My excellent adventure through some battery builds

Batteries, Chargers, and Battery Management Systems.
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My excellent adventure through some battery builds

Post by ElectricGod » Feb 02, 2016 3:45 pm

I originally was on another thread asking about the best LIPO R/C packs. I was already running at 48volts on 4 8000mah LIPO packs that I had built from individual cells. They had worked reliably and I have had a single minor problem with one cell. I figured since I was wanting go to 72 volts that I would stick with LIPO and use R/C packs. Before long several megawatters were on the thread and making suggestions. One person posted a link to another thread for a hybrid LIPO/LION battery solution. I hadn't considered the option since I was going to upgrade to more LIPOs. I am a scrounger by nature and keep things that lots of folks throw out. One of those scrounge-able items is laptop batteries. Rarely are all the cells in a battery pack bad. Usually its more like 30-60% are bad and the rest of the cells are still good. I've been collecting discarded laptop packs for a long time and as a result have been powering flashlights and other things with used 18650's for a long time. When the hybrid option was presented to me I had about 50 cells that were all good cells. I got to thinking about it more and quickly realized I could use all those cells and many more to supplement my LIPOs to get me to 72 volts without the huge sticker shock and hole in my wallet that all new batteries were going to cost. I have spent about $130 on 18650 battery holders, balance cables, wire and misc items to make myself seven 20S2P LION battery holders. Below is the saga...

If you go here and to page 7, you get to more or less the start of the battery build stuff that evolved on the HK thread...or just ignore that and read this new thread. all the important details are here.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 02, 2016 6:29 pm

A little about me...
In 1985 I went to college for an EE degree. While in school, I discovered I liked working on computers more than I liked designing electronic circuits. Several jobs and years later we get to now and I have never worked a minute as an electrical engineer, but many years in IT and software development. Electronics has remained a constant hobby through all those years. When other kids my age were trying to figure out how to put D batteries in their flashlights, I was playing with transistors, 555 timers and TTL logic gates. I can't tell you how many electrolytic caps I have blown up or how many IC's I've let the magic smoke out of...but it's been a lot! I should be dead 12 or 15 times over from electrocution fiddling inside live TVs, heaters, microwave ovens and other things as a 10 year old!

Admittedly I am new to EV, but all the components that make up an EV have been with me for many years. When young teens were trying to convince their parents to let them get a drivers permit, I was buried in building H-bridges and motor drivers and doing things that modern cordless tools do all the time. There were 4 things on my bench in my dads basement that I considered invaluable. I found a 50 pound transformer somewhere that had like 10 secondary windings on it. It was a goldmine of voltages to me. I wish I still had that beast! My dad scrapped it out for the copper...what an idiot! I had an uber old soldering station I got from HP and an analog volt/amp/ohm meter. With those few things I knew I could invent cold fusion and artificial intelligence. Well I've eaten my fair share of preservatives and who knows what over the years so I'm partly artificial by now and I'm writing this thread so I must be slightly intelligent. I think I have come a good long way in the AI field. Cold fusion on the other hand has still got me stumped. I just can't figure out where the string cheese goes!!!

On to the battery build...
I bought a 48 volt electric scooter online from a guy in Florida. His customer service completely sucks. His follow through on orders could be magnitudes better to just get to marginally lousy and his ability to take criticism when he screws up (which is all the time) is absolutely non-existent. If you ever want to buy from hyperpowersports...just look on alibaba or elsewhere. He has cool products and the build quality of the Chinese scooters he sells are not overly bad. It's pretty much the company and the owner and his employees that make buying from him a bad experience. Before I ever had the scooter I was going to buy, I already had planned out what I was going to do to it. So far, most of those things have happened or are in process. If you have ever bought chinese products, then you know that product quality can be lacking sometimes. My greatest concern was that the frame, wheels, brakes and structure were sound. The electrical and electronics to me were 100% replaceable. The only original wires are the ones going to the key switch and all the electronics and switches have since been replaced with better stuff. Before I ever bought the scooter I had already spent $500 on 8000mah LIPO cells that I was building into 48 volt packs. Several tries later I had built packs that I was happy with and felt were going to be reliable and they have done a great job. I don't know why I never took any pictures of them. All I have is screen captures from video. The packs don't exist anymore.

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I used a $40 BMS I found on ebay. They worked OK and fit on top of the 12 LIPO cells like someone had intended that this BMS should go with those 12 cells. The BMS worked OK, but I have been playing with LIPOs for one or 2 seconds now and I know what balance charging should look like. The BMS I used allowed some cells to get to 4.35 volts or to discharge past 3 volts and other cells it charged correctly. I'm certain the BMS has taken life from my LIPOs with it's lousy cell control. This is the BMS I used. You can find them on ebay and elsewhere. I don't recommend using them. They also come in more or less cells. IF they look like this, but with more rows of small components to the left of the mosfets, then it's the same board design and they are not very good.

