Questions about Group 31 starting batteries getting run down overnight by fridge and also solar.

[onanysunday]

If that gray wire is your refer power line, it looks like it is on the coach side, not the chassis side. Are you sure it is your fridge that’s drawing down your chassis batteries? 

Whatever they are calling it I tested and charged every day for a week. It ran the starting batteries down for sure. I have also had issues a few times not realizing the draw to where I had to run the gennie for 20-30 minutes to even start the coach when leaving. Even the jump switch on the dash would not work. (Most likely meaning the 4 6v batteries were run down as well. Then night before last I turned of the fridge and tested at 12.7. It only dropped to 12.4 by morning. 

 

[wopachop]

You obviously removed the 15a fuse to the grey wire in order to confirm it controls the fridge? I guess "coach switched" is sometimes/always getting power from the chassis batteries? 

I would buy a budget clamp meter. I use mine all the time for stuff like this. Could easily clamp the positive wire on the chassis batteries and note the power draw. Then turn the fridge on and note the change. Im not convinced the fridge is hooked to the 12v batteries because the panel is calling it COACH. 

Wouldnt you want the fridge to be on F5? The coach battery? I believe your instructions called for an 8a fuse for the fridge. There might an online fuse somewhere downstream of the 15a fuse. Might be best to switch the 15a fuse over to 8a anyway. Dont see any reason the F5 spot would not work. As long as it gets power while youre driving down the road. If you feel its safe. Some people dont drive with the fridge going. I guess pulling into a gas station is actually illegal. Something weird. Its a fire danger due to possible propane leaks. I read something about it years ago. There are fulltime RV people who will pull over and shut down their propane before getting fuel. Maybe it has to do with that static spark issue. Arent we supposed to touch metal before grabbing the nozzle? Or maybe it was the pilot light spark from the fridge that is the danger at the gas station. Whatever it was there is a fulltimer dude who posted links to a couple fires that happened. I might be wrong about the "illegal" part. 

.....

I just thought of a test you could do. 

Do you have a battery disconnect switch that turns off the inside lights? 

See if it also turns off the fridge. Im wondering if thats what "coach switched" means.

Second option is "Coach switched" is controlled by the disconnect, but its powered from chassis batteries. 

Another reason im leaning towards the fridge being on the 6v bank is because look at all those wires on the panel. What are the purple and blue wires F24 and F19? Its probably water pump and furnace. The set of 3 whites could be lighting. Stuff thats on the 6v bank. Im just guessing here and sorry if its hard to follow along with a big long ramble. A clamp meter would answer the question in 30 seconds. Will also help to chase down a power draw in the future. Or its fun to see how much different things draw. Both AC and DC. 

You could very well have a draw on the chassis batteries. Maybe its just like youre saying that its the new fridge that draws more power. Its enough to run down the chassis batteries that are somewhat old. Especially when they are starting batteries and not really made to run things all night long. Matched with not getting fully charged to the brim during the day. That would help i think. Like ive mentioned over and over they need to be seeing 14.4v to get filled back up with juice. Hold a chance during the night. Cold night makes it worse. 

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In terms of running down the 6v batteries with a heater consider a Mr Buddy. When i first started typing this i came to my trailer thats maybe 45-50F inside. I crank the trailer furnace and the (i have flame king) Mr Buddy style. Man it gets warm quick. I have both turned off now. Turned them off halfway through however long it took to type this. The portable heater shines when you want to blast yourself with a ton of heat real quick. Really warms you up fast. Almost catches you on fire. On high i actually consider the thing unsafe. Should use tongs and hang a napkin above it. Start to lower and get a distance to combustion. You can find them brand new on offer up for a deal. Probably not flame king because its new and i dont know how many they made. I dont like the thermostat feature and wish i got the mr buddy. Would get the smaller version too and run it off a 5g tank. Nice backup if your batteries are super low in the early morning and you dont want to use the furnace. Takes a bit for the sun to come up and start charging your batteries if you move towards solar. Mr Buddy style will save you. I use mine even plugged into shore power. The furnace comes out freezing damn cold. Mr buddy style is a big warm hug in about 8 seconds. 

