If I regroup my 12 paralled cells in 10 modules, can I then join these in series using single wires (one for neg, one for pos) between modules, instead of wiring each terminals of each cells like you are doing. Could this affect BMS and/or have any negative impact on cells balance?

and i also have another question if i charge the 2 packs seperately then connect them to my bike in parallel do they both have to have the same capacity and the same wear for instance i currently have 2 sets of batteries (sla’s) one of which is an old set at half original capacity or there abouts and the new ones hold batteries for electric scooters canada full charge so can they be connected together to give me 1 1/2 x my range? or if im going to put a double pack on do i have to use and charge them together so theyre all at the same state of charge and wear the same as ideally i would like to only have to carry a second pack when i require the extra range.

I’ve been building a 13s6p Li-ion battery based on your article, and everything went swimmingly (except underestimating the amount of nickel I’d need) until I started hooking up the BMS. I was in the middle of hooking up the sense lines, and the BMS smoked. Opening it up, it looks like a few of the caps that couple adjacent nodes burned. Have you seen this before? Any thoughts on what I may have done wrong, or does this just happen sometimes when a cap’s voltage tolerance is outside spec?

Nickel Metal Hydride is quite similar to Nickel Cadmium, but with a higher energy density and a safer environmental record when disposed of in landfills. This is the dominant rechargeable battery type in digital cameras and other consumer products that offer user replaceable cells.

Regarding your first question: as long as your BMS has a balancing function (most do) then you do NOT need a charger that does balancing, and in fact you should not use one. The BMS takes care of all the balancing, so all you need is a simple ebike charger. What is important though is that it is a CC-CV (constant current, constant voltage) charger. Most ebike chargers are, but just check to make sure it says that somewhere in the description, or ask the vendor if you can’t find it. The CC-CV part means that the charger will supply a constant current first, bringing the battery voltage up slowly until it reaches the full voltage (54.6V for your 13S battery). Then it switches to CV mode and holds a constant voltage while it gradually backs the current down to zero, which is the ‘finishing’ part of the charge.

Yes, I’ve seen this problem. Homes that have only a 10A circuit breaker are often not enough for these welders. The room I wanted to use mine in had a 10A, so I switched it for a 20A breaker at the breaker box and now it works fine.

i have the exact same BMS but i only have 6 cells, 2p x s3 , i have 2x 3.7v @ 2000 mah batteries in parallel connected to another 2 parallel batteries in series and another parallel pack in series if that makes sense to make a total of 11.1 v @ 12mah for a small project.

I am currently building my own 36v battery and now using some of the ideas you have put here. but I am wondering what is going to be the best charger for charging the battery?? As I am doing on the cheap, I am utilising a 12v 6A charger which I previously had. My plan was to couple with a 12v to 36v step up DC transformer but then realised that this may not be enough to charge the battery fully. This is because the full charge voltage on the battery is actually 41v which would be higher than the step up transformer. The next option is a 48v charger which would be too high.. Or would the BMS kick in and protect from over voltage?? This is all theory at the moment so I am probably missing something.. Could you suggest a charger method. Am I on the right track?

Before I seal my batteries in heat shrink, I like to wrap them in a thin layer of foam for added protection. This helps keep the ends of your cells from getting dinged if the battery receives any rough treatment, which can happen accidentally in the form of a dropped battery or ebike accident. The foam also helps to dampen the vibrations that the battery will experience on the bike.

Table 2 provides a brief comparison of lead acid to LiNMC on a pack level. It should be noted that both chemistries have a wide range of parameter values, so this table is only a simplified representation of a very complex comparison.

When you series connect batteries, you want to make sure they are packs with identical capacity and specs. You also want to make sure that either your controller or Cycle Analyst low voltage cutoff is set such that the discharge stops as soon as one pack trips. Otherwise continuous current will continue to flow through the pass diode when you are running off just the one non-tripped battery, causing the diode to overheat and fail.

Thank you for the very informative post, and it has helped a lot. I plan on building a battery pack with 20 cells with blocks of 4 in parallel, and then I am going to put those in series to make an 18.5V, 13.6A pack. Sorry if these sounds a little bit foolish, but I am not sure what kind of BMS I should be using. Would I be able to use any BMS or would there be an issue with having extra wires if the BMS can power more batteries in series?

To calculate the max amps the battery can deliver, you have to know the max amps of the cells you used. For example, Panasonic 18650pf cells can deliver 10A continuous, and I used 3 cells in series in this battery, so the battery can deliver 3 x 10A = 30A. However, you also need to know how much current the BMS can deliver. If I put a 15A continous BMS on this pack then that would be the “weakest link” so to speak, meaning the pack with the BMS could only deliver 15A continuous.

Capacity: 20Ah. 36V 3A Charger. Lifecycle of single cell: >85% capacity after 1500 cycles, > 70% capacity after 3000 cycles. (<1C discharge rate and <1C charge rate). It will take about 7 hours to cha... thanks for detail explanation , I was enjoj reading it. Well, I am interesting why did you pick this tipe of battery, I was thinking to use LiFePO4, I know there are usualy 3.2V it is less than 3.6V like here? Also, can you explain me how to calculate max current of battery, it says that you get 8.7Ah, but how much Ampers and what is the power of battery, how many Watts (P = U * I)? Furthermore, without welding, can I do on contact connection, like for example are battery in remote control? Note that in the article it says that LiFePo is the most commonly used chemistry. I think that depends on where you are looking. I suspect that LiNiCoMn or the older LiMn is actually most common in terms of total unit cells because they’re the cheapest and get used in the low end E-Bike market in China. Also I wanted to “hide” the batteries in the Brompton frame aligning the batteries in file, I understand it would not have a long range but would be quite stealthy. If you have any recommendations please do tell me [redirect url='http://electricbikebatterys.com//bump' sec='7']