Driving In 110F Extreme Heat And My Victron MPPT Shuts Down

[tourdejour]

This summer I was driving in 110F temperatures of NV and AZ and my Victron Solar Charge Controllers shut down.

I have 3 Victron MPPTS to manage and control 3 solar arrays (2400W total) and every one of them shut down when I'm driving in 105-110F weather.

The previous owner installed a Victron MultiPlus-1 where the previous inverter goes, and it has been very reliable. However, in 105-110F+ heat, it would seem I am pushing the limits of Victron's temp limits -- and for that matter all electronics that shut down when temperatures exceed 125F.

I.e., when the OAT is above 105F I find my inverter compartment clocks-in at +20F above OAT.

Note: The inverter still "puts-out" 120V when driving in 110F driving weather, but I'm bothered by 125F temperatures in my inverter compartment.

MORE: I crawled under my engine compartment to determine if the heat source was coming from my Turbo and I found a surprise: Right behind my inverter compartment is the ISC-350 turbo and exhaust tube, but that does not seem to be the heat source causing my inverter compartment to rise above 125F. Instead, I think the heat coming from the side radiator fan is the heat source, but I want to make sure.

So... I probed for an exhaust leak (with my bare hand) and found no down-tube exhaust leaks, and I found no black smoke anywhere in this area.

What I found was a lot of "very hot blowing air" created by the side radiator; and I think this is the problem. What do you think?


MORE FEEDBACK: I touched the metal chassis/frame in this area, and I found this area to be very hot the touch.

...And then I thought, this makes sense, since the side radiator is cooling 180F-205F of the engine radiator water inside the radiator and trans cooler. So, maybe, it is normal that this area would be really hot? Is this a correct assumption?

Moreover, if this is the case, is there nothing that can be done to cool an inverter compartment that is co-located next to a side radiator fan?

[oldenavy]

The 125f you measure is over 50C! That’s extremely hot for any power electronics. Victron advertises operating up to 60C with fan cooling, so you could add fans directly on your MPPT controllers, blowing over the cooling fins. That may help a little bit, but your operating right at the design limits, so a self protection shutdown is not surprising at all.

BTW, are they mounted vertical with the cooling fins vertical? If not, remount them that way to maximize cooling. Another option is to mount them to a heat sink to try and improve cooling.

[tourdejour]

Well, 60C = 140F so my operating temperatures while the inverter and MPPT temps are on the high side, these temperatures are still well within spec... and yet my MPPT charge current is 0V at these temperatures. Why?

T did some more thinking and reviews the data points I collected and conclude:

* The inverter compartment will register temperatures that run about +15F to +20F above ambient.

* And may other MPPT compartment will register temperatures at about +10F to +15F above ambient.

... and yet the MPPT voltage to my Lithiums will be 0V in high heat. Why?


Note: My MPPTS are all mounted to a 1/4" piece of aluminum stock, which acts as a pretty good heat sink. And yes, the fins run vertical, but that's a good point to make as a reminder. (And now that you mention it, I seem to remember Victron literature saying the MPPT should be mounted vertical.)

I'm perplexed as to why the MPPT charge controller is shutting down when the operating temperature is under 125F? This inverter is not shutting down so let's put off talking about ways to cool down the inverter compartment for now.

Could it be that heat under the solar panels (during 110F weather) is heating up the 10-gauge solar wires, so much that this would shut down the MPPT?

Or maybe the MPPT is talking to the Victron bluetooth sync'd battery temp monitor I have installed, and this device is somehow telling the Cerbo to shut down the MPPT voltage output?

More specifically, now I'm wondering: How does the Victron software monitor, control, and shut down the MPPT voltage in high heat?

[TacomaJoe]

The BMS on my battery shuts charging off at 149F. You should review the numbers for yours and check battery temperature as well.

[Captain8]

Originally Posted by tourdejour

Well, 60C = 140F so my operating temperatures while the inverter and MPPT temps are on the high side, these temperatures are still well within spec... and yet my MPPT charge current is 0V at these temperatures. Why?

T did some more thinking and reviews the data points I collected and conclude:

* The inverter compartment will register temperatures that run about +15F to +20F above ambient.

* And may other MPPT compartment will register temperatures at about +10F to +15F above ambient.

... and yet the MPPT voltage to my Lithiums will be 0V in high heat. Why?


Note: My MPPTS are all mounted to a 1/4" piece of aluminum stock, which acts as a pretty good heat sink. And yes, the fins run vertical, but that's a good point to make as a reminder. (And now that you mention it, I seem to remember Victron literature saying the MPPT should be mounted vertical.)

I'm perplexed as to why the MPPT charge controller is shutting down when the operating temperature is under 125F? This inverter is not shutting down so let's put off talking about ways to cool down the inverter compartment for now.

Could it be that heat under the solar panels (during 110F weather) is heating up the 10-gauge solar wires, so much that this would shut down the MPPT?

Or maybe the MPPT is talking to the Victron bluetooth sync'd battery temp monitor I have installed, and this device is somehow telling the Cerbo to shut down the MPPT voltage output?

More specifically, now I'm wondering: How does the Victron software monitor, control, and shut down the MPPT voltage in high heat?

At 40c the mppts derate then shutoff at 60c per their specs. They have temp sensors inside on the heatsinks and also right where the wires are.

The MPPTs create heat when converting so they'll be hotter at the heat sink than the bay. You need to cool the bay then make sure there's ventilation to cool the heat sinks. Fans near the heat sinks work well to circulate

[tourdejour]

So it sounds like fans blowing over the MPPTs will allow the heat to escape? I will look into that. Thanks.

As for the 10 gauge roof wires, do you think this high temp "cutoff" problem would not exist if the install called for the use of 8-gauge wires?

BTW, I have 24V solar panels and a 24V Victron Inverter.

Same question: Do 48V solar panels work better in 110F weather vs. 24V vs 12V?

In all cases, should a RV solar insulation use heavy silicon cased 10-gauge wire... and will this help to avoid high heat MPPT voltage shut down?

I'm now thinking all these factors are cumulative, but only come into play when the OAT is above 100F. What do you think?

For example: Is it worth the cost of using 8-gauge wire vs 10-gauge?

Should a new installation benefit from 48V solar and a 48V inverter if you commonly operate your RV in 110F weather?

Or are these just uncommon annoyances that all RV solar installations suffer from?