Angus Digital

Strangely enough I did actually use some stanley knife blades to practice on before I went onto welding cells for real.

I really appreciate your knowledge and advice as I'm relatively inexperienced when it comes to cells, batteries, welders etc. I will check out the links...

I really fancy those Samsung 50E 21700's

Yes I take your point about the positive and negative connections being close together, but the beauty of doing drawings first and then posting them on forums like this is that I can get feedback. I'm pretty certain I can re-design the layout so that the terminals aren't so close together or even at opposite ends of the battery... I'm on it.

Maybe I'm asking too much but, it would be nice if the manufacturers of cell holders be it for 18650, 21700 or 26650 cells etc, would at least provide a diagram of how one would typically configure some cells into their products. Because of the shape of many bicycle frames it's not always easy to just install a square or rectangular battery pack which makes for a simple X,Y matrix layout I know that there are a few combinations possible for a given cell holder but it can't be that taxing to just at least have an online link with a page of battery cell combination graphics say for 36v, 48v or 52v batteries, (for e-bikes) I think those voltages are the most common although I know there are others. I have put just one set together here on my computer with a picture of the cell holder in question but it took me absolutely ages. Hopefully I haven't made any errors. Correct me if the pictures are wrong.

Thank you for the advice, I will be spending over £70 for sure so I'll be checking out Fogstars' website later to start with.

I see that Fogstar seem to be coming up time and again as a reputable supplier. I don't want to be spending any money except on genuine cells from reputable suppliers. Fogstar appear to be the way to go, among others...

Sounds promising. Is there somewhere reputable where I could obtain these P28a cells? I've just seen these cells online and the price varies wildly from different suppliers.

I see what you're saying, good point. There are so many factors for me to consider...

The reason I'm making such a big battery is because I sometimes have to make short trips as part of my work to trade counters etc, which are all within five miles of my place of work, and I wanted the option to do that and still be able to get home at the end of the day. I plan to use pedal assist not just throttle. I do have the option to charge the battery at work but I was hearing a lot about 'range anxiety' when I first became interested in e-bikes a couple of years ago so I just didn't want to be caught short bearing in mind I had no real idea how far my now soon-to-be-finished project could potentially go. I was seeing various theoretical figures of how far my e-bike could go depending on various factors so thought it might be a good idea to try and get a battery pack bigger than what I actually needed and maybe give myself some headroom without possibly having to charge the battery during the day. On top of that there is a fairly steep hill about a quarter of a mile long on the way to work and I wanted a battery that would deliver the power I needed in combination with a motor that wouldn't over-heat on the way up which is the reason why I went for the BBSHD. I am more interested in range rather than speed even though a few extra MPH on top of what I would get on a conventional bike would be appreciated.

I did take a look at the pedelecs law section. It's a minefield out there when it comes to uk laws and regulations concerning e-bikes. It appears that I basically have an electrically powered motorbike, which means I need mirrors, indicators, headlight, crash helmet (I already have the crash helmet) and a plethora of other requirements in order to become street legal. However, I'm not put off. I've come too far now and I'm looking forward to eventually taking my e-bike on the road. (legally)

This is some very useful information as I have not yet made my maiden ride yet. Thank you.

I already have the motor and I really don't fancy buying another one. I did get a programming cable in order to limit the power output to comply with the local regulations. As you'll be aware the stock motor is at least 1000 watts. I believe for legal street use the power should not exceed 250 watts and a top speed of 15 mph (in the UK at least).

It's not looking good is it ?, in terms of using these cells in my battery pack. However, the good news is that I have at least three old power tools that have dead ni-cad cells in. I could always modify the batteries and power the tools with the lithium ion cells I already have and give my old power tools a new lease of life. I've seen many tutorials online of how to do this safely.

I will be checking out Fogstar.

