12volt system problems 2024 Micro Minnie 2108FBS

[pdxjoanne]

We have a new 2024 2108FBS. We have 2 LifePo4 lithium batteries and the solar system the trailer came with. The batteries appeared to be charging OK and then would drain out for no apparent reason when we weren’t even using anything. The rig is currently at the dealer and I am not getting any good answer from them except they are “working on it”. My main concern is that we are leaving in a few weeks for 6 weeks. My question is this. If we have NO 12 volt power available but are plugged in to shore power, what will work? I have gotten differing answers to this and am now totally confused. I have been told that shore power will supply 12 volt power to those appliances that require it for starting up even if they run on electric or propane. Mainly I need to know if our lame dealership cannot fix it in time, will we be camping in a functional trailer, or camping in a glorified tent?! Thanks in advance!

[Morich]

Sounds like time to start the education on Rv as it is a pretty steady diet!
We all keep learning new things!
One of the big thing on an RV is learning what makes the electrical stuff work,
so time for some basics!

Not meaning to talk down to you if lots of it are things you know but easier /quicker to mention it all on start than to skip too much and leave you in the dark! Sorry about any unintended insults!

When you plug into power it sends 110volt Ac power to a converter lots of times that converter is built into the back of what we call a load center. The load center is a big deal to know about as it does lots of things for different parts of the RV.
One big thing is to know where the load center and converter are! There is likley to be a cover with lots of breakers and fuses in the Rv. That is the load center and if the converter is behind it, there will often be a hum when plugged into power as well as a fan which runs when the converter gets warm.
Inside the cover there are often breakers or fuses and many times they are labeled.
Some are to protect things like the wiring to the Air conditioner, normal 110AC outlets, and microwave that use 110 Ac for power.
Often under the same cover is the group of fuses that provide protection for 12 volt DC things. Those are often the little plugin fuses for the inside lights, vent fans and controls for some of the 110AC thing like the furnace and thermostat that works it and the Air conditioner.
Looking it over and knowing where to look for a blown fuse or breaker tripped is one way to feel better and recover quicker if you do have trouble later! It's easier to learn what makes what work if you are doing it when you can see it work! Pull a fuse out of the circuit for lights and at least some of the lights will go out until you put the fuse back!

Understanding what will work when plugged in but the batteries are not working is not that hard in many cases.

I did a little shaky drawing to help!
Click this snip to see it better!

Power from the cord comes into the load center and converter on back as 110AC. Some goes directly to the breakers or fuses for AC power and out to microwave Air conditioner, and outlets.
But some of that AC power also goes to the converter which uses it to "make" DC power!
Some of that DC power goes to fuses which feed lots of stuff like lights, fans and controls for heat and AIR.
BUT the part you are asking is the way the batteries help or hurt! There is a connection from the 12VDC out of the converter which connects to the batteries. Think of batteries as simple storage like a pantry! It's where you put extra when you have more than needed but also where we can get what we need if we have none coming in from the outside! The blue line shows this as a two way street, it goes into or out of the batteries as needed!

This is kind of sketchy and may miss lots of small points on how and where things connect but the general idea is the same on all Rv I've seen!

If the power cord is NOT connected, we expect to use the stored power in the batteries. But yours may not work!
So when plugged into power We use the AC for Air cond and microwave and expect the 12VDC things to work off what the converter is making, so not a lot of loss of function!
The bad part is that we are not going to store any for later when we unplug!
If a shop has the drawings and any idea of what they are doing, they should easily be able to find and fix this in 3-4 hours as it is not that big a deal!
If they know where the converter is and it is working, they should be able to tell if power is getting from there to the batteries!
If they know where the batteries are and where things like the lights are, they should be able to see power gets from one point to the other!
It's not like they have a hundred feet to lose it while looking!

One thing they may not know about is the bunch of fuses or breakers under the front frame of the trailer in many cases! It's been a pretty common source of problems on the forum if that is the problem as folks who never worked on a trailer DO have trouble spotting a tiny little breaker inside a metal box there! But the reason you took it to a shop is because they are supposed to know about those things!

Maybe they need to call Winnebago and ask for help? That's what lots of folks here have to do when we run out of good ideas!

I hope that helps some and know that the group is with you and wishing life was different!

[creativepart]

We would love to help you, but don’t have enough info to guess what the issue is.

Who installed the LFP batteries? How many amp hours do you have in total. Do you have a Lithium capable Converter? Did you also install an inverter? How about a battery monitor?

You’ve said they went dead. You’ll need to tell us what the battery’s state of charge was at the beginning and what exactly was running when they “went dead.”

What do you expect of your batteries? You said you have the stock solar. How much is that… how many watts? Do you expect that to always keep you charged up?

Plugging into shore power should both operate everything 12v on your TT and charge your batteries IF your converter is working and you give enough time.

This is a long shot but since we don’t know exactly what’s happening with your TT - it’s worth a shot.

If all your 12v is out there is a main resettable breaker on the front of the TT under the RV where the 12v from the batteries attached to the bottom of the A-Frame.

We regularly see people with new Micro Minnie’s that blow this fuse and are unaware of its existence. A push of a button on the red body of the breaker box restores all 12v power.

Here’s a link to a thread on this topic that shows the breaker and it’s location:

https://www.winnieowners.com/forums/...ie-355101.html

It may not be this breaker, but we have so little to go on.

