300Ah build for a sailboat.

[wholybee]

I am working on a 300Ah battery for my sailboat. This is replacing 230Ah of FLA. I am using an Overkill solar BMS, Renogy 60 DCDC Charger, and Victron 100/30 MPPT. Primary charging will be via solar, and only running the engine after a couple days of clouds. Solar worked with the smaller FLA bank, so it should work even better with the larger LFE bank. My usage maxes at about 100Ah per day. I also have a 20A Renogy AC charger, but probably won't have that permanently connected, but will just carry it so I can use it if needed.

I purchased the cells from Electric Motorsports. They shipped from California in the factory crate from Calb, with the factory test data in the crate.
https://www.electricmotorsport.com/...lb-ca100-3-2v-100ah-lithium-battery-cell.html

I will be top balancing this weekend. Bus bars are 1/8" x 3/4", and I feel that might be a bit on the small side, there isn't much material left around the holes.

 

[snoobler]

Nice to see what you get when you purchase through official channels!

What's the bus bar thickness?

The contact face of the busbar on the terminal is more important than how much is left. As long as the contact area is larger than the cross section of the bus bar, you haven't lost anything.

 

[wholybee]

Nice to see what you get when you purchase through official channels!

What's the bus bar thickness?

The contact face of the busbar on the terminal is more important than how much is left. As long as the contact area is larger than the cross section of the bus bar, you haven't lost anything.

That does make sense. The bus bars are 1/8" thick. They do just completely cover the terminal boss. I'm not sure the contact area is as long as the cross section, but will take a closer look. It is probably close.

 

[snoobler]

Duh... you already said it. I saw it as length and width for some reason.... .125 * .75 = .094sq-in

Your maximum contact diameter would be 0.75 (width of bus bar). Assume 1/2" hole, you have .245sq-in of contact area between the bottom of the bus bar and the terminal surface... that's 2.6X as much. Important the terminals and bus bar are clean, flat and properly torqued. Note that this does not consider the additional contact area of the bolt/washer and threads - that's all just bonus.

 

[wholybee]

Duh... you already said it. I saw it as length and width for some reason.... .125 * .75 = .094sq-in

Your maximum contact diameter would be 0.75 (width of bus bar). Assume 1/2" hole, you have .245sq-in of contact area between the bottom of the bus bar and the terminal surface... that's 2.6X as much. Important the terminals and bus bar are clean, flat and properly torqued. Note that this does not consider the additional contact area of the bolt/washer and threads - that's all just bonus.

Ok. There is a raised boss on the terminals that is significantly smaller than what shows in the pictures. The terminal boss is (I am guessing without having measured it) only about 5/8", which limits the contact diameter. The hole in the bar is 3/8" So, if I did my high school math right, the contact area is 0.196, which is still about twice the cross section.

 

[snoobler]

Ah... I forgot about those. Same thing on my CALB 40Ah.

 

[wholybee]

One interesting observation, the included bolts had blue locktite pre-applied. It makes it difficult to properly torque as they go in pretty tight.

 

[snoobler]

Yuck. Is that a CALB thing? If they are, and CALB specifies a torque with the loctite applied, hopefully they compensated.