I just bought a new to me 5th wheel. A 2008 cardinal. I have the unit plugged in and my 12v lights went dim after 45 min or so. Had quite a few 12v lights on and the furnace. I put the battery on a battery charger for a while, but it's been to cold to go back out and tinker on it. My battery is a large deep cycle that I put in my boat new last summer. Is there a way to test the converter to see if it's Charging my battery while plugged into power?

If you have one of these Sears Clamp Ammeterit is real easy to do. I wanted one of these for a long time and kept hinting what a nice birthday or Christmas give it would make.. it finally came and I love it. This would make it easy to clamp around a lead to your battery and see if your converter is charging or not!

Using a volt meter you can measure both the input and the output voltage of your converter.See if you can find an electrical person to help you.

Rob, A voltmeter - even a 2$ CCV should tell you what you need to know. As nearly I can find out (and you should find and read the tag) your 5er has a 70amp converter. This should handle everything. So, I would suspect it is not getting line power to it. First, check that you have AC in the unit. Then, see if the breaker for the converter is set. Next, put the little meter on the converter terminals. They better be over 13V. If you see less than 12.5, the converter is either not making it or is dead all together. Now, if you have 13~15V at the converter and things are still dim, find and check the battery terminals. The same numbers work here. If the converter is working and the batteries aren't, go looking for what came loose. Thing come loose all the time. Matt

Put the red lead of the tester on the red wire in the middlee of the fuse panal and the black lead to the white wire and read the voltage. If it has a deck mount then red lead to the red wire and black lead to the white wire

If it is a deck mount check the dc fuses on the unit, found all 3 of mine bad on brand new 5th wheel. If someone reversed the battery cables for even a second they will blow as a safety to the converter.

How to test converter? | Good Sam Community

15 Replies

64thunderbolt
Explorer II
Feb 12, 2014
It could be working fine. Maybe it fired up in boost then came down to bulk. That would explain the dimming of the lights. Losing a full volt will get your attn. Just need to check the voltages.
BFL13
Explorer II
Feb 11, 2014
A friend has a Cardinal 5er. (model 30 something? RL) It has a WFCO converter in a 50a (AC) power centre at the back right side of the front cargo bay (behind a cover) opposite the wall going into the doorway in the middle of the rig. There is a red tab key on/off switch in the doorway that isolates the converter. Find which way that goes to be "on"

In her case the WFCO works as it is supposed to, being not far from the batteries in the front of the same cargo bay.
Dick_A
Explorer
Feb 11, 2014
Moved from General RV'ing forum.
wa8yxm
Explorer III
Feb 11, 2014
By the way the sears clamp on ammeter, Which I have, will not tell you WHICH WAY the current is flowing, A common pocket compass can tell you that, IF I could remember if it's the left or right hand rule that is.

When you find the converter (ON many RV's it is part of the power distribution panel, On these panels you open the door and you find both breakers and fuses, Usually the make and model is on said door, and the converter itself behind the panel,, On others it will be.... Elsewhere)

Measure voltage, plugged in, as close to the converter as you can get

12.anything,, TOO LOW
13.6 FLOAT
13.8 or higher CHARGING.

Now measure at the battery, 12 Sucking amps
13.6 Float
13.8 or higher,, Approaching full charge.

NOTE: Voltages are from memory DO look them up on the battery manufacturer's web site please.
Fish__n___Grits
Explorer
Feb 11, 2014
If you can actually see the converter, check to see if the cooling fan is running when there is a load on the converter. If the fan is not working, the converter won't put out full power under load, and should go off completely from thermal overload.
Rob8484
Explorer
Feb 11, 2014
Thanks for all the replies. I'm not sure which converter I have. I hope to get out and do some testing later today or tomorrow.
wa8yxm
Explorer III
Feb 11, 2014
Just out of curiosity... What converter do you have?

Some converters deserve an instant upgrade.. Some .. It would be hard to upgrade.
Shadow_Catcher
Explorer
Feb 11, 2014
http://www.youtube.com/watch?v=PbxpsiwP2bQ
I am a visual learner and tend to try and find Youtube videos if it is an area I am not familiar with. Since I rewired our converter (came from the factory wired incorrectly) I am well versed.
tatest
Explorer II
Feb 11, 2014
To check outthe converter, you need to know what it is supposed to. do.

Sounds like your converter is doing not much of anything (when plugged in, should be providing all 12V power while charging batteries) and you've been running on battery power.

Starting points, the convertor will be on a breaker on the 120 V side. Make sure that is not open. It will be fused or on a breaker, one or more circuits, on the 12V side.

Those checked, you need to determine whether shore power is even getting to the RV from the plug, i.e is 120v stuff working, hot at supply side of breaker box. Sometimes the problem is shore power plug, wiring to breaker box, or over the exterior circuit you plugged into.
mobilefleet
Explorer
Feb 11, 2014
revflyer has the right idea. check the fuses on the converter itself first