Help! Newbie almost blows a hole in his face with MPP 3KVA 24V

[Bud Martin]

Look below PV and it shows DC input. Sure seemed strange to me. My Growatt has lugs, not sure on the MPP

I wonder which MPP Solar model that is. I have two MPP Solar and they use posts for batteries connections.

 

[RStone13]

Look below PV and it shows DC input. Sure seemed strange to me. My Growatt has lugs, not sure on the MPP

I think those look like dc out-put under pv inputs?

 

[Bud Martin]

Too bad WATT24/7 did not ask OP to verify if the meter is good and properly connected or not, hopefully they are reading this thread.

 

[EEnginerd]

I wonder which MPP Solar model that is. I have two MPP Solar and they use posts for batteries connections.

That's the 2724LV-MR.

 

[Zwy]

That's the 2724LV-MR.

That is correct. Exactly how do those ports work? Do they utilize some type of plug like a triple Anderson connection?

 

[RStone13]

That's the 2724LV-MR.

In the title of his post he states "MPP 3KVA 24V" a European model only

 

[MisterSandals]

Everything about the setup is backwards except the MPP. Look at the battery, OP is thinking the tan cell terminal is positive. The black cell terminal is positive (yes a problem in itself because it causes misunderstandings like this).

 

[HighTechLab]

And this is why I always put a red positive sticker next to the battery terminals, no matter what. It's just way too easy of a mistake to make.

 

[Zwy]

Everything about the setup is backwards except the MPP. Look at the battery, OP is thinking the tan cell terminal is positive. The black cell terminal is positive (yes a problem in itself because it causes misunderstandings like this).

I had to take a double take on it and go look at my bank just to be certain. Scares the heck out of me on what could have happened.

 

[EEnginerd]

In the title of his post he states "MPP 3KVA 24V" a European model only

As far as I know, the 2724LV-MR is the only MPP Solar product that comes with a battery cable with Anderson connectors and integrated MC4s. It's a US 120V model. Watts247 has a video of it.

Everything about the setup is backwards except the MPP. Look at the battery, OP is thinking the tan cell terminal is positive. The black cell terminal is positive (yes a problem in itself because it causes misunderstandings like this).

Yeah, looks like OP plugged the battery into the all-in-one with reversed polarity and probably shorted the battery across a forward biased junction in a power transistor.

That is correct. Exactly how do those ports work? Do they utilize some type of plug like a triple Anderson connection?

Looks like MPP Solar bundled together 3x Anderson PP15/30/45 connectors.

 

[MrNatural22]

DOH!!

 

[RStone13]

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[RStone13]

DOH!!

View attachment 45300

Funny!!!!!!

 

[Gazoo]

He sure is lucky.
He also need to check his BMS connections! and hope that the BMS is still OK.

I don't see any signs of a BMS.

 

[Third Rail]

As far as I know, the 2724LV-MR is the only MPP Solar product that comes with a battery cable with Anderson connectors and integrated MC4s. It's a US 120V model. Watts247 has a video of it.

Looks like MPP Solar bundled together 3x Anderson PP15/30/45 connectors.

I was taking a closer look at this unit and am somewhat intrigued by the connector and cable. Watts247 say it comes with the "42 battery cable" and the 3 wires look to be around 10 AWG (maybe 8?). I'd like to see the math on what it is rated for.

 

[ArthurEld]

Make cables red on one end black on the other. Problem solved.

 

[curiouscarbon]

hope yer ok. wow!

 

[Gazoo]

I was taking a closer look at this unit and am somewhat intrigued by the connector and cable. Watts247 say it comes with the "42 battery cable" and the 3 wires look to be around 10 AWG (maybe 8?). I'd like to see the math on what it is rated for.

I don't know why they chose to use a 3 prong socket. Maybe to provide extra support for the 2 cables?

I was looking at this unit too and If I recall correctly the cables are 4awg. Don't hold me to that. 8awg would be too light.

 

[Supervstech]

I will say it again, electrons don’t know insulation color.
Verify everything.
Of course... it is good to know your tools are correct...

 

[Gazoo]

I built my 24 V battery from 16 x 3.2 V 90AH Littokola batteries . It tested at 25.9 v. Then I plugged the DC cable into the bottom of my new MPP unit. You can't mistake polarity on these new ones the cable only goes in one way with red plugging into red and black plugging into black. Next I attached the black cable from the MPP to the negative terminal on my battery and then took the red cable and touched the positive terminal ... that's when a lightening bolt shot a piece of shrapnel at my face.
I retested the battery and I definitely have polarity correct.

So I retested the MPP and it seems the red is negative and black is positive. How is this possible? Has anyone else had this happen from MPP? What do I do next?

Summary:

1: The leads on your meter are reversed. The black lead should be plugged into the common port of your meter.

2: The black terminals on the cells are positive. The brown terminals are negative.

3: I don't see a fuse or breaker shown in the attached photos. Always use a fuse or breaker.

4: There is no BMS in use? Always use a BMS.

If you had a BMS the BMS's over current protection would have kicked in. If you had a fuse or breaker either one would have interrupted the current flow instantly. It's possible the 2724 is damaged....that remains to be seen.

It appears you dove into a DIY project before researching the forum and asking for help. There is lots of help available if you ask.