GXMnow
Solar Wizard
- Joined
- Jul 17, 2020
- Messages
- 2,673
I finally had some time to work on the new Bolt Battery modules. I got one of the 10S blocks cut into 4S/2S/4S and have mechanically spliced the 4S sections onto the end of each 10S block, here are a few pics.
It is certainly a bit nerve racking when you cut into that plastic insert. There is more room than you think, but it still feels wrong to be pushing a saw into a lithium battery bank. I chose a little different approach to combining them.
The pack with all the cells the same direction, and no separator plate has the added 4S section upside down. So the negative stud is down instead of up. This way, I just need to make a single buss bar to go from the minus stud of the 10S pack to the tabs and buss bar right there in the 4S block. I had to get a little creative on the end of that pack. I used one of the center separator plates, then cut a plastic plate to fill in the back side where there is no cell, and used a heavy steel plate which is meant to hold ratchet strap in a box truck. I also made spacers to go around the 4 studs so the threaded rods are under tension clamping the corners, and the end plates are just held at the thickness of the battery pack with no bulging. Since the cells are very near fully charged, they are bulging a tiny bit, so here is a bit of pressure on them now, I really need to pull them down a bit.
The second pack actually turned out much nicer, and I knew it would when I chose how to arrange the batteries. I picked the full 10S that was the same polarity as the cut pack when the output studs are facing towards me and up. The factory GM/LG mounting plates are then at opposite ends just as they would be in the car, just missing a group of cells. The inner end of both packs has the cull extending out with the aluminum cover. I had a second of the center spacer plate from my first packs still. It fit perfectly between the cells and properly retains the tension just as it would between full packs in the car. I just had to cut new threaded rod the correct length, and it bolted up perfectly. Again, it just needs a single custom buss bar to go from the 10S pack stud to the 4S block tab. And then I have to make up the balance wire harness.
After trying to lug these beasts into my kitchen (ceramic floor) I was curious what they did end up weighing. One of the 14S bricks, 9 KWH's, came in just over 98 pounds. How does that compare with an LFP bank?
It is certainly a bit nerve racking when you cut into that plastic insert. There is more room than you think, but it still feels wrong to be pushing a saw into a lithium battery bank. I chose a little different approach to combining them.
The pack with all the cells the same direction, and no separator plate has the added 4S section upside down. So the negative stud is down instead of up. This way, I just need to make a single buss bar to go from the minus stud of the 10S pack to the tabs and buss bar right there in the 4S block. I had to get a little creative on the end of that pack. I used one of the center separator plates, then cut a plastic plate to fill in the back side where there is no cell, and used a heavy steel plate which is meant to hold ratchet strap in a box truck. I also made spacers to go around the 4 studs so the threaded rods are under tension clamping the corners, and the end plates are just held at the thickness of the battery pack with no bulging. Since the cells are very near fully charged, they are bulging a tiny bit, so here is a bit of pressure on them now, I really need to pull them down a bit.
The second pack actually turned out much nicer, and I knew it would when I chose how to arrange the batteries. I picked the full 10S that was the same polarity as the cut pack when the output studs are facing towards me and up. The factory GM/LG mounting plates are then at opposite ends just as they would be in the car, just missing a group of cells. The inner end of both packs has the cull extending out with the aluminum cover. I had a second of the center spacer plate from my first packs still. It fit perfectly between the cells and properly retains the tension just as it would between full packs in the car. I just had to cut new threaded rod the correct length, and it bolted up perfectly. Again, it just needs a single custom buss bar to go from the 10S pack stud to the 4S block tab. And then I have to make up the balance wire harness.
After trying to lug these beasts into my kitchen (ceramic floor) I was curious what they did end up weighing. One of the 14S bricks, 9 KWH's, came in just over 98 pounds. How does that compare with an LFP bank?