Multiplus Compact 12/1600/70 on LiFePO4 - power on and temperature sensor

DIY
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Hello,

I will install a Multiplus Compact 12/1600/70 in my campervan and after checking all the documentation I still have some questions:

  1. I still need to install the prewired temperature sensor if I am using a Lithium battery with integrated BMS? In my opinion doesn’t make sens, because there is no need for temperature compensation or to disable charging below 5C (managed by BMS).
  2. When powering on for the first time, I need to pre charge the capacitors with a resistor in my setup? I didn’t find anything in the manual and usually I turn off my battery when I’m not using my campervan for more than 1 month.
  3. I assume it will be easy to set a charging profile with 14.4V/ 13.5V via MK3-USB, isn’t it?

thank you in advance

2
  1. You don’t need the temperature sensor.
  2. It is better to use a pre-charge circuit to avoid damage of the contacts. If the battery can be switched on/off, you could switch it off, conect all cables and then turn in on. This is not the best solution, but still better then damaging contacts by high current sparks.
  3. This should be no problem. I don’t have any MP1, but I guess this should work.
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THanks.

The pre-charge should be done with the inverter in “on” state ?

Turning on the battery with the inverter connected could affect the BMS? How big are the capacitors in the 1600VA MP1?

4

No, the inverter should be off. The capacitors at the DC input are not switched off. They are always connected to the input. So it does not matter. But it is better if the inverter is off, and first switched on when the voltage is stable.

Well, the inrush current is for sure several 100A for a few micro seconds or so. But the BMS should be able to handle this.

You could use some 12V Bulb for precharge, just as a hint.

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Some BMSs have been known to shut down on high current if you have a small battery or a low amp rated BMS. We have seen people on the older community forum reporting this problem. Best to make sure and have the precharge equipment ready.

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It’s rated to 150A continuous or 200A <30sec, so it should… but probably I’ll put a pre charging circuit in place just to be sure.

Oh, indeed, great ideea. Thanks. I think even a 10W bulb could be enough and I can install one permanently near the fuse.

Thank you for your answers!

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A 10W bulb is perfect! It will directly indicate if the pre-charge is ready or not by lightig up at first and then rapidly getting dark again. Then the current flow is over and the caps are pre-charged.

The only tricky thing is always to switch over from the bulb to the battery contact/harness fast enough. That’s why I prefer a permanent solution with a push button.

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