My excellent adventure through some battery builds

Batteries, Chargers, and Battery Management Systems.
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ElectricGod   10 MW

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 30 2016 1:33pm

15 miles today...not riding hard (25-35mph) and hardly no stops...76 volts...:):):):)

A cop rode next to me for .5 miles too. I made sure I wasn't going full out. 40mph might have gotten his attention. There's an advantage to riding something diminutive that doesn't look fast...the cops don't think you can be fast either! HAHAHAHAHAHA!!!
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Re: My excellent adventure through some battery builds

Post by 999zip999 » Mar 31 2016 1:27am

13 miles in 40 min is like 20 mph. I meet a guy with one of those scooters and he went 25 mph in the pack the cops made him slow down. As I on a ebike was left alone at 30mph. At 40mph they be chasing you down. Where you live ?

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 31 2016 5:18pm

999zip999 wrote:13 miles in 40 min is like 20 mph. I meet a guy with one of those scooters and he went 25 mph in the pack the cops made him slow down. As I on a ebike was left alone at 30mph. At 40mph they be chasing you down. Where you live ?
Yeah...that's average speed. Sometimes I was stopped at lights for 5 minutes and other times cruising along at 15 or 25 and others 40. I didn't do 40mph all the time...just in bursts where it was acceptable.

I guess it depends on the cops??? The cops around here have completely ignored me so far. I watch for them (obviously) and most of the time I'm riding through neighborhood streets. When on the main roads, I'm always watching for them. On the neighborhood streets I almost never see any cops. Hmmm...maybe I should get a radar detector for my scooter! ;9
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Apr 01 2016 10:20pm

I'm sure anyone keeping up with this thread would like to hear about my used battery build. Acceleration was finally dropping off a little the last few miles, but 35-40 mph was still doable...it just took a little longer to get there. I still kept up with traffic. After 25 miles on one charge I was down to 65 volts. That's low enough, but I'm pretty sure I could have gotten another 5 miles out of it on the one charge. I checked every cell in the scooter on my celllog8 and found 6 18650s that were 3.2 volts or lower. Every other cell was reading 3.4-3.7 volts. I have 20+ spare 18650 laptop cells that I already tested and are 1950mah or better. With everything in battery holders it's so easy to replace a weak cell...or 6. Anyway, 6 good cells are now in place of the weak ones. I'll test the weak ones to determine their current mah, but frankly I don't care what it is. They wont get used in the scooter again. I have yet to see any cells work loose from their holders and there is no evidence of overheating issues. I have to say the battery holders are working very well with no failures. On general heating of the battery box, it was 80F inside the battery box when I got home. That's so not a problem!

If there is anything I would do differently, or add it would be to add a couple of strips of 1/8" plywood to the tops and bottoms of each 20S2P pack to make them more rigid. Each pack weighs several pounds with 40 cells in it and that's a lot of weight to hold together with just superglue and a few solder connections. Otherwise, these battery holders work great.

How many people do you know that have 36,000mah or more in 280 18650's that cost them $300 and most of that was spent on battery holders and wiring? In my opinion, the used laptop battery build-up I did was really worth it! For something that needs lots of compact power, this might not be a good solution since the battery holders take up extra space and laptop cells are pretty much 1C only and since 90% of the cells are all used, they wont have the charge density anyway of a bunch of new samsung 31Gs. If you want cheap or virtually free and those things don't matter so much to you, well then this is a superb solution to get lots of wattage for next to no money. I will definitely use battery holders and used laptop batteries anywhere I can in the future.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Apr 15 2016 8:22pm

I let my charge level get right down to the wire today...60 volts under load...power got kind of saggy towards the end. With no load, voltage would bump up to 65-68 volts and then with a few amps of draw, drop back down to 62-64 volts. Just to see what would happen, I cranked the throttle at 60 volts and voltage dipped to 53 volts until I backed off again. OUCH! Acceleration from a stop was generally sluggish, but once I got going I pulled hills just fine. Top speed was obviously lower than normal. I maxed out at 28mph which was still pretty good. I checked my used laptop batteries and found 4 more weak ones which I replaced in a few seconds time. I'll drop a BMS on everything LION now. I've probably found all the weak ones now. Everything left is doing 2000mah or better.

