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erikelmgren avatar image

Can Blue Power or Blue Smart 12V chargers be connected to serially connected 12V batteries?

Hi,

I have a small 24V system with two 12V batteries in series that I need a new charger for. Can I charge these with 2 separate Blue Power or Blue Smart IP22 12V chargers, one connected directly to each battery? If these chargers somehow connect the - with PE or N this would of course be a bad idea as it would cause a short circuit.

I have some constraints on available items in stock locally and time to get deliveries through customs etc. before I want to leave, thus looking for an un-orthodox solution.

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3 Answers
Peter Polz avatar image

Nevertheless of using a 24V charger. It would also interessst me if it technical would be allowed to charger with 2 12V Victron BlueChargers a 24V bank or do we would have a problem of shortcut over N/PE?

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I think it would be a very unique case to do this, I can only think that someone wants to have 12 / and 24V supplies. Then why not use 1x MPPT and 1x Orion.
If the negative (or positive) of the battery is NOT referenced to ground (or anything else) in any way then it is technically possible. It does limit options for other things too, like BMV balance monitoring will be affected / not possible. Each 12V side will be out of balance most of the time, one MPPT will be busy while the other one is doing nothing all day.

Yes it is possible, the chargers are isolated from the AC-side


I have done this to balance batteries in a 24V system after user errors (user taking 12V from midpoint of batteries).

You can think of situations where it can be helpfull...but please only do this under supervision, possible problems ahead.


When using two chargers, if one charger charges a bit more or less than the other, or if one is not functioning (not plugged in for example), a big unbalance can occur in the batteries, and with normal 24V 'empty' voltages one battery can still be 50% SOC while the other one is severely discharged

(I couldn't post this message in one piece, even though I was under the 600 character limit)

Thank you Boekel, this was the information I was lookng for. Will also need to implement some monitoring.

I am a Boekel fan, he is always coming up, with the answer needed :o)

Thx... exaktly what i hoped to get as answer. Your intention is the same like mine. I just need it in "some" situations to selektiv recover a bank.

Tonka avatar image

How about charging 2x12V in series with a ip22 12/30 (3), is that possible? I will be installing cutoff switches anyway, so the batteries can be separated easily. Just wondering.

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Markus avatar image

I would strongly suggest to use a 24V charger. So you are under better control of the charging Voltage and minimizing the risk of short circuits. ;o)

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Also, the Blue / Smart chargers are either 12V or 24V capable right out of the box.

You mean 12V "or" 24V capable?

Thank you Markus, you are quite correct. I have edited my comment appropriately.

Problem is that all the boxes on the shelf here are 12V because there are so few 24V systems. They can order, but that will take a fair amount of time I do not want to wait. Yes, waiting is a workable solution—asking about the options.