High capacity DC-DC Charger

[AJMike]

Originally Posted by Morich

Since this seems to be a bit of a hit and miss problem that is hard to spot, perhaps going a bit far out to get a better idea of when it is failing and how, will be worth the time?
It should run but doesn't and hard to tell when or why, so I might want to get a remote reading thermometer so I could watch the temp as I drive?

There are lots of options and you may find one you like better but for a cheap one that I can mod to do what I want, I go to E-bay and shop for a digital thermometer/ temperature controller as it is cheap and gives me lots of ways to use it for other things like fish tanks or greenhouse use. I even have one set on the old cat's house to keep her bones warm during the colder weather!

I like something like this for car use but they also come in 110 AC versions as well. I like them as I am able to extend the wiring for the probe to set the readout inside rather than going to the greenhouse to check?

https://www.ebay.com/itm/14177709018...Cclp%3A2334524

In my case, I avoid getting up to check the heater is working but just rollover and crack an eye before going back to sleep! But in your case, you can set it near you as you drive and avoid stopping until you see the temp going higher and know something is wrong as it has failed and that makes it much easier to spot what is going on, Maybe?

When buying I like to get things that have multiple uses as it gives far more flexible uses for a couple dollars over the cost of a thermometer alone. It turns the fan or heaters on in the greenhouse and tells me things are working!

I actually already have a remote sensing thermometer that I use for both the refrigerator and freezer sections, and that is how I know what the inside temperatures are. What I use is this:

In terms of what I see, this pretty much is how it works.

1. Pre-cooling before we leave. I hook the RV to our 20 amp outlet at our garage and by morning both the refrigerator and freezer are very cold - low 30s for the fridge and low single digits for the freezer. Given that I assume that the unit works properly on AC.

2. We put the food in before we leave and after that the fridge is generally in the low 40s and the freezer in the high single digits or low teens.

3. After a couple of hours of driving with the fridge set on propane it is generally in the high 40s to low 50s and the freezer in the upper teens or low 20s. I assume it is working because otherwise I think the temperatures would be even higher.

4. If we set the fridge to DC instead of propane then the temperatures get higher more quickly.

5. Once we arrive at wherever we are camping (usually dry camping or boondocking) the refrigerator temperatures during the day do not drop below mid 40s when running on propane. At night they generally drop to about 40 and stay in the 40s the next day while we are camping.

I bought some small fans to place in the fridge to see if that helps, but I will not know if it will do any good until our next trip (which is planned for later this week).

[Morich]

A small point that I might look at is the way heat seems to spread more when running on propane than electrical of either AC or DC as it also may make things like the controls heat more. I find it kind of gets warmer around the frig back when on propane as the coils for electrical seem to lay tighter against the point they want to heat but the flame lets it heat more air around, if that makes sense?

So one way that "might" relate is how heat makes some electronics fail as the boards and such expand a bit. It is super hard to spot problems like that if it is not "broken" when you are there to fix it! Drives techs crazy when things heat up and shut down but work fine when you drive a coupe hours out there to fix something that is not broken!
I have been paid to sleep at the repeater hut, so that I would be there when the darn thing decided it was hot enough to break!
That may be where you need to go if you can find a way to monitor the temp well enough to spot when it breaks and look to see if the fire is out or try to spot what is going on while it is NOT running as it may be running fine when you are home again????

But that is part of the big guessing game, until you can get a better idea of WHY!

Meanwhile the best I could suggest is cleaning the back end as much as seems right, make sure there are no wasp or bug nests blocking airflow and tighten or look at any wiring points that might be loose or corroded. You have a tough one and it may wind up you fix it when you do some of those things and you never know exactly what it was that helped the most. ARGH!