My batteries be trippin yo!

[kholmz]

Hi I've got a brand new Growatt SPF 3000TL LVM-48P inverter connected to 4 brand new Li Time LiFePO4 12.8V 100AH (self heating) batteries in series. When I first connected the batteries to the inverter the batteries went into protect mode. That might have been the capacitance of the inverter so I used a resistor to precharge the caps. The Growatt powered up fine after that, but every time I turn on a significant load the batteries go into protect mode. In fact, if I have nothing connected to it except the batteries and my generator, the batteries will trip when I unplug my generator (Yamaha EF2000iS). After resetting the batteries I can plug my generator in and it works fine and the batteries appear to be charging, but unplugging it trips the batteries.

I thought the batteries might be over sensitive, but if I pull each battery aside and connect a 12V compressor to it and turn the compressor off and on and the batteries are fine.

Do I have a faulty Growatt?

 

[MisterSandals]

The Growatt powered up fine after that, but every time I turn on a significant load the batteries go into protect mode.

Define "significant load".

the batteries will trip when I unplug my generator

How is your generator connected to your Growatt that you can unplug it?

 

[kholmz]

Define "significant load".

How is your generator connected to your Growatt that you c

Define "significant load".

How is your generator connected to your Growatt that you can unplug it?

I was using a regular chop saw for the load. It wouldn't even attempt to power it. The nano-second I pull the trigger that batteries would trip.

I have an extension cord connected to the AC IN of the Growatt and that simply plugs into my generators AC out. The Growatt shows that it's charging properly on the screen but the second I unplug it from the generator the batteries trip. I've tried charging with 20, 10 and 5 amps, still the same.

 

[MisterSandals]

I was using a regular chop saw for the load. It wouldn't even attempt to power it. The nano-second I pull the trigger that batteries would trip.

You should check the surge amps on that with a suitable clamp meter. Perhaps 10x running amps.

The Growatt shows that it's charging properly on the screen but the second I unplug it from the generator the batteries trip.

That is odd. I suspect the Growatt might send a surge on cutoff though i cannot imagine why. A clamp meter would help here too

 

[mikefitz]

Perhaps similar issues,

 

[Solar Guppy]

That chop saw is a nasty load, no surprise the surge is over 100 amps on the DC side

 

[yodamota]

That chop saw is a nasty load, no surprise the surge is over 100 amps on the DC side

100 amps at 48v? at least it looks like a 48v growatt.


any chance the batteries were all top balanced, than connected in parallel(look this up as there is a process for series connecting lithium batteries) before connecting them all in series?

 

[kholmz]

Perhaps similar issues,

Ya it does look like this is definitely related. I'm not sure why unplugging the generator makes the batteries trip. I thought the Growatt would protect against any voltage or current spikes. So that is why I thought it was the Growatt and not the batteries. Now I'm back thinking it might be the batteries.

 

[kholmz]

100 amps at 48v? at least it looks like a 48v growatt.


any chance the batteries were all top balanced, than connected in parallel(look this up as there is a process for series connecting lithium batteries) before connecting them all in series?

I'm not sure if top balancing will help, but at least it gives me some hope. So thanks for that. The Growatt and the batteries are installed in a remote cabin so it makes it difficult to troubleshoot. If it does turn out to be the batteries, I can't even imaging the headache it is going to be to return them. I don't even have the boxes anymore.

 

[Brett V]

As others have remarked, that saw is likely overloading at least one BMS. I'm not a fan of putting BMS's in series

 

[kholmz]

As others have remarked, that saw is likely overloading at least one BMS. I'm not a fan of putting BMS's in series

So you think it is an over current thing tripping at least one BMS?. Why do you suppose it trips when I unplug the generator? Over voltage? I'm curious at to whether top balancing will help.

 

[kholmz]

I guess I'm just looking for the best way to troubleshoot the issue to determine whether it is the Growatt or the batteries themselves which are causing them to trip. Any ideas anyone?

(I'm also still hoping top balancing will help)