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Impact of low Ambient Temperatures (-40F) on MPPT and Inverter

sobee

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Oct 18, 2020
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I'm looking at putting a small solar system in an unheated/uninsulated storage shed. I expect temperatures in the shed to drop to -40C (-40F) once every 5 years and below -30C (-22F) pretty much every year for a day or two. I need charge controller/inverter that can survive these temperatures. I haven't found anything rated to these temperatures. I'm aware of battery concerns, but I don't want to touch that in this thread.

I'm intrigued by the Victron 100/20 MPPT. It is rated to -30C. No LCD. No fan. I suspect it could likely operate at -40C, but I don't know. I have seen MPPT's that are rated for -35C, but I haven't seen any for -40C.

I'm also intrigued by the Samlex PST-300-12 inverter. It is rated to only -20C. No LCD. It has temperature controlled fan. I don't expect the fan will have any need to run on cold days as there will be next to nothing for a load.

I'm new to solar, but in my experience brutal cold doesn't seem to wreck any other electronics I own. Should I expect problems with the above solar equipment?
 
so my team-mates up north -- like Alaska north -- had the same issue a while back .. what they finally settled on was as long as the inverter or SCC did NOT have a LCD then literally everyone of them that they tried was fine... The SCC and the Inverter will both generate energy somewhat just doing what they are suppose to do -- so after they got past the LCD issue - virtually everyone of them worked ... i know that probably doesn't help you much
 
Capacitors is probably the biggest problem but any decent charger/inverter will be built to work just fine in the temperature range in the specs. Questionable items made in China, and be aware that Chinese cheapies export to other countries then claim manufactured in that other country too, might be an issue but the risk of that stuff blowing up is ever present anyway.

Plastics can become brittle in low temperatures but if you can survive, so can your electronics.
 
Thank you. I just noted that Victron Phoenix 12/250 inverter is rated for -40C. It has a programmable low voltage shut down which I can use to prevent over discharge of the battery and freezing of the electrolyte. I'm curious why the Victron Phoenix 12/250 is so inexpensive compared to the Samlex PST-300-12, yet it appears to be more feature rich? It seems like Samlex is much more popular. Why?

 
These have never let me down for low wattage 120v AC (now 115) needs. I moved to DC with everything but have had a morning star in a freezing environment 3+ years. Not used these newer 115V versions before however....https://www.morningstarcorp.com/products/suresine/

EDIT: I should had I never used them as low as you plan but have had it sub 30F 4 months at a time 6800'
 
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