BYqSXt8Z
100 W
*sorry, some pictures aren't showing up right. The downloads are still there though*
It seems that most have completely given up on the use that stock-pressure battery holders could be used to make a decent pack, but I managed to find a quality device that seem to be up to the task. Some people have already worked on making large pressure holders, these will be more affordable for large packs, but for small test-packs, or for light-weight short-range packs (a few mile range for nearby errands or just for the hill on your commute, etc.), this method affords absolute flexibility and a decent price. It would be much cheaper to solder your cells of course, but people who are looking for pressure holders usually have very specific reasons not to do that in the first place, so there is the unavoidable added cost of using more material in a more complex setup. This also means that single cells can be popped in and out.
The Keystone battery holders (available for 18650 and 26650 cells, in single or dual holders, and with board mounting pins or larger pads; I used the dual 18650 holders with pads) are made to endure high current and temperature
Before ordering them, I did some rough calculations, and just by the volume of metal used for the contacts, over the length of the contacts, the tabbed version was the equivalent of a gauge that was more than sufficient for the kind of current I would use (~20 amp per contact/parallel string; the pack can handle way more). I'll pretty much leave it at that for the specs of the holders, if you want to know more, explore the sheets. If you want to read more on them, here is the corporate website as well as the digikey listings with spec sheets:
18350
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/18350-Lithium-Ion-Holders-and-Contacts/id/1200
18650
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/18650-Lithium-Ion-Holders-and-Contacts/id/1198
http://www.digikey.com/en/product-highlight/k/keystone/pcb-plastic-18650-battery-holders
26650
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/26650-Lithium-Ion-Battery-Holders/id/1244
http://www.digikey.com/en/product-highlight/k/keystone/26650-battery-holders
In my case I wanted a modular design when I could change s/p as wanted*, but this could obviously be used to make a "fixed" setup as well, where you just permanently solder the path you want with easy cell replacement.
*I know that normally everything should be in parallel before being in series, but in this case my goal was to make a small light-weight pack that can change format as I want. These are series in parallel, not parallel packs in series. However, to charge my packs I either do single-cell charging, or 3s1p (36v) charging with my bulk charger and battery medics (possibly a BMS to come in the future). For now I will be monitoring the cells.
In this case, I set up my batteries in 12v packs with Anderson terminals, by connecting the terminals in different ways, I can get the many configurations
where each unit is a 4s sub-pack;
Here is the sub-pack:
The wiring is made so that I can join the packs as I want. Series is acheived with direct connections, parallel segments with an aditional harness.
Here is the Harness:
Here are the configurations with some pictures (no necessary for all, I only put a few)
12v: 1s up to 6p
24v: 2s up to 3p
36v: 3s up to 2p
first without harness
now harness half attached
48v: 4s
60v: 5s
72v: 6s
I then use my connector to bridge my battery to my power input, and in the process create the parallel packs as wanted.
Now waiting for my shrink wrap to go test this (don't want a short!) *minor update, got my shrink wrap, was sent the wrong size. Second time from a second vendor! Let's hope 3rd time's the charm!*
It seems that most have completely given up on the use that stock-pressure battery holders could be used to make a decent pack, but I managed to find a quality device that seem to be up to the task. Some people have already worked on making large pressure holders, these will be more affordable for large packs, but for small test-packs, or for light-weight short-range packs (a few mile range for nearby errands or just for the hill on your commute, etc.), this method affords absolute flexibility and a decent price. It would be much cheaper to solder your cells of course, but people who are looking for pressure holders usually have very specific reasons not to do that in the first place, so there is the unavoidable added cost of using more material in a more complex setup. This also means that single cells can be popped in and out.
The Keystone battery holders (available for 18650 and 26650 cells, in single or dual holders, and with board mounting pins or larger pads; I used the dual 18650 holders with pads) are made to endure high current and temperature
Before ordering them, I did some rough calculations, and just by the volume of metal used for the contacts, over the length of the contacts, the tabbed version was the equivalent of a gauge that was more than sufficient for the kind of current I would use (~20 amp per contact/parallel string; the pack can handle way more). I'll pretty much leave it at that for the specs of the holders, if you want to know more, explore the sheets. If you want to read more on them, here is the corporate website as well as the digikey listings with spec sheets:
18350
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/18350-Lithium-Ion-Holders-and-Contacts/id/1200
18650
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/18650-Lithium-Ion-Holders-and-Contacts/id/1198
http://www.digikey.com/en/product-highlight/k/keystone/pcb-plastic-18650-battery-holders
26650
http://www.keyelco.com/category.cfm/Holders-Plastic-PCB/26650-Lithium-Ion-Battery-Holders/id/1244
http://www.digikey.com/en/product-highlight/k/keystone/26650-battery-holders
In my case I wanted a modular design when I could change s/p as wanted*, but this could obviously be used to make a "fixed" setup as well, where you just permanently solder the path you want with easy cell replacement.
*I know that normally everything should be in parallel before being in series, but in this case my goal was to make a small light-weight pack that can change format as I want. These are series in parallel, not parallel packs in series. However, to charge my packs I either do single-cell charging, or 3s1p (36v) charging with my bulk charger and battery medics (possibly a BMS to come in the future). For now I will be monitoring the cells.
In this case, I set up my batteries in 12v packs with Anderson terminals, by connecting the terminals in different ways, I can get the many configurations
where each unit is a 4s sub-pack;
Here is the sub-pack:
The wiring is made so that I can join the packs as I want. Series is acheived with direct connections, parallel segments with an aditional harness.
Here is the Harness:
Here are the configurations with some pictures (no necessary for all, I only put a few)
12v: 1s up to 6p
24v: 2s up to 3p
36v: 3s up to 2p
first without harness
now harness half attached
48v: 4s
60v: 5s
72v: 6s
I then use my connector to bridge my battery to my power input, and in the process create the parallel packs as wanted.
Now waiting for my shrink wrap to go test this (don't want a short!) *minor update, got my shrink wrap, was sent the wrong size. Second time from a second vendor! Let's hope 3rd time's the charm!*
