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jim-small asked

Multiplus limiting charge current

Hi All,

I have an Airstream that I installed 4 Battleborn 100amp batteries and a multiplus 3000. When I plug in my 30amp service to bulk charge the batteries, I only get a max of about 2000 watts charging the batteries. I know the AC input can handle more. If I turn on the AC or add another load, I see the watts jump to around 3600. As soon as I turn off those loads, it goes back down to 2000 watts bulk charging batteries. I've set every option with the software to the BattleBorn specs. I don't have weak AC checked. I'm stumped. I really would like to use either my 30 amp shore power or my F150 truck with 3600 watt generator to charge my batteries more quickly that 2k watts. I know the Victron and batteries can handle this. I also have the victron solar charger, but that should not matter here. Looking for any advice.. thanks

battery charging
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derrick thomas answered ·

What is the exact model inverter?

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jim-small answered ·

HQ203F 12/3000/120-50 120v

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derrick thomas answered ·

You are limited to 120 amps DC charging from the inverter. That's all you're going to get.

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jim-small answered ·

ok, but wouldn't that be a bit more than 2000 watts coming into batteries? My generator maxes out at 3600 watts, but in bulk, I'm only seeing 2k watts coming in to batteries for bulk charging.

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derrick thomas answered ·

Depends on the battery voltage. Say your bulk voltage is 14.4, at 120 amps you have 1728 watts. Add in some losses for conversion and inefficiency and you are at 2000 watts.

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jim-small answered ·

interesting.. so i guess this is normal behavior. 14.4 is what Battleborn specs out. I assume this is the same for everybody with battle born batteries? too bad.. I'll never take full advantage of the 3600 generator unless I'm also running a load while charging.

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derrick thomas answered ·

120 amps is about the maximum your going to find in any inverter/charger combo. If you spend a lot of time off-grid and fast recharging is desired, there are a few options. Any solar you add will add on top of the 120 amps by the mp. You could also add another dedicated charger. Victron has stand alone chargers that integrate nicely. Anything else you add to the system (for charging) is not bridled by the 120 amp limit of the mp.

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jim-small answered ·

thank you! sorry, a bit of a rooky on electrical. did not realize the 14.4 bulk volts was the limiting factor.

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jim-small answered ·

hi, so still confused here. The Current input setting is 120amps. At what point is that in the charge flow? My shore plus is 120v x30amps + 3600 watts.

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derrick thomas avatar image derrick thomas commented ·
The charger portion of the inverter is limited to 120 amps DC output. Regardless of how many watts you have available on the ac input, the charger will only provide up to it's limit of 120 amps DC. Ac amps and DC amps are not the same thing. Amps = watts/volts, watts = amps*volts. Watts is a measure of energy regardless of AC or DC.
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jim-small answered ·

thank you!

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