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This is the 4 original LIPO packs in the scooters battery bay. The cells are separated from each other by a thin layer of high density craft foam. Then the entire stack of cells is wrapped in more of the craft foam sheet. The cells have kapton tape touching their edges, but no tape touching any flat surfaces. I wanted to be sure that I never lifted the foil covers away from the insides of the cells by pulling off tape. The long sides of each pack has a single layer of foam. The bottom and narrower ends have 2 layers. My concern was that the these were the surfaces of the packs that would see the most abuse so I doubled the amount of foam protection. The packs inside the scooters battery bay laid on one end so I ended up adding a third layer of foam to the short sides for better protection. Once the cells were all bound together in foam and Kapton tape, I soldered together the battery leads, added balance cables for the BMS and my own 6S balance connectors. I wanted to be able to easily monitor the cells in each pack with a cell log or to balance charge via an R/C charger. I then added 2 thicknesses of 1" wide strips of craft foam over the exposed battery leads and taped them down with Kapton. I wanted to ensure that the wires and battey terminals were very secure and that there was no way they could ever short against anything. The BMS was then plugged in and battery wires soldered to them and then it too was covered in a heavy layer of kapton tape. The only exposure was the balance cables and the battery power cable. I once rode home in a heavy downpour and water got in the battery bay. I was happy to see that my batteries never got wet inside.

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Here's my re-purposed 12S packs made into 20S packs before adding the power and balance cables and after they are complete. Ironically 2 20S packs take up almost the same amount of space as 3 12S packs. Those are 5S balance cables on them. My R/C chargers can all do 5 cells and 2 can do 6 cells. Also, 5S breaks up the cells into equal groups.

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I looked at 20S BMs boards, but decided to go the route of mass charging this time and random balancing as needed. If I raise the deck a little, I could add BMS boards to each pack, but standing on the cell ends like they are, the balance connectors just clear the underside of the lid. I have a great idea for bulk balance charging. All I have to do is buy a single 20S BMS and then adapt it's balance connector to my 5S connectors and I can balance charge an entire pack all at once rather than 5 cells at a time. With multiple balance connectors like I have, every fifth cell connection has 2 balance wires on it. One wire is the last wire of the previous balance cable and the other is the first wire of the next balance cable. It's pretty easy to keep it straight in your head. Just do one balance cable at a time. Wherever one cable ends, the next one needs to start from that same spot. Then I take a cell log or other LIPO tester that plugs into the balance connector and try each connector. IF each balance connector shows 5 cells on the display and no errors, then I know I got it right. A miswired balance cable will show up as missing cells on the tester. Also, buy balance cables that have a black wire and the wires are silicon coated. The wires are much more flexible, less prone to breakage from bending and the insulation wont melt off. IF you ever have a short in a battery pack, the last thing you want to do is make it worse by shorting wires together when their insulation melts off. The black wire should be the negative connection of the first cell in the balance cable. I'll post a pick of the balance cables I bought later. They have a black wire on one end and a red wire on the other. It's much harder to miswire the cable with colored wires to steer you. When I built the 20S packs I did one thing different than I did with the 12S packs. The 12S packs have the wires laying across the battery terminals. This is a potential place for something to wear through or get cut or whatever and create a short. It never happened, but when I took them apart, I realized the potential. With the 20S packs, I routed all the wires down the center of the cells between the battery poles. This way only the soldered end of a wire was touching any battery pole. The battery poles were then covered by 2 layers of craft foam and taped down. This left a shallow channel down the middle of each pack for all the balance and power wires. The wires were then taped down with more Kapton and the power leads were routed out one end of each pack. The tops of the packs are not water proof. The best I could do was tape down the balance cables all laid out flat, then bend them over the other direction and tape them down again, then I went back the other direction and taped them down again. Hopefully with all those bends if water gets on the top of the packs it wont penetrate very far.

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On the subject of balance cables, they are easy to add to any battery pack. The below picture is the schematic I drew of the 12S batteries, BMS and balance connectors. The right most connection on balance 1 is the negative end of the entire pack (B-). This is where the black wire in the first balance cable gets connected. Starting from the negative end of the pack (B- or the right most cell in the schematic) that's cell 1. The left most cell is the positive end of the pack and cell 12. So the first wire after the black wire solders to the connection between cell 1 and cell 2. The third wire in the cable solders to the connection between cell 2 and cell 3 and so on. Whatever junction between cells got the last wire in the balance cable should also get the black wire in the next balance cable. In the below schematic that is the connection between cell 6 and cell 7 where the little upside down "Y" is. . In the schematic I used 6S balance cables since it split my 12S pack exactly in half. In my 20S packs that wasn't possible so I went with whatever split the pack into equal sections and my R/C chargers could handle or four 5S connectors. The connection technique was exactly the same as doing a 12S pack with 2 6S balance cables except that there is 4 5S cables instead. You still start and end each cable exactly the same.

