Winnebago Vectra Low Battery Voltage

David Clark · 05-05-2022, 07:07 PM

I pugged my class a 50 amp motorhome into a 50amp to 15 amp adapter. I don't know how to tell if the charger is working or how to know if the battery charger is working. After 24 hours the battery level is 4 volts not the 12 or 13 that it should be. How and what do I test to see what is the problem?

**Eagle5** · 05-05-2022, 07:41 PM

Hi David,
A 50 amp shore power cord is really two 120 VAC legs out-of-phase, both at 50 amps. This gives you 12,000 watts of power; either at 120 VAC or combined into 240 VAC. When you use an adapter, only one of the two shore power legs is energized. So the question is determining if your battery charging circuit is on the leg which has the 1,800 watts of power (see Leg 1 in the diagram below.) Four volts on a lead-acid battery also means that the lead-acid batteries associated with that low voltage are probably shot and will need to be replace.
How long ago was it that the batteries were in a good state of charge? Are they lead-acid?
Welcome to the forum.
Eagle5

emiddleb · 05-05-2022, 07:46 PM

Need a bit more info to help you...

What year Vectra? Many different equipment options over the 10-15 years the model was offered.

Battery level - are you talking the chassis batteries or the house batteries?

Does your utility panel show that you are on A/C? Even though you are on a 15amp plug you should see the 30amp light lit on the panel. Are your A/C items/plugs working?

How's the DC side? Are the overhead lights working? Vent fans?

Have you accidently hit the "Salesman switch?" The battery disconnect switch? If it's turned off, the Inverter will not function and not charge the house batteries. Do you have a Dimensions panel where the tank monitors etc are located? It's what controls the inverter (post 2000 models roughly) and it should show you if the charger is working.

cbeierl · 05-06-2022, 01:29 AM

Quote:

Originally Posted by Eagle5

Hi David,
...When you use an adapter, only one of the two shore power legs is energized. ...

This isn't typically true. Most (all?) adapters from 15/20A to 50A and 30A to 50A will connect the single incoming power leg to BOTH legs of the 50A circuit, thus powering all of the RV circuits, albeit with only a total of 15/20A or 30A available to the RV. Both legs of the 50A circuit will therefore be the same phase, which is how the RV will be able to detect that it's NOT connected to a full 50A shore line.

cbeierl · 05-06-2022, 01:47 AM

Also be aware that the Dimensions inverter/charger (the OEM unit in your RV) won't be able to charge the batteries if the initial charge level is too low (must be greater than 9V, I think) to start with. If your measured voltage is accurate this sounds like it may be the issue.

You'll need to put a separate charger on the batteries to get them back up to a normal voltage, or ideally remove them and take them to be charged/load tested to see if they can still function up to spec.

Morich · 05-06-2022, 08:54 AM

Several points of info on the RVwill be neededto get down to real answer, rather than guesses!
Take a look here to see the problems as each year and each model do have different wiring schemes, so knowing which year, make and model is a good place to start:
https://www.winnebago.com/Files/File...ram/Wiring.htm

But then also we do have two different sets of battery supply in the RV, so we need to know which battery is not charged, start or coach ?

But in the wild guess area, it is common for the newer user, to miss that the start battery will not be charged from the coach charger, even when plugged into power, unless there is an added option to connect them. Some RV have it, some not.
Also it is worth mention that both sets of battery will have "parasitic drains" on them even when battery disconnect switches are turned off.
Frequent problem when new to an RV? The battery goes dead and we thought we turned it off! Safety items are still left connected....

Not trying to make life difficult but the batteries are one of the most vexing sections we run into. Common complaint, so don't feel bad!
Just human?

David Clark · 05-06-2022, 07:16 PM

It is a 2004 Vectra. The ac receptacles are working, however the 12 volt overhead lights don't work. The problem is the coach batteries, on the hall monitor nothing is showing for the shore power. The battery level today for the coach batteries is reading -1, not 12 or 13 as it use to read, The switch at the front door is in the on position for the batteries.
Thanks for the help Joe and Joie. Let me know if you have any ideas. I think that I am going to replace the batteries since they are 8 years old.

emiddleb · 05-06-2022, 09:39 PM

Ok, that helps a lot.

First thing I would do is follow what Chris said in msg #5... charge up your house batteries using an external battery charger. Nothing will work without some power in the house batteries. The Dimensions unit shuts down when the batteries are below 9v.

On your (same as ours) coach, I expected to hear that your AC power is working. When you are plugged into shore power, the Dimensions inverter is just doing a pass-through on the shore power so things like the outlets, microwave, tv etc should all work.

Once you have some charge, see if the Dimensions panel will work. That's where you can tell if your Inverter is working properly... you can see the charge mode etc. Turn it on and see what it tells you.

Mostly likely replacing your batteries will be the solution, but you also need to ensure that "old batteries" are the root problem, and not an issue with your Dimensions unit not keeping them charged for some reason.

**creativepart** · 05-06-2022, 11:21 PM

It should be mentioned that in the past couple of years that we have had at least two, maybe more, members mention here that the charger in their early 2000’s Dimension inverter/charger had failed.

When they contacted Dimensions they found the company was sold to become Magnum-Dimensions and that former Dimension products were no longer supported. But if I remember correctly there was someone online that independently fixed Dimensions products.

Ray,IN · 05-07-2022, 02:59 AM

David said the batteries are 8 yrs old. That's very old for lead acid batteries in this application.

David, please use your phone camera and take a picture of your battery wiring arrangement before removing any connections. You'll be glad you did.
Your inverter/charger should have a "force charge" setting, turn it on and the charger should begin charging the battery bank it it is functioning.

David Clark · 05-09-2022, 09:20 AM

Since the batteries on the coach were 8 years old I replaced them with new batteries and that solved the problem. Everything is responding as it should. Thanks to everyone for the help. It is great to get you knowledge and opinions.

**Eagle5** · 05-09-2022, 09:42 AM

Hi David,
Glad that new batteries have you back in business. I learned something in this thread too (that both Legs of the 50 amp service are powered by a 15 amp adapter plug.) OK now; let's go camping!
Thanks, Eagle5

MadMaxWinny · 05-11-2022, 05:47 PM

Keep an eye on those new batteries (specifically voltage) for a couple of months. Some people consider 8 years to be a good run, but that's closer to middle-aged than elderly. There might be another reason that they failed...

NeilV · 05-12-2022, 07:15 AM

The converter chargers in the late 90's/early 2000's were notorious for over charging batteries and destroying them especially if you left them plugged in for extended periods of time in a warm climate. You may want to protect your battery investment by upgrading to a Progressive Dynamics Charger/Converter with the ChargeWizard which has a True Float Charge Mode and will automatically run a DeSulfate Cycle to ensure the longest batter life.

Just get one with the same amperage rating as the existing one and it should be an easy swap.