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mseelos avatar image
mseelos asked

Multiplus 12/3000 Shutdown

Hello,

I have a Multiplus 12/3000 that I just installed. It is wired with AWG2 to two 200 amp hour lithium iron phosphate batteries that are connected in parallel. From the inverter, I wired Romex 8/2 wire, and connected each cable (positive, neutral, ground) to two sets of Romex 12/2 wires with large, waterproof twist connectors. These two sets of Romex 12/2 wires then go through a main lug load center, protected by breakers. One goes to a 120v AC outlet, and the other to a separate 120v outlet that I'm using to power an induction stove.


The induction stove is 1800 watts, well within the Mutliplus output capacity. When I turn the stove on, it works for a bit, but after about a minute, especially when it is turned up to a high heat setting, the inverter shuts off and restarts. I looked at the lights on the inverter as this happened, and I saw (in a split second) the "low battery" warning go on, then the "overload" warning, then it shut off. The batteries were at near full charge, and the max of 15 amps required by the induction stove is well within the operating capacity of the inverter.


Is this caused by an overload or something else? How should I go about fixing this so the stove is fully operational?


I appreciate your time and feedback.


Thanks,


Mark

MultiPlus Quattro Inverter Charger
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tinybluehouse avatar image tinybluehouse commented ·

Yeah what's the voltage at the point of the shutdown, is your low voltage protection set too low? I use an induction stove on mine and it runs great but it does reduce the voltage while it's on.

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stavarda avatar image stavarda commented ·

Are you realy using twist wire connectors?

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7 Answers
bluepowershop avatar image
bluepowershop answered ·

@mseelos AWG2 is more or less equal to 35mm² cable.

The manual for your unit states that the minimum wire gauge should be 2 x 50mm² per pole.
So a total of 4 pcs 50mm² to the unit.

35mm² is to small for your unit to perform at maximum power.
You should use 4 wires (2 positive/2 negative) of AWG0 minimum or 1x AWG0000 per pole!
See your manual chapter 4.2 at page 10.

Please connect your unit to your computer via VE.Configure and check the DC ripple, this is your problem.

Regards, Mark

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Leslie Olson avatar image Leslie Olson commented ·

Mark, I have a 4 foot long, awg 4/0 cable going from each terminal (Pos and Neg) to the Multiplus with the Victron BMV712 Shunt in Neg side and Cut-off switch and 300A Fuse in Pos side. I have 6, 100 AH Lithium Iron Phosphate (Battle Born Batteries (BMS and lots of battery protections built into each battery)) batteries in parallel with 2/0 between each battery). Pos and Neg battery connections are at opposite ends of the battery bank.

Is this not sufficient? We have been using this setup for 4 solid months, full time and this issue just started about two weeks ago.

Thank you for your help!!

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klaus-pedersen avatar image
klaus-pedersen answered ·

First of all, I would check with the battery manufactorer that the load are within the specs for the batteries (it should be with 400ah Li-ion), but I just wanted to rule out that it is a build-in battery BMS that is cutting off the power, because I find it strange that you get a low battery just before the shut off.

Have you tried measuring the voltage directly at the battery when the inverter shuts off? If the voltage drops I will assume that the problem is related to capacity or more likely BMS. If you don't see a noticeable drop in voltage (which you shouldn't if the battery is fully charged) then it is most likely a voltage drop between your battery bank and your Multiplus. If this is the case then you need to look at wire gauge and length. I'm not familiar with the american standards, so I can't advice on that, but this should help you in trying to locate the source of the problem.

Best of luck

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mseelos avatar image mseelos commented ·

Thanks. It turned out to be poor quality/too small wire between the batteries and inverter, that was causing too much resistance, and voltage drop like you mentioned. I replaced it with larger 2/0 wire and it works now!

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wkirby avatar image
wkirby answered ·

Please could you clarify AWG2? Is this the same as 2/0 aka 00 cable? 2AWG would be a bit small for 250A.

What stove is it? More specifically what is the power factor or VA rating of the stove.
What happens if you run a 2KW heater, kettle or some other resistive load?

I have often wondered how my 3KVA MultiPlus would react to my 2KW induction stove, never tried it, might be a fun experiment.

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mseelos avatar image mseelos commented ·

Thanks for your reply!

It's not 2/0, it's 2 gauge. It's a very short cable run (<0.5 m). The cables are not warm when it trips and shuts off. Could there be too much voltage drop? Do I need to set anything on the Multiplus to specify lithium batteries?

It's a True Induction 2 burner stove. It's 120 V / 80 Hz and 1800 watts.

I ran a 1500 watt heat gun from each outlet, and it trips both after about 10-20 seconds. A 980 watt vacuum cleaner seems to work fine.

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mseelos avatar image mseelos mseelos commented ·

Usually when it trips, there are no warning lights on, but I ran the heat gun and the vacuum at the same time, it stopped, and I got the "low battery" light instead of it shutting off entirely and resetting.

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Tom avatar image
Tom answered ·

#2 gauge copper wire is not the same as 2/0 cable. Why are you using such small cable?The instructions clearly call for 2x50mm2 or 2x 1/0cable (or one 4/0 cable) on each lead for the 12 volt 3000 watt inverter. #2 wire is only 35mm2.

The flow of electrons is like the flow of water through a pipe. If the pipe is too small you restrict the flow. IE resistance = heat = fire.

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blond2silver avatar image
blond2silver answered ·

If you believe you're wiring sizes are correct, then it could be the inverter parameters. Here's an example I would suggest trying:


multiplus-123000-inverter-params.png (74.8 KiB)
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walter-casey avatar image
walter-casey answered ·

@mseelos I have the same problem with the same unit.

Firmware Version 430

Sense voltage connected. When sense voltage drops to 12.38 volts "Low Battery" light comes on and the unit goes offline for about one minute. The load is only 1400 Watts.

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mward avatar image
mward answered ·

I have the same problem. I'm running my 5kw genset, ac loads are about 300w and it's charging the batteries, I start the AC and it says low voltage warning and disconnects the ac / resets, then comes back on. Even AC + 1600w of charging is under the limit for the device, I guess the drawdown on startup for the ac is pulling the batteries down but it shouldn't be, the generator is running and there should be more than enough voltage to start the ac. I'll check my low voltage limits and adjust as necessary I think I set them up rather conservatively.

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