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Something to note about electricity...(for dummies)
There is a common misconception that electricity flows from the positive pole of a battery or DC power source to the negative pole. This is exactly opposite of the truth. Electrons flow or move...they are what electricity is. Electrons have a negative charge to them and they flow from wherever there is a lot of electrons to where ever there is less electrons. When ever you get shocked by touching something grounded it is because you have extra electrons gathered onto your body that are looking for someplace to go. The ZAP is them flowing from you to a place that has less negative potential than you do. Watch lightning...sometimes it comes from the clouds and hits the ground. Sometimes it comes from the ground and hits the clouds (this is less likely, but happens). The direction of flow tells you where the abundance of electrons is. So then where do the electrons go? The simple answer is imagine that there are tiny buckets built to hold a single electron. The electrons fill the buckets. In the case of a battery, there is an abundance of extra electrons at the negative pole of the battery and an abundance of empty buckets at the positive pole of the battery. When you turn on your flashlight, they flow through the light bulb and make it glow and then back into the "buckets" in the positive end of the battery. When you recharge a battery, essentially what you are doing is dumping the electrons out of the buckets and pushing them them back into the negative pole of the battery where they will later flow back out and into the buckets again. For everyone who knows how electron flow really works, just roll your eyes and pretend you can endure this overly simplistic example. That's what I am doing right now!!! For the people out there that think electricity flows from plus to minus like we are commonly taught from birth...well this is for them. So all of that deep electron theory (LOL!!!) to point out one tiny thing. Notice in the schematic P- on the BMS. That is a 14 awg wire that goes to the XT60 connector. The wire going from B- to the first cell is also a 14awg wire. This is the current path out of the cells. All the other connections between the BMS and the cells are very small wires capable of maybe 1 or 2 amps. The red 14awg wire coming from the positive end of the batteries to the XT60 connector is the return path for electrons back into the batteries. Even the wire connecting the positive end of cell 12 to the BMS is a very small wire. That's because electrons flow out the negative end of the pack and into the BMS (B-) and then out of the P- and then into your motor or lights or whatever to make them do work and then back into the positive (red wire) end of the battery pack where the empty buckets are waiting to be filled. Remember that electrons flow. The "buckets" don't flow. They are containers for electrons after they have been used and since they have no electrons in them they have a positive potential to them that attracts electrons. So effectively dump out the buckets and push more electrons into the negative poles of the batteries to charge AND let the electrons flow out of the negative poles and into the positive poles to discharge. God! I think I nearly suffered an anurism writing that!
Last edited by ElectricGod on Sep 02, 2017 6:47 pm, edited 2 times in total.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 02, 2016 9:01 pm

So here I am a scrounger of things with an abundance of LION 18650 cells that I have scrounged from laptop batteries. Also, I have ready access to lots of laptops and lots of old laptop batteries. What to do, what to do! On the HK LIPO thread it was mentioned to me that since I can't afford to buy all new batteries to upgrade to 72 volts, why not do a hybrid solution where I reuse my LIPOs and also purchase smaller quantity of 18650 cells that I could afford. I was pointed to a thread on ES that talked about it using both LIPO and LION cells side by side. At first, I scoffed and thought the guy had simply miscalculated his capacity needs and as a result his LION pack was way under capacity so he made up the difference with R/C LIPO packs. I dismissed the idea as "a bad idea". Then I thought about all those 18650's I already had and the easy access I had to many more. I had already made a 6 cell charger for the cells I had that plugged into my R/C chargers. I use those old 18650 cells for flashlights, projects, whatever. They are still good and work reliably and are free rechargeable cells!!! The more I thought about it, the more I realized that a hybrid battery solution was actually a great idea. The problem is that old laptop batteries are well...old and some are of limited use. I didn't want to spot weld together a battery pack with old cells that may fail or simply had poor capacity. I wanted to be able to remove low grade cells easily and replace them with better cells with minimal effort and time. Eureka! 18650 battery holders!!! I was already using them for other things, why not use them in an EV solution? So the goal is easy access to all the cells, reasonably good current capacity and a compact design that works well.

The goal is to use a pile of used cells. That's less than half of what I have right now.

