LFP reverse polarity.

[Skyler]

So more B.C.H or you through with those guys?

Who ? Don't get what you said.

I was talking about US vs China for LIFEPO4 batteries and shipping.

My choices are TOP BAND , HEADWAY or cells from Battery hookup or clearinghouse.

556 AM 11/13/23

I hooked up the proper 33.6V Charger for 12S LTO. 2.8 * 12 33.6V. Two 6S packs in series charging.

The 28V charger is hooked to the 10S LTO pack. All four external balancers are reading perfect voltages. All between 2.5 and 2.6V charging. It is amazing. Probably wont be able to tell which cells were reverse polarity.

8 miles of 25 to 30 mph both motors 60 amp total load but did not do full throttle for either motor. Was a test. It passed as well as the LTOs.. I love doing this. I am living the dream. Got to check voltage now on my external balancers. IF or when I see a cell skyrocketing I can pull the plug to avoid damage.

Thanks

Skyler out.

 

[Skyler]

My LTOs did 8 miles at 20 to 30 mph and see no issues. Cells are 2.48V to 2.56V. ALL 22 of them.

Balancing now with 12S 33V charger and 10S 28V. Looking perfect as cells are finally balanced.

They are now perfectly balanced.

I really don't need another 1500W kit when I already have one plus five other ebikes and #6 pending so might get a spot welder for Christmas.

Not sure. , Looking at other options maybe that require no welding or solder to the cells just the power wires.
I got a few ideas from reading old posts here and other forums so we will see what happens.

12/16/23

I did not even need glue. I cut strips of electric and max strength black duck. I drilled the holes in that 8 foot piece of plastic strip. It was about $5 with tax and less than $6 for the nuts and bolts.

First I used a Dremel tool to grind any pieces of the tabs and make sure good contact will happen for the bolts.

I used 3 drill bits to get the holes so would not split the material , Slightly smaller hole than the nut so can pound in with a hammer.

Lots of strips of electric and duck follow. Right now when I try each bolt it is firm contact. The next step is two strips of 12 gage wire. wrapped around each bolt. I want to strip long enough pieces to connect two cell banks in series.

Before I do it though I am temporary wiring 18 gauge for parallel charging at 2 amp. I will just wrap around each bolt twice and use small pieces of duct at the ends to hold it tightly in place. I can use the same wires over for parallel charging any banks in the future.

After the series connections strips of electric and duck will wrap around the top of each bolt and then strips all the way around the top.

All six banks will lay out on a table and when all balance wires are hooked up it will just fold up one bank on top of the other. A few more zip ties and some duck tape and will be ready for a custom wood box.

If it works I wont get a spot welder. I will use shorter bolts for any future packs. I got 3/4" and should have got 1/2".

11/16/23

There is no doubt it will work. That is a fact. The drawbacks are it takes a lot more time to do than spot welding. The drill bit makes sloppy holes and thin strips of tape is required to keep the nuts in place.

I actually taped all around the nuts to get a tight fit. I will also be taping over the tops of the bolts after the series connections are done and balance wires installed.so 100% positive that all cells will have contact with the bolts.

What I might do instead of ordering a spot welder is order a 3D printer. With 3D printed plastic strips with holes the nuts will simply slide in for a perfect fit. A very tiny amount of glue around the edge. Very little glue will be needed. No tape will be required. see pic below.

. Then all that will be needed is four zip ties the right length. I had to use two so the ends of the zip ties will add some space when stacking them.. I will need to replace with longer ties. Space is precious when building batteries.

The more compact the better. Stacking will work and only the width due to the bolts will be around 1 inch inch larger than a spot welded pack. The height and length will be equal or less than a spot welded pack. When I switch to 1/2" bolts then 1/2" wider than a spot welded pack.

The time it will take to install and glue in the nuts and zip tie and screw it together will be much shorter if no tape is required.
If the width of the box is exact enough then will be pressure against the top of the bolts with a tight fit. NO tape over the bolts will be required.

Also thick nickel strip like double or triple the thickness of what is used for spot welding can work by drilling holes and simply sliding it over the bolts with an extra nut to tighten it down..

Finally the other advantage is all the hardware can be re used to rebuild a wore out cell bank or even an entire pack. Hopefully someone with a 3D printer will take a look at this and start printing.

I was going to invest in a 3D printer awhile ago but the problem is how to find or create with the software. How would I go about designing such a thing. I no absolutely nothing about programming a 3D printer to print anything.

I have watched a lot of videos on 3D printers printing stuff so what I want to do would be easy as pie for just about any modern printer. Please let me know what you all think.

Thanks.

Skyler.