I will be using a Bafang BBSHD mid-drive motor with a GT Avalanche 3.0 donor mountain bike. I was tempted to go for the ASI BAC855 controller but decided to keep the stock controller and use a motor programming kit instead. I intend to use the bike for commuting to and from work, it's only a nine mile round trip so the range shouldn't be an issue. The project is practically finished, I'm just trying to decide which seat to use. I'm more interested in comfort than performance although the BBSHD is no slow coach.

It does look as if the Sony VTC5 is the way to go, given the power and discharge rate figures. I have seen some ludicrously low prices for these cells on the more 'popular' websites. I can only assume that these cells are not genuine. I will be sticking to the UK based, tried and trusted suppliers. Thanks for the advice everyone.

That's why I'm on this forum, to glean advice from those who have more experience than myself. It's not such a disaster for me because I have plenty of gadgets that can use these cells. I was aware that it's not wise to mix cells in the same battery pack for various reasons, that I won't go into here. To say that I've been careful with these and other Li-ion cells is an under-statement, a couple of youtube video's showing 18650's catching fire was enough to convince me that they are not to be mistreated or short circuited. LG, Panasonic and Sony brands seem to be the most popular for self build batteries from what I've seen so far...

Hi, These are some battery cells that I currently plan to use in my battery packs. I have two sets:- VANON 18650 FP20R 200822 3.6V / THG190063090 THISS 18650HR20R 2020. 11. 30 3.6V As I understand it, these cells should be suitable for my battery packs because they were intended to be used in high current drain power tools. I know that there is at least one website I visited a couple of months ago that provides ratings and technical information on many, many 18650 cells but I can't remember which site it was and I've emptied my browsing history since then. Can anyone direct me to a website that I can use to at least give me the expected performance or specification of these two cells? please check out the pictures.

Thank you, I know that 18650's can be extremely volatile if not treated correctly. These are the battery cells that I currently plan to use in my battery packs. I have two sets:- VANON 18650 FP20R 200822 3.6V / THG190063090 THISS 18650HR20R 2020. 11. 30 3.6V As I understand it, these cells should be suitable for my battery packs because they were intended to be used in high current drain power tools. I know that there is at least one website I visited a couple of months ago that provides ratings and technical information on many, many 18650 cells but I can't remember which site it was and I've emptied my browsing history since then. Can anyone direct me to a website that I can use to at least give me the expected performance or specification of these two cells? please check out the pictures as well.

Your advice is greatly appreciated. The batteries I have were all bought from the same supplier at the same time from Ebay. I cannot guarantee the batteries came from the same factory but they all look identical. The battery packs had good reviews. And the voltages of the cells are within .01v and .02v of a volt of one another. 94 of the 100 cells are exactly the same voltage to two decimal places, I only need 91 for my 13s 7p battery pack. I will be doing a capacity check on twenty of the cells at random with my Imax B6's, one is genuine, the other is a clone. I also will be checking with a ZB2L3 module as well. I have fifteen of those.

I am aware that there are a lot of fake, sub-standard batteries out there, it is a minefield. I will be checking the cell capacities over the next couple of days.

Hi, I put together these drawings on my computer to illustrate how I plan to spot weld the cell groups together based on the photo John Jones posted recently on this forum. I would be grateful for your comments. Hopefully I haven't made any mistakes. Any improvements or corrections to my battery pack would be welcome. If all is well then I will put together a graphic for the BMS wiring as well. As for the 18650's themselves, I have harvested them from brand new never used Makita batteries. I bought ten packs altogether. Each battery pack contained 10 cells each, and each cell measures approximately 3.55 volts according to my multimeter. I haven't charged them as yet. I will post the exact model number of the cells here shortly.

Thank you for the prompt reply. I found the information you supplied very useful.

Thank you so very much for what appears to be the solution to my problem. This is exactly what I've been looking for. I have tried so many different cell combinations myself without being totally satisfied with the layout. Once again, you have my sincere gratitude and have possibly saved me many more hours of trawling the Internet. Fantastic. Yes, the home-made spot welder looks a little complicated, but it really isn't. Planning and research is the key I guess. There are lots of examples and variants of what I've built. Especially on Youtube.