Are my batteries really dead...?

[Just smiffy]

I have another thread running about my batteries but this is a new different question .....

Batteries have finally given up....

My banner AGM’s died over night, luckily we came back from a 4week trip from France yesterday.... I believe these may be 7yrs old from new in my Hymer B544... certainly more than 5yrs old. They were showing 12.5v on my little monitor and the victron monitor is telling me the state of charge is...

www.motorhomefun.co.uk

so, been away for nearly weeks and came back Saturday evening driving from tunnel to cornwall.... Sunday morning agm batteries showing 12.5v and step tries to come out but stalls, batteries appear dead... 300w of solar puts a little back in on Sunday and on Monday I plugged in the EHU for 24hrs....

been busy till tonight and went to have a look and my small battery monitor is showing 12.9v and cab battery also 12.9.....

so i put all the lights on and inverter turned on and put a 650w kettle on.... monitor went down to 12.6 and stayed there so i put low watt toaster on and it went down to 12.4v after 5 mins of that within 20 seconds monitor back up to 12.9v.... so i put toaster on again and again for 20mins... 10 mins of rest batteries up to 12.8v.

victron bmv monitor says, state of charge 88% after that punishment and probably still rising....

so, my question is could something of happened when we got back Saturday evening ...? Fridge stayed on 12v instead of changing to gas? And drained the batteries over night? And then being plugged in for a day and the solar charging them back up?

of the 3 of my victron mppt controllers only one is now blinking “battery life”

the hab batteries must have had a full charge today as my cab battery has trickle charged from the overflow..? (12.9)

it was dark when i did all this, sorry if this goes on but trying to explain it all and electrics is my weakest point..

so are my batteries dead or dying and have i just finished them off..?

feel free to belittle my knowledge because i need to know before i buy £350 worth of batteries...?

 

[Lenny HB]

If you are keeping the van Garry I would change them for peace of mind the are well past their use by date.

The only way to test them is with a controlled discharge. You need to test each one individually.
Fully charge the battery then put a 10 amp load on it for 2½ hours let it rest for 30-60 min then check the voltage it should be approx 25% discharged for your battery.
Repeat and should be down to 50%.
Repeat should be down to 75%.

State of Charge	Sealed or Flooded Lead Acid battery voltage	Gel battery voltage	AGM battery voltage
100%	12.70+	12.85+	12.80+
75%	12.40	12.65	12.60
50%	12.20	12.35	12.30
25%	12.00	12.00	12.00
0%	11.80	11.80	11.80

 

[HandyAndy]

Have you tested anything?
Start off with running the vehicle and checking the alternator is actually charging the battery.
You need to be seeing well above 13.2 volts AT THE HAB BATTERY WITH A VOLT METER
Ideal minimum 13.9v
Perfect world 14.2-14.4v
If that passes
fully charge one of the hab batteries directly on to the posts of the battery with a known good mains charger of suitable amperage.
Once charged, disconnect and let the surface charge settle (about 30 mins, the volts will drop from 13.2 down to 12.8v)
With the battery disconnected "drop test it" with a battery tester.. Hold the button for 10 seconds and read the CCA output, if it's at or above the relevant notch, it's good.
If the needle drops down into the orange / red below 10v it's fooked.

Do not spend £350 quid without checking, it's no good asking us for advice here until you have done the above as we are going to be just as in the dark as you

Battery tester is pence!
Amazon product ASIN B00157KANE

 

[Lenny HB]

With the battery disconnected "drop test it" with a battery tester.. Hold the button for 10 seconds and read the CCA output, if it's at or above the relevant notch, it's good.

Sorry but that is totally ilrelavant for a leisure battery, that is a starter battery test. The only way to test for lesiure use is by a controlled discharge.
When my AGM's failed on my last van they passed a CCA test with flying colours with an 80% pass so they would not replace them under warranty, even though they could only deliver 10a/h on a controlled discharge

 

[autorouter]

Sunday morning agm batteries showing 12.5v and step tries to come out but stalls, batteries appear dead..

Sorry to disagree but this doesn't sound like a clear-cut case of flat battery. At 12.5V the battery is only 50% discharged, and should be perfectly capable of hauling the step in and out. I'd be looking to see if there's a bad connection anywhere - battery terminals, earth strap, corroded fuse, that kind of thing.

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[HandyAndy]

Fair comment, that was the old school tester that's cheap, never took into consideration that detail..
You should be able to test it with a capacitance tester though rather than sustained discharge method.
Quicker but more expensive option..

 

[Just smiffy]

For tonight ive left a couple of lights on...

will do some more testing tomorrow..??

 

[Just smiffy]

Checked today and it appears that the sticky labels on top of one battery has bubbles on it like its been gassing out of the caps...? Unlikely as they are both vented..?

the solar is doing its job well as they are fully charged but the state of charge goes down more then normally when i switch stuff on.... i dont think they are dead but not of much use for long...

I’ve ordered some excide g80’s ??

 

[Just smiffy]

New G80’s came today, fitted and keeping a close eye on the controllers...

the old AGM’s have definitely been in from new ....

 

[HandyAndy]

hahaha Banner AND an AGM.. People on here will be spitting feathers.

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[pappajohn]

hahaha Banner AND an AGM.. People on here will be spitting feathers.

When those where new both BANNER and AGM where the holy grail of batteries.

How thing change with time and experience!

 

[pappajohn]

I had my AGM car battery tested using a digital capacity type tester.... Its now 4 years old.
12.9v, 90% capacity or 'life' as they called it.
It didn't have the capacity to operate the auto stop/start.... I've had this trouble for almost two years so the battery was just over two years old when it started.
I put it on my bench AGM charger overnight.... Fully charged, 60% capacity. Left it all day then put it on again overnight.... Fully charged, 65% capacity
Even with 65% Capacity the stop/start worked for around 8 cycles before giving up again so it's anyone's guess what it's getting to in a normal days town driving.

 

[Just smiffy]

All my controllers are now connected and batteries are doing fine...

the controllers are behaving ..?

the second old agm has definitely gone as my smart charger had trouble charging it, I will put it under test to make sure...

 

[Lenny HB]

All my controllers are now connected and batteries are doing fine...

the controllers are behaving ..?

the second old agm has definitely gone as my smart charger had trouble charging it, I will put it under test to make sure...

Take then to your local scrapie worth £12 - £15 each.