Can using a Generator cause permanent heater problems?

Algae_Farmer · Sep 28, 2020

Anybody have problems with equipment after being powered by a generator?

I have two finnex 300 W heaters (~1 yr old) and they're both acting up for the last 6 weeks, basically since I ran them off of a generator for a couple days. The generator was brand new, good quality, and has plenty of power for the load I applied. The heaters worked well before that, although the numerical temp setting didn't match their output temp

Algae_Farmer · Sep 28, 2020

... Now they both have a hard time holding a consistent temp, swinging by sever degrees and requiring me to constantly fiddle with the setting. I'll probably replace them and add a temp controller, but I'm wondering if I should avoid using the generator in the future?

Biglew11 · Sep 28, 2020

are these heaters with built in thermostats? or heaters with no thermostat that you need external controller?
if thermostat built in then yes a generator with dirty output voltage can cause damage to electronic devices.
most people will recommend an inverter type generator.

Algae_Farmer · Sep 29, 2020

Yes, built in thermostats. Fascinating, I didn't know there was a difference in generators, although honestly I think we got the very last generator in the state after the derecho storm came through so we were lucky we got anything.

I just tested the heaters (by plugging them into a "kill-a-watt" meter). They look like theyre on, they're displaying the actual tank temp accurately, and the indicator light says they're heating, but the meter says they're not using any significant juice. Also the tank temp is low, so that pretty much settles it - the non-invertor generator fried my heaters.
Thanks for the tip @Biglew11

Awesome Dennis · Sep 29, 2020

Which generator did you get?

Algae_Farmer · Sep 29, 2020

Mi-T-M 9000 watt, it's a great commercial grade generator, for power tools, well pump, freezer etc. But apparently not ok for sensitive electronics.

ichthyoid · Sep 29, 2020

Some power sources, including some generators and switching power supplies, may produce a lot of electrical noise along with the power being generated. Some devices deal with that noise better than others.

Devices with an electronic control section, like some heaters have, may not respond well to the noise. In order to eliminate the likelihood of poor performance and/or circuit damage one solution is to filter out the noise prior to reaching vulnerable devices.

I picked one such 3,000 watt device, randomly, which is made for audio/video applications (below). There are many brands & manufacturers, just know that some may be much better than others, so read reviews, etc. before investing. Hope this helps.

AC 8.8 3000W Hi-Fi Advanced Audio Power Conditioner Power Filter Purifier with Dual LED Display

The AC 8.8 3000W Hi-Fi Advanced Audio Power Conditioner discreetly provides clean and safe power to electronic devices. The Series Multi-Stage Protection (SMP) ensures that components are protected without sacrificing the power conditioner, while the Extreme-Voltage Shutdown guards against...

www.bittychoice.com

chipmunkofdoom2 · Sep 29, 2020

Do you have a link to the generator? There doesn't appear to be a 9kW generator on Mi-T-M's site. The next closest generator, the 8kW model, appears to have an inverter and boasts THD less than 6%, which should be fine for heaters.

ScottB · Sep 29, 2020

While I won't rule out noise from a generator as possible cause, it may having nothing to do with this. Instead, the grid itself can generate spikes and troughs in big storms until they shut down.

Once or twice a year I have to replace random relays, switches etc. My AC condensers are especially prone.

I should check into "whole-house" power conditioners.

Algae_Farmer · Sep 29, 2020

Thanks @ichthyoid , I'll check that out!

Good call @chipmunkofdoom2 , it actually is the 8000 watt model ("9kw peak"), I don't think it is an inverter model though, I believe it's their "portable gas powered" line which seems to be different than their "inverter" models. (live and learn I guess)

@ScottB I do have a whole house surge suppressor that we added after a surge fried a PC a couple years ago (we live in the country so power is a bit less predictable). I assume a whole house conditioner is a whole different thing? I can't recall the model/size of the suppressor but it was expensive (~$150), I'll check when I get home...

ichthyoid · Sep 29, 2020

Right, surge suppression & electrical noise filters are two different things-

-One protects sensitive equipment from surges/spikes in voltage (aka- overvoltage)

-Other protects sensitive equipment from spurious variations in the voltage, especially of high frequency (aka- noise).

