Solar panel, with no aero loss. what gain?

[Isaac Zachary]

Originally Posted by serialk11r

Lithium titanate is nowhere close to lead acid. It's the same as lithium iron phosphate per Ah just lower voltage. 6 in series will be 50% heavier. 14.4V on a 6S pack is 80% charge which is not that bad.

I know because I run a lithium titanate starter battery. It's 15lbs 5S 40Ah. The voltage curve is steeper than some images on the internet suggest.

I still think you can use a lithium polymer battery if temperature isn't a problem (I assume it's not if it sits in the back of the car). It will only cycle in a narrow range and will probably never be depleted.

Ok, so LTO's are better than LA's. But they are still less energy dense than LFP's by quite a bit. Running 80% would be even less energy dense. But a lot comes down to price per Wh too, and the kind of temperatures you'll be in.

According to Wikipedia:

• LA 35-40 Wh/kg 80-90 Wh/L
• LTO 60-110 Wh/kg 177 Wh/L
• LFP 90-160 Wh/Kg 325 Wh/L

I've been very interested in LTO's for two reasons. One is for ham radio power. I live where it gets cold, and LFP's don't do well in the freezing weather. But the voltages aren't ideal as ham radios like to stay around 13.5V and can't be used much over 14V. So a 6S LTO battery could work, but would not even make it to 80% charge. I don't know, maybe I'll at least try a LTO 6S if it isn't too expensive.

The other reason is for a hybrid battery replacement for the NiMH battery in the Prius and eventually Avalon, but again, keeping it within the voltage tolerances of the BMS of 12S NiMH cell blocks running at around 14.4V to 18.5 per block is also hard to fit a block of LTO's into. A 5S LFP block would work and has been demonstrated to work very well actually as a NiMH replacemnt for Prius HV batteries.

[Phase]

apparently the guys at the ioniq forum said the ioniq doesnt even have an alternator. the hybrid battery just charges the 12v battery on its own. so for solar im screwed i guess. sucks that i cant solar charge the hybrid main battery. you normal car people are lucky

[Isaac Zachary]

Originally Posted by Phase

apparently the guys at the ioniq forum said the ioniq doesnt even have an alternator. the hybrid battery just charges the 12v battery on its own. so for solar im screwed i guess. sucks that i cant solar charge the hybrid main battery. you normal car people are lucky

I have two hybrids and the same story, both charge the 12V off the HV battery.

[Phase]

Originally Posted by Isaac Zachary

I have two hybrids and the same story, both charge the 12V off the HV battery.

it would be nice for solar to help charge the HV battery. free energy is free energy

[Isaac Zachary]

Originally Posted by Phase

it would be nice for solar to help charge the HV battery. free energy is free energy

Yep. The Prius needs a new HV battery and I'm tempted to install a Nexpower Lithium Project Prius battery which holds more Ah than the NiMH battery but costs about the same as an OEM battery, and then put a solar panel on top of that.

Since having my Leaf, I've envisioned a canopy solar panel, one that sits up off the top of the vehicle, is thin, and is curved to the contour of the air flow. If placed over a vehicle with a boat tail, I do believe that up to 2kW would be possible. Even at 1kW, that would possibly get me enough juice I could drive off electricity entirely from my place of work and back to my house every day instead of getting a pathetic 25mph in my Prius because of the short distance and never warming up the engine fully. Even now I sometimes don't get past 110°F engine temps from point A to point B.