 

[onanysunday]

You obviously removed the 15a fuse to the grey wire in order to confirm it controls the fridge? I guess "coach switched" is sometimes/always getting power from the chassis batteries? 

Yes I removed the fuse. This was after pulling plugs and checking the fridge for power. 

I would buy a budget clamp meter. I use mine all the time for stuff like this. Could easily clamp the positive wire on the chassis batteries and note the power draw. Then turn the fridge on and note the change. Im not convinced the fridge is hooked to the 12v batteries because the panel is calling it COACH. 

Wouldnt you want the fridge to be on F5? The coach battery? I believe your instructions called for an 8a fuse for the fridge. There might an online fuse somewhere downstream of the 15a fuse. Might be best to switch the 15a fuse over to 8a anyway. Dont see any reason the F5 spot would not work. As long as it gets power while youre driving down the road. If you feel its safe. Some people dont drive with the fridge going. I guess pulling into a gas station is actually illegal. Something weird. Its a fire danger due to possible propane leaks. I read something about it years ago. There are fulltime RV people who will pull over and shut down their propane before getting fuel. Maybe it has to do with that static spark issue. Arent we supposed to touch metal before grabbing the nozzle? Or maybe it was the pilot light spark from the fridge that is the danger at the gas station. Whatever it was there is a fulltimer dude who posted links to a couple fires that happened. I might be wrong about the "illegal" part. 

I always drive with the fridge on. Would want to melt the ice cream!  Right now it does have the 15amp fuse but the installation book says 6. So not sure there. 

.....

I just thought of a test you could do. 

Do you have a battery disconnect switch that turns off the inside lights? 

Yes there is a switch for this. I never use it and leave it on.

See if it also turns off the fridge. Im wondering if thats what "coach switched" means.

Second option is "Coach switched" is controlled by the disconnect, but its powered from chassis batteries. 

Another reason im leaning towards the fridge being on the 6v bank is because look at all those wires on the panel. What are the purple and blue wires F24 and F19? Its probably water pump and furnace. The set of 3 whites could be lighting. Stuff thats on the 6v bank. Im just guessing here and sorry if its hard to follow along with a big long ramble. A clamp meter would answer the question in 30 seconds. Will also help to chase down a power draw in the future. Or its fun to see how much different things draw. Both AC and DC. 

I have verified the fridge was drawing from the 12v starting batts. 

You could very well have a draw on the chassis batteries. Maybe its just like youre saying that its the new fridge that draws more power. Its enough to run down the chassis batteries that are somewhat old. Especially when they are starting batteries and not really made to run things all night long. Matched with not getting fully charged to the brim during the day. That would help i think. Like ive mentioned over and over they need to be seeing 14.4v to get filled back up with juice. Hold a chance during the night. Cold night makes it worse. 

-----------

In terms of running down the 6v batteries with a heater consider a Mr Buddy. When i first started typing this i came to my trailer thats maybe 45-50F inside. I crank the trailer furnace and the (i have flame king) Mr Buddy style. Man it gets warm quick. I have both turned off now. Turned them off halfway through however long it took to type this. The portable heater shines when you want to blast yourself with a ton of heat real quick. Really warms you up fast. Almost catches you on fire. On high i actually consider the thing unsafe. Should use tongs and hang a napkin above it. Start to lower and get a distance to combustion. You can find them brand new on offer up for a deal. Probably not flame king because its new and i dont know how many they made. I dont like the thermostat feature and wish i got the mr buddy. Would get the smaller version too and run it off a 5g tank. Nice backup if your batteries are super low in the early morning and you dont want to use the furnace. Takes a bit for the sun to come up and start charging your batteries if you move towards solar. Mr Buddy style will save you. I use mine even plugged into shore power. The furnace comes out freezing damn cold. Mr buddy style is a big warm hug in about 8 seconds. 

