In Wh/kg or Wh/m³? And do you want primary cells or rechargeable?
LiPo can achieve about 400Wh/kg in large installations, but small cells more like 150Wh/kg and 3kWh/m³
LiFeS primary cells can do >300Wh/kg and >5kWh/m³ in small (AA cell) packages even at high (0.3C) discharge rates
There are other exotic/experimental chemistries which can beat those (but not necessarily at the discharge rate you want), but those two would be your main options for easily packaged home brewed power packs.
Wh/kg, rechargeable. To power a Garmin for a few days, so small.
Although if it was possible to connect one-use cells to a battery pack then perhaps they're an option?
I have no idea of the power requirements of a Garmin though.
@hippy
Wh/kg, rechargeable. To power a Garmin for a few days, so small.
Although if it was possible to connect one-use cells to a battery pack then perhaps they're an option?
I have no idea of the power requirements of a Garmin though.