Inverter and BMS Thoughts/Recommendations

[TheGriz]

Hello folks,

Well the four 280AH cells are ordered and shipped. So while waiting, I figure its not to soon to now investigate and order the BMS and inverter. I'm thinking 2000 watt constant/4000 watt peak pure sine wave inverter. So doing the math, 2000w/12v=166Amp. This is my first build, so my understanding is 166A would require next size up BMS or 200 amp BMS. Am I correct??? I am not made of money, so looking for quality, but don't want to overbuy. One concern I have are the leads off the BMS's I have looked at on line...the wire leads don't seem adequate for the rated amps. Thoughts on wire lead, and sizing of amps of a good BMS 4S. And link(s) to appropriate BMS.

Here is one BMS I did see that I "think" fits the bill..the 200amp version for $189. Again, thoughts?

4S 12V 3.2V LFP LiFePO4 Lithium Battery Protection Board BMS Balance Waterproof | eBay

◆BMS manufactured by high quality Mos and IC imported. What current BMS should I choose ?. Short Circuit protection. Over current and short circuit protection. With balance. ◆Use top quality (A-level) protective integrated circuit IC, from the solution of Seiko of Japan.

www.ebay.com

Thank you for your anticipated insight and recommendations!
Mike

 

[Steve_S]

ON the BMS, seriously, I would look for a smart 4S with blue tooth for monitoring, configuration & management. Might be hard pressed to find 200A 4S... most FET based BMS' stop around 120A to 150A, after that your into heavier gear. Several people are buying & using the Smart BMS' and are doing well with them. Mind you, there have been some not so good ones too... Will has reviewed some good ones. BTW: None of the Daly's are smart in that respect, unless they've come out with new ones.

Work with the 166A figure for general everyday use that's fine ... but run a coffee maker & nukalator and you'll be past 160A on 12V real quick. At 4000W @ 12V is 333A and if you think you may get that high, time to re-calculate things and mod the plan.

Leads:
Balancing Cell leads are small gauge and that's fine. No big juice flowing through there.
(+)-(-) Leads get funny. Depends on the BMS maker, the typical FET based BMS' have the leads on them and usually soldered to the board. From what I have seen, it's enough to make it minimally for the rated power handling. Some folks have been replacing them with better quality & higher grade wire to be more "sure footed". I don't use this type of BMS so what I can say on that is minimal.

That BMS you posted: 150A Same Port = $142 200A same port = $190
HOLY SHNOOTZ ! for a FET Special ! eeeekkkkkkk Ohh my.... I think @Craig has a stock of Chargery BMS8T's (will work 4s) and they will come close to it and give you 100 times more BMS with built in balancer.

 

[TheGriz]

ON the BMS, seriously, I would look for a smart 4S with blue tooth for monitoring, configuration & management. Might be hard pressed to find 200A 4S... most FET based BMS' stop around 120A to 150A, after that your into heavier gear. Several people are buying & using the Smart BMS' and are doing well with them. Mind you, there have been some not so good ones too... Will has reviewed some good ones. BTW: None of the Daly's are smart in that respect, unless they've come out with new ones.

Work with the 166A figure for general everyday use that's fine ... but run a coffee maker & nukalator and you'll be past 160A on 12V real quick. At 4000W @ 12V is 333A and if you think you may get that high, time to re-calculate things and mod the plan.

Leads:
Balancing Cell leads are small gauge and that's fine. No big juice flowing through there.
(+)-(-) Leads get funny. Depends on the BMS maker, the typical FET based BMS' have the leads on them and usually soldered to the board. From what I have seen, it's enough to make it minimally for the rated power handling. Some folks have been replacing them with better quality & higher grade wire to be more "sure footed". I don't use this type of BMS so what I can say on that is minimal.

That BMS you posted: 150A Same Port = $142 200A same port = $190
HOLY SHNOOTZ ! for a FET Special ! eeeekkkkkkk Ohh my.... I think @Craig has a stock of Chargery BMS8T's (will work 4s) and they will come close to it and give you 100 times more BMS with built in balancer.

Thanks Steve. As a noob, this is why I almost found out the hard way to run my thoughts through this forum. Quick question, what is difference between common port and separate port? And which is appropriate for my 4 cell configuration?

 

[Steve_S]

BMS common port vs seperate port

Can someone explain the difference? When would you want one or the other? Benefits?

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