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To power this.

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This is the battery holder I am using. For this project, I found them on alibaba for $1.20 each shipped to me. I bought 40 of them. That leaves me with a few spares for whatever. 5 battery holders in series is 20 cells long. I wanted to fill a specific space as efficiently as possible with them so that got me 14 rows of 20 cells. I bought them for much less money from littlebear.

http://www.ebay.com/itm/Black-Plastic-B ... SwjVVVqQdG

This is the battery holders glued together side by side. The plastic is smooth and super glue doesn't bond to it very well so I used my hand sander to rough up the ends before gluing them together. As you can see the battery holders are an inch longer than 20 cells side by side...not bad for a removable/replaceable cell solution!

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This is the back side of a 20 cell strip. The black wires connect the pins together so the cells are in series. The cells need to alternate in the holders. So if cell 1 is plus end up, then cell 2 is negative end up. There is 19" of interconnecting wire to make this work. I used 18awg wire for all the interconnects. The battery holders wont see more than maybe 4 amps each so this plenty good enough. 18 awg silicon wire can handle 20 amps easily. Big wire has less resistance to electrical flow than little wire so I went with something that wouldn't limit current flow and would still be fairly small.

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I originally wired a strip where all the positive poles were all oriented the same direction. It looked like the below picture.This added significant wire length to a complete strip of battery holders so I took it all off and went with the shortest wire lengths I could. Wire creates a small loss of electricity. More wire creates more loss. You want as much possible potential electricity getting to your motor as possible so short wires is better than long wires. There is 60+ inches or 5 feet of interconnect wire to make this work. In this case way less is way more!!!.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 02, 2016 9:19 pm

Here's a balance cable. Notice the black and red wires. Black is the negative most end on the balance cable. Red is the positive most end on the balance cable.

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This is a single 20S battery slab with the balance cables soldered down. The black wire on the far right is the negative end of the pack. Notice how there are 3 places with both a black and red wire soldered to them. That's where one balance cable ends and the next one starts. I have all of them soldered together like this, but I need to secure the wires with hot glue on the other six yet. This first picture looks like a rats nest of wires since I haven't secured them yet with hot glue. They are laid out just like I described earlier.

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I'm not worried about the middle of the wires possibly moving around...just that they are out of the way of any solder connection and wont get pinched. The wire ends where they are soldered down need to be secured so the wires don't vibrate and break loose. Also I don't want the connectors moving around too much so I have hot glued the wires down about an inch below the connectors.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 03, 2016 3:23 pm

In case anyone was confused about my description of adding balance cables to a battery pack, I drew a schematic of a 12S pack with balance cables. I know there's lots of really smart people on here that think this is elementary information and I agree with you, but then I have a long history in electronics. There's lots of folks that have some basics under their belts, but have no idea about how things really work. This is a schematic with 12 cells. They could be LIPO or LION or LIFE...or even NiCAD...it really doesn't matter. You have a bunch of same type and capacity cells that you want to balance charge. I have built balance adapters for 18650 LION, LIFE and LIPO cells, but that's not really important. It works the same regardless of the cell type. I labled all the plus and minus ends of the cells so it should be easy to understand what goes where. Balance cables that plug into most R/C chargers use JST-XH connectors, but there are exceptions. JST connectors are really common on chargers for the balance connector. If you go on ebay or any R/C site and look up balance cables, just about all of them have JST-XH connectors on them. As a result I am going to assume that as the defacto standard. In my previous post in this thread, I posted a picture of a 5S balance cable. It conveniently has red and black wires. When dealing with groups of cells that you want to balance charge, thing in terms of things relative to that group of cells. So if I have 20 cells in series and I am dealing with the 6th through 10th cells, then there is one cell that is the negative end of that group and another that is the positive end of that group of cells. The black wire is always going to attach to the negative end of the group of cells. Consider the black wire to be on pin 1 of the connector. The last wire in the balance cable may or may not be labeled or color coded. That's OK as long as you know where to start from and where each wire goes. From right to left...the right most cell or battery is the negative end of the battery pack and I will refer to it as cell 1. The next cell is cell 2 and so on until the left most cell or positive end of the battery pack which is cell 12. This schematic could have 3 cells or 300 cells in series. It all still works the same.

Image

A small detail about balance cables... It seems logical that a 6S balance cable would have 6 wires, but it has 7 wires. Each cell has 2 connection points so to get 6 cells in series all connected requires 7 connections to get all the poles for all the cells connected. A 20S balance cable has 21 wires. A 2S cable has 3 wires. You get the idea.

