Cooling electronics - Page 1
Forum section: electronics / general

author: rthorntn
author_rank: Frequent Contributor
timestamp: February 18, 2024, 10:29:29 am
content: Hi,So I have two off-grid inverters, these are not outdoor rated.The inverters sit in a small weatherproof cabinet (~80x80x20cm) attached to an outside wall. There are two fast 80mm AC fans moving air through.On a hot sunny day the inverters are busy and their temperature goes over 65°C quite a bit. I worry that the temperatures are shortening the inverters lifetime.Now I'm starting to think that getting cooled air (below ambient) into this cabinet might be a good idea as those hot parts of the day also provide a lot of solar energy to drive a small AC unit for free.Has anyone seen an outdoor rated small AC that would be useful for this purpose (that doesn't cost the earth), I envisage a small box (under 30x30x30cm) that mounts on the wall and has two pipes coming out of it, basically cabinet out (warm air) and cabinet in (cool air) pipes.Thanks.Richard

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2024, 05:29:27 pm
content: Many electronic parts are fine at high temperatures: some semiconductors, such as MOSFETs, can take as high as 175°C without being damaged.Does it have any smart capability? Some inverters can communicate via Ethernet. Does it have a diagnostic tool for monitoring the temperature?

author: magic
author_rank: Super Contributor
timestamp: February 18, 2024, 05:38:05 pm
content: Wouldn't it be simpler to get more airflow in there with larger fans?

author: jonpaul
author_rank: Super Contributor
timestamp: February 18, 2024, 07:02:34 pm
content: Air Cond power will eat into solar and inverter load.Just larger fans as 80 mm is tiny.j

author: SeanB
author_rank: Super Contributor
timestamp: February 18, 2024, 07:22:18 pm
content: Yes simplest is to add an external cabinet, which provides shade, and which has a pair of 120mm AC fans to move lots of air across them, from the bottom air inlet to top air outlet. Shade from the sun with an awning of some sort mounted 300mm above it, and with white outside, and it should run cooler.Have seen a bank of Sunny Boy inverters at a large commercial solar install that have, in the locked wire mesh enclosure that protects them, a trio of Big Ass fans that provide extra cooling for them, seeing as that area reaches 40C ambient due to it being concrete and tar paved outside. Around 16 of the largest inverters all there, providing a big part of the power for the complex.

author: coppercone2
author_rank: Super Contributor
timestamp: February 19, 2024, 01:45:42 am
content: any reasonable ambient temperature save the death valley desert will be drastically more power efficient with greater flow then any sort of cooling technology to cool a smaller airflowif you need active cooling for a restricted air flow it means the systems engineer fucked upthe suggestion to go from 80mm to bigger fans will be like turning summer into winter for your inverter. Try 100 or 120mm. The extra sun shield idea is also good. Furthermore bright highly reflective, white paint might be the easiest solution.

author: indeterminate
author_rank: Regular Contributor
timestamp: February 19, 2024, 10:13:17 am
content: I have a couple of inverters mounted in a cabinet of similar size to youthere are two low speed fans that cum on @ 40c via a thermostat switch you can see in the upper right.The second thermostat switch turns on the other four fans if the cabinet temp exceeds 50cat the base of the cabinet are eight 60mm holes with fly wire coveringthe fans are powered by the din rail mount 12v power supply, its been running happily for the past nine years.

author: 5U4GB
author_rank: Super Contributor
timestamp: February 20, 2024, 12:50:02 pm
content: Quote from: SeanB on February 18, 2024, 07:22:18 pmNote that in a lot of cases you don't need huge amounts of forced-air cooling but just anything that's better than natural convection cooling. I haven't actually taken readings for this so don't have hard data, this is just from experience, but even the woosiest fan providing at least some air movement will give you a huge leap over natural convection, after which you only get comparatively small increments in cooling with increased fan power and noise. So anything is better than no fan at all, you don't necessarily need an industrial-grade ventilator to see benefits.

author: rthorntn
author_rank: Frequent Contributor
timestamp: February 20, 2024, 08:24:23 pm
content: Thanks!I should reiterate that my inverters are off-grid, they have active cooling, the main problem is that the two tiny fans inside are garbage and there is only minimal heatsinking.These 3 spare parts are pretty much the whole inverter:https://maximumsolar.online/product/5048mgx-fan-set/https://maximumsolar.online/product/5048mg-mainboard/https://maximumsolar.online/product/hv2-5048-mppt-board/So it's cheap and nasty and does the job but the enclosure is too small for two of these and the 80mm enclosure fans don't move enough air.The enclosure is pretty crammed, there is no real depth to put bigger fans in there, I got my estimated depth of 20cm wrong, it's more like 12cm. I could put thin 120mm computer fans behind the vent on the enclosure door but thin fans tend to be weak.I can't just put a bigger enclosure there, the wall is pretty crammed.I could shade it or build a bit of a lean-to shed over it. It's already on the shady side of the house.

author: coppercone2
author_rank: Super Contributor
timestamp: February 20, 2024, 10:37:15 pm
content: the easiest way is to make like a shell that you screw on to the unit with bigger fans in it and cut holes in the old enclosure