AGM batteries dead ? Big mistake.

[Maxi]

Hi everyone, well , just new at this and I did the biggest mistake…
I switched on my inverter ( 1800W) so as to use the sockets to charge my laptop.
Then,while driving, I set THE FRIDGE on automatic, THINKING, that it would, either stay on gas or work with battery while the alternator helps…
BUT, the fridge “thought” “ Oh, I have 220V, !! So the fridge used the inverter, for about …36 hrs ( don’t laugh) , of course, from my house batteries. (AGM x 2 , 95amh each ).
Imagine, alarms went off and now it shows a red light flashing and below 11V.
So I believe I have f€&#ed up the batteries ?
batteries are 6 months old.
Now, I am connected since yesterday on 220V,( for almost 24hrs) and nothing has changed. Batteries are not charging. Also solar panels, it shows 0A coming in ?
any comments or hints? Did I definitely kill the batteries?
thanks.
Maxi

 

[Jimbohorlicks]

Try charging the batteries independently with a separate charger. Aldi are doing one currently that can regenerate a flattened battery.
You may get lucky.

 

[Phill D]

Many chargers have an in built block on supplying charge to a battery that is below a certain voltage.
So the solution above by Jimbohorlicks may be your only answer.
You may be lucky

 

[Maxi]

Try charging the batteries independently with a separate charger. Aldi are doing one currently that can regenerate a flattened battery.
You may get lucky.

Thanks Jim, yep well, I will have to remove the passenger seat, and remove the batteries and do that…

 

[Maxi]

Many chargers have an in built block on supplying charge to a battery that is below a certain voltage.
So the solution above by Jimbohorlicks may be your only answer.
You may be lucky

Yes, I read this in the manual, but not much more. In some occasions charges or the system just disconnects when the battery is below 11V. I might park in front of a garage, and sleep there while they try to recover the batteries, but don’t you think, it would be better anyways to buy two new batteries? I would pay the price for the mistake

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[olley]

Start the engine and then connect the engine battery to the agm's

 

[Maxi]

Start the engine and then connect the engine battery to the agm's

This sounds dangerous and will not do it. Thanks. To manipulate the batteries while engine is on, is something I would never do,sorry.

 

[Emmit]

No doubt a Funster will be along shortly to tell you the biggest mistake you made is to have AGM batteries.

It wasn't.

You made a beginners c*ck up that you will remember forever you have a van.

It wouldnt have made the slightest difference what kind of battery had been installed. Given time, even Lithium would have gone belly up with your Inverter doing the mains supply over a protracted period.
Don't beat yourself up but as previously said, get the batteries recharged by a good quality charger. If the fitted batteries haven't been abused on previous occasions you might just be able to put this episode down to experience.

 

[Maxi]

No doubt a Funster will be along shortly to tell you the biggest mistake you made is to have AGM batteries.

It wasn't.

You made a beginners c*ck up that you will remember forever you have a van.

It wouldnt have made the slightest difference what kind of battery had been installed. Given time, even Lithium would have gone belly up with your Inverter doing the mains supply over a protracted period.
Don't beat yourself up but as previously said, get the batteries recharged by a good quality charger. If the fitted batteries haven't been abused on previous occasions you might just be able to put this episode down to experience.

Thanks Emmit. I know, stupid mistake. I know “a little” about batteries, I hope I can recover these AGM after discharging them completely. Imagine, a big fridge sucking on the two batteries ( 190A) for 36 hrs… poor batteries

 

[Stealaway]

Thanks Jim, yep well, I will have to remove the passenger seat, and remove the batteries and do that…

Try disconnecting the solar panels.
Then reconnect solar panels
The solar controller needs to take a reading of the batteries before it knows what it's charging.

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[funflair]

Thanks Emmit. I know, stupid mistake. I know “a little” about batteries, I hope I can recover these AGM after discharging them completely. Imagine, a big fridge sucking on the two batteries ( 190A) for 36 hrs… poor batteries

I would have thought the inverter would have shut down at some point to protect the batteries and if the fridge was on Auto it would/should then go to gas.

 

[Emmit]

Thanks Emmit. I know, stupid mistake. I know “a little” about batteries, I hope I can recover these AGM after discharging them completely. Imagine, a big fridge sucking on the two batteries ( 190A) for 36 hrs… poor batteries

You can comfort yourself in the knowledge that your fridge/freezer was NOT drawing 190amps for 36hrs. (Unless the doors to it were open.
A fridge is very well insulated and, because of the installed thermostat, it will have been switching itself on and off periodically.
Also remember that it's not Summer yet so the climate wasn't having such a negative impact.

 

[Lenny HB]

AGM's are very intolerant of being miss used they are not very good as leisure batteries, yours are probably a bin job.
As you have a Dethleffs the charger in the EBL should have settings for AGM & Gel, I would replace them with Gels far more reliable, you would also need to change your solar controller setting and the B2B if you have one.

