I am planning my
Lithium conversion, and weighing various options.
DIY or Drop-in, and which
parts of drop-in.
To start, the space I have isn't ideal, it is 15"W x 13"L x 11"H. My primary reason for considering a
DIY would be to squeeze more capacity than a pair of 100Ah drop ins will provide. I could almost do that with 260Ah cells, but would need to install them on their side. I'm open to quality cell recommendations that will get me close to 300Ah in this space.
Otherwise, especially for a smaller bank, DIY saves some
money, but not a tremendous amount, at the expense of more
work, a long lead time ordering from
China, and essentially no warranty.
So I am looking at drop-ins primarily at this point, which also have the advantage that if one of a pair of drop-ins fails I still have
power just at reduced capacity. I have made some interesting observations. Most drop ins seem to use prismatic cells, with a few notable exceptions.
Renogy seems to use pouch cells. Looking at Will Prowse's teardown they appear tightly packed in a metal case. What happens when they swell? It otherwise seems a decent product, and I like that there is an inexpensive panel that will allow
battery monitoring without the need to use a BT app. I hate needing to use my
phone for everything instead of having a panel meter. Should the pouch cells be a deal-killer?
Battleborn and Dakota both use cylindrical cells. Cylindrical cells have the advantage of better
cooling, and if a cell dies the whole
battery doesn't fail. In fact, if my math is correct, a whopping 34 cells could die and the battery would still make 80 of rated capacity. (each cell is 2.3Ah so 8 cells in each 3.2V block could fail) This seems a huge advantage, and interestingly Dakota and Battleborn seem to be the only 10+ year warranties. Neither Battleborn or Dakota have a way to
monitor the BMS.
Should I be able to expect 10+ years from a drop-in based on prismatic cells that has a short warranty? I am specifically looking a Kilovault, which I have heard good things about, but open to others. After 3 or 5 years, what are the chances that a
single cell might die leaving me SOL? The Kilovault opens up and is serviceable, which seems a huge plus down the road if something goes wrong.
Thoughts?