Hi all-
Long time lurker in San Diego, I've been on the fence about building one as I didn't' want to start another project. In the past I've sourced 1000 cells, sold them, given others away, and this past week sat there looking at this box of 280 tested cells I still have. I've tried selling them locally to others on Craigslist, but no bites.
so.... I was sick of moving them around the garage so I built my 1st large pack. I've built small 3s and 4s in the past, and a 7s10p for an electric bike a few years ago, but just completed my 1st 7s40p pack.
Why 7s? I have a 24v UPS, 24v of spare solar panels (180w), and a grid tie inverter that supports 24v.
Took me a few hours of sorting, counting, soldering, and assembling, but it's done. I plan on making additional modules as I harvest/grab cells.
I used 1/4 watt resistor wires and soldered them quickly with a big-fat soldering iron (to keep the battery temps down).The cheap-o solar charge controller (shown)supports 24v setups, and stops charging cells at ~28.4v.The whole pack has a 30a in-line fuse.
I'm storing them in large plastic trays w/ voltage output via terminals in the front.
I haven't hooked it up to the UPS for any load tests, but did hook it up to a 600w grid tie inverter and it put out 440w back into the grid (I have an inter-tie agreement w/ the local utility for an existing solar setup).
We (in San Diego) are heading into our expensive on-peak period. $0.50/kwh on-peak, and $0.19 off peak. I plan on charging it during the night w/ cheap power (and a 3a 7s charger), and spitting it back in their faces mid-day.
I feel like I'm part of an elite club of lap-top battery hoarding peeps now!
BMS and cell monitor to follow. any cheap-o "made in china" options that you're using?
Long time lurker in San Diego, I've been on the fence about building one as I didn't' want to start another project. In the past I've sourced 1000 cells, sold them, given others away, and this past week sat there looking at this box of 280 tested cells I still have. I've tried selling them locally to others on Craigslist, but no bites.
so.... I was sick of moving them around the garage so I built my 1st large pack. I've built small 3s and 4s in the past, and a 7s10p for an electric bike a few years ago, but just completed my 1st 7s40p pack.
Why 7s? I have a 24v UPS, 24v of spare solar panels (180w), and a grid tie inverter that supports 24v.
Took me a few hours of sorting, counting, soldering, and assembling, but it's done. I plan on making additional modules as I harvest/grab cells.
I used 1/4 watt resistor wires and soldered them quickly with a big-fat soldering iron (to keep the battery temps down).The cheap-o solar charge controller (shown)supports 24v setups, and stops charging cells at ~28.4v.The whole pack has a 30a in-line fuse.
I'm storing them in large plastic trays w/ voltage output via terminals in the front.
I haven't hooked it up to the UPS for any load tests, but did hook it up to a 600w grid tie inverter and it put out 440w back into the grid (I have an inter-tie agreement w/ the local utility for an existing solar setup).
We (in San Diego) are heading into our expensive on-peak period. $0.50/kwh on-peak, and $0.19 off peak. I plan on charging it during the night w/ cheap power (and a 3a 7s charger), and spitting it back in their faces mid-day.
I feel like I'm part of an elite club of lap-top battery hoarding peeps now!
BMS and cell monitor to follow. any cheap-o "made in china" options that you're using?