Hi, I’m in Argentina and customs suck here, but heard from a guy that could import a battery pack, so may have to take a chance and try that
Oh yeah, customs are really bad in a lot of South America from my understanding. I spent 2 years in Brazil and it was pretty bad there as well. I’m sorry man.
Not sure if vaping is common in Argentina, but a vaping store may have some better cells for sale.
i would recommend LG HE4 or HE2 both are model very simillar to samsung 25R and in many cases cheaper if you are going for over 100A setup you should choose LG HD2C OR samsung 20R
does 100a pulse mean that i can run 2p with a 6s setup no bms?
100A pulse means that per the manufacturer, the cell can handle a split second current draw of 100 Amps. Having said that, I would only look at that as breathing room. Definitely not something the cell can sustain.
So with that in mind, I would not recommend a 6s2p setup with these, or any, Lithium-Ion battery. The lower the number of cells in series (thus lower voltage), the higher the amp draw will be. So the 6s is already pretty low in that sense. I would strongly recommend against any 2p Li-Ion pack, unless you’re considering a larger cell (a 26650 instead of 18640) and a larger series count 8-10s
6s 5p no bms tho?
I suppose that would work. I would still recommend a BMS though, but there’s no consensus on that. For protection, many argue that the VESC does a good enough job (which I think it does) to not need a BMS. For charging, some just use an external balance charger while others just rely on the relative stability of Li-Ion cells (at least compared to Li-Po cells) to not become too unbalanced.
I decided to kind of meld the two ideas together. I’m bypassing the BMS for discharging and instead relying on the VESC for voltage and current cutoff (protection). I did that so i could use a pretty cheap BMS that has a low discharge rate, since it didn’t matter if it has a low discharge rate. In essence I’m only using a BMS for balance charging, so I would only have to carry around a simple power source with a simple DC power jack and just plug it in to charge
I don’t quite understand that part, can you guys explain what happens with the discharge rate when joining cells? What happens in series and in parallel with it? Do they add up? Thanks.
You add charge/discharge rates when they’re connected in parallel, not in series. You also add capacity in parallel. You add voltage in series, but not capacity/discharge.
By adding batteries in series you increase voltage. 1x cell = 3.6v nominal (li ion) / 3.7v (lipo), 6x cells = 3.6/3.7x 6 = 21.6v (aka 24v)
When paralleling, you increase total capacity and also discharge ‘‘capacity’’ or rate. E,g, - joining 2x cells, who has 2500mah each and 10A discharge, you get 5000mah and 20A discharge.
Basically, by adding two (or more) in parallel, you make one ‘‘bigger’’ battery with the same voltage.
You can combine series and parallel. combine 6 ‘‘packs’’ in series, and get the 24v (21.6 nominal), where each ‘‘pack’’ might consist of multiple cells,
Search around. Someone might have explained this better.
Thanks, that totally clarifies it! I knew about the voltage and amperage but not the charge/discharge rates. So you could in theory use a lot of low dicharge rate cells in parallel (maybe cheaper) with the drawback of adding a lot of weight right? See you!
Yes, although… it seems more cost effective just to get ‘‘decent’’ cells… and not mess around with many low discharge ones… unless you get them for ‘‘dirt cheap’’… like salvage them from somewhere or get them for hald price, idk
Price will tell your the best option… there’'s an option to build a high capacity pack, since for higher capacity cells discharge rates are usually lower.
Here’s a good infographic I found in one of the vaping forums, there’s some russian text but you should be able to get the right idea… (I hope there’s no copyright, otherwise I might just direct to the original source)
So yes, by adding many cells in parallel, you will soon come across how much space do you really have to house all of these cells… There might be extra hassle balancing or getting a protection for them, but as I have not built a battery pack yet, cannot comment decently on this matter.
I found an EU battery builder who has been cool & responsive, but he seems fixed on different cells from what you guys are saying… This is latest I got:
Okay 1 vesc per board, so not crazy high power I think we can install regular 10a cells.
If you can have pack with dimensions 53cm14cm2cm and in one spot height from 2cm to 4.5cm(for bms 12x12cm) then you have 48cells. That equals to 6s8p - 22V 26Ah ~520Wh Bms will be good for 60A continous. Cells can give 80A burst for few seconds, for continous use i would stay around 30Amps(~700W).
To summarise: Pack of 48 sanyo ga cells 6s8p bms 60A (with balancing led)
What do you guys think? Everything I’ve read so far says that’s not what everyone else does… But I don’t know how to revert back to him in a technical enough way (want to avoid sounding like a spoilt kid)… Or is the suggestion cool?
If i were you , i would go 10S 5P (50cells) with the sanyo GA cells . Higher voltage =better for electronics and higher speed.
5 in parallel will give you 50 amps continous power if needed.
Well you can consult other ppl here… and 80A is more than enough for continous power I think… you can contact @whitepony to find out at what speed / power he managed to ‘‘break the barrier’’ and reach close to that amp draw…
10S5P seems like a good solution… you will still get around 15+ah (at ~3200 mah for sanyo)
50GAs is probably ok with 1 vesc - overall you should check how fast you want to run on average, how flat your hood is and how hard you want to ride your board.
I managed to warm up my 10S4P HG2 with excessive full throttle, full braking hard riding. if i keep constant velocity with 30-40kph riding speed it stays cool.
Thanks millions guys. Appreciated. What about two vescs (dual diagonal setup)? Does that change anything?
Anyone using Samsung’s 30Q? The same performance as the HG2 but a little bit cheaper, I’m thinking in using then on my next build in the place of the Panasonic’s NCR18650B, they sag a lot with 0,11 ohm internal resistance, versus 0,02 on the 30Q
The trouble with HG2 cells is they are more tightly wound and the coulombic efficiency will decrease more rapidly than a similar cell with a lower capacity like the HE4 or HE2. This is only a problem if driving the cells hard in a small pack, if you were to use the HG2 in a very large pack the cells would not be stressed hard enough to cause much plating.
Is this why I notice serious loss of power with my vesc, carvon v2, and lg hg2 12s4p pack? @chaka