My used laptop batteries are working pretty well in my opinion! Maybe not as good as brand new High C cells, but for the price (free)...pretty damned good!

My co-workers see me ride into work every day. Most of them are at least basically aware of how electronics work and that an EV is going to draw some serious current. It's not uncommon that I get asked how I was able to afford all the batteries needed. I laugh and then brag that I'm running on used laptop batteries. There's several guys that are EV'rs at work. They love the idea of free batteries running my scooter. This isn't an ideal solution, but hey the cost (free) really makes it compelling.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » May 17 2016 6:35pm

For anyone that cares...

The laptop batteries are holding up very well. I'm sure I could get the same capacity with less weight if I was willing to spend $1200 for EV cells, but mine are free and the weight is a small price to pay for no cost batteries.

I developed a minor problem with my 20S packs. Vibration caused several of the glue joints to break. The battery packs are all trapped inside the battery box so nothing truly came apart or stressed any wires. I cut 15" long strips of 1/8" thick plywood and used silicon caulk to glue them to the tops and bottoms of the packs. I only had 3 sections break apart so that's not so bad considering that there are 35 joints that could have broken apart. Between the superglue in the joints and the wood strips, it will take a lot more than some minor vibration to get them to break apart now. The packs sit a little bit more tightly in the battery box, but they have foam tape on top and bottom that was taking up the slack already. Now it gets compressed a little more...no big deal.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Jun 06 2016 2:17pm

Its been a month since I posted here last...

The laptop batteries are still holding up well, but my mounts over the back wheel for the battery box keep breaking. There's a lot of weight over the back wheel and the tire is the only thing that absorbs any of the shocks of going over a curb or bumps in the road. The entire platform is made of wood to keep it light. I'm going to replace the mounting arms with aluminum ones and then support the platform in 5 places rather than 3. I'm also going to eliminate a single 20S2P pack to get the battery box almost 3" narrower and save me 10 pounds of battery weight. This essentially means making a whole new battery box and platform. Ah well...live and learn! The original platform was never intended to carry that much weight all the time anyway so the fact that it has broken a few times now is no surprise.

The addition of the long strips of wood to the tops and bottoms of each 20S2P pack completely solved the super glue joint failure issue. The packs are long and narrow and heavy which is why the joints failed a few times. The wood strips stiffened the packs sufficiently that the glue joints can no longer be stressed.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Jun 07 2016 11:17am

I have made new support arms out of aluminum angle and new support blocks that mount under the battery box that attach to the support arms. There's also an adapter block that bolts to the old wheel well bracket parts. I made a new one out of wood that is beefier than the previous one and is centered over the scooter more. The previous setup was centered over the back wheel which sits about 1" closer to the left side of the scooter. Hopefully with the platform centered over the scooter, damage to the one side that used to over hang more will be alleviated. The support arm on that side broke 3 times and the other side once. Of course with the aluminum arms, that should no longer be an issue at all. I got everything assembled on the old platform and I was impressed how much stiffer the whole back deck is now. There's no side to side flexing anymore. Apparently I should have used aluminum a long time ago! I also went with larger mounting screws. The old screws were 8/32 and now they are 10/32.

The new battery box wont bolt to the original platform anymore. It will be the new platform and the box will have a hinge on it and several screws to secure it shut. I'll use a piano hinge under one of the sides to pivot from and then the other side will have several security torx screws holding it shut. Later if I go to a different battery solution (all new LION cells meant for EV use) and put them in the battery bay, well I will still have a secured box for carrying things.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Jun 21 2016 7:36pm

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Jul 21 2016 8:11pm

It's been a month since I posted here...

I noticed a drop off in battery run time last week. I pulled the LION packs and checked all the cells and found that 7 cells had died across the 6 battery packs. One can say that I was really relieved that they were in battery holders so that replacing them was quite easy. Otherwise I would have been taking apart spot welded packs to replace the bad cells. I know the battery holders take up more space than the same cells spot welded together, but since I'm running on free, used laptop cells and there's hundreds more to replace the ones that die, well I'll take the losses of extra space every day of the year!

