Converter and battery confusion (yes, really)

[racebitz]

Greetings! Newbie to RV, but recently a frequent lurker as the vertical learning curve continues!
I appreciate in advance any help offered, thanks!

Several months ago, I purchased an ancient (1983) Lindy Skyline 26 on a Ford Econoline chassis. Happy days.
We went on a quick trip to a local campground, and all was well. Plugged in, sockets worked, but the air con kept tripping. Not to mind, it wasn't even warm.
*note, at this point, though it clearly says '30 amp' on the access to the plugs etc, it was plugged into the 20 amp socket.
Next trip, the chassis battery suddenly dies. I picked it up at lunch, no problems though turned the engine over slowly, 6pm I jump in and it is dead. I pop to Autozone, they check the battery (pretty old), announce it has 0% charge, I buy a new chassis battery, install it and off we go.
Next morning, battery is dead. I get a jump start, thinking I left a light on or something and assume the best. Next day, battery is again dead.
For a few trips, I just disconnect the chassis battery when parked and re-connect in the morning, no issues.
In the middle of this (and many, many short trips) I remember the previous owner telling me the deep cycle battery wasn't being charged by the vehicle. I take it out, get it tested, they tell me it is dead but in good shape, charge it for me and send me on my way.

Summary at this point: chassis battery draining overnight, deep cycle slowly draining, but sockets work, lights work etc. I am disconnecting the chassis battery overnight and when parked.

Two weeks ago on a trip, the 110V does not come on when I plug in at the campsite. A little messing about with the breaker switches on the RV and on the power pedestal and they come on.

Last week: no power to the 110V, though the lights work ok. It is my kids birthday weekend so I use an extension to keep the fridge and other items going, and we survive.

This weekend: nothing when I get to the site. At this point I have not charged the deep cycle so it must be flattish . I honestly forgot to bring it home.

I tool about for a bit, then notice the '30 amp' on the electrical cover, remove the 20 amp adapter on the main plug in cord, plug in the plug, switch on the air con, it works! Still no power on the 110v and no lights though. I have a booster and I pop it on the deep cycle and immediately we have lights, but I do not leave the booster on the battery for more than a few seconds.

Investigating the chassis battery I notice two wires that are definitely not OEM. When I changed out the chassis battery the connections were worn so I got new ones and fitted all the wires to where i thought they belonged. Now this is where I am getting lost.
Two wires from the battery, but both are to the negative terminal!!!!!
Seems odd. I follow them back and the thicker goes into the converter, the other continues to the negative of the deep cycle battery (should I be calling it the house battery?)
I wondered if I had them incorrect and connected the thicker one to the positive side of the battery. Well, we had light, but so so bright, and hot.
Playing around with the breakers last night we for a moment had sockets working, light and air con. Then the time delay 20 amp fuse blew and no replacement to be found.

So I guess (and thanks for getting this far) I have a few puzzles:
1. why is it not charging the house/deep cycle battery
2. why is/has the chassis battery been connected to the converter?
3. does the lack of charger indicate the charger inverter is dead and if co how difficult to replace? (It is a Magnatek series 3200 model 3240 40 amp unit, unsurprising obsolete I believe)

Again, thanks for the thoughts and help!!!!

[fast_st]

Originally Posted by racebitz

*clip*
Two weeks ago on a trip, the 110V does not come on when I plug in at the campsite. A little messing about with the breaker switches on the RV and on the power pedestal and they come on.

*clip*
I have a booster and I pop it on the deep cycle and immediately we have lights, but I do not leave the booster on the battery for more than a few seconds.

Investigating the chassis battery I notice two wires that are definitely not OEM. When I changed out the chassis battery the connections were worn so I got new ones and fitted all the wires to where i thought they belonged. Now this is where I am getting lost.
Two wires from the battery, but both are to the negative terminal!!!!!
Seems odd. I follow them back and the thicker goes into the converter, the other continues to the negative of the deep cycle battery (should I be calling it the house battery?)
I wondered if I had them incorrect and connected the thicker one to the positive side of the battery. Well, we had light, but so so bright, and hot.
Playing around with the breakers last night we for a moment had sockets working, light and air con. Then the time delay 20 amp fuse blew and no replacement to be found.

So I guess (and thanks for getting this far) I have a few puzzles:
1. why is it not charging the house/deep cycle battery
2. why is/has the chassis battery been connected to the converter?
3. does the lack of charger indicate the charger inverter is dead and if co how difficult to replace? (It is a Magnatek series 3200 model 3240 40 amp unit, unsurprising obsolete I believe)

Again, thanks for the thoughts and help!!!!

