Field Weakening for Efficiency

[Phantom]

I'm not sure if this would work but could you just run 10 8v batteries in a parallel/series setup to give you 40v. I know it would increase the amps but I'm not sure if it would increase the aH.

Or if you would run two strings of 4 12v for 48v and switch to the second string when the batteries are low on the first. This would allow you to also charge one string while using the other.

[TomEV]

Experiments can support or help disprove theories. In this case it appears that FW may have some positive effect, but the gains are relatively low.

Here are the latest numbers -

Day Miles wH/mi
1 - 11.9 - 224
2 - 13.9 - 217
3 - 11.3 - 232
4 - 23 - 227
5 - 15 - 220
6 - 14.1 - 194
7 - 7.9 - 252
8 - 4.9 - 229
9 - 9.4 - 223
10 - 5.6 - 220
11 - 11.9 - 231
12 - 11.4 - 222
13 - 8.9 - 221
14 - 9.9 - 235
15 - 13 - 242

Average wH/mi with FW on - 226 (FW on during steady state driving)
Average wH/mi with FW off - 229 (from previous months)

So far, the experiment points to the use of FW during certain drive environments as not producing a significant difference. I'd probably need about 30 samples to produce a reliable trend line.

Overall this month, I'm at 229 wH/mi using mixed FW and non FW driving, which is about my normal level of efficiency.

[TomEV]

Here are the final numbers -

Day Miles wH/mi
1 - 11.9 - 224
2 - 13.9 - 217
3 - 11.3 - 232
4 - 23 - 227
5 - 15 - 220
6 - 14.1 - 194
7 - 7.9 - 252
8 - 4.9 - 229
9 - 9.4 - 223
10 - 5.6 - 220
11 - 11.9 - 231
12 - 11.4 - 222
13 - 8.9 - 221
14 - 9.9 - 235
15 - 13 - 242
16 - 8.7 - 218
17 - 18 - 235

Average wH/mi with FW on - 226 (FW on during steady state driving)
Average wH/mi with FW off - 229 (from previous months)

Overall this month, I used 232 wH/mi using mixed FW and non FW driving, which is about my normal level of efficiency. According to the data, Field Weakening doesn't improve efficiency to a significant degree at mid power levels.