View attachment 342936View attachment 342937

 

[Skyler]

ok.

I could not open the pics as thumbnail. I need full image.

Could be on my end. Not sure. I cold try and open with my other PC.

 

[Skyler]

ok.

I will take more detailed pics showing the steps taken to build cell bank #2. There will be six cell banks of 8P for my first pack . It is because I already have a soldered 7S - 8P pack. In series they will be 43 working volts which works perfect for my 36V e bikes.

After that I will build two more 6S and a 5S for myself. My friend Tom wants a single 16S pack so will need a 40 amp Bluetooth BMS so he can monitor his cells. Since he is not at all familiar with any type of cell balancing active or external I need to make it simple for him . Hopefully he wont have any issues monitering via. Bluetooth. It is something I need to learn first before I can teach him.

I will be putting up more pictures soon.

#1. cell recovery and preparation.

Notice the piece of blue plastic to raise the tab before snipping so there is no spark / short.

Then a Dremel tool is used to grind any jagged edges form the tabs.



I think before I make any more I should get some super glue to glue the nuts in. I can still use tape but not as much.
I am charging one cell bank now with the LiPo charger.

Looking at the picture it is just a waste of tape. A better way is to cut all the strips needed for the pack and drill all the holes and glue in the screws. If the bolts are already in the hole it can not get glue on the threads. Mabye go around the nuts on the top with hot glue.

I should get voltage to each cell with no tape at all. If I do add tape it will be very thin strips of duct around each nut. Not all that tape in the pictures.

I can charge the other later but before making permeant series connections I should un tape those two packs and use super glue on the nuts as well as any packs in the future.

Also I should wait and balance charge the pack when fully assembled. Running the charger for each cell bank will take too long and extra wear and tear on the charger.

I think I will go with the 12 gauge wire I have. I do not plan on running more than 35 amps. 40 amps tops as all my 36V e bikes are < 40 amps.

The most powerful would be the 750W chain with the 350W Bafang up front so 1,100W / 43V = 25.6 amps continuous. 40 amps would only happen for short peaks or a steep hill.




Thanks


Skyler.

 

[Skyler]

I think before I make any more I should get some super glue to glue the nuts in. I can still use tape but not as much.
I am charging one cell bank now with the LiPo charger.

Looking at the picture it is just a waste of tape. A better way is to cut all the strips needed for the pack and drill all the holes and glue in the screws. If the bolts are already in the hole it can not get glue on the threads. Maybe go around the nuts on the top with hot glue.

I should get voltage to each cell with no tape at all. If I do add tape it will be very thin strips of duct around each nut. Not all that tape in the pictures.

I can charge the other later but before making permeant series connections I should un tape those two packs and use super glue on the nuts as well as any packs in the future.

Yea.

Maybe not.

I have no glue and if I did I would want larger round holes so it fills in the space with the glue. ( see pic below )

What I do have is tape as I got two rolls and the long zip ties at dollar tree for a buck and a quarter each.

Also I do not feel like taking anything apart. ( if not broke do not fix ) I got three cell banks built so three to go. I just want the job done.

cell bank #3 is on the charger so will continue building and charging separately. Then build the pack , Balance and top off the charge and run.

I have posts on three forums and was told so many times not to solder and if I did the packs would never run or be damaged goods.

The cold hard facts is I soldered a lot of packs and traveled hundreds of miles on packs I built which according to many folks should have never ran. Or only ran a few miles and a few cycles before failing. They still run Look at the pictures.

The facts , believe it or not is I can build any battery pack I put my mind to do and can do it by soldering , spot welding or with no solder or welding. I just have not spot welded yet. I do not feel like spending a lot of $$$ on a spot welder. Maybe I will at some later date. Not sure.

The bottom picture shows the #3 cell bank charging and the two on the bottom charged. The pack on the right is the soldered 7S - 8P pack I will be running in series with the 6S solderless pack I am currently building. Mission soon will be accomplished.

It is a lot of work without a 3D printer. If the plastic strips could be printed with hard plastic like they use for gears in a geared hub motor they could be threaded. Only zip ties would be needed and the bolts would simply screw in and a pack could be built just as fast as spot welding.

However the cold hard fact is the mainstream or majority of ebike builders and designers wont embrace something that is new or not test proven. There are solderless kits for 18650 cells out there but are terrible

VRUZEND – Battery building made simple!​

That is a really bad joke. Back when I was building 18650 packs I tried it and the cheap plastic melted. It was a calamity to say the least. I am amazed the company still exists. It is what made me start thinking how it could be done correctly. I just made it better but without a 3D printer not really practical.