1. Starting from the negative end of the group of cells, attach the black wire (pin 1 on the JST connector) in the balance cable.
2. It's not uncommon that the rest of the wires are all the same color so just keep them in order. The next wire will connect to the connection between the positive end and negative end between cell 1 and cell 2.
3. The third wire connects between cell 2 and cell 3
4. The fourth wire connects between the 3rd and fourth cell and so on.
5. in the above schematic I have 6S balance cables. At the connection between cell 6 and 7, the 7th wire in the first balance cable connects here. Also, since there is another 6S balance cable for the next set of 6 cells, the black wire (pin 1) for the next balance cable also needs to connect here too. That's the upside down "Y" in the schematic. finish the rest of the second balance cable like you did the first one, but for the remaining cells. The last wire in the second balance cable should connect to the positive end of cell 12.
6. Connecting the wires in a balance cable in the order they are in the connector is super important. A simple "test to be sure you got it right is to plug in an R/C cell tester. If you have a 3S balance connector, then you should see 3 cells listed in the tester. If you have 8 cells on and 8S balance connector, then the tester should list 8 cells. Balance wires hooked up out of order or wrong will always give you an error on the tester or there will be missing cells. I have 4 different battery testers that use balance connectors. They all behave similarly if I have a connection error. There will be too few cells or a gap in the list of cells or the cell log 8 displays a flashing error message where the wiring error is. You can't fry a battery tester by plugging it in backwards. It will either work or it wont.

You don't have to use 6S balance cables. If you have an R/C charger that handles 20 cells, well that's fantastic! Use a 20S balance cable. If your charger maxes out at 5S, then use 5S balance cables or whatever works for you. I will be getting the below BMS soon. It will act as a 20 cell R/C balance charger. I will have to adapt its 21 wires to work on 5S balance connectors. I'll post that later when I get to doing that build.

http://bestechpower.com/74v20spcmbmspcb ... -D276.html

If you buy R/C battery packs they already have balance connectors on them. Personally, I like R/C packs, but then I take them apart to build up the pack size I want. For my 72 volt conversion, I was originaly going to use 6S R/C packs, but changed my mind when the idea of making LION battery holders came to me. If I had used R/C packs, I would have tested them a little and then taken the packs apart to get direct access to the cells. I would have removed the balance and power cables and anything else that separated me from the actual battery poles. I would have then reconnected the packs and cells together into one giant 20S pack with whatever balance cables I decided were best. Since my best R/C chargers can do 6 cells, I would have wanted to go to 6S balance charging, but in a 20S pack, that leaves an odd number of cells (2S) in the last group or 3 groups of 6 cells and a group of 2 cells. As a result I would want to break up my cells into equal numbers of cells while grouping them together in the largest grouping I could balance charge. Well that's 5 cells which worked out really well because I have 4 R/C chargers and they can all do 5 cells. If I had gone with 24S I would have used 4 6S balance cables and not used my 2 5 cell chargers. You can break up your balance connectors however works for you...just keep the wiring pattern the same!!!
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 03, 2016 5:14 pm

So now you have balance connectors on groups of cells in your UBER battery pack, you still can't use them for charging...just for monitoring with a cell tester. LOL...OK not quite. Most R/C chargers need the battery power wires and the balance connectors to charge or balance a battery pack. You will need to make a simple hack to a balance extension cable. This is why you want your cell groups to all be the same size so you only have to make one cable hack.

Get balance extension cables for whatever your balance connectors are. I'm using 5S balance connections so I'm getting 5S extensions like these. They have a male connector on one end and a female connector on the other end.
http://www.ebay.com/itm/Apex-RC-Product ... SwQPlV8GFv

Also get a set of these cables. You will be using the banana connectors and some wire from these cables.
http://www.ebay.com/itm/1-pair-Banana-P ... Swo3pWcZxz

1. Cut the wires about 4" back from the banana connectors and then strip a little insulation off the ends. Keep the alligator clips for some other project or for testing stuff.
2. On the end of the extension cable that plugs into your R/C charger and an inch or 2 back from that connector strip a little insulation from the outside 2 wires in the cable.
3. Solder the black banana wire to the black wire in the balance extension cable.
4. Solder the red banana wire to the wire in the other end of the balance extension cable.
5. Cover the solder connections with electrical tape or heat shrink tubing.
6. Plug in the banana connectors and the balance connector into the charger and the other end into the balance connector on the battery pack.
7. Set your charger to whatever cell count is in the balance cable. That's 5 cells for me and start charging. The charger cant detect the difference between the hacked cable and the power wires since they are electrically the same.
8. Whatever you can do with a standard battery plugged directly into the charger can be done via the balance connector in the pack and the hacked balance extension cable.

