Idea for batteries

Thread Starter


Joined Jul 23, 2009
Hi all

I have two 80v lawn mower battery packs that are doing nothing most of the summer, and nothing at all during the winter.
I would like to use them for a backup power source around the house, but DC-DC converters (down to say 5 or 12v @ 1A) in this range are far too expensive.
Anybody have any suggestions other than a zener diode?



Joined Nov 6, 2012
You don't want a Buck-Converter with that wide of a Voltage range.
80-Volts is somewhat unusually high, this tends to complicate matters a little.

What do You call "expensive" ?, ~$100.oo ?,
are You experienced enough to Build it Yourself ?


Joined Sep 17, 2013
You could experiment with a spare cheapo mains-powered AC-to-DC switch-mode wall-wart (e.g. a USB charger). You will probably find it will happily accept 80V DC input. Internally it rectifies the mains input to high voltage DC before bucking it down to a lower output voltage. If you want, say, 1A at the lower voltage then use a 2A output rated wall-wart, because the rectifier diode(s) will be operating continuously instead of on alternate half-cycles of an input waveform.