No, it not just you, I don't get it either -  running 12V batteries pancake  flat seems to be a design blind spot on a lot of equipment, especially vehicle mounted, when cutting off at 11.5V or something for loads, and rather higher for chargers would save a lot of lead from a premature trip to  the scrap man.

I reckon less than half lead acid cells  survive the full decade and a  thousand or more charge cycles they could do if managed well.

For some corner case military situations using a rechargeable to the death may make sense, but not normally, so even there could easily be a training/ warfare switch even for that.

With modern power FETs that can swing tens of amps when fully on and turn off to the nano-amp level there really is no excuse for a standing load of any kind that is even comparable to the natural ageing of the battery - which would be at most a few % of capacity per month or a shelf life of a year or more from full  to half flat. So for every amp hour of capacity, a 'dead load' of 100uA say.

10mA is nowhere near 'negligible' !!  (unless you have a spare few hundred amp hour battery capacity I guess) that's less than 1k ohm for heaven's sake !  I could run you a slow data radio link on that .Are they still using bipolar transistors ?

M.

I think it's because of all the pretty LEDs they use to indicate the battery and solar panel statuses - we're going to show you lots of LED lights to indicate that it's the middle of the night so we're running your battery flat by lighting all these lights to show you what's happening! Although from a very brief look at online forums it looks as if the LCD panel versions may have the same sort of drain.

I found it because I was testing the charging setup out on a little 1.2Ah battery and wondered why the battery had gone flat overnight with no load... 

even that's not great - LEDs that only need a mA or that flash are available. And dropping 10 out of 12V to light an LED that needs less than 2v  is not  best done by resistor.

M.

even that's not great - LEDs that only need a mA or that flash are available. And dropping 10 out of 12V to light an LED that needs less than 2v  is not  best done by resistor.

M.