Simple battery pack 'Fuel Gauge' links/hints needed.

[herulach]

Can anyone point me in the direction of a reasonbly simple (specifically doesn't need a PIC) homebrew fuel gauge type thing for Li-Ion battery packs? I know I could get the battery junction ones, but for my application they're too big, not to mention postageto the uk is exorbitant.

Thanks

 

[TigerhawkT3]

With Li-Ion, voltage is actually a reasonable indicator of charge state. How big is your pack? DX has a few voltage indicators for small (fewer than 5 cells) Li-Ion packs under "Hobbies & Toys > RC Helicopters."

 

[LukeA]

I have the 3-or-fewer-cell DX indicator in use with a li-poly pack. It works very well for me. The DX comments say the bigger 6-cell indicator is less accurate, but it would still give reasonable SOC indication through voltage.

You can use either a balance jack to get each cell's voltage or you can use the power connectr to read pack voltage. It has 3 digits, so it goes hexadecimal after 9.99V.

 

[herulach]

They look pretty spot on. Thanks guys.