First part, well your unit has some age on it, its entirely possible that your breakers are defective, opening up or tripping for no real specific reason, cycling the beakers will bring the items online for a bit but they may trip early for no obvious reason. Also check the 12v fuses that should be in the power converter center. Pull and check each one, look for cracks and test with a good meter. It sounds almost like your 'converter' really just a built in battery charger of sorts is possibly dead, I've seen it before. Does the converter have a model/type printed on it?


Good grounds are a must! It sounds like all major grounds are made to the chassis/engine battery.

[l1v3fr33ord1]

racebiz-

First off



Second, you should do some reading before experimenting any more. That's because the batteries, even at 12V, contain enough energy to cause serious damage to your coach's equipment, wiring, and you- as you found out when you tried to connect a ground to a positive terminal.

A place to start is with this site:

The 12volt Side of Life (Part 1)

Third, if you don't have one already, buy a decent multimeter and learn how to use the simple functions, such as measuring voltage.

Fourth, your coach is old enough that many "improvements" could have been made by prior owners, including some that may not have been wise to make. Get a sheet of paper, or several, and start writing down how things are connected. Compare it with what you learn from the Web site listed above. Once you have things documented and know what each part is supposed to do, you can reconfigure the wiring to make everything simple and easy to understand.

Finally, there's nothing magical about electricity. Batteries need to be in decent condition, and charged to full as often as possible. A converter takes 120VAC and changes it to 12VDC to supply the coach devices and to charge the house batteries. The alternator does the same for the chassis battery. In some coaches the house and chassis batteries are interconnected for cross-charging. The AC side of the coach works in the same way as AC in a house. And so on. In all cases, be concerned about self-preservation (i.e., safety), proceed cautiously, test before hooking things up, take pictures before unhooking things, and most of all, enjoy the learning experience!

[racebitz]

Thanks for the speedy replies!
This vehicle has definitely had some ...ahem..improvements!
Does it make sense that the negative terminal on the chassis battery would have one connection to the house battery and one to the converter?
Multimeter on the way..!
Thanks

[l1v3fr33ord1]

Originally Posted by racebitz

Does it make sense that the negative terminal on the chassis battery would have one connection to the house battery and one to the converter?

All 12V grounds can be connected together. On some coaches, there may be multiple grounds to the frame. A direct connection between batteries, of adequate size and properly fastened, should be as or more reliable than a connection for each to the frame. I'd expect the converter ground to go to the house battery. That all said, this is a 37-year old coach, and who knows what "standard" practice was then?

You may want to introduce yourself and coach to the Vintage RV forum.

Also, create a signature for yourself. This helps folks know the particulars of your coach without you having to tell that in each post. The instructions are in this post.

[racebitz]

Thanks, really very helpful. I wonder if the previous owner connected the negative terminals to work out some grounding issues.

As it is not charging would it be likely the house battery drains the chassis battery? Or is it not charging as I disconnect the chassis battery and thus the house battery is not grounded?

Thanks again, folks.

[fast_st]

If there seem to have been a lot of repairs, you may be onto something, a previous owner trying to find an electrical problem. Its good to have a couple multimeters, even the inexpensive ones and a package of alligator test leads so you can monitor a couple things at once.

[racebitz]

Update:

Got the RV home, plugged it in, nothing on any socket, even after I changed the time-delay fuse.
Upon investigation, it seemed the breakers were a little shaky, definitely old. A quick trip to Lowes, a charge on the deep cycle battery and hey presto! All sockets work, fridges, the lot. Even the air con worked (I forgot it was on for a day an a half!).
Deep cycle still not charging, but that is really not an issue for our use. Chassis battery still draining if I leave it connected, but that is more of an inconvenience.
Thanks for the help folks!

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

Congrats on the new rig! Sorry I can't offer suggestions on the battery problem.

Keep her between the ditches!

Good luck, happy trails, and God bless!

[JohnBoyToo]

Obviously you have some grounding/shorting issues...
I would be concerned about shock hazards until I sorted it out

Had someone almost die in front of me from an old fridge that some decided it didn't need the ground portion of the plug ! be careful.

in the interim, get you a knife blade type battery disconnect so you can isolate the batteries when you need to..

then you can use a continuity tester on NON-live wires

good luck