There are 2 warnings I should make...
1. If you are used to charging at 10 zillion amps, you can't do that through the balance cables because they can only handle around 2 amps. Use your 10 zillion amp charger first and then use your R/C charger to do the balancing.
2. There will be an urge to plug in the power connector from your UBER battery pack into your R/C charger. DON"T!!! STOP NOW!!! YOU WILL PROBABLY DESTROY YOUR CHARGER!!! Seriously...a typical RC charger is designed for 5 or 6 cells. Plugging in 7 or 8 cells might not cause damage. 12 cells plugged into a 5 or 6 cell charger will destroy the charger and more is probably going to be explosive for the charger. Just don't EVER plug in more cells into your charger than it was designed to handle. This is a great way to turn an expensive charger into scrap electronics.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 04, 2016 2:59 am

And now back to the 20S2P LION 18650 pack build...

Last post on these packs, I had said I needed to secure the rest of the balance cables and then solder them together. This is 2 of the 20S1P slabs soldered back to back. You can see the parallel sets of interconnect wires between cells. The pins over lap a little and then are soldered together. The interconnect wires create a hump on the pin. When the pins are over lapped a little, it creates a little valley between the humps. I filled the little valley with solder. There's a lot of solder bridging between the two 1S20P slabs.

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This is a complete 20S2P pack complete with the power wires and an xt60 connector. The gap between the 20S1P slabs is a natural channel to put the red power wire in. I used the 2 interconnect wires and filled them with hot glue and then pressed the red wire down into the hot glue. There was a small gap on either side of the red wire and so I filled that with hot glue too. The power wires are quite secure.

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This is a pack fully loaded with 18650's. I get 81.3 volts with the cells randomly put in it. Some of the cells don't charge to 4.1 volts and others do so the voltage is a little bit low as a result. Right now I don't know what are the good cells and what cells have poor capacity. I filled 3 20S2P packs with cells and have 11 more cells. I need more laptop batteries to get cells from. I'm at 3 of the 7 20S2P packs full right now.

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This is all 7 20S2P packs that I built. Damn...that was a lot of soldering and work! I used probably 10 hot glue sticks securing wires. I'm running low on solder now too. Almost all the 14 awg wire I had is used up too.

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Looking at how many batteries this is right now and the fact that I still have 4 more packs to fill and there are 3 LIPO packs too...well I have an insane amount of capacity! With my four 48 volt LIPO packs I had 1536 watts. This got me about 24 miles of distance and a maximum speed of 32mph. With the 3 72 volt LIPO packs I have 1728 watts and then there is the LION packs. With the used cells I'm assuming 4 amps per pack so that's an additional 2016 watts for a total of 3744 watts. I've more than doubled my capacity and gone to 72 volts. I have no idea what my new maximum speed or range will be, but it will be lots more than it was.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 06, 2016 2:36 am

The fuse block and power connections are done...

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 06, 2016 9:52 pm

More progress....

I ran power leads to the back deck. This is an XT90 connector and 10 awg wires.

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I had to drill a second hole in the side of the box since the other hole was too small for two more fat wires. The lower right hole was original to the scooter and was never intended to hold three 12 awg feild wires, a hall cable and the rear lights cable which are all in the lower right area. The two new power wires had to go in a new hole. Since the power wires had to go around a fairly sharp curve to go into the hole and then immediately turn again, I thought some heat shrink would be good to keep the wires from possibly getting cut or chafed.

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This is the power wires terminating in the power distribution blocks. The smaller wires are 14 awg for the internal batteries or for distributing power to other things. The clear box with a black bottom is the internal fuse block.

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And some pics of the battery box with plenty of room for fans if they are needed. I left a small gap on the sides so I could put a layer of foam there to act as a cushion. It's about 3/16"

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 08, 2016 3:27 am

I've been working on the battery box today. The bottom is effectively done, but the lid is still needing further work. It takes forever for paint to cure in the cold garage. I finally took the parts inside and now my house stinks like paint fumes. I'm not sure faster curing was worth it! I've tried the 3 populated 20S2P packs on the fuse block and they each run the scooter individually with no load on the back wheel. As soon as the battery box is complete and the roads have cleared up again after the 14" snow storm we just had, I'll do an actual riding test.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 09, 2016 11:36 am

I scrounged 4 more laptop packs yesterday and that got me enough cells to finish filling the 4th 20S2P pack...3 more to go and I am at capacity. Who knows how well those used cells will work. Load testing and bad cell elimination to come this weekend most likely.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 09, 2016 6:59 pm

SWEET!!! I just scored 3 brand new 12 cell laptop packs!!! They have 2600mah cells in them. That totally was awesome!!!
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 09, 2016 11:42 pm

The lid was a pain to make It's a snug fit on the bottom which is what I wanted. Getting it to fit bottom perfectly was time consuming to say the least. I wanted the lid pieces to all knit together so that took time and a lot of care to get it right. I wanted the lid parts to be snug fits so if I have to leave the scooter outside in the rain, water wont get in the battery box.

