[Shop-talk] EE question

[Matt]

Our flight department generates some nice 28V batteries that have a time limit
in the planes but have a lot of life still in them.  I was thinking of making
a UPS with them.  I guess it would mean a 28V float charger and in inverter
that would work off 28V.
A 28V to 110AC inverter should be a relatively common aircraft item.  Finding
one no longer flight worthy would be the way to go.
I know there are 28V Li-ion tool chargers but I don't think they would work
for lead acid.
Any ideas from the group?  How hard would it be to have someone  with the
capability draw up the design and I build from components?  It doesn't have to
look pretty.
Thanks,
Matt