I got my present ride from Pushkar last year and as you guys know I built it up from the frame and motor. Well I wanted to build the largest Ahr Battery that would comfortably fit so I went with a 52v 10 pack and built a 34.5ahr battery.
Well after riding this bike for awhile now and it being more economical than the old BBSHD I rarely get it down to even 50% capacity after a long ride so I decided to go a little smaller, yes I said smaller, and build up a combo pack. What I mean by that is when you spot weld up these batteries you get one shot at it as you can't really tear it apart to go with a different configuration and use those same batteries without a whole lot of problems. Repairing a single battery in a group yeah but you gotta cut the jumpers to that cell and remove in place if that makes any sense. Have not had to repair any of the battery packs that I have built for myself or friends but I have wrenched on a few Luna packs where the jumper flexed and broke off or a sensing wire came loose from the solder, but I digress.
Back to the combo pack. I wanted to go smaller but not to small so I designed a 7 pack ( 24ahr ). So if after using it I find it is not sufficient enough in range I would easily be able to open it back up add another cell to each of the 14 groups thus making it a 8 pack ( 28ahr ). The original configuration would stay the same as I would just be adding cells and jumpers along the outer perimeter in such a way as to keep it compact and not change the overall shape to much. Still using the Sanyo GA batteries at 3450mahr/10a discharge and with a minimum of (10) jumpers from group to group to keep the current flow very low. Controller is limited to 30a, BMS also, so doing the math at full load 1500w I got about 30a running from group to group and ten jumpers per so it equates out to about 3a per nickel jumper so not much heat which is a killer for battery's. Typically never run a full load anyway so it's kinda mute.
Reducing the size of the battery down should save me about 6 lbs and I was 66lbs before with the larger battery. It will be interesting to see how my range compares with my buddys battery's as their's are the bigger 34.5ahr models. Battery is charging up as we speak, or type, so I will get it out on a ride here pretty quick to see if I'm a hero or a zero.
Well after riding this bike for awhile now and it being more economical than the old BBSHD I rarely get it down to even 50% capacity after a long ride so I decided to go a little smaller, yes I said smaller, and build up a combo pack. What I mean by that is when you spot weld up these batteries you get one shot at it as you can't really tear it apart to go with a different configuration and use those same batteries without a whole lot of problems. Repairing a single battery in a group yeah but you gotta cut the jumpers to that cell and remove in place if that makes any sense. Have not had to repair any of the battery packs that I have built for myself or friends but I have wrenched on a few Luna packs where the jumper flexed and broke off or a sensing wire came loose from the solder, but I digress.
Back to the combo pack. I wanted to go smaller but not to small so I designed a 7 pack ( 24ahr ). So if after using it I find it is not sufficient enough in range I would easily be able to open it back up add another cell to each of the 14 groups thus making it a 8 pack ( 28ahr ). The original configuration would stay the same as I would just be adding cells and jumpers along the outer perimeter in such a way as to keep it compact and not change the overall shape to much. Still using the Sanyo GA batteries at 3450mahr/10a discharge and with a minimum of (10) jumpers from group to group to keep the current flow very low. Controller is limited to 30a, BMS also, so doing the math at full load 1500w I got about 30a running from group to group and ten jumpers per so it equates out to about 3a per nickel jumper so not much heat which is a killer for battery's. Typically never run a full load anyway so it's kinda mute.
Reducing the size of the battery down should save me about 6 lbs and I was 66lbs before with the larger battery. It will be interesting to see how my range compares with my buddys battery's as their's are the bigger 34.5ahr models. Battery is charging up as we speak, or type, so I will get it out on a ride here pretty quick to see if I'm a hero or a zero.
