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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) | |
| Power Available | ~1.4kW at 115VAC |
| Power source |
Prius HV system - no power from 12V |
| Converters used | One Cherokee 48V 30A switcher |
| Voltage supplied to UPS | 48VDC - runs UPS and fits in empty battery compartment |
| DC from Prius HV | 210-230VDC, 10Amps |
| UPS model | HP/COMPAQ R1500XR (2U rackmount) |
| Weight incl. UPS batteries | 30 lbs UPS, 8 lbs switcher. (No batteries) |
| Weight w/o UPS batteries | 38lbs |
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This is an HP/Compaq R1500XR power supply as I bought it on eBay. The "Cosmetic Damage" was a missing front trim panel, which somehow is not a huge issue in the trunk of a car. |
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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. |
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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. |
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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. |
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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. |
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Here, the UPS is plugged in to the Prius HV battery and strapped to the Prius hardpoint ringbolts. Ready for Field Day! |
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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
provided it
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 system.
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Updated 13 May 2006