Batteries not charging with 30A or 110 service

PlasticNerd · 08-31-2021, 04:45 PM

HI all. I'm new here, just got our first motor home. 2004 Minnie wf329k on E450 chassis and the batteries under the entry step don't seem to be charging correctly and they are new. I'm first going to check their voltage and water levels. The AC/Heat and fridge worked on 110 at home, then we went on a local shakedown trip and this all happened. Generator wont start unless engine is running first, there's not enough juice in the 2 batteries to start the generator, water heater, or run the water pump, even when plugged in! Interior lights are super dim. Am i missing a fuse somewhere? We checked the fuse box by the door and breakers and all fuses were good. Any help appreciated, TIA. Gary

DavidM · 08-31-2021, 05:47 PM

Is the use/store switch on? It has to be on to charge the batteries.

David

Morich · 08-31-2021, 06:02 PM

New to RV and having battery questions? No big deal as it is almost normal and it usually is not that difficult to work out. But it may turn out to be a bit of expense as bad batteries are often caused by lack of care by previous owners and they often sell those bad batteries to let the next guy deal with it!

But before jumping too high and spending a fair amount of money, it is always best to figure out if it is actually the batteries or some of the small parts that feed the batteries power.

A brief picture of the electrical situation, in case it is ALL new to you.

I think of it as being three systems.
One is the normal 12VDC like a car/truck has that runs the things a car has.
Outside lights, horn, wipers?

Two is the inside things that work off two or more "coach" batteries and work things like water pump, inside lights, vent fans and controls on things like the heat/air and any monitor panels.

Three is the 110 VAC that we get when we plug in or have the generator running. It feeds the bigger power items like microwave, air conditioner and outlets where we plug hair driers, or coffee pots!

What gets tricky is that these are separate but connected at different times for different reasons! And like you notice some being bad will keep others from working as the coach batteries have to have power to send to the generator starter for it to run! So when lights are weak and genset would turn over, the coach batteries are likely not good or not charged, so we need to check there as step one!

A meter to check voltage is also a "requirement" for DIY on RV, so consider needing one, even if it is a ten dollar one from Harbor Freight! The $30 one is better over long term but just something to measure voltage.

After setting unused for a few hours or more, the coach batteries should test at 12Volts or more but since you report weak lights, likely you have less than 11, so you need to find why by testing the things that charge them.

They normally get charged when the RV is plugged in as there is a converter changes 110AC to 12volt or more DC to charge the coach batteries. You likely have three batteries and two of them will have the positive (+) posts connected together. those are the coach batteries that need checked when the RV is not been running nor plugged in for a few hours. If the reading is low and then you plug in, the converter should send voltage to the batteries and you should see the reading jump up to maybe around 14.3 or 14 volts, showing the converter is sending power that should charge them, given time like 6 hours or more! How about check that and see if the converter is doing it's thing and then we can look at the batteries more or converter, etc, if the power is not getting there.

Second thing to test while there is when the engine is running, the engine alternator sends power through a connection that is made when the engine is running! So while unplugged, look at the coach batteries voltage and then start the engine and expect the voltage to jump up. Just a way to see that part if working right as that would also explain why the generator WILL start when the engine is running as it can then use the power of both sets of batteries as well as the alternator to get going!

Shout back with what you find as it is not uncommon for the batteries to be bad when we buy a used RV. Just one of those things that we often do see happen??? But if the converter and alternator are sending power and it is the batteries are not holding the charge, the batteries are a big failure point!
Look at the connections on the cables and make sure they are clean while there, of course and you might get lucky on cleaning them???

Note:
I would assume the battery disconnect is correct as you do get weak lights and they should be totally out if the disconnect switch is not right.

PlasticNerd · 09-01-2021, 11:51 AM

Thanks Richard. I am familiar with how the system works, and do have a couple different volt meters (way better than Harbor Freight brand!) and will be able to check the voltage tomorrow when I have some time. The batteries were purchased by former owner a couple months be for he sold to us, he got at Costco- Interstate RV/Marine type. The Ford engine alternator is putting out 14V as it should, we checked that at the campground! The host had a meter. Im thinking the converter isnt working properly. It is the original from 2004. So was the LP detector! Which I replaced with a LP/CO detector. Also I contacted the former owner who is very knowledgeable on RV's and he is willing to come help me figure it out!! I will keep you in the loop on what the problem was, Gary

PlasticNerd · 09-01-2021, 12:13 PM

Quote:

Originally Posted by DavidM

Is the use/store switch on? It has to be on to charge the batteries.