[pdxjoanne]

Morich: Thanks so much for the response. I do know about most everything you discussed (but it never hurts to review!��). Near as I can determine, our converter is working fine, all beakers and fuses are ok too. My husband knows about the breaker under the tongue and checked that as did the repair guy at the dealer. Hubby thinks there is a bad short somewhere. The dealer guys haven’t even responded to the message I left. Unfortunately, I have no faith in them right now. What I am faced with is planning this six week trip with the worst case scenario being NO 12 volt power available except for whatever the shore power will provide. We usually do a lot of boondocking but with these problems I am planning to be sure to have shore power available. I am trying to determine what systems will run while on shore power but with NO battery input. Fridge? Furnace? Water heater? Pump? Slide? I assume the microwave, A/C, and stove burners would be ok? Thanks, again.

[Morich]

OK! Time to get down to the real question of what should be expected to work.
Some will be a "best guess" as there can be varied degrees of a short!
What I would expect to see if there is a major short, is the batteries would run down quicker, depending on how solid that short is and what it is shorted to!
We often think of a short as a wire that is connecting to something it should not and that point is often thought of as a ground and letting the battery get to ground instead of going out to what we want powered and then ground.
But it doesn't sound like you have a really solid ground because the fuse which controls how much power goes through the wire is not blowing.

Thinking of it as we would water in a hose the hose is not fully cut in two but just leaking along the path before it gets to the end where we want to use the water?
If it were leaking really big time, the fuse would blow!

As an estimate of what to expect, I would say the 110 AC is likely to be okay and run everything as normal. Microwave, outlets, are straight 110 AC and likely normal. But the furnace and Air conditioner use 110AC for the main operation but 12VDC for the controls. Then there are lots of things like lights, vents and water pump that use just the 12VDC.

Where it gets tricky is part of the 12VDC is likely to work fine with no change, other than they run out of power much sooner if the batteries don't get charged and hold it long enough to use it! We can kind of guess at that as being okay because none of them are blowing the fuse or breaker!
Not a real solid "leak" since things seem to work while plugged in and that goes through the same path (fuses) as when using the batteries. You use more power as part of it is going somewhere and wasted but as long as the converter keeps pumping more than is used or lost, it may still work?
No guarantee because it can be very prone to changing as time goes on. If a part in something like the board on the frig or water heater has failed, there is a good chance it stays like it is now. But if it is a wire that is rubbing along an edge of metal, the more it rubs the bigger the "leak" may get!
UGHH! At some point does it make good enough contact that it blows the fuse and you can't keep it working? It's the unknown that kills us!

But that is where I'm not understanding why it is that hard for the shop to find the cause? I'm assuming they have the drawings of how the trailer is wired. that is a big problem for us on the towables as those are not easily available to us. We assume dealers get them easy!

There are meters to show how much power is passing through a wire. Different types and different names but ammeter is a common name.
It can tell you how much current/power is going past a point. If you have too much power going out of the battery, it has to be going out on a wire! You test and see too much going through, so you begin to disconnect the different fuses where the power spreads out to all the different uses! When you get to the one that has the short and pull it, the power reading drops way down !
You gotta keep looking until you find where the leak is happening! Not really rocket science if you have a plan of where and how it is wired?

But that is from the outside looking in and there are certainly times when things are not like we expect them to be.
Repair work can look easy but just nothing works out when you try to fix it!
I admit to taking days to fix things that folks thought should be simple!

[bigb]

Originally Posted by pdxjoanne

I am trying to determine what systems will run while on shore power but with NO battery input. Fridge? Furnace? Water heater? Pump? Slide? I assume the microwave, A/C, and stove burners would be ok? Thanks, again.

You won't be able to run the fridge while traveling, and your break-away braking system needs 12 volts. When parked and plugged in, you may not have enough power from the converter alone for the slides or the tongue jack, as they usually draw heavy amps from the batteries. Your other things should work when plugged in.

[pdxjoanne]

Thanks for all that, Morich. It will be very helpful when we have to deal with the dealer. I am giving them a couple more days and then we are going to go over there, bang on tables if we have to, and either get it fixed or bring it home and work on it ourselves. I am REALLY hoping we can get the 12 volt system fixed before we leave, but at least I have a better idea of what we’re up against if we don’t. My husband has testers and can do a lot of what you suggested so we’ll just have to take it step by step. And find a new dealer!

[Morich]

Originally Posted by pdxjoanne

Thanks for all that, Morich. It will be very helpful when we have to deal with the dealer. I am giving them a couple more days and then we are going to go over there, bang on tables if we have to, and either get it fixed or bring it home and work on it ourselves. I am REALLY hoping we can get the 12 volt system fixed before we leave, but at least I have a better idea of what we’re up against if we don’t. My husband has testers and can do a lot of what you suggested so we’ll just have to take it step by step. And find a new dealer!

Sometimes we need to look on the bright side but prep for the dark side?
One way to try to move things forward without yet knowing what results you will get at the shop is to try to gather some info! It can take time and looking for different sources for the info. Starting early can help speed it along----Just in case!
While it may seem a drag, one of the really important things to have on hand when DIY electrical repair is the plans and drawings of your specific RV. In the motorized, we get a lot online but not the trailer group.
However we do hear of a lot of info found in calling Winnebago direct on things. Some get plans for things like how the walls are built, so I might expect a set of drawings of the electrical could be had??

One way to prep for a storm is to try to get the act together before the storm!
Maybe worth the effort to do some calling and see just how much good info you can get direct from Winnebago?
If you can get hands on the "schematic drawings" for your trailer, it is then much like a road map and it takes a little practice to see how to read each companies info.
But it does the same as a road map! If you want to go from Chicago to St. Louis, it sure gets easier if you can find a map! If you want to know how to get power from the battery to a light, a road map is great!

[eatSleepWoof]

If you're plugged in to shore power, everything that runs on 12v will work, even if you don't have batteries physically installed in your trailer.

Some Lithium batteries can go into a "sleep" mode after extended periods of not being used. Connect them to a charger for 30 minutes or so and they'll be back to normal operation. Chances are there's nothing wrong with your trailer.