I have a portable device which draws 2A at 12V and is powered by two 12V Li-Ion batteries (so it draws 2A from each battery).
The batteries are made for hobbyists and are used in model boats, planes etc. They have no on-board protection.
As (small) size and compactness is of great importance, I place the two batteries together in an enclosure and provide DC sockets on the front panel to allow connectivity.
I have made a small-ish circuit to protect the (expensive) batteries. It has a relay which cuts off supply at 2.5A and it also monitors the voltage and, again, cuts off supply at some low voltage (eg 10V or 10.5V). I have to add here, that such devices are not used by hobbyists because the supply must never be switched off while powering a model craft.
My own circuits work well, but are rather large as I cannot use SMDs yet. Each battery protection board which I have made measures 75mm x 50mm x 25mm (height).
For the larger battery packs this board doers not present a big problem, but for smaller battery packs it is too large. I have noticed there are "battery protectors" out there (eg ebay) which have under voltage and over current protection (at various arbitrary ranges) but am not sure this is exactly what I want.
Do you happen to know of a ready-made, miniature design that will do what I need?
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