How to connect batteries to two EG4 6000xp's with no battery rack.

[bikerider4818]

I do not have a battery rack, so how do I configure the wires from the 6000xp's to the batteries? Especially with the small terminal area for the cable lugs on the EG4 Lifepower batteries. Is the only way to do it is to have a bus bar? While we're at it, what awg cable should I use from the inverters to the batteries or, if needed, from the inverts to the bus bar and then to the batteries? I currently have one 6000xp connected to two Lifepower batteries which was easy, but I'm adding a second inverter (and eventually another battery) so I'm trying to figure out the proper way to connect the two inverters to the batteries without having to fork out hundreds of $ for a rack with bus bars. Thanks

 

[DIYrich]

One or more batteries to two inverters in parallel: Busbar
https://www.amazon.com/Blue-Sea-Systems-2107-Powerbar/dp/B000MMDL6Q
If you want to be safer, find a busbar rated for 60v

6000 watts at 48v is 125 amps. I would use 1 awg or 1/0 awg (chassis wiring) between busbar and inverter. 1/0 or larger if conduit. 2 or 3 awg in chassis may work, but for such a short run, I would use the thicker wire. Also, the thicker wire is better able to handle surge current.

 

[bikerider4818]

One or more batteries to two inverters in parallel: Busbar
https://www.amazon.com/Blue-Sea-Systems-2107-Powerbar/dp/B000MMDL6Q
If you want to be safer, find a busbar rated for 60v

6000 watts at 48v is 125 amps. I would use 1 awg or 1/0 awg (chassis wiring) between busbar and inverter. 1/0 or larger if conduit. 2 or 3 awg in chassis may work, but for such a short run, I would use the thicker wire. Also, the thicker wire is better able to handle surge current.

Thanks for the reply.
1) I already have Current Connected bus bars that are 300 amp and the voltage range is stated as 0-64 volt. Will they work? 300 amps enough?
2) Do the positive and negative cables still need to be the same length for both 6000xp to the bus bar?
3) Should each battery get connected separately to the bus bar or do you just connect each battery in parallel to each other and then run one positive and one negative (larger sized cables) from the bus bar to the top left and bottom right of the stack of batteries?

 

[Bridgetown]

Thanks for the reply.
1) I already have Current Connected bus bars that are 300 amp and the voltage range is stated as 0-64 volt. Will they work? 300 amps enough?
2) Do the positive and negative cables still need to be the same length for both 6000xp to the bus bar?
3) Should each battery get connected separately to the bus bar or do you just connect each battery in parallel to each other and then run one positive and one negative (larger sized cables) from the bus bar to the top left and bottom right of the stack of batteries?

Another perspective:

1) Per 6000XP spec. in theory:

• Two 6000XP inverters (while considering efficiency) could demand 268.8 amps (continuous) from three batteries - Okay.
• Two 6000XP inverters (per spec) could demand 497 amps peak demand for (5 sec) from three batteries however, your Battery BMS would kick in and limit the three batteries to 300A - Fully utilizing the buss bar at 100%
• Two 6000XP inverters (per spec) could demand 537.6 amps peak demand for (3.5 sec) from three batteries however your battery BMS would kick in and limit the three batteries to 300A - Fully utilizing the buss bar at 100%

So in theory, the 300amp buss bars will not melt. However, I would much prefer more current carrying capacity within my buss bars. Meaning two 6000XP's really need a 4th battery to fully support the surge capacities of the 6000XP's. Thus, I would increase my buss bars to meet the surge demand of the two 6000XP's.

2) Try your best to keep same length pos/neg cables from 6000XP to buss bar. This will keep the battery drain consistent between batteries. Added a wiring diagram to help.

3) Best to connect each battery to buss bar. Again keep these wire lengths the same also.

Diagrams only with one inverter (with and without buss bars using 2 or 3 batteries). Hope this helps.

 

[DIYrich]

If you go B-I-B-I-B on the bus bar, then you won't exceed 125a over any section of the busbar (assuming everything is working). If you add a 4th battery then: B-I-B-B-I-B. Surging to 497 amps for 5 seconds is 240 amps to each inverter, which is under the 300 amp limit. 537 amps for 3.5 seconds is still under the 300 amp limit over any section. In 5 seconds at 537 amps, it shouldn't heat up that much. Also, only 1/4 of the amps flows across any one section. If the bar is rated for 300 amps, it should be able to handle 300 amps from one end to the opposite end (300 amps across all sections).

If all but one of the end batteries drop out, and you surge on both inverters, then you may have a problem. 537 amps from B-I, and half that from I-I. The one remaining battery may drop out before you reach that much current.

Just my opinion, and I may not be thinking about this right.

 

[bikerider4818]

Thank you guys. I owe you a coffee.