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How can I be sure Conditioning has been successful?

I have a motorhome with two 12v 110ah leisure batteries. I have no idea how old the leisure batteries are, the motorhome is 20 years old and still operating on the original charger! I suspect the charger wasn't designed to maintain two leisure batteries and this is why I purchased a Victron Energy Blue Smart IP22 Charger 1230(3) 230V charger.
It became clear the existing leisure batteries weren't lasting as long as they should powering mainly LED devices. I did what many do and replaced the batteries with new.

I've used the Victron Energy Blue Smart IP22 Charger to condition (Normal Condition) the old batteries and everything seems to have proceeded without issues BUT, how can I be sure the old batteries have been restored to a good/original capacity? I that the purpose of 'conditioning'?

Any comments/tips would be most welcome :)


battery capacity
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3 Answers
mrhappy avatar image
mrhappy answered ·

From my experience, battery reconditioning success is very much depended on how degraded the battery is, I have had no luck in conditioning batteries that have been "bad" for any length of time but I have successfully reconditioned batteries that have been discharged too deep for a couple of days but the capacity will never reach original and probably never reach the exact capacity from before the damage was done. In my view conditioning is a function that only works in very few situations and almost never with old long-time depleted batteries.

So how do you know if it have been successful? There are indications as follows:

1. If you have ran the battery through the conditioning cycle with the Blue Smart charger, you would see in VictronConnect a history where some values are represented. Something like this:


If your charge cycle have a high number on "Maintain" and a low number of "Charge" that would indicate that the battery does not take very much charge but pulls a lot of current to maintain it's voltage, which means un-successful conditioning, only an indication though.

2. If you let the battery rest for a couple of days after the condition cycle, the voltage will also give you an indication of the result.

3. If you put a load on the battery, how much does the voltage drop? That's yet another indication to decide whether successful or not.

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Thanks for the detailed reply and I have to say my experience of reconditioning batteries is also fairly dismal! Why battery charger manufacturers make these claims and even suggest starting a business using their charger to recondition batteries is extremely far fetched.

I've just connected a headlight bulb rated at 45watts across the battery - it'll be interesting to see if Victron's reconditioning has made any difference.

Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

With reconditioning you may can get the battery back to a "usable" condition, but you never can restore the full capacity.

If the batteries are 20 years old they are dead and you have to replace them.

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stitch-up answered ·

Thank you Matthias. Before reconditioning the battery and after charging with A N Other charger, I connected a 45w bulb and it lasted 5 hours on a 120ah battery - hence the reason for replacing.
Yesterday I carried out a normal recondition followed by a normal charge and the light remained on for 12 hours - so there was some progress but still less than half usable power I would expect from a new battery. Still, some progress was made.
I have no idea how old the batteries are!

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