Using a MGE Pulsar EX 1500 RT for a DC Inverter (Test) - Need Input

Vikelf

So I have this old MGE UPS which was the model we used to power Vessel Control systems on offshore vessels... ie Navigation/Thruster control/autopilot etc. These proved to be very reliable running for years on generator power with no real ground (ie used on vessels). Here's the manual: https://www.bwi.com/document/16842

I believe it has a pure sinewave output (page 25) and I can attest for it's reliability as very few failed in a fleet of 100+ vessels over the years.

So instead of purchasing a pure sinewave inverter to run 24/7 (those are rather expensive and I am not at that level of need at this time), I would like to use the inverter inside of this UPS.


Goal:

Alternate power source in my workshop. I would like to charge batteries for cordless tools, run a few LED lights, an occasional power tool via this solar setup. Have it run relatively maintenance free...



Three questions:

1) 1500 VA in my understanding is usually referenced to DC, so 1500VA = 1500Watts DC, but AC volts & amps are not always in phase so to determine Watts I need a PF but I think in this case I can assume that the unit is ~1000w AC ?

2) It requires 36VDC! I have 2 units, one is UPS with 3 12v 14AH batteries in series and the battery unit with 2 strings of 3 12v 14AH for a total of 9 batteries between 2 modules.
This is difficult to adapt into my solar project, any recommendations on how to charge batteries via solar while still allowing the unit to operate? FYI, I have 3 12v 35AH to add to the mix.

3) I'm sure several UPS to solar projects have been done before, is this just a stupid idea or can I make this work?






Side Note: Anyone heard anything about these:
http://www.ebay.com/itm/Semi-Flexible-100-Watt-Solar-Panel-12V-High-Efficiency-Sunpower-/141108693824?pt=CPUs&hash=item20dabbcb40

100 Watt Semi-Flexible High-Efficiency 12V Solar Panel

Efficiency rated at 21.5% <<< I smell something...

Electrical Characteristics (+/-5%)*
Rated Power Output: 100W
Optimum Operating Voltage [Vmp]: 17.8V
Optimum Operating Current [Imp]: 5.62A
Open Circuit Voltage [Voc]: 21.6V
Short Circuit Current [Isc]: 5.97A
Cell Technology: Monocrystalline Silicon
Number of Cells: 32 high-efficiency Sunpower cells in series
Output Type: 36" MC connector cables
Approx. Dimensions: 1060 x 540 x 3 mm (41¾" x 21¼" x 1/16")
Approx. Weight: 2 kg (5 lbs)
* At Standard Test Conditions (STC): 25°C, 1 kW/m², AM 1.5



Thanks again for all the great education!

Cariboocoot

Re: Using a MGE Pulsar EX 1500 RT for a DC Inverter (Test) - Need Input

Welcome to the forum.

1). The PF is dependent on the loads, not the inverter. So long as the loads' power demand including power factor does not exceed 1500 Volt Amps it will work. AC induction motors can be particularly problematic at this. If you're getting it for free it might be worth experimenting with.

2). 36 VDC charging can be had with certain higher-end charge controllers. Read that "better quality, more expensive MPPT type".

3). A UPS unit designed for continuous, long use (as opposed to one for temporary short outages) can be used. Quite often they are not very efficient, with either poor conversion efficiency or high self-consumption or both.

I don't know where they get that 21.5% efficiency rating on those panels either, but if they are monocrystaline then they would be the most efficient type (more power per square area than polycrystaline or amorphous). Sanyo has some that are around 20% efficient for example. I am particularly suspicious as these are flexible panels, which doesn't really fit.

Vikelf

Re: Using a MGE Pulsar EX 1500 RT for a DC Inverter (Test) - Need Input

Cariboocoot wrote: »

Welcome to the forum.

1). The PF is dependent on the loads, not the inverter. So long as the loads' power demand including power factor does not exceed 1500 Volt Amps it will work. AC induction motors can be particularly problematic at this. If you're getting it for free it might be worth experimenting with.

2). 36 VDC charging can be had with certain higher-end charge controllers. Read that "better quality, more expensive MPPT type".

3). A UPS unit designed for continuous, long use (as opposed to one for temporary short outages) can be used. Quite often they are not very efficient, with either poor conversion efficiency or high self-consumption or both.

1. It's free so I figured why not experiment

2. Well, the unit charges the batteries but I was hoping to find a way to charge the batteries via solar while they are connected in the UPS. This is the big issue.

3. I think this is a Non-issue as I have 3 generators, Grid power, and this just for my own personal experiments