Inverters - How hot do they run

Submitted: Thursday, Oct 27, 2005 at 11:06

ThreadID: 27598 Views:2699 Replies:4 FollowUps:8

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Brian B (QLD)

Hi Folks,

I have been looking at a number of inverters recently and was just wondering what sort of heat they generate while running.

The reason I ask is that some models I have looked at have information that comes with them that tells you that the inverters case is used as a type of heat sync for the unit and that it can get fairly hot while running.

This leads me to think where you should set one up in your vehicle etc, so I would be grateful of any advice.

Thanks.

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Reply By: joc45 - Thursday, Oct 27, 2005 at 11:43

Thursday, Oct 27, 2005 at 11:43

Heed their advice! Some inverters have a thermo fan installed; leave plenty of space for air circulation. I wouldn't be putting it in the engine bay - lol!

AnswerID: 136607

Follow Up By: Brian B (QLD) - Thursday, Oct 27, 2005 at 22:20

Thursday, Oct 27, 2005 at 22:20

OK Thanks for the info.

FollowupID: 390470

Reply By: TerraFirma - Thursday, Oct 27, 2005 at 11:58

Thursday, Oct 27, 2005 at 11:58

Yes inverters are typically air cooled and hence need plenty of ventilation. I have a 1500w unit on my Riviera (Boat) and when the cupboard door is shut, it starts whislting after a while cos it's overheating. The trick with all inverters is to remember their draw on your battery. I have installed 2 extra batteries in the boat so I can use the inverter for longer.

AnswerID: 136614

Follow Up By: Brian B (QLD) - Thursday, Oct 27, 2005 at 22:21

Thursday, Oct 27, 2005 at 22:21

A well ventilated spot will be the go I think.

Thanks

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Reply By: P.G. (Tas) - Thursday, Oct 27, 2005 at 12:04

Thursday, Oct 27, 2005 at 12:04

Simple answer - If you run them up to their maximum rated capacity, they can get VERY hot, best idea is to work out how much power you need and then select a model with 25-50% more capacity. It will allow them to run much cooler.

I mounted my 600watt invertor onto a piece of 300X300X10mm aluminium to help dissipate heat and then screwed the aluminium on to the top of the cargo drawers out of the way. Never load anything on top of them!

Hope this helps.

Cheers

AnswerID: 136616

Follow Up By: V8troopie - Thursday, Oct 27, 2005 at 14:41

Thursday, Oct 27, 2005 at 14:41

Funny that, what I read is that an inverter is MOST efficient at or near maximum capacity, which would indicate it should run cooler then.
At 50% or less capacity the efficiency of these things goes down, more power is wasted in the DC to AC conversion and this waste is the source of the heat.

If the inverter was 100% efficient then NO power is lost during the conversion and NO heat generated within the inverter. The cables might run warm though if they are undersized.

If you have an efficiency diagram of the inerter you can figure out how many watts are expelled as heat at various capacity levels. With the higher output inverters, even a 5-10% loss due to efficiency will produce a fair amount of heat though.

Klaus

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Follow Up By: P.G. (Tas) - Thursday, Oct 27, 2005 at 16:18

Thursday, Oct 27, 2005 at 16:18

I can't give you a technical reason, all I know is my inverter was hot enough to make me jump one night after I had been running a 500watt halogen spotlight to do some bush repairs on the 100 series I had. Was only running the light for about 1/2 hour.

I usually only run the laptop from it and with that it barely warms up.

Cheers

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Follow Up By: Bob of KAOS - Thursday, Oct 27, 2005 at 17:15

Thursday, Oct 27, 2005 at 17:15

V8 Troopie
I think when they say it is most efficient near its rated power, they are talking about the percentage of power drawn from the battery versus the power delivered on the converted side. If it was say 80% efficient at 1000W and 70% efficient at 500 watts, the amount of heat at 1000W is 200W, and the amount of heat at 500W is 150W. So relatively less at high power, but still more in absolute terms. But a lot of heat either way.

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Follow Up By: Brian B (QLD) - Thursday, Oct 27, 2005 at 22:24

Thursday, Oct 27, 2005 at 22:24

Thanks for your advice guys.

It seems to me that installing it in a well ventilated spot and being aware of the heat it can develop are the key issues.

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Follow Up By: techie - Thursday, Oct 27, 2005 at 22:45

Thursday, Oct 27, 2005 at 22:45

Yes
ditto with what Bob of KAOS says.
don't forget it may appear hot to us but still be within operating range.
we consider anything over 55C to be hot - these things can safely operate at 80+ degrees as long as there is cooling.
Putting a larger heatsink helps, as does adding a fan to extract the heat.
There are heatsinks one can buy with fins that increase the surface area which, with a suitable fan, does wonders to improve the adequate operating condition of the inverter.

FollowupID: 390478

Reply By: Truckster (Vic) - Thursday, Oct 27, 2005 at 13:39

Thursday, Oct 27, 2005 at 13:39

Mount it to the cargo barrier, plenty of air flow, and the metal could draw away some heat..
Im watching these inverter threads too, in the market for one, just NFI what size, watt, shape, wave, etc to go yet.

AnswerID: 136630