Bluetti EB70 solar charge polarity

Hi all,

My EB70 came with the DC to MC4 cable. The positive MC4 is male and the negative is female. However the positive MC4 is also male and the negative is also female on my solar panels. So they can’t connect.

I have 3 solar panels all with the same connector, so I am assuming the bluetti solar cable has been wired with the wrong polarity?!

Or does polarity not matter for the MPPT controller?

I can’t find any male to male or female to female MC4 connectors anywhere.

I don’t want to connect the panels if the polarity is incorrect as I’m not sure there is reverse polarity protection.

I have 2x identical 100W panels waiting to be connected in parallel.

Any thoughts appreciated!

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Use a meter to verify the polarity of your panels vs the Bluetti cables. The “gender” of the black plastic housing on the MC4 panels is not indicative of the polarity. Most likely if they will snap together you will be fine. But…verify with a meter first.


I compared my EB70 MC4 to 8mm cable that came with it to my Renogy panel. As shown in the picture, the RED positive wire is a female MC4 which does connect to the male positive MC4 on my Renogy.

I also compared this to my Bluetti PV200 panel and like the Renogy, it mates correctly.

As Scott mentions, getting an inexpensive (Hobo Freight) multi-meter will allow you to test in a few seconds and be useful for lots of garage stuff. I see they have one for 6.99.

Thanks for your speedy replies Scott-Benson and Sierravancampers. Much appreciated!

The polarity that is moulded into the wire is indeed the wrong way round, as seen in your photo! Having a + moulded onto a connector with a black wire is confusing in my book. Perhaps the MC4 connector moulds could be updated to not specify a polarity, to avoid the confusion.

Whilst many will work it out with a multimeter, or not bother to check in the first place, some might fabricate their own wires leading them to fry their unit.

But I’m a very happy customer, plugged in and was getting 140W+ off a 200W solar array.

And great customer support :relaxed:

Many thanks