Adding Solar to a -48VDC/Positive Ground/Telecom System?

[Swervin]

I previously worked in the telecom industry and I have a -48VDC (positive ground) battery back up system I built from surplus telecom equipment. I have about 40kwh of AGM batteries, a pair of old Xantrex XDI 2048 1.5kW rack mount inverters, and an undersized line powered charger that charges at around 3A. I mostly use this system for emergency backup power to run lights and furnace during weather problems.

What I'd like to do is add solar power to my set up but from what I have researched positive ground doesn't seem to be very common with solar set ups, I'm mostly seeing negative ground or floating battery systems. I reached out to Morningstar and they gave me a link to their white paper on positive ground systems, so I know I have at least one decent option for charge controllers, but I'm open to other suggestions.

I'm totally new to any sort of solar installation, so my biggest question is how can I tell which panels I can use with a positive ground system? Am I better off just redoing my existing setup and getting rid of my line power charger and inverters and switching to negative ground?

Thanks in advance for any help.

[bcroe]

In more recent times, there is more telecom equipment with power circuitry
isolated from ground. I would at least look at, if your equipment could operate
with a negative ground. Bruce Roe

[Mike90250]

Positive ground is used in comm centers because leakage currents don't erode the signal lines as much ( super short simple version ) So maybe your gear will work floating or - gnd.

[sdold]

We're soon going to be trying a few Morningstar Tristar 60A controllers on some radio sites with -48V for the microwave, I think I saw the same white paper you did and their tech support confirmed that positive ground was no problem. I like that I can call them on the phone for easy tech support, unlike another company I won't name whose employees always seem to be "out back" and not answering the phone.

[Swervin]

We're soon going to be trying a few Morningstar Tristar 60A controllers on some radio sites with -48V for the microwave, I think I saw the same white paper you did and their tech support confirmed that positive ground was no problem. I like that I can call them on the phone for easy tech support, unlike another company I won't name whose employees always seem to be "out back" and not answering the phone.

If you don't mind me asking, what solar panels are you planning on using? I emailed a few companies and was basically told they wouldn't confirm that their panels would work with positive ground. Makes me nervous when I can't get any assurance from a manufacturer about their products.

[sdold]

LG LG410n2w, it's a 410 watt grid tie panel. They claim it's not a problem although we haven't actually tried one yet I also talked a bit about this with some tech support folks at Morningstar who have only heard of older Sunpowers having "some" problem with polarity, but it's best to check for yourself.

[Swervin]

LG LG410n2w, it's a 410 watt grid tie panel. They claim it's not a problem although we haven't actually tried one yet I also talked a bit about this with some tech support folks at Morningstar who have only heard of older Sunpowers having "some" problem with polarity, but it's best to check for yourself.

Thanks for the information, much appreciated. I was really surprised there weren't more off the shelf equipment packages aimed at telecom setups, considering all the remote equipment.