AGMbattery charger recommendation

[spk]

Morning,

 

Has anyone been able to successfully charge an AGM battery from below the "magic" 10.5v successfully? If so, any charger you can recommend? It sounds like most smart chargers won't charge an AGM battery that's too low on charge. Bit unclear why this might be - either it thinks nothing is connected or could the battery have been damaged?

 

Bonus points if you've done it on the v6 - the owner's manual that came with mine largely ignores v6 and/or AGM batteries exist.

 

Cheers,

Steve

[BigEjit]

10.5 v is the golden spot for a failed cell within the battery. A decent charger will still recharge it but if the fault is a permanent short, the voltage will drop back to 10.5 v in a day or two.

 

Another way to check once recharged will be to stick something like the tyre compressor on the battery for a moment. The voltage will drop back towards 10.5v +/- 1v if the battery is short circuit in a cell and won’t recover.

 

Time to change the battery. 
 

Otherwise if it holds charge well above 12v up to 13.8v, all good. 
 

CTEK mxs 5 is a good charger to benchmark from.

 

5v is about as low as a charger will work from unless you piggy back with a second good battery. 

Edited 3 June, 2020 by BigEjit

[tuningmania]

To @spk - I have "Ctek MXS 7" and recommend it to You. In the City environment I charge my "AGM"-Battery once a month for at least 24 Hours.

[spk]

Thanks for the replies @tuningmania and @BigEjit - looks like it's a CTEK MXS5 or 7 to go for.

 

It's lack of use that's the issue - car hasn't left the drive for quite some time. Slightly concerned that I'm going to need to piggyback it based on what the multimeter is telling me but I guess we'll see how we go.

 

Cheers,

Steve

[BigEjit]

If it’s really low to around 5v, only trickle charge it and make sure it’s not heating up too much In the initial few hours. Stop the charge for a bit if it’s more than warm. It will need 24 hours to properly fully recharge though. AGMs will recover well from deep discharge but you have to feed them slowly.

 

Using the car to recharge a deep discharged battery will overheat it and damage it long term as it’s too aggressive. 

[rover220]

Victron ip65 smart over ctek in my opinion. 

[Slimy]

I have one of the cheap Aldi intelligent chargers, same size as CTEK but probably about the only thing that it has in common. However it's been fine with my AGM battery, and it's marked as such in the manual too. But as said, it does take a lot longer to charge the battery. It took 24-36 hours to register as full. My wife's car (albeit much smaller and standard battery) takes only a few hours. 

 

 

[Mykul]

+1 on the CTEK mxs 5

[Charade]

I've not had a problem with Halfords Smart Charger Plus for different batteries, even brought 2 golf trolley lead acids back from the dead.  Not used it on an AGM though so maybe doesn't answer you question.

The specs say it's for - Lead Acid, Gel, Calcium, AGM, EFB, Start/Stop, Lithium (LiFePO4)

[spk]

I thought I'd close the loop on this one to say thanks to everyone who responded, I splashed out the Victron IP65 Smart in 12V 10A guise in end. After nearly 20 hours charging across 3 days it was able to restore the battery to what seems to be full charge, which I was doubtful it was going to be able to do initially! 😀

 

Really pleased with the unit - seems really well put together, the cables are well made and the connect system so you can swap crocodile clips for another attachment, insert extension cables etc is nice. Unit is also somewhat waterproof apparently - I declined to put that to the test! I was a bit sceptical about the Bluetooth connectivity (unit is clearly aimed at some more static or marine applications I think) but it was handy given the time it took to charge etc. It meant I could monitor what it was doing and get some reassurance it was actually charging the battery etc. without having to go and look at it. Just sat near enough my window whilst working that I could check the status on my phone every so often

 

Anyway, thumbs up from me for the unit. On to the next problem not moving for 19 weeks has caused...

 

Cheers,

Steve

[rover220]

On 01/08/2020 at 16:44, spk said:

I thought I'd close the loop on this one to say thanks to everyone who responded, I splashed out the Victron IP65 Smart in 12V 10A guise in end. After nearly 20 hours charging across 3 days it was able to restore the battery to what seems to be full charge, which I was doubtful it was going to be able to do initially! 😀

 

Really pleased with the unit - seems really well put together, the cables are well made and the connect system so you can swap crocodile clips for another attachment, insert extension cables etc is nice. Unit is also somewhat waterproof apparently - I declined to put that to the test! I was a bit sceptical about the Bluetooth connectivity (unit is clearly aimed at some more static or marine applications I think) but it was handy given the time it took to charge etc. It meant I could monitor what it was doing and get some reassurance it was actually charging the battery etc. without having to go and look at it. Just sat near enough my window whilst working that I could check the status on my phone every so often

 

Anyway, thumbs up from me for the unit. On to the next problem not moving for 19 weeks has caused...

 

Cheers,

Steve

Really nice bits of kit and with you Bluetooth you can monitor charge and tweak parameters.