PriUPS Bonus: Multiple Supply Examples - The MEDIUM
I had an opportunity to obtain both the Compaq UPS and a number of 48V
supplies at a good price, and was pleased to discover that the 48V supply would
easily fit in the battery compartment of the UPS. I took this as a Sign
that I should make this system first, and that I should try it without any UPS
batteries, thus running the whole system on just the switcher alone. I discovered
(loud zap) that the Compaq has a nice capacitor across the batteries, so I
became less worried about the battery surge capacity.
||System 2 (Medium)
||~1.4kW at 115VAC
Prius HV system - no power from 12V
||One Cherokee 48V 30A switcher
|Voltage supplied to UPS
||48VDC - runs UPS and fits in empty battery compartment
|DC from Prius HV
||HP/COMPAQ R1500XR (2U rackmount)
|Weight incl. UPS batteries
||30 lbs UPS, 8 lbs switcher. (No batteries)
|Weight w/o UPS batteries
||This is an HP/Compaq R1500XR power supply as I bought it on eBay.
"Cosmetic Damage" was a missing front trim panel, which somehow is not a
huge issue in the trunk of a car.
||Here's the unit with the top cover off and the plastic battery tray
removed. The empty space is more than large enough for one of the
48V switching supplies.
Incidentally, other than the mounting holes for the switcher, the
Compaq needs no modifications at all, and can be re-converted to normal
operation in a few minutes. I deliberately didn't cut the battery
cable to fit but rather stowed the excess length in the battery
compartment. By clipping it onto the switcher instead of soldering
it can be left intact.
||Here, the switcher is mounted in the battery area. I punched a
hole in the side and covered it with a fan grill to provide additional
ventilation for the switcher. So far it's been positively
cucumbric, but as it gets hot out and I try to take more power from the
system I wanted to sure there was enough cooling. The channel to
the right of the switcher and holes in the top of the UPS provide
additional air flow.
||Here's the complete system on a scale. 38 pounds is the
weight equivalent of less than half a tank gas, so even if you keep it
in the car all the time its effect on mileage is likely to be unnoticeable.
||It fits with room to spare in the tray underneath the Prius trunk
area. For a permanent installation this would probably be the best
place for it. As I intend to continue experimenting with different
systems, I've simply strapped it into the trunk area (see below).
Serendipity! The plastic bag you see at the left contains two
straps that came with the Prius, intended to hold down a flat tire when
it's replaced with the spare. They are exactly the right size to
hold the UPS in a fixed position.
||Here, the UPS is plugged in to the Prius HV battery and strapped to
the Prius hardpoint ringbolts. Ready for Field Day!
||I was invited to "Tour
De Sol" to demo the PriUPS system but between the forecast rain and
an unfortunate event that sidelined my driving companion I didn't go.
However, I did put together this demo system using a second R1500XR and
for their use.
This system is very easy to put together. After working out the
details on the first one, the second one required less than two hours,
which period included the switcher modifications. It took longer
to find a page protector for the "instruction manual" and to cut and
paste (literally) the "Ventilation" stickers than it did to assemble the