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    Forming a battery around a cylinder

    That's a good point. I should do the math on this. I haven't purchased any of these systems yet, but a fair number of users have reported that they can feel their wheels wobbling/shimmying from the imbalance. Also this has the effect of limiting the pack size because larger pack sizes will...
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    Forming a battery around a cylinder

    So I haven't done the math on that yet. Some of the more popular wheel lights on the market use 2-3 AA batteries. I'm not sure if they are running in series or in parallel. In series that's 3.0-4.5 V, capacity of 2.5 Ah (7.5-11.3 Wh). In parallel that's 1.5 V, capacity of 5-7.5 Ah (also...
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    Forming a battery around a cylinder

    Are there any batteries on the market that would be able to wrap 360 degrees around a cylinder? Or for that matter, any fairly thin batteries that could comply to a curved surface without being damaged? Can any sufficiently thin LiPo cell do this, or do they have to be specifically designed for...
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    BMS wiring help

    So I wired it up as pictured - I am able to pull power to drive the load (my ebike motor) no problem, but when I try to charge the pack, my charger is not working. I tried removing the load from the parallel (so it is just the charger hooked up to the battery+BMS), and still the same result, no...
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    BMS wiring help

    Hi guys, just wanted to double-check before I wire this up - does this look correct? Does the load really go in parallel with the charger? Meaning that all of this can be left connected while the battery charges, and there is no need to disconnect the load? Thanks.
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    Homemade Battery Packs

    I've been monitoring the pack voltage and it has stayed constant since I built it... I'm probably going to proceed with wiring it up to my bike tonight. Edit: Successful first ebike build (for now) and ride! :) Now I need to figure out how to wire the charger tomorrow (maybe after I figure...
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    Homemade Battery Packs

    Sorry that was a pretty vague/dumb question of mine. I checked the wiring diagram for the BMS, and I now understand how it is wired, but I think I have a problem - my 13S BMS has only 13 balance wires whereas its wiring drawing indicates 14. And any BMS should have N+1 balance wires (where N is...
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    Homemade Battery Packs

    Cool. Went ahead and did that. I'm going to go ahead and make all the series connections next. Do I need to be careful about how I connect my BMS? I'm going to do that after everything is connected in series.
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    Homemade Battery Packs

    Hi guys, I've assembled my parallel groups of 18650s and am about to connect them in series (with redundant series connections). Do you think any kind of padding material between cells is needed, or is it okay to have them in a tight staggered configuration? I intend to go easy on these cells...
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    Homemade Battery Packs

    This is how I'm going to lay the pack out, if I proceed with soldering. Both series tabs and parallel rails will be tinned copper braid.
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    Homemade Battery Packs

    Hey DrkAngel, After attempting this, I realized I have questions about the process: Are both the solder bead on the cell and the solder bead on the braid facing up? Meaning that they do not touch? And you are pressing the solder iron onto the solder pre-applied to the braid, which then in turn...
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    Homemade Battery Packs

    I would use solder in a heartbeat if I didn't think the heat would damage the cells. That would be a much better build. But how do I do it without frying my cells?
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    Homemade Battery Packs

    Those pictures were taken by me - that's how I did it. It's just cut up 35 mm bike tube for the bands, and duct tape to hold the bands in place. Also, what sort of magnets? Neodynium? Cool solution but may be quite pricey (or unpredictable? I'd be worried about them causing havoc)
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    Homemade Battery Packs

    Hey DrkAngel - I like your idea, I think I do just need some kind of bridging material like you described. The batteries have a protrusion the positive end, and that end seems fine, but the negative is slightly concave with the green outer wrapping and that is the side I'm concerned about - so I...
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    Homemade Battery Packs

    Hey guys. I posted about my proposed build back in May, and got very sidetracked and never started on it. Well, I've finally started. I put together my first parallel group and... well, I'm questioning my whole design altogether. I'm not sure if there is enough compressive force from the rubber...
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    Phone LiPo that has reached ~5% charge over 8 mo storage

    I've fully charged & discharged it without any issues (which I'm sure is of no surprise to anyone, I just wanted to conclude this thread). The battery capacity is meager, but it always was.
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    Phone LiPo that has reached ~5% charge over 8 mo storage

    I thought storage at 40-80% SOC was ideal, and that going outside of that in either direction caused problems (that accumulate over time). I guess I need to read more.
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    Phone LiPo that has reached ~5% charge over 8 mo storage

    That information is just based on the battery charge indicator the phone shows when plugged in. I'm sure it has a BMS, being a not-terribly-old Motorola phone. I wanted to be cautious because I don't know how battery damage due to time spent at low SoC works, or if passive discharge can...
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    Phone LiPo that has reached ~5% charge over 8 mo storage

    I have an old Droid Mini phone (w/ integrated LiPo battery) that has been collecting dust for 8 months & that I was considering reviving temporarily for a friend whose phone broke. Unfortunately, I have let the battery waste away to 5% charge. Could it potentially be dangerous to charge/use this...
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    Batteries for "dumb"

    "Read the forum" can answer all questions, but that's like saying "read the encyclopedia" (times ten).
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    Homemade Battery Packs

    Check out this thread, then, which is where I found the idea: https://www.endless-sphere.com/forums/viewtopic.php?f=14&t=59758&start=25 It's the perfect design for me because it's easy to take apart without destroying the pack (although you'll probably need new shrink tubing), and it allows me...
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    Homemade Battery Packs

    Going back to this. This is a really nice layout. I didn't really realize that it was even possible to lay the pack out like this, and I still don't know a lot about this, but this seems as "optimal" as possible as far as how things are connected. But I'm fairly committed to imitating the...
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    Recycled 18650 testing - new method - more info.

    When you connect cells in series & parallel when you're initially building the pack, what's the rule of thumb for the max acceptable voltage difference? I've confirmed that my charger will charge all cells to within +/- 0.005 V.
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    Recycled 18650 testing - new method - more info.

    So apparently my charger is CC/CV. It's just misleading because it displays the CC setting (options are 0.50 A or 1.00 A) even when it reaches CV mode. Not thrilled that I bought it (when the manual is 2 tiny pages in broken English, you've probably f'ed up) but I'm going to at least attempt to...
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    Recycled 18650 testing - new method - more info.

    I am well aware of what cells I have. But I did not know if they were all from the same production lot, or how long ago they were manufactured. I had assumed that the cells were unbalanced and that I would have to charge them. My bulk charger was still in the mail, and I had that time to charge...
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