Mounting inverter outside

hillside · January 14

I'm thinking of putting a Samlex PST3000 inverter outside under a deck canopy. It'll be protected from rain and overnight moisture and wind...until we get another hurricane. 10 miles from the ocean so salt air is a minor concern.
At first I rejected the idea but then space and convenience took hold. Then I thought about people that put them on sailboats and trawlers where inverters exist in a humid salt air environment constantly.
This is a tropical location so...
Thoughts?

Photowhit · January 14

Mine have always been outside in protected enclosures/power centers along with the batteries and inverters;

I like the battery and power center thing I mae from similar to a design I saw in Homepower or a Backwoods Solar article.

Image: https://us.v-cdn.net/6024911/uploads/editor/5w/j3cvy8um72dp.jpg

Current setup at new place, battery is a forklift battery that started life in the battery box above and moved to new home! It's in a 'skin tight' box to the right of the power center;

Image: https://us.v-cdn.net/6024911/uploads/editor/nv/hdhxr1e9fsxm.jpg

706jim · January 14

Both battery and inverter compartments need to be ventilated

BB. · January 14

Battery compartments need to be vented to release hydrogen gas (flooded cell lead acid) and some electrolyte "mist" (acid mist--Which corrodes/shorts nearby metal components).

Inverters need to run cool (and, ideally, at a stable temperature). But they do not need "air exchange"--especially if that air is moist/has salt in it... A "small" inverter in a large(r) box with good internal air circulation (don't put "hot inverter" at top of box, under self, etc.) will usually be OK... Keep box in shade/cool helps.

Electronics in general, age 2x faster (1/2 the aging life) for every 10C(18F) over room temperature (25C/77F)... Run inverter at 95F, it will last 1/2 as long (on average).

Temperature cycling is also a killer for electronics... Freezing in AM, >100F in afternoon sun--That can cause solder joints and component failures too.

-Bill

hillside · January 14

Nice setup Photowhit..
No need to be concerned about cold temps. Overnight lows might get to mid 60's...I read that these Samlexes are Taiwan production so better than typical Chinese mfr. (think I read it here) so I'll probably put it outside on the concrete wall.
My main concern was with humidity but inside the house it would only be marginally lower.

hillside · February 6

So, adding another stand alone system here...I have the 4 L16 batteries and Samlex inverter mounted outside the kitchen wall and the controller will be inside. I plan to run two Romex wires into the house from the inverter (to outlets) and of course the 2 wires from the panels and two back outside to the batteries (from the controller).
The house is cinder block/concrete and drilling holes is easy enough but can I run all these wires through one hole rather than two? I'd use a length of pvc pipe thru the wall probably to house them in, either 3/4" or 1" diameter.
It's just easier to drill one hole!

BB. · February 6

First question... The "controller" is what? Solar charge controller?

In general, you want the charge controller to be at the same temperature as the battery bank (i.e., don't want controller at 70F, and the batteries at 0F to 100F. The charge controller should be setup to adjust charging voltage for battery bank based on "battery" temperature (typically around -5mV per degree C per Cell).

If the charger has a "remote battery temperature sensor"--Then mounting the charger inside is not an issue.

Second question... There are several issues with using the same "conduit" for DC and AC wiring...

In the NEC, the wiring for the "low voltage circuit" needs to have the same insulation voltage rating as the shared lines in the "high voltage" circuit (120/240 VAC wiring is 600 VAC minimum insulation rating--Therefore the 12/24/48 VDC wiring needs the same minimum insulation rating.

Also NEC does not support running low voltage wiring (i.e., 12 VDC "touch safe") in the same conduit as 120+ VAC wiring.

When you get into ROMEX--I am not sure if running two ROMEX in the same hole is the same as wiring sharing the same conduit (probably not?).

Since this is not an NEC installation--As long as you are "safe" (right insulation for right voltages)--Not an issue.

Next. Bringing solar panel wiring into the home. If you have lightning strike possibilities--You want to be very careful here.

I would not overlook mounting the charge controller on the outside wall (in a ventilated box to avoid weather/sun) and keep that all separate (panel wiring away from wiring going into the home. This may suggest getting a remote LCD display for the charge controller (if available) so you can monitor your system inside the home.

Also, for lightning, you can get a nice set of DC and AC surge suppressors, with 6 AWG ground wire to an 8-10 foot ground rod outside the building (next/near foundation--keep ground wiring short and straight/gentle bends).

https://www.solar-electric.com/search/?q=surge+protection

Lastly--Many times there is a lot of "hash" on DC power lines (and even from solar panel power lines). To keep radio/RF noise to a minimum, avoid parallel runs of AC+DC wiring next to each (bundle tied together, in same conduit run, etc.). Generally, cross DC and AC wiring at right angles to avoid too much coupling of noise.

Or in this case, if sharing same hole in wall--Separate AC and DC wiring as soon as the wiring leaves the "hole" (both outside and inside of wall).

-Bill

hillside · February 6

Thanks, Bill. So the controller will now go outside and in this location it's going to be safe from sun and rain, under the deck awning. Temperatures should be similar as all will be weather/sun shaded.
The main reason I wanted the controller inside was to be able to check voltage easier but since it's under the awning it's only a mattter of going outside the kitchen door to check. Here in this climate the door is always open when we're home anyway. Unless we get a hurricane.

So the only wires going through the wall now will be 2 Romex AC wires to the inside outlets.
I'll look into the surge protection link, thanks. We get frequent lightning strikes in summer but so far we haven't lost anything, although many friends have stories to tell.
Now humidity is another story. Picture South Florida type.

Mounting inverter outside

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