.co.uk/news/scien ... 17996.html

[steve_earwig]

Oh, the stupidity

[DaiRees]

Well it's charging right now so I hope it doesn't explode....