I respectfully disagree.
While Wh are commonly used that number is only a very rough guide to how much range (running time) you might get. Unless all of the packs you are comparing use the same cells itâs not a great number to use.
For exampleâŚtwo packs with equal Wh specs, one made with Molicel P42Aâs and the other with Panasonic NCR18650Bâs, will give you hugely different run times. Even worse, at low power levels the Panasonic pack could run longer and at high power levels the Molicel pack will run longer.
But until everyone realizes this and stops using capacity and nominal Wh specs as their guide to how long a pack runs weâre stuck with those numbers.
Yes, Wh is not the ideal solution. Thatâs why the specific cell type is also included for everyone to look at.
Imo we canât rate the batteries with your E-Scores because everyone uses his board differently and also all the different power levels arenât available for every cell.
The average current we use usually isnât that high. We just need the max power for acceleration pulls and steep uphill climbs. The average ride has a lot of coasting, breaking and stops too tho.
My apologiesâŚI definitely wasnât thinking that my E-Scores should be used, only that the nominal Wh rating isnât nearly as useful as so many feel.
Excellent!
I agree, it can still be used. But assuming the pack manufacturer has chosen a good cell is not advisable IMO. Iâve seen too many bad packs.
IMO the nominal Wh spec is just relied upon too much (along with nominal capacity) when comparing packs with different or unknown cells.
Agreed on the nominal watt hour not telling the full story. Iâve been trying to decide on a cell and yeah, turns out itâs pretty complicatedâŚ
Watt hour changes dramatically with load, and higher nominal capacity cells like the 50E actually provide less energy than a lower nominal capacity high discharge cell like the P42A at just 15A. If you were pushing a board hard, say hilly roads at 35mph with a 12s3p, a 50E pack would have less range than a P42A pack. However, riding easy with a 12s8p and the 50E doesnât look as bad. This doesnât even factor in all the temperature and life cycle impacts of running these cells at high amps
Watt Hour (Wh) to Voltage Cutoff at different amp draws
3A to 3.0v*
10A to 3.0v
15A to 3.0v
20A to 3.0v
30A to 3.0v
30Q
9.8
9.0
8.5
6.9
N/A
50E
16.4
14.5
12.2
9.0
N/A
P42A
14.1
13.4
13.0
12.6
10.7
48x
15.8
14.7
14.0
11.0
7.6
50G
16.4
15.4
14.7
10.1 (est)
8 (est)
50S/T50
16.8
15.7
15.0
14.2
12 (est)
Too bad all the better performing cells than P42A are unobtainiumâŚ
