Looking for battery for telescope to replace FLA that is too small

[Linwood]

So completely ignorant of all this (but trying to learn so thank you), I'm still stuck on the "compression or flexible busbars" part?

Postscript: Oh, I think I get it. if not compressed but at fixed distances as they expand, they will put stress on the top connections due to a fixed width busbar. If compressed, they would not actually expand. Am I close?

 

[Supervstech]

So completely ignorant of all this (but trying to learn so thank you), I'm still stuck on the "compression or flexible busbars" part?

Postscript: Oh, I think I get it. if not compressed but at fixed distances as they expand, they will put stress on the top connections due to a fixed width busbar. If compressed, they would not actually expand. Am I close?

Exactly.
Compression provides longer life out of the cells, and prevents damage from solid bussbars. So, flexible bussbars prevents bussbar damage to the terminals, so the cells function their lifespan.

#6 isn’t a very large conductor. I’d use a pair of #6 crimped to lugs. Larger than 6 copper gets kinda stiff in short chunks like a bussbar link would be.

 

[Linwood]

#6 isn’t a very large conductor. I’d use a pair of #6 crimped to lugs. Larger than 6 copper gets kinda stiff in short chunks like a bussbar link would be.

With a 20A charger and 10A or so discharge is there a circumstance where that capacity is really needed?

Or is the idea "just in case you decide to start your car with it" (which having written that, I guess it might happen)?

Let me look at this with fresh eyes, but that size modules fit nice, and are not terribly expensive, I may have a go at it.

 

[Supervstech]

With a 20A charger and 10A or so discharge is there a circumstance where that capacity is really needed?

Or is the idea "just in case you decide to start your car with it" (which having written that, I guess it might happen)?

Let me look at this with fresh eyes, but that size modules fit nice, and are not terribly expensive, I may have a go at it.

It isn’t about the capacity, it’s about minimizing voltage drop between cells. You want very low resistance, and #6 will have twice the resistance as two #6 will… remember, the usable cell voltage between cells is less than 1 volt… 2.5 minimum to3.4 so ANY resistance adds up. You want the cell bridges as close to zero resistance as possible.

 

[Linwood]

Got it. Thanks.

 

[JoeHam]

And I assume I should separate to charge? I.e. not build them together in a box?

Just parallel them once at the same state of charge and from then on you can discharge and charge them without separating.

Each will pick up it’s own share of the load, and it’s own share of the charge, no problem.

On YT the off grid garage did an episode with something like a 5 Ah paralleled with something over 200 Ah IIRC as an extreme experiment and it was amazing how well they worked.

Always same chemistry, always same SOC when paralleled and no problem.

Just another option to consider, do what works for you.