That or any cell holders for 26650 cells will take up extra room due to the spacing of the cells. Since 26650 cells naturally run much cooler than 18650 there is no need for the extra space. When I build my strings of 8 cells I do add extra tale on top and bottom for about a millimeter or so spacing , plenty for 30 to 40 amps. I would need more only if I were pushing 60 or 80 amps continuous for an extended period of time.

The second pic shows my 43V LIFEPO4 all soldered and 55V of KICK ASS LTO. Might be heavy but the discharge factor and performance will only be beaten by solid state batteries when they come out. Right now I have the best batteries in the world.

Thanks.

Skyler out.

 

[Skyler]

Looks like my first and last solderless pack for awhile.

pic #1 top - 140 cells. I can save most or all the tabs. . I built all 17S with those cells and only needed to solder a wire to the tabs. Not directly to the cells.

Pic. #2 $5 for 15 cells. Even if only 10 are good it is still a great deal. I got two of those awhile ago.

pic #3 The Canada listing is a nightmare. I bought one awhile ago when they were shipping them to the USA. I pounded the shit out of it with a hammer outside. for about a half an hour and still did not get it apart. I actually had to hire my friend to help me get it apart for 3 - 24 oz beers LOL. Some cells got too banged up to use. I lost at least a dozen and a few more were zero voltage.

You need to look at what your buying when dealing with them. The first two are a go but the Canada listing is no go. It is most of those and a few cells in pic #2 that I am building the solderless pack with as could not save the tabs.

I will be ordering the 140 cells in pic #1 as soon as my disability check comes in. For around $80 with shipping I can build a 17S - 8P pack. I am thinking about doing a 10S - 8P and wiring it with two 5S balance plugs like I did with my 10S LTO pack. Then another 7S - 8P pack like the one I got shown in the picture in my last post.

So I got three more solderless cell banks to do and will be finished. Since solderless packs with no glue for the bolts is a little sketchy I will be testing for voltage after I am done charging each cell bank. After that will be a simple series connection for the banks then tape around the top of each bolt. Electric stretch then duck to hold in place.

After that I will stack them on the side panel when constructing the box. I will use a layer or more of Styrofoam between the panel and the bolts.. Then the same Styrofoam on top of the bolts and then the other side panel. I will then stack about 20 pounds of weights on that to keep pressure on all the bolts. I will then install the ends , top and bottom.

Thanks.

Skyler out.

 

[nicobie]

I am going to leave this up for awhile just for it's entrainment value.

Of course another mod might disagree.

 

[nicobie]

Curtis,

Even if what you post is correct there is no way anybody can understand what you are talking about. Slow down a bit.

 

[floydr]

No hammer needed to open the case on the EMC packs (NEC)

I ordered 9 nec/emc battery pack and dissembled them. after viewing the above video
Later floyd

 

[Skyler]

My laptop wont play it.

If you post the name I can do a youtube search.

I will be ordering the 140 cells though as easier to save the tabs. I just hope they will still have them on the third.

If I were ever lucky enough to find brand new 26650 cells affordable then my solderless packs could work. The thin plastic strip is perfect but an extra 1/8 " in width would enable me to drill slightly larger holes and then fill with hot glue around the edges of the nuts. My pictures are in detail and easy to see. I also explained everything.

With a 3D printer almost anybody could build solderless packs just as easy as that

VRUZEND – Battery building made simple! kit.​

The only difference is the 26650 cells in 8P configuration wont melt plastic and my kit would not take up as much space as a VRUZEND kit if they even made one for 26650 cells.. I dont think they do.

Thanks guys for posting and nicobie for your patience moving forwards .

Skyler out.

 

[floydr]

Lithium Solar made the video

NEC Energy Solutions A123 LiFePO4 Batteries, Cell Harvesting (Battery Hookup)​

I bought my modules from BCH. Same modules.
later floyd

 

[Skyler]

Thank you.

Maybe not.

I have no glue and if I did I would want larger round holes so it fills in the space with the glue. ( see pic below )

What I do have is tape as I got two rolls and the long zip ties at dollar tree for a buck and a quarter each. Also I do not feel like taking

anything apart. ( if not broke do not fix ) I got three cell banks built so three to go. I just want the job done.

Well I am fixing it. I just took one of the packs apart. It was a messy job but filled each hole I drilled up with hot glue. Then used the hammer to pound the nuts back into the glue filled holes. This will prevent the nuts from spinning when tightening the bolts.

I used some olive oil to soak the bolts in and then screwed them in the nuts pushing out the glue from the inside of the nuts. I made sure by repeating it that the threads in the nuts would not have any glue.