I can safely say that taking the time when I see capacity drop off a little to replace a few free but dead cells is still working out wonderfully well. All I can say is BUILD SOME BATTERY HOLDERS FOR YOURSELF AND SCROUNGE LAPTOP CELLS!!! This is a lovely solution that costs me virtually nothing to use. Oh yeah...I forgot to mention that besides motor cycles and fast cars no one accelerates faster than me. From a dead stop I am most of the time the fastest thing on wheels! Gotta love that it costs me almost nothing to do too.
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Re: My excellent adventure through some battery builds

Post by 4LivesPerGallon » Jul 26 2016 10:59pm

ElectricGod wrote:It's been a month since I posted here...

I noticed a drop off in battery run time last week. I pulled the LION packs and checked all the cells and found that 7 cells had died across the 6 battery packs. One can say that I was really relieved that they were in battery holders so that replacing them was quite easy. Otherwise I would have been taking apart spot welded packs to replace the bad cells. I know the battery holders take up more space than the same cells spot welded together, but since I'm running on free, used laptop cells and there's hundreds more to replace the ones that die, well I'll take the losses of extra space every day of the year!

I can safely say that taking the time when I see capacity drop off a little to replace a few free but dead cells is still working out wonderfully well. All I can say is BUILD SOME BATTERY HOLDERS FOR YOURSELF AND SCROUNGE LAPTOP CELLS!!! This is a lovely solution that costs me virtually nothing to use. Oh yeah...I forgot to mention that besides motor cycles and fast cars no one accelerates faster than me. From a dead stop I am most of the time the fastest thing on wheels! Gotta love that it costs me almost nothing to do too.

What's the fire-protection in this build?

There's been many fires for this type of build.

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Re: My excellent adventure through some battery builds

Post by Wheazel » Jul 27 2016 2:45am

How are the 18650 holders working for you? Any problems with them?
Do they increase pack resistance a lot?

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Aug 01 2016 1:27pm

Wheazel wrote:How are the 18650 holders working for you? Any problems with them?
Do they increase pack resistance a lot?
No significantly noticeable pack resistance increases. I pull 50 amps off of 12P used laptop cells. They get a little warm as expected, but the battery holders have been solid. The cells can slowly rattle loose of the battery holder if the cells aren't trapped inside the holders, but that's the worst of it. My battery packs are packed together sufficiently well that there is minimal gaps between packs and so the cells never get a chance to come loose. If you are building from new EV grade cells, I wouldn't necessarily suggest this solution as spot welding all the cells together is more efficient space wise, but in the case of used laptop cells wher eyou will get a few cell failures from time to time, well this is a great solution. Since I started using this solution I have had 14 or 15 cells die out of 280...all of which are used laptop battery packs scrounged for the 18650s. Considering that I have no idea what the ages are of the cells and I am using them in a non-recommended configuration, well I can't complain too much. Laptop cells are usually 1-4C discharge and I'm obviously pulling 4C all the time, they are holding up quite well. The best I can really do is charge/discharge/charge all the cells and then look for the ones that won't charge to 4.0+ volts or have low capacities. Those ones get used in flashlights or other things, the ones that fully charge get used to power my scooter. The battery holders I built are longish so reinforcing the pack so it doesn't flex is helpful. A couple of my original glue joints between holders have come apart over time, but then I added a 1/8" thick strip of plywood to the tops and bottoms of each pack and that took all the flex out of the packs and they never come apart anymore.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Aug 01 2016 1:31pm

4LivesPerGallon wrote:
ElectricGod wrote:It's been a month since I posted here...

I noticed a drop off in battery run time last week. I pulled the LION packs and checked all the cells and found that 7 cells had died across the 6 battery packs. One can say that I was really relieved that they were in battery holders so that replacing them was quite easy. Otherwise I would have been taking apart spot welded packs to replace the bad cells. I know the battery holders take up more space than the same cells spot welded together, but since I'm running on free, used laptop cells and there's hundreds more to replace the ones that die, well I'll take the losses of extra space every day of the year!

