$20?...only if you build it yourself
3 good quality 18650 cells, a 3 cell battery holder, a "h" plug and wire,
some way to charge it,,, that would be about $20
You most definitely do NOT NOT NOT want to charge normal lithium cells over 4.2V
3 x 4.2 =12.6 which would be fine, unless there is something in pcie slot consuming 12v power
If it would 'drop out at 3.6 x 3 (battery dead) = 10.8V,,, I don't know
I suspect not
The amazon thing only has 4 18650's in it, normal capacity, but no sales or reviews
The cheap way would be to recycle "dead" laptop battery packs, often 6 cells
3s2p (3 series, 2 parallel) ,often only 1 or 2 dead cells, usually some life left in rest
3 good quality 18650 cells, a 3 cell battery holder, a "h" plug and wire,
some way to charge it,,, that would be about $20
You most definitely do NOT NOT NOT want to charge normal lithium cells over 4.2V
3 x 4.2 =12.6 which would be fine, unless there is something in pcie slot consuming 12v power
If it would 'drop out at 3.6 x 3 (battery dead) = 10.8V,,, I don't know
I suspect not
The amazon thing only has 4 18650's in it, normal capacity, but no sales or reviews
The cheap way would be to recycle "dead" laptop battery packs, often 6 cells
3s2p (3 series, 2 parallel) ,often only 1 or 2 dead cells, usually some life left in rest