David

Yes it is, we switched that on and off a few times to see if it was a weird connection, we are going to check that also. Thanks.

Morich · 09-01-2021, 01:35 PM

Okay, good deal on being familiar with the meters. Sometimes new to RV also comes with being new to DIY and that can get to be a tricky situation.
So maybe this is a good time to refer you to some of the really good info Winnebago puts online and then step back to let you do the testing!

This will get you to the wiring diagrams for your specific RV:
https://www.winnebago.com/Files/File...ram/Wiring.htm

If you look at the 12VDC drawing, page one has what I was talking about on the big questions on how both systems start and coach get tied together at different times. One of the more frequent problem areas and your drawings are about as bad at telling you the whole story as any I've seen, so I added a few details that really help make sense of it. They seem to have left off that there is connections to the batteries!

Coach power comes into the solenoid and meets a short jumper to the disconnect relay and then IF the relay is operated to pass the power on, it goes out the right side and to lots of the coach breakers. Not all the power is cut off here as some safety items like co detector, propane detector, etc. are always left on. Just important to know that when you turn the disconnect off, some power will still run the coach batteries down if we don't watch and do something else to keep them up.

That's where lots of newer folks let the batteries go bad while they are stored and thinking the power is ALL cut off!

PlasticNerd · 09-01-2021, 03:01 PM

Quote:

Originally Posted by Morich

Okay, good deal on being familiar with the meters. Sometimes new to RV also comes with being new to DIY and that can get to be a tricky situation.
So maybe this is a good time to refer you to some of the really good info Winnebago puts online and then step back to let you do the testing!

This will get you to the wiring diagrams for your specific RV:
https://www.winnebago.com/Files/File...ram/Wiring.htm

If you look at the 12VDC drawing, page one has what I was talking about on the big questions on how both systems start and coach get tied together at different times. One of the more frequent problem areas and your drawings are about as bad at telling you the whole story as any I've seen, so I added a few details that really help make sense of it. They seem to have left off that there is connections to the batteries!

Coach power comes into the solenoid and meets a short jumper to the disconnect relay and then IF the relay is operated to pass the power on, it goes out the right side and to lots of the coach breakers. Not all the power is cut off here as some safety items like co detector, propane detector, etc. are always left on. Just important to know that when you turn the disconnect off, some power will still run the coach batteries down if we don't watch and do something else to keep them up.

That's where lots of newer folks let the batteries go bad while they are stored and thinking the power is ALL cut off!

How funny, i just printed out all the schematics from that page last night, but this is a great place to start! Thank you, Gary

BobC · 09-04-2021, 07:05 AM

I'm not going to jump in too far since Morich/Richard knows his stuff but, even if it's OK, replacing your original converter (if your's is original) is a good idea. The new converters have a multi-stage charger which will be much kinder to your batteries.

Here's what I used for my 2002:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Try to match the amperage as closely as possible to your existing converter so as not to overload the wiring from the converter to your batteries.

Morich · 09-04-2021, 07:49 AM

When looking at the drawings, there is a big help that many overlook that is different for Winnebago. They print codes on the sides of wires that match up with this chart:
https://www.winnebago.com/Files/File...ical_guide.pdf

It comes out in alphabetic order and if we hit "cntrl" and "F" on the computer is brings up a dropdown where we can enter the code like "JJU" and it drops us into a section where we can scroll each place that item is listed as a fast way to sort the info. From there it gives two columns, one "from" and the other "to" that lets us go both ways on deciding if that specific wire involves what we are looking for. Or going the other way, if we want to know about wires to the water pump, we can put in "water pump" and it drops us into all places where that is shown.

So if we happen to find a wire that is not connected, we look for the code and decode it and we may find it is a spare that we don't have that option!

Rarely do we have too much info!

PlasticNerd · 09-04-2021, 11:37 AM

Quote:

Originally Posted by BobC

I'm not going to jump in too far since Morich/Richard knows his stuff but, even if it's OK, replacing your original converter (if your's is original) is a good idea. The new converters have a multi-stage charger which will be much kinder to your batteries.

Here's what I used for my 2002:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Try to match the amperage as closely as possible to your existing converter so as not to overload the wiring from the converter to your batteries.

Thanks, we were thinking that also.

