Im leaning toward my first Lithium build to move away from lead acid. Still very new to this, but trying to learn.
Originally I was considering biting the bullet and getting LTO's- But the cost is still very high.
My next considerations was prismatic cells- still more expensive than 18650's per KW, and I don't very much like the fact that most sources can come and go- meaning if you don't get them now, they may be hard to get in the future in the same form factor.
So Im leaning to the 18650's- seems pretty much tried and true.
Im building for use on the MPP solar LV2424- so it has a 29.2V max config, and I believe low voltage is 20V.
I've seen some folks build a simple 80P pack, and just series 7 of them. It seemed they were just using a 24V 7s BMS.
However, that doesn't seem to make it easy to add extra packs on, and some significantly less protection within the packs.
Can I Just do 7S80P for a 24V pack with its own BMS, and just keep adding more and more of these packs (with their own BMS) to add capacity?
Can I use Generic off the shelf BMS? Do I want balance versions?
Also, can I run packs of different capacities but of the same voltage? For example, 7S80P of 2A batteries will live in harmony with a 7S100P of 2A batteries and a 7S180P of 1A batteries. (I don't actually think there's an issue with this, as the BMS should cut out the packs with lower capacity first, though increase the draw on the other packs).
Short term goal is 3kw of storage. Im after long operational life, so Im thinking of 28.5v charge cutoff, and a 21v disconnect?
Help is appreciated!
Originally I was considering biting the bullet and getting LTO's- But the cost is still very high.
My next considerations was prismatic cells- still more expensive than 18650's per KW, and I don't very much like the fact that most sources can come and go- meaning if you don't get them now, they may be hard to get in the future in the same form factor.
So Im leaning to the 18650's- seems pretty much tried and true.
Im building for use on the MPP solar LV2424- so it has a 29.2V max config, and I believe low voltage is 20V.
I've seen some folks build a simple 80P pack, and just series 7 of them. It seemed they were just using a 24V 7s BMS.
However, that doesn't seem to make it easy to add extra packs on, and some significantly less protection within the packs.
Can I Just do 7S80P for a 24V pack with its own BMS, and just keep adding more and more of these packs (with their own BMS) to add capacity?
Can I use Generic off the shelf BMS? Do I want balance versions?
Also, can I run packs of different capacities but of the same voltage? For example, 7S80P of 2A batteries will live in harmony with a 7S100P of 2A batteries and a 7S180P of 1A batteries. (I don't actually think there's an issue with this, as the BMS should cut out the packs with lower capacity first, though increase the draw on the other packs).
Short term goal is 3kw of storage. Im after long operational life, so Im thinking of 28.5v charge cutoff, and a 21v disconnect?
Help is appreciated!