Rebuilding my 48V 14AH 18650 Pack 13S7P to 13S8P

You have to be careful with a home made soldered battery pack and with assorted cells. Lots of soldered connections. I only say these as I have had a battery fire in my garage. A very bad thing. It doesn't need to be on fire to be a total lost. Things just melt. So be careful. Good luck.

999zip999 said:

You have to be careful with a home made soldered battery pack and with assorted cells. Lots of soldered connections. I only say these as I have had a battery fire in my garage. A very bad thing. It doesn't need to be on fire to be a total lost. Things just melt. So be careful. Good luck.

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Ah man I saw that. Permanently etched in my memory now. I'm taking every precautionary measure to ensure its a safe battery.

Made some excellent progress over the weekend! The battery is finished except for the main 10awg outlet plug that I haven't decided yet where i want to have it... Because my battery bag wasn't the correct size, I'm having to once again go back to the drawing board of how to build a battery box and i think I figured it out...so stay tuned for that.

I'm hoping I get my new charger this week. I'm really excited to get my hands on a real li-ion charger. Especially a 4A one... The tracking number doesn't work so I have no idea. The charge port is a standard 5.5x2.5mm port.

I'm thinking the battery box is going to be project board and vinyl sheets to create the box for the battery.

Well the pack is complete. Took the bike for a short little ride this am since I didn't have much time and it was freaking freezing out. Can easily ramp right up to 1450w no problem and really doesn't voltage sag much. Thanks to 59 new cells in the pack it's going to be healthy.

Something on the cheap that might work for you for your battery box is at True Value I found little black plastic garbage cans for $2.99, ones like you'd use in an office or bedroom, actually pretty nice thick black plastic that cuts with a box knife or tin snips. Making a small case out of acrylic sheet and using Dap plastic adhesive to glue the black plastic to the outside, it looks similar to black shrink wrap but is more rigid and looks pretty nice, the plastic has kind of a black matte finish, not glossy. I think it would be possible to make a case out of 1/4" plywood and cover with the black plastic stuff for a decent look, some protection and waterproofing.

I think I like the way the cut up bag is right now. It's more like a battery sleeve. Lol. I literally have to jam the battery in the bag which actually works great because then I can just attach it right to the frame.




So the charge port is hot glued in place. It's super sturdy and secured very well. Everything is insulated very well with plenty of heatshrink. Same goes for the deans output. I used 12awg wire for it which should be sufficient.

I'm really happy with the battery. It fits the bag well. It attaches to the frame quick and easy and is very secure...its got plenty of power and easily does 1000w+ no issues and barely gets warm at least for the little trek I went on.

The bms is exposed and not taped over. I like it that way because I can check the voltage of each series via the jst connector and it's also to vent any heat from balancing. I don't have my new charger yet so it doesn't really charge it full which it hasn't gone through balancing yet. Cell voltages range from 4.15 to 4.18 with most at 4.18, only 2 series at 4.15

It doesn't have good power sharing. More series links. I had battery fire. The worse thing you can do is run it to lvc or close.

999zip999 said:

It doesn't have good power sharing. More series links. I had battery fire. The worse thing you can do is run it to lvc or close.

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With my upcoming commute I won't even discharge half the battery. Heck more like 1/4. I really over did it with the battery. I figured I get around 35miles on a charge and we're talking a 4 mile commute tops...

I'm hopefully going to be starting a vlog this summer similar to kobevision on YouTube. I'll be the east coast kobevision. Lol

Batteries live happiest not at full charge and not to be drained to the bottom they live best in the middle happy ground.

Well after putting about 25 miles on the bike I think I've come up with a good solution for my battery. So the frame bag isn't big enough and I've chopped that up. It's now expanding some and the battery is starting to slide like its going to slide out and drop off on the side of the road... Since my plan is to commute a few miles then bring the entire battery with me to work, I'm just going to have it in my backpack at all times and just ride with my backpack. There won't be a time where I don't so that will be the quickest and easiest solution. The battery might get a little warmer in there but I'm only going max 2-3 miles on my commute so I'm not worried about it.

I'll have to rewire where my battery hookup is which isn't a problem and I can just plug it in while the battery is in the bag no problem. Then when I get to the metro I can just pop off the bike and lock her up without having to unstrap the battery bag every time...

I'm pretty happy with the bike. It's jumpy when I first get started and you can tell after awhile that the hub motor heats up because it's less jumpy. Either that or the batteries sag more as they warm up but I don't think they do. Went 9 miles and had the battery go from 53 to 50.2V. Not bad. Thing is gonna get crazy range

Well I'm reverting back to my original plan for a battery box. Fiberglass sounds great and light but I don't have the space and it'd likely be the most expensive option that requires the most time. A better option is to use hdpe from cutting boards and make my own box. I think this is going to be the best option and Im planning to relocate the battery down toward the bottom of the frame rather than up top near the front. That way I'll lower my center of gravity even more and it'll be slightly more stealthy. I think if done properly, I can make it look really good! Basically what I need is a compartment where I can just drop in the battery, plug in and go.

Stay tuned. Going to pick up the supplies this weekend hopefully and start to moc up the design.

After considering going the hdpe route I quickly realized I'm making more work for myself than needed. I ended up getting 4" wide 1/4" thick project wood from home depot and that is the frame of my new battery box. The side will be made with vinyl sheeting that is very ridged and thin. I will wrap the box after its complete and sealed up with a vinyl wrap so it looks decent. I will have a door on the side of it that can swing open and the battery will just side right in. The sides will be covered in textured toolbox liner to protect the battery from any impacts on the road. I'll probably have like a wing nut or something to close the door securely when I put the battery in and I'm riding. I'll have the electrical hookup right there and it should make for a very easy battery box. Then I can just leave work, put the battery in and plug it in and go. Should only take me a few seconds.