I can safely say that taking the time when I see capacity drop off a little to replace a few free but dead cells is still working out wonderfully well. All I can say is BUILD SOME BATTERY HOLDERS FOR YOURSELF AND SCROUNGE LAPTOP CELLS!!! This is a lovely solution that costs me virtually nothing to use. Oh yeah...I forgot to mention that besides motor cycles and fast cars no one accelerates faster than me. From a dead stop I am most of the time the fastest thing on wheels! Gotta love that it costs me almost nothing to do too.

What's the fire-protection in this build?

There's been many fires for this type of build.

https://endless-sphere.com/forums/viewt ... 35&t=79539
That's a burnt LIPO pack...not LION so already the fire resistance is better in LION. I've run my packs pretty hard a few times and they get warm, but nothing close to catching fire. Notice how there was no BMS in that skateboard. He was able to run that LIPO pack way hard and well below it's lowest voltage. So yeah...it got way hot and started to burn. Just keep your packs on a BMS and that solves lots of problems. Also, that was one tiny pack pushing a human around. It was running at full amperage all the time. That generates a lot of heat all by itself. More packs in parallel shares the load so none of them get hot.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Aug 25 2016 8:31pm

It's been a while since I posted on this thread. Well it's been a great day. My IT guy at work handed me a cardboard box today full of these. YEAH!!! More free batteries!!! Are the cells as reliable as an expensive 18650 that has a 5C discharge? Nope...sometimes a cell dies, but then I'm riding on 100% free batteries so I really don't care very much if I lose one now and then. It will take a few hours to take these packs all apart and harvest the cells, but I don't really care that much since they are free and probably 80% or more good cells. I have yet to take apart a Dell or Lenovo pack and not found Sanyo or Samsung or some other name brand cell inside. I love my free batteries!!!

Image
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Sep 06 2016 1:54pm

I've now taken apart all those battery packs and preliminary testing of the cells is pretty good. About 30% of the cells wont charge to better than 3.9 volts. As an initial test, I consider them to not be usable for EV purposes since they already have significantly reduced capacities. They will serve well for flash lights and other purposes. I have probably 50 or 60 cells that wont charge to a minimum of 3.9 volts. There were 6 cells that were completely dead and would not charge at all. There were no cells that charged that did not at least charge to 3.7 volts (good enough for goverment work!). Then there is 200-300 cells that charged to 3.98 volts or higher. I have no idea how many cells I really have that are currently in the "good" pile, but it's a lot! The next step is to load test the "good" cells and cull out the ones that fall below 2000mah. Anything above 2000mah will go into a new scooter I am building. Anything else will go into my existing scooter as replacements for the occasional dead/weak cell that pops up. So far, I have to say, this was a spectacular harvest. I've looked up the cells I have gotten and the vast majority are LG cells that are good for 2C discharge at 2800mah. There's some Samsung, Sanyo and others, but all are 2600mah or better with 2C discharge.

BTW...
Each Dell battery pack had 12 cells in it. I had 6 or 8 Lenovo packs that were also 12 cells and then 5-6 packs that were 4 to 9 cells each.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Sep 09 2016 2:13am

This is my total supply of used but good laptop cells waiting to get used in something.

Image
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Re: My excellent adventure through some battery builds

Post by BeachRider2016 » Sep 12 2016 8:40am

Been reading through your posts, very efficient way of building the pack. I might build one this way to closely monitor/change out bad cells.
How do you make the battery holders? or where to buy them?

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Sep 12 2016 11:39pm

BeachRider2016 wrote:Been reading through your posts, very efficient way of building the pack. I might build one this way to closely monitor/change out bad cells.
How do you make the battery holders? or where to buy them?
First off...this is a shout out to me...LOL and my 500th post. Damn...didn't know I was that prolific!

OK...so to your question.

I originally found the battery holders on ebay. Just search for 18650 battery holder and you will find them. There are some lesser quality ones and better quality ones. Get the ones in my pictures, they are the better ones and hold up very well. My battery box fell apart some time ago and as a result all my battery packs went spilling all over the road. A couple were skinned up and a few glue joints came apart between the 4 cell holders, but that was the worst of it. I stopped of course and picked up my battery packs and kind of pulled it all together with a ratcheting strap I carry with me. I had never intended to use it to hold my battery box together, but it worked well enough to get me 5 miles back home. I reglued the broken glue joints and made a much better battery box that has held up really well. These battery holders have held up despite the daily abuse of being over my unsprung back wheel for close to a year now.

