eFoil Battery Packs

It’s EVA foam sheet.

@Skysurfer what BMS did you use instead?

Hi, I use now a 100A BMS. I hope, this will be strong enough! It’s the 12s Version of this BMS.

€ 55,27 11%OFF | 48 v 100A smart BMS mit Bluetooth und PC kommunikation für 54,6 v Lithium-18650 batterie pack von Elektrische motorrad li PCB board

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Regarding discharge rate, when you have multiple batteries in parallel or series, does the max discharge rate increase?

For example, this cell is 3.7v and 42aH with a 1C discharge rate:

I understand that 1C is essentially 42A in this case for max continuous discharge. If I build a 16S2P, to get up to 60V and 84aH battery pack, will my theoretical max discharge rate ever be larger than 42A? From what I read around here, we need 100A+ max continuous discharge to get out of the water, for a rider of my size (250lbs).

Thanks to anyone with some words of wisdom. I’m just starting to put together the parts for a build and the battery bank appears the hardest (most expensive) element of them all.

If u put 2 of those cells in series, u will end up with 7.4V and 42Ah pack with max 42A discharge. (if 1C is max discharge)
If u put 2 of those cells in parallel, u will end up with 3.7V and 84Ah pack with max 84A discharge. (if 1C is max discharge)

Series connection raises voltage, parallel connection raises amperes. 3P pack would give u 126Ah of energy stored (well, under 126Ah since u wont be dischargeing it to 0) and 126A max discharge.

16s 2p i think it will be around 30kg, way to heavy, so you need to increase C rating, and these are not easy to solder together
100A to take off, not sure if you increase the size of the board and the foil wing

if you built something , built a 12s12p battery with 18650 cells (easier to solder) with 30Q for exemple you will have the power needed for 8kg

Thanks to both.

After searching & researching most of the day, I stumbled on this one on Alibaba:

60V @ 50AH with 150A max discharge, all in a nice package. The site doesn’t talk about dimensions and the weight is obviously wrong…

I use these guys off aliexpress. They have good turnover and basically 100 percent positive reviews. Only 1 negitive review in the last 6 months.

I just recieved a 14s7p samsung 18650 INR 35E Pack a few days ago for my new project. Quality is great and they went out of their way to get it shipped to NZ which can be problematic for Lithium batteries. Got it through customs without charge too which was a plus!

https://www.aliexpress.com/store/407696?spm=2114.12010617.0.0.25802e8bHr5VvP

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Thanks Michion…

The supplier I found responded with this:

Battery pack : Chinese 60V 18650 rechargeable 50Ah li-ion battery pack

1)Norminal voltage: 60V
2)Norminal capacity: 50Ah
3)Battery cell: Chinese 3.7v 2500mah
4)With PCM for circuit protection, work current design: 40A(design for 1680W motor)
5)Battery cell combination: 16S20P
6)Weight: About 16kg/pc
7)size:330220150mm/pc
8)Unit price : EXW USD525/PC (without including ship cost
9)Delivery time : 15 working days
10)Warranty period:1year
11)payment : trade assurance

4pcs 60V 50Ah li-ion battery pack shipped to USA:USD546(including import tax, door to door,around 8~10working days arrive.

So in total:battery cost 4*525+ship cost USD 546=USD 2646

That will be a very heavy battery. About 16 Kg.
I dont think I would want any more than 8 kg of battery on an efoil.

If you spend more on quality cells you can get a lot more Ah for the weight.
For example you could get a 14s12p with quality 3500mah cells.
That would give you 42ah and weight about 8.5 Kg.

if i was to build another efoil I would be using this battery.
14s10p 35Ah and about 7 Kg.

The discharge rate could be a little bit to low.

yeah, true! forgot to add that I would ask for a 70Amp BMS. The cells are capable of more.

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For me the best value on the market is:
N.e.s.e modules sold by @agniusm
30q cells sold on nkon

Yes it is not cheap and a full 8p1s module is 500gr

But you built the battery in less than 1 hour with no soldering or special tool , it is bullet proof , full copper , the module have been tested over 200a …

When the cells are dead just change the cells and re use the module

So safety , time built , and long term money wise : is it a good deal i think and i will update my build post with this soon

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Fogstar wholesale comes in a bit cheaper than nkon.

Got 200 cells from nkon on sale for 3,45€/ cells ( have to check this… ) at the Time

That would have come to about 2.89 €/cell at fogstar…

All including vat and rate € for grade A cells ? Indeed that was a good price !

Thanks everyone - It is very nice to see helpful responses and encouraging people in a forum…

To continue the parrallel / battery pack / bms discussion…

Assuming we have 2 * pre-made battery packs (60v @ 20Ah for example) in parallel and each one has BMS protection, then would an additional BMS be required? I assume they would balance out in voltage naturally if the proper voltage was injected into the 2 parallel battery packs (each with BMS). Any disadvantage to that?

Hey @michion Did you buy any pack from this seller before? Problem with Chinese seller is you never can be sure if they are genuine cells or not otherwise this pack for around 500$ is an amazing deal

I received one of their packs last week. They have a lot of really good reviews and some of their reviewers have tested the batteries they have received.
I agree that most of the Chinese suppliers cant be trusted, but I did my homework on this supplier before I bought it, and Im glad I did. Great quality.
The price was OK, but this is only a 24Ah pack I bought.