Pretty cool. 93% 4 or 5 star ratings. https://www.amazon.com/Mr-Heater-F232017-Indoor-Safe-Portable/dp/B01DD6C4MY/ref=sr_1_2?gclid=Cj0KCQiAzfuNBhCGARIsAD1nu-9phXlBlLAYI0e9nAGEiWQIYy5LRJN50_W4wTDQdugtoX2rEkHIb5IaAvzAEALw_wcB&hvadid=345118249587&hvdev=c&hvlocphy=9061146&hvnetw=g&hvqmt=e&hvrand=2540262022445365611&hvtargid=kwd-331731376004&hydadcr=7331_9589998&keywords=mr%2Bbuddy%2Bheater&qid=1639931277&sr=8-2&th=1

 

[wopachop]

Thats the heater i wish i got. Make sure to get the newest version. Tractor supply had them. It might be on sale for $79 there. 

The larger 20k version looked cool. It has a fan. I want to say it was more maroon colored. Doubt the fan works well. The heat alone rising upward creates a noticeable draft. Could do a little kid science experiment and make a hot air balloon effect. Singed eyebrows at the same time. Could star in a high school play of The Wall???

Im fine with being cold. Maybe others can chime in and say if the 10k heater was able to keep up in an RV. 

I have foam boards in my windows. Probably growing a petri dish of mold on the window frame. Its worth it to help with the poor insulation of trailers. I find the 20k unit to be too much heat. Also not ice fishing. 

Read your answers. So wow yeah that panel labeled coach switched is actually powered by the 12v batteries like you first said. 

 

[onanysunday]

Now the fridge is wired to the (4) 6v batteries and it is doing much better. With my 22 year old solar panel and running the big gennie 15 minutes each evening they have not dropped lower than 12.1. (It has been testing 12.4 in the evening) Today after 4 days my (2) starting batteries are at 12.1 so there must be a slight draw. I am thinking a little better portable solar panel will do the trick. At least now I am not going from 12.7 to 11.7 overnight. 

 

[onanysunday]

So my old 22 year old panel says 2.33 amp output and 35 watts.  This panel for $104 says 100 watts  and the specs are:  https://www.renogy.com/template/files/Specifications/RNG-100D-SS spec.pdf   Page 2

 It says operating current is 5.72 amps

Short circuit current is 6.24 amps.

Not sure exactly what the two different numbers mean. My old panel is keeping the batteries basically level and not letting them drain down. I wonder how much this would bring them up with good sun all day. Output is more than double but not sure how much it would charge the 4 batteries. 

 

[onanysunday]

So my 4 6v batteries are wired like this. My other question is do I need a controller with one of these smaller solar panels. If I do two things can I do without the controller. #1 take it off each night so power can't feed back to the panel. And number 2, just make sure it does not overcharge. The old panel I am using shows 15v max output. My dad had this hooked to his moho batteries all the time for years. Never thought about it charging at to high of a rate. The Renogy panel shows 17.9v optimum operating voltage and open circuit voltage at 21.6. So for either of these panels is the voltage to high going direct and you should use a controller? It is only a few bucks more for the controller but is something else to mount and deal with. Direct with alligator clips has been easy with the panel I have at least. This kit has a controller but in the reviews numerous people have had the controller go bad.

 

[wopachop]

In a way you have 3 basic options. 

1. Alligator clips with a small panel. This could maintain batteries in storage. Not enough power for camping. 

2. Larger panel with a built in controller. I believe some of these hook up with alligator clips? This could work for camping if you dont use much power. 

3. Panels on the roof with a controller mounted inside the RV.

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For your situation a hybrid option #4 might work well. 

4. Buy a nice solar controller and build your own portable alligator clip system. Down the road you could mount the panel on the roof and buy more wire to run through the trailer. 

 

[wopachop]

Output is more than double but not sure how much it would charge the 4 batteries. 

For flooded 6v an easy way to remember is to charge at 10% of the AH.

The picture above is showing a battery bank with 450ah so you would try to charge them around 45a. 

That allows you to get a feel for what the 100w solar panel is doing at 5a. 

You can see its more of a trickle charge when you have such a large battery bank.

While that same 5a would be too much if you tried to charge a little kids quad battery. My tw200 has an 8ah battery. A 5amp charge would be over 50%. Much too high. While a small battery tender is 0.75a. Thats right there around 10% charge rate.