The inverter should never have been wired to allow the fridge to run of it, it has probably been wired straight into the mains circuit which will mean the charger will run from it as well making the situation even worse. So if you use it again without rewiring remember to turn the fridge to gas and turn off the charger.

For the laptop it is more efficient to use a 12v charger there are plenty available.
I don't know what else you use the inverter for but if you want your batteries to last about the most you can load the inverter with is 500 watts for your size of battery bank.

 

[Lenny HB]

No doubt a Funster will be along shortly to tell you the biggest mistake you made is to have AGM batteries.

Now who would do that? I can't think of anyone.

 

[Emmit]

Emmit's 'old' van laid in a dealers forecourt for over four months. (it may have been longer) waiting to be snapped up.

When the new 'lucky' Funster bought it, the 2 AGMS were dead, they were extinct, they had shuffled off and joined the choir invisible, you get the picture.
The dealer, this is where Simon-Alan Kerr gets a leg up. They installed two new batteries and left the 'old' batteries in the van.

I was told by the new owner that, following a charge, the old AGMS were back up and running normally.

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[Lenny HB]

I was told by the new owner that, following a charge, the old AGMS were back up and running normally.

I bet he never checked the capacity of them, I expect they would have been way down.

 

[Emmit]

AGM's are very intolerant of being miss used they are not very good as leisure batteries, yours are probably a bin job.
As you have a Dethleffs the charger in the EBL should have settings for AGM & Gel, I would replace them with Gels far more reliable, you would also need to change your solar controller setting and the B2B if you have one.

The inverter should never have been wired to allow the fridge to run of it, it has probably been wired straight into the mains circuit which will mean the charger will run from it as well making the situation even worse. So if you use it again without rewiring remember to turn the fridge to gas and turn off the charger.

For the laptop it is more efficient to use a 12v charger there are plenty available.
I don't know what else you use the inverter for but if you want your batteries to last about the most you can load the inverter with is 500 watts for your size of battery bank.

Told you there'd be someone along.
Thanks for restoring my faith Lenny

 

[Emmit]

I bet he never checked the capacity of them, I expect they would have been way down.

I'm not hypothesising Lenny. I'm not guessing. I doubt any battery would like to be discharged and left for a protracted period.
All I'm quoting is a set of circumstances that actually occurred, reported to me by someone who had first hand experience of those circs.
Oh! and by the way, those much maligned AGMS were not new when this happened. They were well past middle aged, used by a Funster who went off piste as a matter of regularity.

 

[Raul]

This sounds dangerous and will not do it. Thanks. To manipulate the batteries while engine is on, is something I would never do,sorry.

That’s not dangerous, you are practically using the alternator to charge, rather than over protective chargers that don’t charge below a threshold. The Aldi charger may do it slower, or not at all. All smart chargers will not charge below a certain voltage.
And you haven’t killed it, yet, just discharged a bit deeper. Recharge back, and resume.

 

[VXman]

This sounds dangerous and will not do it. Thanks. To manipulate the batteries while engine is on, is something I would never do,sorry.

That wouldn't be dangerous. It's only 12 volt. Seems a good idea to me. I'd give it a go.

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[olley]

This sounds dangerous and will not do it. Thanks. To manipulate the batteries while engine is on, is something I would never do,sorry.

Why dangerous, I did the reverse a few months back after my engine battery was flat, both negative earth so you only need to connect the reds.
AGM's are sealed so little chance of any problems.
Get the voltage up a bit and his charger might kick in.

 

[NicM]

I have connected 12v batteries together quite a few times now to get a modern charger to work, 1 flat battery and 1 charged battery.

 

[autorouter]

This sounds dangerous and will not do it. Thanks. To manipulate the batteries while engine is on, is something I would never do,sorry.

In normal use, when you start the engine there is an electrically operated switch that automatically connects the leisure battery and starter battery together, so that the alternator can charge both of them at the same time while you are driving. When the engine stops, the switch automatically disconnects them so they are separate batteries again.

Some battery chargers will not charge a battery if the voltage is below a certain value, others will attempt to charge even a totally flat battery. If the batteries were on a bench in front of me I'd temporarily connect a good battery to the flat battery, they would share their charge, and the flat battery would be boosted up to a voltage that the charger could start from.

I think if you start the engine, the starter will be connected to the flat leisure batteries, the alternator will start pushing charge into both starter and leisure batteries and will boost them to the state where the mains charger will work on them. It would probably only take five minutes of running for that to happen, although if you have an excuse for a longer drive it would be better.

It's worth recharging the batteries and seeing how good they are. If they seem OK, they will probably be fine. It's leaving a battery flat for weeks that is the real killer, if you get them back up to full quickly they might be fine.