Charging Battery

[Missing Lincs]

I've used a small solar charger on several vehicles, it's enough to replace a small current drain from the battery. I've found they work better when placed on the top of the dash, obviously subject to shade. It means have a longer wire to get to the socket in the rear but for occasional use it wasn't a problem.

With mains chargers I've always used the terminal under the bonnet, I've never had any problems with not disconnecting the battery but I've always used an electronic, regulated charger/maintainer. Some of the older high current unregulated chargers can generate voltages well over 25 volts, personally I'd rather not risk it.

[Georgeandkira]

A point involving AGM batteries.

In brief, I've read that old fashioned chargers -ones we'd commonly attach and leave for days- are OK for charging an AGM battery except for the home stretch.
The warning is that as AGMs approach full charge, the charging voltage must be lowered. Continued over-charging of a near fully charged AGM is deadly to them.

Newer chargers with proper circuitry are what's called for. This "accommodation" is what battery addressing in some new cars is for.
Some newer chargers I've seen have other features such as "dead battery resurrection".

Also, as many who work in garages have posted, I'll only replace a battery with a like kind.

[Roy V70 850]

Thanks for the comments everyone.

I feel more at ease now just hooking up the charger without removing any leads, the battery certainly serves as a big smoothing capacitor and yes it looks like my battery isn't holding charge like it should. I've had the car two and a half years now, and have no idea how old the battery is. Just checked the voltage to find that it's registering 12.2V after a week on the drive, which Is not brilliant.

I never thought of putting the charger on the terminal under the bonnet, that's a lot less hassle than unbolting plates to access the battery itself.

I've put the 10W solar panel on just to see how effective it is. Yesterday in bright conditions it was charging at 0.2A. With the sun shinning it was 0.5A.

However, the engine only just cranked over so I'll probably have to hook the charger up soon. I can't see the solar panel restoring it to full capacity.
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2004 V70 2.4 D5 (163bhp) P2 manual 150k

[stuart bowes]

I would just stick a new battery in, for £100 or so it's surely well worth not getting caught out

depending what size you have already and what your requirements are it could be worth an upgrade and getting a slightly bigger one in, there's plenty of room.. I did because I knew we'd be going camping in it and I'd be having my phone plugged in, and the chiller box plugged in the boot, etc. plus I've got a silly big bass amp in the boot

for example https://advancedbatterysupplies.co.u...0-car-battery/

someone else suggested a Yuasa one (90ah?) last time it was discussed which would also be a good option I'm sure

[Georgeandkira]

Here's a handy little reference...words to live by.

Check with volt meter 4-12 hours after shut down:
12.8v = NEW BATTERY
12.5v = '3 year old battery'
12.3v = eyes peeled for special offers
12.2v = failed battery
Some profess using a lower number for a failed battery.

T'was January 2020 the last time I referred to this guide.
My overnight battery reading was 10.6v so I didn't overthink it.

A snowman on the neighbor's lawn was holding a sign which read, "NO BATTERY SALES IN WINTER, PAL"

[Org]

I had a failing battery on my Jag and connected a spare motorbike charger I had to it using a fly lead that came with the charger, these leads are supposed to be permanently connected to the battery and you just clip them to the charger when finished riding if its hoping to be a while before using the bike again. It stops the battery's going flat and also the chargers are a smart charger where by they maintain the battery. Fortunately I was able to recover the battery for a short while but eventually replaced it ,I bought a battery froma company on ebay called number one batteries, delivery was prompt and all was good especially the price, might be worth a look.

[Missing Lincs]

Originally Posted by Roy V70 850

Just checked the voltage to find that it's registering 12.2V after a week on the drive, which Is not brilliant.

I don't think 12.2V after a week is bad, however I would measure the voltage when you crank the engine, that's a better measure of the condition of the battery. Or just get the battery tested. A battery tester simply places a load on the battery and measures either the current (with the old fashioned resistor type tester) or voltage drop (with an electronic tester).

[Roy V70 850]

I've just charged the battery up by connecting to the front terminal and cranked the engine over a couple of times to remove the surface charge giving a false reading. It now reads 12.45V, which probably means that it's ok for another year, possibly two.

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2004 V70 2.4 D5 (163bhp) P2 manual 150k

[stuart bowes]

if it holds that charge for a while should be ok

maybe worth while still at home and near the charger if you're not going out for a while, leave the side lights on for a couple of hours and go back and see if the car starts up, that's my usual simple test that doesn't need any special equipment

had you left something switched on before then or something? previous comment was based on the relatively low reading and the fact it's 'at least' 2 and a half years old, quite likely more? most decent batteries at best give you 5 years waruntee, and they're not exactly expensive.. I guess it depends if you plan on keeping it a few more years, or just trying to keep it going short term

[Georgeandkira]

One battery article suggested attaching a charger to lesser used vehicles once every 2 months. This maintenance was said to slow the inevitable time-aging of a battery. Batteries lose capacity over time.
Also, the article claimed no charging system recharges to "100%" in the first place.

I've begun to leave my old, basic charger on overnight as our vehicles have only FLA (Flooded Lead Acid) batteries. As advised, I do this bimonthly.

'07 Volvo H6 is in service 4.75 years.
'16 Mazda G35 is in service 5.25 years.
'05 Ford G59 is in service 1.75 years.