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Here's some more pics of the box bottom. I added 3 strips of foam tape so the box wouldn't touch the back platform which is covered with grip tape. IT will also create a small air gap so any water that gets trapped between the box and the platform can dry out.

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The 4 holes are for the bolts that will secure the box to the platform.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 12, 2016 1:29 am

I got the LIPO cells 2 days ago for the third LIPO pack. They came with 1S protection boards that I had to remove first. Then I soldered the tabs together and inserted foam slips between each cell. No kapton tape adheres directly to the cells. The packs is wrapped in 2 layers of foam and then wrapped tightly in kapton. The bottom has 2 layers of foam and then it's covered in several layers of kapton. I added the power wires and then the 5S balance cables, directed all the balance wires to the centers of the cells and laid down a layer of foam over the battery terminals and taped it down. This left a narrow channel down the middle of each row of cells that was perfect for stuffing the extra little bits of balance wires. I then laid down the balance wires so they pointed outward and secured them with kapton. Then came another layer of foam on top of the battery pack and lots more kapton. I then folded over the balance cables and secured them and then more kapton to close up everything very securely and to make it as water proof as possible. I'm charging the pack right now.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 13, 2016 7:32 pm

This is the completed 20S2P LION battery battery box. I didn't connect up the battery packs that didn't have cells in them. There's no point...yet. The kapton tape around the edge of the box is to keep the lid and the box from adhering to each other and to protect the edges from dings to the paint until it fully cures.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 16, 2016 12:01 pm

Status update...

The LIPO packs will run everything for about 10 miles by themselves, but are a bit saggy since 2 of the packs are made of old cells. At fully charged (82 volts) and then cranking the throttle all the way up, pulls about 60 amps and the LIPOs would drop to 70 volts. That's significantly saggy! Once I got up to speed, they popped back up to 78 volts or so. I never expected the LIPOs to do all the work so this is expected. When I got home, I checked my cell voltages on the LIPO packs and something has happened to one of my balance wires. On the 3rd balance cable in one of the packs, I can't measure one of the cells. The pack still works, so I must have a balance wire wire that has come loose. It's a pain to pull all that kapton off, but there's not another option. Ironically, I charged the cells via that connector and have checked them several times too before now. The 4 populated LION packs are made of whatever cells I had scrounged so there has been no capacity testing on them yet. I ran them in parallel to my run-down LIPO packs and they improved the "sagginess" of the LIPO packs quite a lot. This was a preliminary test of the LION packs and they worked pretty well. I'm confident that I will be able to ride to and from work on them and the LIPOs and be able to maintain 40mph. Towards the end of the test as I was approaching 60 volts, it took longer to get up to 40mph, but I still got there. With better LION cells or even the elimination of the worthless ones and replacement with more used laptop cells will keep me going longer and stronger. I feel the electronic version of Viagra coming on strong!
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 19, 2016 6:48 pm

I am running off of 5 of 7 LION 20S2P packs and 3 LIPO packs. I can definitely feel the weight of all those 18650's on my back deck. Sagging is reasonable under full acceleration. I'm waiting until I fill all 7 LION packs to try running exclusively off of them. The last time I tried that I had 10 amp fuses on each pack and there were 4 full packs. It ran for several seconds and then blew the fuses. I then replaced all of them with 15 amp fuses and haven't tried it again. Hopefully tomorrow...with 5 packs I wont blow any fuses!
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 23, 2016 11:57 am

My batteries work well so far...considering they are almost exclusively used laptop cells. My old charger wasn't up to the task of charging all those cells so I am building a much higher wattage charger. I bought a 20 amp power supply, but it failed after 20 minutes. No smoke or burning smell...just stopped working. Anyway, that was going to be my new charger...GRRR! I can't ride unless I can charge. Yesterday, I got enough cells to fully populate my 20S2P packs. 40 are nearly new and came from a 36v EV pack. The rest are cells of unknown type or manufacture that came from Tesla motors. Now it's time to ride on the 20S2P packs and see which cells are crap and need to get tossed in the recycle bin. There's no point in having cells that are doing less than 1000mah. since this is 100% used cells, I'm setting that as the "rock bottom" I will accept. As I find out the actual mah of a cell, I write it on the cell. Later as I get better cells, the bottom of the barrel cells will get replaced. anything that I have that is new all goes in the same pack and is labeled so I know it's new. Everything else is more or less thrown together as I pulled them randomly out of the box full of cells.
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Re: My excellent adventure through some battery builds

