Hello everyone. Been doing my research through everyone’s posts and decided to add some of my own.
I made this cool spreadsheet of the best performing 18650 battery cells for high current draw (140-150A). The information is based on tested reviews found on the following website:
Thank you. Very informative spreadsheet.
Mooch, the guy behind the tests makes excellent videos. Minding your mAhs Episode 5 is a nice example.
His YT channel: Battery Mooch and the first episodes of “Minding your mAhs” are soo informative.
Something to pay attention to (and it’s difficult because the eFoil activity is too recent) is the longevity of the cell. What does the area under the mAh curve become after, say, 50 or 100 cycles of charge ?
Well made thank you , but i don’t think we can run at max current discharge rate , most of the cell will get to hot
I think we can use 5-10a /cell for cruising and some more for take off
We should consider the w/h per cell at around 10a / cell discharge rate to 3.2v
Heat might be a problem …
I really like the 30q with 7.5w/h and the vtc6 with 7.7w/h (10a until 3,2v)
I think we cannot use 18650 like lipo we have to built large battery pack , more money on the table at first but better capacity
For my propeller setup i got with probably 12x18 30q. Which is 1,17€/1s/A vs lipo multistar 1,33€/1s/A ( simplified)
Are you saying that 150A constant rating is not enough for the foil? From what I’ve read, it seems that it takes only 2-3kW to ride on the foil, and up to 6kW in order to start. I see figures people are posting that say 50-80A draw while riding on foil.
Assuming that the time spent getting up on the foil is not very long, and the ESC is water cooled, I believe that 150A constant draw rating from the batteries should be enough to work without overheating, given that the highest amp draw seen should be around 150-180A or even less with higher voltage, and the batteries have an even higher burst rating than 150.
If you run 18650 batteries close to their max current ratings, they will have less charge cycles. Therefore you want to run them at around half of their max current. You want the battery to have around 200A max constant current potential which will give you a longer life battery.
If you run a cell at its max discharge rate it will get hot and you will only have 1/2 or 1/3 of it capacity : a good 3a cell running at 10a , you will get around 2a capacity before voltage drop to low , the lipo can stand more without a huge voltage drop … Less rpm , voltage sag , take off harder …
It is the same at the end : run a small pack hard, change more often , or run a big pack , if you look at long terme money wise
And as building pack .15 nickel strip are good for 5-10a same as fuse busbar , so 80a ok , but for take off you may have some trouble , you can away with 10p cells , i prefer 14-18p
Actually nowadays with 14S systems it’s not too uncommon to see about 30A continuous when foiling. 100A continuous spec for battery would be enough for sure, as long as it is a true and not a marketing spec. Mind your voltage, though. If you plan to make a low voltage system, you’ll have to figure out a reasonable continuous current for your system. Most systems seem to use around 1.5-2.5 kW when foiling. The best systems can be a bit better than that.
If I was to build another battery pack I would be tempted to go for 16s Lifepo4 32650 cells 16s7p for 42ah pack. If I lived in the US I definitely would.
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