Oops!

[Steve Swenson]

Hello folks, I am going to build a 24v 90ah battery and I think I screwed up by ordering the wrong BMS. I have a Daly 8s 24v 40A common port BMS coming. From all the things I've been reading I think i may have ordered a BMS that is too small. I will probably get a 2000w inverter and I have a Epever 40A charge controller with 1- 400W Jinko solar panel. What do you guys think?
Should I look for something other than Daly?
I need low temp disconnect for sure in Minnesota.

 

[snoobler]

40A * 24V = 960W

 

[Supervstech]

a 90Ah battery will struggle powering a 2000W inverter for long...
You will need a 100 amp bms to feed that size inverter, unless you use a directly wired inverter, and only use the bms for charging and low voltage disconnect.

 

[Steve Swenson]

Thanks guys, would a 1500W inverter be more suitable?
I think I should probably order a 100A BMS and return the 40A. I plan on installing another 24V 90AH battery in the near future.

40A * 24V = 960W

Does that mean that is the size inverter I can handle? I'm not sure what that means. I'm pretty ignorant about these things.

 

[Supervstech]

Thanks guys, would a 1500W inverter be more suitable?
I think I should probably order a 100A BMS and return the 40A. I plan on installing another 24V 90AH battery in the near future.

Does that mean that is the size inverter I can handle? I'm not sure what that means. I'm pretty ignorant about these things.

Yes, if the inverter is tied to the BMS, 40A means, that is the largest load you can draw, so pulling over this would trigger the BMS shutdown, or simply fry it.

 

[Steve Swenson]

Thanks again. Between the two of you I got educated today!
I just found out it is a 60A BMS, that means 1440W and a 1500W inverter should work.
What would be the best sized BMS for a 1500W Inverter.
I would imagine that you would want the BMS larger than the inverter correct?

 

[cypher2001]

I know this wasnt mentioned -- but I think its better to start with the loads you want to power. I do think it was mentioned above -- 90ah batteries won't last really long on 1500W. This might be fine if its just for a couple of minutes for coffee but if you plan on running that load for any period of time you might want to rethink your battery setup. Additionally, My personal experience has been not to look at pushing equipment to the maximum on the sticker.

 

[Steve Swenson]

I know this wasnt mentioned -- but I think its better to start with the loads you want to power. I do think it was mentioned above -- 90ah batteries won't last really long on 1500W. This might be fine if its just for a couple of minutes for coffee but if you plan on running that load for any period of time you might want to rethink your battery setup. Additionally, My personal experience has been not to look at pushing equipment to the maximum on the sticker.

Thank you for your help!

 

[boondox]

Cypher is so right. Start with an energy audit. If you don't know what you need to run takes your odds of building a system that works for you is about the same as hitting a bullseye blindfold.

So, what do you need to run and for how long?