If you read through the build process you can see how I built up the individual battery holders into a 20S2P pack.

Later I found the holders elsewhere for much less money. Talk to this person in China. They sell batteries all over the world and are quite reliable and trustworthy. I will be buying from them again. And yes she goes by the name Ms. Little Bear. They also sell 18650's in whatever kind you want.
littlebear@cl-rd.cn
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Sep 20 2016 2:38pm

The new battery holders arrived yesterday from China. Ms Little Bear was very helpful and shipped via DHL. It took just a couple of days to arrive once I paid. I'll soon be building 24S2P battery packs. I have the connectors and wire already, it's just a matter of getting the assembly done. These battery packs will be a lot harder to assemble since there will be two stacks of battery holders and the cells will snake back and forth in each pack to make up the 24S arrangement.
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Re: My excellent adventure through some battery builds

Post by wayover13 » Sep 20 2016 3:42pm

Interesting thread. Not working in IT, I don't have a source for free, cast-off laptop batteries. I'm also not real well versed in electronics. But I like the concept of, not just free, but of making good use of materials others just want to get rid of. Yet my main question in posting here is, why can't I see any of the images embedded in your posts? That seems a really crucial element--especially for someone not terribly savvy in the electronics area--to understanding your project(s).

Addendum: ummm, weird. I was logged into the forum already when I started reading this thread, but it was only after I'd made this post that the images in this thread actually showed up. A misconfiguration in the forum's settings, perhaps? Anyway, I can now see the embedded images, so disregard that part of my post.
Minimalist-assist advocate. Minimal assist means only enough to ease some of the physical strain the rider must output to propel the bike at or near more typical unassisted cycling speed. Such assist usually plays no role in increasing the bike's top speed, being brought into play mostly when facing challenging terrain (steep uphill grades) or weather conditions (strong headwinds). Assist may remain completely disengaged for large segments of any given ride.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Sep 20 2016 4:56pm

wayover13 wrote:Interesting thread. Not working in IT, I don't have a source for free, cast-off laptop batteries. I'm also not real well versed in electronics. But I like the concept of, not just free, but of making good use of materials others just want to get rid of. Yet my main question in posting here is, why can't I see any of the images embedded in your posts? That seems a really crucial element--especially for someone not terribly savvy in the electronics area--to understanding your project(s).

Addendum: ummm, weird. I was logged into the forum already when I started reading this thread, but it was only after I'd made this post that the images in this thread actually showed up. A misconfiguration in the forum's settings, perhaps? Anyway, I can now see the embedded images, so disregard that part of my post.
There is a possibility that a few pics are gone. Photobucket glitched on me a while ago and I had to re-upload a bunch of pics. AS a result the links in some of my threads don't have all the pics anymore.

I've been scrounging laptop batteries for quite a while now. I bet if I went to a recycled computer place, that I could get their laptop batteries. It's going to be a crap shoot no matter what. Sometimes you get good cells, sometimes you don't, but they are uber cheap either way so who cares. Whatever you have that's dead, recycle so the lithium gets recovered.
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ElectricGod   10 MW

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Oct 03 2016 7:27pm

I'm starting a new battery holder build. I have the 18650's, battery holders and wire. Now it's time to get these things made into packs. These packs will be 12S each, but will run two of them in series to get 24S.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Oct 13 2016 10:26pm

I know, I know, this isn't really a battery build, but this is my battery thread so I figured I would post my latest acquisitions here. I got 7 of the 10,000mah packs for $45 each and the other 6 for $40.79 each. The 16.000mh packs were $74 each for 10 of them. All in all a good deal. These batteries will go in my moped and a small kick scooter project.

