diy solar

diy solar

BMS make my head hurt

Greybeard

New Member
Joined
Dec 30, 2019
Messages
89
Maybe I'm just not that smart but starting to set up this system i thought was straight forward untill I got to BMS's
So many options, even ones I don't know about I'm sure. So let me ask the professionallies here for some recommendations on which ones to look at and which ones to avoid.
I'm in the usa but this system is going to be sent to the Philippines for my house there in the mountains to run off grid (I may have grid power backup to run into the invertors). So I'll be using either mpp or growatt invertors. I'll have two 3k watt units paralleled. I really don't see using more then one. But everything in this system I'm building with backup redundancy or bringing spare parts with me as shipping stuff there gets "interesting"
I just ordered 16 of the 280ah cells. I'm going to run v2 24v banks of 8s paralleled together.
So I can set charge perimeters in those units

I don't need low temp cutoff.

I'm looking for is easy to set up and work because I'm not always there myself and need to be able to teach my wife to operate it if a problem comes up

I'd like to be able to monitor cell levels so I know if I need to Ballance but I don't see that I really need to be able to change perimeters since I can do that in the invertor (or am I wrong here)

3k invertors come in at 125amps each draw. They are 6k peak but I think 200 amps per bank is more then enough. But are the 200amp bms really capable of running 125 constant, 200 as a surge? Or am I better to parralel 2 100amp units on each bank? That just seems overly complicated tho.

Chargers seems very complicated to me and I don't see the need for all that funtionality to me. Daly would work I just wish I could monitor the cells. Is there something in between?

This may sound like one of those tell me what to do threads but I think of it more as a point me in a direction to look thread. There is just Soooo many
 
Right now I'm leaning tword the battery hookups 100 bms and just using it to trigger a solinoid.

Is there a switch I could use to replace the solinoid that doesn't have the parisitic draw?

This will still give me overcharge and undercharge disconnect am I right? I only loose the over current disconnect? I can recify that with a 200 or 250amp fuse between the solinoid and the load correct?
 
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