Yesterday, 12:49 PM
I plugged my XT90'd wattmeter into the ESC parallel port and it shows battery voltage, so it seems there is no damage from directly shorting battery for a few seconds. not to ESC, not to battery, not to any wiring.
It was supposed to be cool and wet today so I did not bother charging the Sk8 last night and it revealed a 34.1v battery.
It rained only a little and the cold air has not yet reached this far south.
3.4 volts per cell was enough to get us the mile to the park but it hit the soft cut once there.
I plugged in the portable charger and Dialed up 250 watts and then a bit later cranked it to 315 watts, then a bit later down to 250 watts.
I kept dialing it down, not for the battery or heatsink heating, but in order to squeeze out as much Wh and AH as I could.
I was watching a voltmeter plugged into its charge port when it was delivering just 71 watts, and it cut out at 18.6 volts which is an average of 2.65 volts among the 7 P groups. It said it delivered over 4 amp hours, but only 152.2 watt hours into the BAK 45D 10s2p.
So the lower the BAK battery voltage the lower the watt hours the portable charger can deliver.
Anyway, it was enough to cruise 4+ more miles at a good clip, and return with about another mile or so left in it.
The BAK 45D 10s2P has many hundreds of partial cycles on it, and must have lost some capacity, but it does not seem to be a significant amount.
The lack of top speed on a cool day noted in a previous post, and potentially attributed to more voltage sag of aging cells, was likely mostly caused by cold temps causing much lower tire PSI on Esk8 and chariot.
Reliance has a top performing 21700 power cell available now, the RS50. They are teasing us with the release of the RS60, a 6000mah cell with a 50 amp CDR, which is another giant step ahead. It could be available to us Peons by the second half of the year.
Amprius has released a high capacity Energy cell which is testing in over its 6500 mah claim, at low amperages. It has a CDR of only 13 amps, but enough in parallel could make a good high capacity compact battery.
Molicel and Tenpower are collaborating on the M65, a 6500mah 21700 cell which is kind of a hybrid power energy cell with 6500mah and a 26 amp CDR.
That too might be available the second half of this year.
My esk8's ESC with a 10s2P battery can only draw 12 amps per cell so the 60 amp CDR( temp limited to 80C) of the BAK45D means my cells run very cool, which helps them not degrade as fast, and also not sag a bunch of voltage under load.
If one of these newer cells can still stay relatively cool and not sag too much and deliver 30% more capacity, that would be quite a game changer.
Until then, I am glad i have the portable charger, parallel battery ability, and the less refined battery + booster methods, to fill the range gap.
It was supposed to be cool and wet today so I did not bother charging the Sk8 last night and it revealed a 34.1v battery.
It rained only a little and the cold air has not yet reached this far south.
3.4 volts per cell was enough to get us the mile to the park but it hit the soft cut once there.
I plugged in the portable charger and Dialed up 250 watts and then a bit later cranked it to 315 watts, then a bit later down to 250 watts.
I kept dialing it down, not for the battery or heatsink heating, but in order to squeeze out as much Wh and AH as I could.
I was watching a voltmeter plugged into its charge port when it was delivering just 71 watts, and it cut out at 18.6 volts which is an average of 2.65 volts among the 7 P groups. It said it delivered over 4 amp hours, but only 152.2 watt hours into the BAK 45D 10s2p.
So the lower the BAK battery voltage the lower the watt hours the portable charger can deliver.
Anyway, it was enough to cruise 4+ more miles at a good clip, and return with about another mile or so left in it.
The BAK 45D 10s2P has many hundreds of partial cycles on it, and must have lost some capacity, but it does not seem to be a significant amount.
The lack of top speed on a cool day noted in a previous post, and potentially attributed to more voltage sag of aging cells, was likely mostly caused by cold temps causing much lower tire PSI on Esk8 and chariot.
Reliance has a top performing 21700 power cell available now, the RS50. They are teasing us with the release of the RS60, a 6000mah cell with a 50 amp CDR, which is another giant step ahead. It could be available to us Peons by the second half of the year.
Amprius has released a high capacity Energy cell which is testing in over its 6500 mah claim, at low amperages. It has a CDR of only 13 amps, but enough in parallel could make a good high capacity compact battery.
Molicel and Tenpower are collaborating on the M65, a 6500mah 21700 cell which is kind of a hybrid power energy cell with 6500mah and a 26 amp CDR.
That too might be available the second half of this year.
My esk8's ESC with a 10s2P battery can only draw 12 amps per cell so the 60 amp CDR( temp limited to 80C) of the BAK45D means my cells run very cool, which helps them not degrade as fast, and also not sag a bunch of voltage under load.
If one of these newer cells can still stay relatively cool and not sag too much and deliver 30% more capacity, that would be quite a game changer.
Until then, I am glad i have the portable charger, parallel battery ability, and the less refined battery + booster methods, to fill the range gap.
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