PlasticNerd · 09-04-2021, 11:44 AM

So, we charged both batteries, and did a draw/load test on them and they are fine. I really cleaned the parts on all of the connections well, and tightened the clamps/wing nuts. Then in a couple days i tested the batteries, they were at 12.39V each. I hadn't plugged in to my garage power, nor ran the generator, so they seem to be good batteries. Everything works properly now, but there may be a problem with a solenoid type unit that clicks when i turn on the battery switch that's located really low on the left wall as you enter the coach. It seems like its not working correctly? Can look into that soon. I'm not sure how to properly use this switch, so that may have been our problem? When should it be on or off? The manual isn't clear on this!! Thanks for all the ideas folks. Gary

Morich · 09-04-2021, 01:33 PM

Sounds right on the batteries being good enough! What I was talking earlier was that there are some loads which do not get disconnected and given time they will run the batteries down, so being slightly less than 12.8 for perfect is expected, just don't let them go too far and stay down to be damaged!

I may have given bad info on the name for one switch as this drawing seems to use a different name. They do that, I've found!

Main idea is that there are two different switches that control these two different parts.
One switch is often called boost or aux and is usually on the dash so the driver can reach it to boost the the start battery with the coach batteries if it is run down. This drawing looks like they call it a "battery changeover" instead of boost or aux. Aux is what they sometimes called the coach batteries!

That solenoid is usually next to the battery disconnect relay in some compartment and works at two different times. When you push the dash switch it sends battery down wire LR, through the solenoid coil to ground on FM. FM is often attached to a mounting screw to get good ground there as well as through the wire! That solenoid is usually a pretty big silver "can" with big lugs on left and right.
It also operates when the engine of the RV is running to connect both battery groups together to get a bit of charge back into the coach batteries as we drive! So you can often hear it go "thunk" as you push the dash switch or you maybe can hear or feel it move when somebody starts the engine.

Often near the door there is a switch to disconnect the coach batteries and it gets different labels or none at all! Maybe where I've marked on the drawing near the left side at door?

This switch operates the disconnect relay that is usually found next to the mode relay above. When you push the momentary switch at the door one way it engages and disengages when pushed the other way. you may hear it but lighter sounding than the mode relay beside it.
It is different type relay called a "latching relay" because it pulled open/closed and then has a magnetic gizmo which keeps it latched when we let loose of the switch, so that it doesn't require using battery full time to keep it set where we want it! Tricky, yes!

Tricky to find at times, also. They are sometimes labeled and outside in a compartment behind the drivers side or other times under the passenger seat or compartment on that side. Pretty big and look much like the drawing but may be hidden!

The solenoid has a big red battery cable run to each side so following cables from the batteries is one way to find them???
If you still have OEM cables and the tape is still there, this code may help sort which goes where?

Marty57 · 09-06-2021, 12:26 AM

My 2004 did the exact same thing. The battery disconnect relay went out. If your batteries are low, turn on your couch lights. Observe the brightness. When you turn on the ignition key, the lights should get brighter. When my relay went out, there was no change when I turned on the ignition or started the engine. I replaced the relay with a newer numbered part that was an upgrade for the original part. Never any issues since; 4 years now.
Marty

PlasticNerd · 09-07-2021, 05:31 PM

What relay did you replace it with? Gary

Morich · 09-07-2021, 07:19 PM

Quote:

Originally Posted by Marty57

My 2004 did the exact same thing. The battery disconnect relay went out. If your batteries are low, turn on your couch lights. Observe the brightness. When you turn on the ignition key, the lights should get brighter. When my relay went out, there was no change when I turned on the ignition or started the engine. I replaced the relay with a newer numbered part that was an upgrade for the original part. Never any issues since; 4 years now.
Marty

Are you sure it was the relay that was changed or the solenoid? The relay failing would not be expected to effect the light brightness either way but more likely to either be off or on????
A mode solenoid failing would prevent the two battery strings from being connected together and that connection will change the voltage going to the coach lights, fans, etc. as they are then powered by both battery strings as well as the alternator.

Marty57 · 09-09-2021, 02:14 PM

It probably was the solenoid; looked like typical Ford solenoid in the starter circuit. It was located in the fues area, inside the cargo storage area next to the batteries. If fixed the issue.
Marty57

Morich · 09-09-2021, 04:59 PM

Okay, easy enough to go with that being the fix and easy to find things like solenoids and relay called by the same name as they are pretty close on what they do.

You are totally correct in the solenoid making contact does often make the lights come up brighter as it gives you power from the start battery backed by the alternator and that is often higher than the coach batteries alone might be.

Just wanted to make clear that the solenoid ties them together, while the relay connects or disconnects the coach items.