I then used sand paper to remove any excess glue from the plastic strip. I am waiting 24 hours for the glue to dry before re building the cell bank. It is a temporary set back but well worth the effort so it is built right. It will also save tape in the future.

It was not broke but I made a big mistake in putting them together. The nuts were on the top which is the side I hammered them in. When I tightened down the bolts the nuts would raise up.

That was why I used tape to keep them from falling out. But any tape stretchers. It was a crucial design flaw on my part and am really glad I caught it before building the rest of the pack.

Now with the nuts facing down or over the cells the nuts have nowhere to go so can not raise up. The bolts will go thru from the other end and with zip ties I can tighten them up and wont need any or very little tape. I will use a zip tie on both sides of each bolt instead of just using four. It should work much better. We shall soon see.

With a 3D printer the plastic strip would either have threaded holes so no nuts needed or it would have the exact shape of the nuts for a perfect fit. No glue would be required in a solderless kit. Just plastic strips. , nuts , bolts , cells , strips of nickel with the holes drilled for the bolts and a lot of zip ties. I think it would be totally worthwhile to do.

Soldering cells can cause damage. Spot welding not as much but the cheap battery powered spot welders might do 0.15 mm nickel strip. These cold be a lot more as just place the plastic strip over the nickel strip and drill out the holes.

It looks so much better without all that tape. (bottom pic.)

After a 6S pack I can use shorter bolts next time making the boxes more compact. It is about uniformity. I wrap each cell with electric tape and red duck.

It is because during cell recovery when cells are glued together the wrap rips and tears so wrap them nice so wont short. I just need to make sure how long the strips are so each cell is the same. Measurements then the 3D drawing for the printer.

I wrap extra tape on top and bottom for a little space but way more compact than 26650 cell holders.3D printed plastic can be strong enough to have threaded holes so no need for nuts. You should not have to tighten down that much anyway.

Also they can be rebuilt with newer cells as many times as you want. Basically 1 kit will last forever. You will just need to replace the zip ties.. Nothing else in the kit.

A very simple kit including the metal strips with the holes drilled can be made then. I don't plan on it any time soon as I can just build my own the way I am doing it

I just wish 26650 cells were more affordable and brand new cells were available for US shipping. Unfortunately due to the ridiculous price for them I am limited to Battery Clearinghouse or Hookup for used cells. The 140 cells I ordered before were rated for 80% capacity. I think the actual capacity to be about 65 to 75% with at least 1 out of 10 dead cells with zero voltage.

. I am not sure if I will order 10 Ah Headway at $10 each or more used 26650 cells. next month. I do plan on buying a 3D printer in the future for many other reasons as well as e bikes parts. Gears in geared hub motors is one idea so can do the kits then maybe.

Does anybody like the idea. ? Any links for low cost brand new 26650 LIFEPO4 cells that ship here from the USA ???

Thanks.

Skyler out.

 

[Skyler]

Almost finished with the 6S - 8P LIFEPO4 pack. I have an idea of weight and dimensions

Not sure what went wrong with the 7S pack I built about a year ago. ( center pic ). It is longer than it should be. 12 maybe 12 - 1//2 inches. I can do 10S in the space I used for 7S.easilly.

Looks like

Weight is about 8 pounds for 6S so 10 pounds with a box and wiring. ( top pic ).

10 / 6 = 1.6 * 17 = 28.3 pounds for 17S -LIFEPO4. I use six - 2.5Ah + two 3.3Ah so about 21.6 Ah new so minus 25% = 16.2 Ah.. I charge to around 80% so 16.2 - 20% = 12.96 so I will say 13 AH..

However after about 700 cycles it will drop to around 10 Ah. That is what I think the LIFEPO4 packs I built a year ago might be. At least 13S.

The 7S pack I built back then I only ran a few times as been running 43V about 80% of the time in the last year. It is the reason for building this 6S pack so I can run it with the 7S pack for 43V.

The scales (bottom pic.) have 22S - 55V - LTO and looks like very close to 50 pounds. 56V - LIFEPO4 is almost 22 pounds lighter. It is why I plan on ordering a lot of 26650 cells. I will build 10S , - 7S and 6S packs for 13S 43V , 16S - 52.8V and 17S - 56.1V.

I like running two packs to get the voltage I want. Not three like the two 5S - LIFEPO4 hooked to the 3S - 3P headway for 43V and the three giant LTO packs to get 55V. I have no choice for the LTO as they need to be split up for better weight distribution.

Two 10S - LIFEPO4 packs would be 66V and 33.3 pounds. 16.8 pounds lighter than 55V - LTO. Each pack will have an 80 amp fuse on the negative side. I will continue to balance externally.

Thanks.

Skyler out.