What amp rating question

I have a small off grid cabin solar system. I am running a single growatt 24v 3000w inverter/charge controller. I have three 375 watt solar panels in series. I currently have 1 EG4 lifepower 24v 200ah battery with 5.1 Wh capacity. I don't have a server rack system due to space issues. I need to add a second battery and need to connect these through a bus bar in parallel. What amp rating should I make sure the busbar has to be safe? I am only running a max of 600w at any one time while reviewing the system output. I'm fairly new to all this so your help is greatly appreciated! Matt

1st, you have to consider how many Amps can go through the busbar. 200AH Battery can push out 200A and Burst Push even more for a few seconds, Add packs in parallel that of course increases. LFP can output 5C Rate in burst but almost all BMS' will prevent that and cutoff.

I HIGHLY Recomend these BusBars as they will handle 400A + easily and are extremely well made. Don't fall for the cheap offshore crap with covers, I had some and they can GLOW ! while melting the cheap plastic around them....

Remember, you GET what you pay for.
Also do not forget to FUSE Each Battery attached to the busbar. I personally opted to use MRBF Fuses from BlueSea rated for 200A connected to Busbar then to Battery Cable.

Premium Pike Brand Busbars (red/black)

At a minimum you should have a 400A bus bar.
"EG4 Lithium battery 25.6V (24V) 200AH 5.12kWh with 100AH internal BMS."
3000w / 24v = 125A
You should exceed 2x 100A, to prevent things from getting toasty. Buy quality.
Use class T fuse or better. LiFePO4 can toast wires and fuses with extreme 20k amps. Before 100A limit kicks in, if FETs don't short out.

Steve_S said:

1st, you have to consider how many Amps can go through the busbar. 200AH Battery can push out 200A and Burst Push even more for a few seconds, Add packs in parallel that of course increases. LFP can output 5C Rate in burst but almost all BMS' will prevent that and cutoff.

I HIGHLY Recomend these BusBars as they will handle 400A + easily and are extremely well made. Don't fall for the cheap offshore crap with covers, I had some and they can GLOW ! while melting the cheap plastic around them....

Remember, you GET what you pay for.
Also do not forget to FUSE Each Battery attached to the busbar. I personally opted to use MRBF Fuses from BlueSea rated for 200A connected to Busbar then to Battery Cable.

Premium Pike Brand Busbars (red/black)

Pike Industries

Pike Industries

www.amazon.com

Click to expand...

Thank you so much for the information. I got two 400a Pike busbars. Also included fuses as well. These should be more than enough for my typical usage, and are rated above even my maximum output.

Pappion said:

At a minimum you should have a 400A bus bar.
"EG4 Lithium battery 25.6V (24V) 200AH 5.12kWh with 100AH internal BMS."
3000w / 24v = 125A
You should exceed 2x 100A, to prevent things from getting toasty. Buy quality.
Use class T fuse or better. LiFePO4 can toast wires and fuses with extreme 20k amps. Before 100A limit kicks in, if FETs don't short out.

Click to expand...

Thanks for the helpful information!

solarnewguy33 said:

Thank you so much for the information. I got two 400a Pike busbars. Also included fuses as well. These should be more than enough for my typical usage, and are rated above even my maximum output.

Click to expand...

Some things you can go cheap on IF you know what you are doing BUT other things to cheap out on are simply foolish. High Quality Fuses/Breakers, and Interconnection devices like Busbars, and main shutoff switches are not to be cheaped on.

Many do not realize that there are different grades (purity) of copper and many of the cheapo Offshore "Chromed" busbars use the lowest grade of copper you can get, which is never a good thing. Even worse are the Brass Battery Terminals ! Brass is one of the most recycled metals there is (almost as high as Lead) but with each remix it get's "whiter" and has less Copper Content. Funny part is, IF you buy a Brass item today, it may actually contain some brass from WW2 shell casings ! The more Orange the Brass is the more copper in it. Low Grade "White Brass" is often Chrome Plated so always avoid those items.

Davis Poz (Youtuber on Solar +) recently did a video on Busbars showing a cheapo set compared to the Pike Set... EYE Opener for the uninitiated. Pike uses 110 Pure Copper which is pricey but is the cleanest & best you can get.

As for LUGS, I Very Strongly recommend Selterm Tinned Lugs, they are also Pure Copper, thick & solid with nice flared ends making it easy to get all the wire strands in there.

Main Corp Site: https://selterm.com/
Their Amazon Store: https://www.amazon.com/stores/SELTERM/Homepage/page/97E45844-AA94-4BC5-8DC9-AC91CBF94343