Post by LockH » Feb 23, 2016 12:33 pm

eGod Guy? E-Pic thread Sir. (following) Cheers L
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Feb 23, 2016 3:58 pm

LockH wrote:eGod Guy? E-Pic thread Sir. (following) Cheers L
Thanks! It works pretty well and the weight is 95% in the batteries. my scooter rides differently with the extra weight over the back wheel, but it's not less stable. I have about $200 into this build now. Nearly all the 18650's cost me nothing.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 03, 2016 7:53 am

These battery packs are working great so far. I haven't eliminated the weak cells yet, but that will happen soon. Sag is minimal at 80 amps load which is my maximum load right now. I'm loving all the power and capacity I have now. I wish the scooter weighed what it used to, but that's not going to happen. It's so much faster and more powerful than it ever was before and that is due to all those used 18650's. So far I have to say the 20S2P battery holder packs were a superb idea. I'm really glad I built them.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 03, 2016 6:27 pm

To anyone out there wondering if using used laptop batteries is a good or bad idea. I have 3 things to say about that.

1. I got a lot of comments from people with GW ratings on here saying that it was a bad idea for various reasons. I agree with them, but only because I understand that used cells and then laptop cells that typically run at 1C are sooo not the ideal solution for EV projects. However, my total cost for 280 cells in a 20S14P arrangement is less than $200. Tell me where you can find a battery pack with with any kind of cheap cells for that price with this capacity? I'll tell you where...in my scooter!

2. I knew going into this project that I was harvesting laptop batteries for 18650s. I knew that some cells would be better than others and some would do better as paper weights than as batteries. I knew that laptop batteries were never designed for power use. I knew I was going to need to run them in parallel A LOT to make them work. I have done that and so far in my tests over the past couple of weeks and then riding it today, that it is more than good enough for daily use. It will take long term use to see if it's sufficiently reliable or not of a way to build battery packs. For example, when I get home tonight, I'll pull out each battery pack and check for overheating (melted plastic) and cells that have vibrated loose. If there is anything like that...well then I might need to make some changes. I never implemented a fan into the battery box. Maybe I need them, but I don't think so. Maybe I need something between the cells to keep them in the battery holders. I'll know that tonight.

3. So having said 1 and 2...my testing so far has given me results far better than I expected. The battery holder solution works well and I can remove bad cells from a pack in a couple of seconds. It literally takes longer to open the box than it does to replace a cell! So...in my opinion...this experiment and build has gone very well and I am really pleased with the results so far.

In conclusion...if you are wondering if salvaged laptop batteries can power your EV and you want to make a battery solution that is 100% serviceable and cheap...well those old laptop cells CAN power your EV for virtually free and you can get lots of current out of them. I was pulling almost 80 amps at maximum acceleration off of a 14P solution. They are all 2600mah cells so that amounts to 2C loads per cell. That's not overly unreasonable. 80 amps is my maximum current load and most of the time I stay under 40 amps. I'm not really overloading these cells by much if at all. All that to say...build the battery holders like I did into packs and harvest tons of laptop batteries and build yourself a virtually free high capacity battery pack. Worst case, you get new cells a little at a time and replace the lowest quality laptop cells on a more affordable scale. This is a very workable solution.
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Re: My excellent adventure through some battery builds

Post by 4LivesPerGallon » Mar 11, 2016 12:02 am

Excellent.

You have a "free battery" scooter.

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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 11, 2016 1:21 pm

Since I'm tearing into everything else because of the field wires melting my light wires together. LOL! My field wires were too small for 3000-5000 watts and got hot enough to melt the low temperature insulation on my lighting wires. They have now been replaced with high temp wire and the field wires are soon to be 8awg rather than 12 awg. Anyway, I looked over my 18650 battery packs and I don't see any evidence of over heating or plastic melting. Admittedly, they need more time, but if a 10 mile ride isn't going to do it, then what will? My ride to and from work is pretty bumpy in several places and I ride over a few railroad tracks. None of the batteries vibrated loose or out of the battery holders. I'm probably going to add a strip of foam between packs anyway to soak up vibration, but it doesn't look like the batteries are going to be a problem staying in the holders.
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Re: My excellent adventure through some battery builds

Post by ElectricGod » Mar 28, 2016 4:26 am

I did a 13 mile, 40 minute ride today, the laptop batteries held up well. I started at 81.4 volts and finished at 71.6 volts. All those free laptop batteries worked out pretty well.
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