It is possible to buy components which perform both of the above functions.

Brew12 · Sep 29, 2020

Algae_Farmer said:
Good call @chipmunkofdoom2 , it actually is the 8000 watt model ("9kw peak"), I don't think it is an inverter model though, I believe it's their "portable gas powered" line which seems to be different than their "inverter" models. (live and learn I guess)

Their portable gas powered line claims to be AVR (Auto Voltage Regulator) with a THD (total harmonic distortion) of under 6%. This should provide clean power that is safe for use in electronics.
You may have an older model generator from before they implemented AVR or your generator may be faulty but I suspect the heaters were damaged by a surge when power was lost.

ichthyoid · Sep 29, 2020

I initially thought the 6% THD could cause problems for CMOS components, but now I’m not sure.

Mostly because the THD is likely measured at 120 VAC, while the CMOS runs at 12 VDC.

So, not sure...?

Brew12 · Sep 29, 2020

ichthyoid said:
I initially thought the 6% THD could cause problems for CMOS components, but now I’m not sure.

Mostly because the THD is likely measured at 120 VAC, while the CMOS runs at 12 VDC.

So, not sure...?

Just saw you edited this.. but you are correct, the 6% THD is still going to be under 6% for the given voltage so it shouldn't damage a CMOS.

Algae_Farmer · Sep 29, 2020

Thanks @Brew12 and @ichthyoid! This is vastly more detail than I expected, but awesome info to consider when selecting a generator / power filter.
The generator was actually brand new and straight from the factory when I got it in early August this year, then went straight to my tank, fridge, and well pump. The factory couldn't make them fast enough after half the state lost power for a week. It's also certainly possible that the storm / power outage fried the circuits right before I got the generator...

ichthyoid · Sep 29, 2020

Fwiw,
While you can buy a combination surge suppressor & filter in one device, this may be not be an advantage, so something to consider.

Buying a separate surge suppressor, and placing it before a separate filter, will enable you to possibly only have to replace the suppressor if/when it fails.

The MOV varistors (a type of electronic component) typically used in suppressors weaken over time, and should be replaced every few years, to offer the best protection.

I know it’s a lot of detail, but these things often aren’t mentioned by manufacturers. Unless you read detailed reviews, or work in a field where these things are part of your job, then you may not be aware of them.

krash7172 · Sep 29, 2020

Hmm, no mention of sine waves. I fried a heater with a generator that was not pure sine wave. I now use an inverter and a 12V battery. I use this for camping and tank emergencies. Silent and you can scale the amount of battery.

3000 Watt Pure Sine Inverter ETL Listed conforms to UL 458 / CSA 22.2

Reliable pure sine wave power for work trucks, RVs, and off-grid use. Easy to install and use, includes a 2-year warranty and lifetime tech support.

www.aimscorp.net

ichthyoid · Sep 29, 2020

Generators inherently produce sine waves. They May be noisy, which is a problem.

Brew12 · Sep 29, 2020

krash7172 said:
Hmm, no mention of sine waves. I fried a heater with a generator that was not pure sine wave. I now use an inverter and a 12V battery. I use this for camping and tank emergencies. Silent and you can scale the amount of battery.

3000 Watt Pure Sine Inverter ETL Listed conforms to UL 458 / CSA 22.2

Reliable pure sine wave power for work trucks, RVs, and off-grid use. Easy to install and use, includes a 2-year warranty and lifetime tech support.

www.aimscorp.net

Non inverter generators naturally produce sine waves, however, they can have issues with harmonic content and voltage stability.
Inverters designated as "pure sine wave" are designed to replicate the mechanical generators as opposed to using a technology such as "pulse width modulation" which is very bad for some electronics.