I just won a bid for twelve Prius packs! They should hopefully be arriving later this week or early next.
Update: Batteries arrived and ready to be installed!
Each pack is a 7.2 volts 6.5 Ah prismatic NiMH battery with six cells. I'll be configuring them as 6S2P for 43.2 volts 13 Ah. I'm hoping that I can get at least 60% of the SOC from them (80% to 20% as on the Prius). That would be 43 volts, 7.8 Ah or 335 watt-hours.
This is perfect as I'm currently consuming 200 watts-hours each way with the heavy SLAs. The lighter NiMH packs should get my power consumption down even lower.
|SLA||Tempest TR35-12 (rated 35Ah) |
-- 35 Ah @ 36 volts
-- I don't get 35Ah, closer to 10 Ah due to Peukerts
Specific Energy 35 Wh/kg nominal
Specific Energy 10 Wh/kg derated
|360 Wh|| 1 @ 11.8 kg
3 @ 35.4 kg (78 lb)
|NiMH||Prius Gen II Battery (rated 6.5Ah) @ 1040 grams|
-- 13 Ah @ 43.2 volts
-- derated 60% for a conservative Ah of 7.8 Ah
Module Weight 1040 g
Specific Power 1300 W/kg
Specific Energy 46 Wh/kg nominal
Specific Energy 27 Wh/kg derated
1 @ 1.04 kg
12 @ 12.48 kg (27.5 lb)
It looks like I'll be saving a good 20 kilograms or 50 pounds with only a slight loss in Watt-hours! I will have to bodge up a new battery carrier as the cells need to be kept under compression when being charged.