question

ks0110 avatar image
ks0110 asked

Did my Multiplus just kill my new lithium batteries?

I am trying to set up a Multiplus Compact 12/2000/80 and BMV 712 to a 200ah LiPo battery. Before starting, I checked the voltage of the battery with a multimeter. It read 13.0v. I then attached 2/0 AWG wires as follows:

Positive battery terminal to 300A ANL fuse to positive terminal on the Multiplus

Negative battery terminal to the "battery only" side of the shunt for the BMV 712. Then the "load and charger" side of the shunt to the negative terminal on the Multiplus.

I did NOT turn on the Multiplus. I hooked up the BMV 712 monitor and it read 13v. I left it on for, at most 2 minutes, then I disconnected the negative lead to my battery.

I came back about 10 minutes later, connected the negative lead to the battery...and nothing. I measured the voltage of the battery. It now reads 0.5.

Did I just destroy my new LiPo battery? What did I do wrong?

Thank you!

MultiPlus Quattro Inverter ChargerBMV Battery Monitor
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

What kind of battery do you have exactly?

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ks0110 avatar image ks0110 Matthias Lange - DE ♦ commented ·

It is an ExpertPower 200Ah 12.8V Lithium Iron Phosphate deep cycle battery:

https://www.expertpower.us/collections/lifepo4-batteries/products/ep12200

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ks0110 avatar image ks0110 ks0110 commented ·

Other notes: the above steps are all I did. I did not have any of the AC lines hooked up (in or out), and I did not have the system grounded. And again, I didn't even turn it on. I'm very confused why this would have drained the battery and done that so quickly.

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5 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Just making connection of the MultiPlus (without switching it on) has a very large inrush current to charge the capacitors.

It sounds to me like there is some kind protection circuit inside the battery that has engaged.

I don't know the specifics of your battery, or it's behaviour.

But in other similar 'self managed' batteries with a build in BMS and overcurrent/undervoltage protection, you might be able to clear this by applying voltage to the battery, either via Solar DC, or connecting the AC input of the Multi, while the battery is connected.

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ks0110 avatar image ks0110 commented ·

That was it! I hooked up AC in to the Multiplus, turned it to charge, got the alarm light for a few seconds, then it moved to charge. I turned the system off and the battery is reading 13v again.

Thanks so much for the quick reply! I finished setting it all up and the inverter and charger are working great!

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zfleming avatar image zfleming ks0110 commented ·

I have the same issue, I have the 12v/3000/120a multiplus and two of the expertpower 200AH batteries in parallel. Did simply connecting the multiplus to the batteries solve the issue completely? I have tried that with no luck so far.

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marekp avatar image
marekp answered ·

I think you have a contact or fuse problem.

If your battery lost 2500kWh of energy in 2 minutes you would have it red hot. :)

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Justin Cook avatar image
Justin Cook answered ·

Please note that, although there are 0 technical specifications published on that battery, it does list 50A as the max charge rate (printed on the side of the battery), so you'll need to dial down the charge rate of the MultiPlus accordingly.

...I will also add that a max charge rate of .25C on a 200Ah LFP battery is very poor design of the BMS, and likely means that .25C is also its max discharge rate, which depending on your system consumers, may cause you significant issues down the road. Personally, if you're anticipating any significant usage whatsoever, I'd advise you to return that battery while you still can and get a decent one capable of at least .5C charge/discharge, if not indeed a full 1C... Just my two cents!

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marekp avatar image marekp commented ·

It is no that bad.

When you read specification for this battery you will find that:

Max. Continue Discharge Current 150A

Max. Permanent Discharge Current 200A 3Sec.

Max. Continue Charge Current 50A

https://www.expertpower.us/collections/lifepo4-batteries/products/ep12200#

If @ks0110 would add second (same) battery and connect it in parallel, than the max charge current will be 100A.

Adding that second battery would be in line with suggested battery capacity (350-1000A) for this inverter,

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klim8skeptic avatar image
klim8skeptic answered ·

Lithium batteries tend to be partially charged at the time of shipping.

Fully charging the battery to the manufacturers guidelines would be recommended before proceeding.

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rickp avatar image
rickp answered ·

As noted, the BMS internal to your batteries will shut it down due to high inrush current charging the capacitors unless you first use a resistor to slow the flow. The batteries should reset after a few minutes.

I also learned this lesson when first connecting my BattleBorn batteries! The positive side of the lesson is that you know your battery protection is working!

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