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Last edited by ElectricGod on Aug 30 2017 5:17pm, edited 2 times in total.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Oct 23 2016 9:07am

I kept threatening that I would get back to another battery holder build. I finally did and made a couple of different kinds. Unfortunately. I neglected to take any pictures while building this first one, but it's not rocket science. Each 3 cell holder has all 3 cells in parallel. The end of one holder is hot glued to the next holder until I have 4 in a row. I made two sets of them. Then I used some 14 awg transformer wire from a failed motor wind and soldered it to the solder tabs between two battery holders. This connected the first holder to the second holder as well. I made lengths of wire that are a little more than 2X the length of the battery holder solder tabs. Once I had one side completely soldered together. I then did the other side. That left a small gap between the two halves of the pack. I then folded the wires over so that the two halves were back to back. That gave me two sets of 12 cells each per side. I then soldered the bottom ends of the 14 awg wire together and pinched the bent in half parts together. A few more bits of soldering onto the folded over section of the wires for balance wires and I was nearly done. Then came some 14awg silicon wire for the battery leads. A little hot glue to secure things in place and it was finished. I've been running this battery holder for 24 hours at least now. I made a small load tester out of some old blow drier parts. I didn't have a way to load test all the used laptop cells I have until I scrounged one up from old blow driers. This battery holder worked exceptionally well with the load tester and allowed me to test 24 cells simultaneously. Of course I can also charge 24 cells at the same time too. I put my celllog on the balance port and watched for cells to reach 3 volts. Once that happened, I quickly pulled all the cells out of the holder and checked their individual voltages. Invariably, One set would run down faster than the others in the 4S series. Whatever ran down first to 3 volts was when I stopped the test. What I noticed is that despite their being 6 cells in parallel times 4 in series that a weak cell could be found anywhere in the pack when I checked them one at a time. As a result, the cells that had lower than average voltage were obviously the weak ones. The rest I considered to be "good". I have culled probably 30 cells from the several hundred I have. I'll pull my 20S2P packs out of my scooter and load test them too. I'm curious to see how many have gone bad...if any.

This pack is 4S6P.

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This battery holder is 6S6P. It's the prototype for the 24S packs for my moped build. I started out with 3 battery holders and hot glued them end to end into a long strip. Then I made 3 more strips. Then I took 2 of them and hot glued their long edges together...times 2. That gave me my two halves. I was wondering how I was going to connect those inner solder tabs to anything and then came up with a foldable interconnect. I soldered the long "leg part" to the individual tabs in the sets of 3 cells. Then once all 4 sets of interconnects were done, I collapsed the whole thing at those large bends. I had to flatten out the bend a little to get the two halves to close up, but it worked very well and since I made sure all my solder joints internally were well flowed and not starved for solder, nothing broke apart. Once it was all collapsed together, I soldered the folded part together and the exposed end solder tabs.

This is the interconnect part. I made 6 of them in case I screwed one up, but that didn't happen.

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A couple of views between the two halves before I collapsed them together. The top half and the bottom half are on separate interconnects that don't meet in the middle. There's about 1/2" gap between them. They can't short together in the middle of the pack.

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This is the " back end" of the pack where the top row connects to the bottom row to make the 6S series.. That scuffed up 14 awg transformer wire sure came in handy for making interconnects! The extra long end was later bent over and buried in hot glue between the two halves after I soldered a balance wire onto it.

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This is the battery lead end. I later shortened those ends by a good bit. When I made these up, I didn't really know how long I should make the ends for attaching the battery wires.

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With all those batteries going back and forth in the pack and on both sides, it would be easy to lose track of which way a cell should go and create a dead short. Every slot in every battery holder is labeled. 2 batteries dead shorted end to end would be a very bad thing! More than likely, it would be 6 batteries with one of them backwards. How long would it take for that single cell to go thermonuclear?

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And the final product...complete with an XT60. Some of the balance wires are longer than others, Any slack was stuffed back inside between the two halves and then hot glued in place so they can't move. At every solder connection for the balance wires, I hot glued them in place too. I suppose if you pulled hard on the balance cable you could pull it loos, but it's buried in quite a lot hot glue. Same for the ends of the battery leads after I closed them up in heat shrink. I've got 36 18650s charging in this battery holder right now. Assuming 2600mah per cell and there are 6 in parallel, well that's 15.600mah times 6 sets in series or 93,000mah. This thing is going to take a good while to charge up! I maxed out the charge current on my balance charger, but it will still run for hours.

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Last edited by ElectricGod on Aug 30 2017 5:29pm, edited 1 time in total.
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