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#### ElectriCar

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Thundersky cells have a higher internal resistance which means voltage drop across the cells. You probably know this but in case you don't, that is power that is consumed internal to the battery and thus lowers voltage output under load, think sag like. Though the sag isn't as much as our lead, I still want all the voltage available to go to the motor and not be consumed internally.

Though the internal resistance may not be much, when you are drawing hundreds of amps it can be rather large. I'm thinking the internal resistance of HP cells is like .001? don't recall exactly but seems like the TS cells were maybe .002. Not a large number but still was double the HP cells, whatever it was.

To figure the voltage drop, multiply the amp draw times the resistance number to get your voltage drop (loss). Ie for 400A across .001 ohm resistance is .4V. Across the TS cells 400*.002=.8V, a HUGE difference!

So for a 144V pack of 45 cells, that's only an 18V drop leaving 126V to your motor versus a 36V drop on the TS cells leaving only 108V for your motor, NOT GOOD!

#### ElectriCar

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Just talked to Keegan and he told me the warranty is 2 yrs. Also noted on the specs the internal resistance is <.0006 ohms. So a 400 amp draw would make the voltage drop per battery .24 or less & for a 45 piece pack at 144V you would have a drop of 10.8V max, leaving 133V minimum to move the vehicle!

#### ElectriCar

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I’m not sure where you got the information on the Thundersky cells but it is incorrect. I have 45 TS 180 Ah cells (144V) and the voltage only sags to 133V when drawing 540 Amps. This includes the voltage drop introduced by all the connecting links and 35 feet of 2/0 welding cable.

This is the voltage and current seen at the controller according to the data logger files I took from the Soliton-1 controller during a typical acceleration event.
Dude that is awesome! Did you run that vehicle on lead before? Just curious the difference in the performance versus the same pack voltage using lead. Also what is the difference in the watts/mile in the TS vs lead pack?

#### ElectriCar

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...internal resistance is a moving target dependent on factors such as temperature and state of charge. 50% state of charge during the winter won't do as well as a battery fresh off its charge on a hot summer day...
Wow, I didn't know that. All I've found is the internal resistance numbers for various batteries on battery vendor websites.

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