Cabin Batteries in parallel. (I’ll explain what that means later)

So, as you have read before, we had an RV that had been neglected and abused by the dealer. So, we take nothing for granted these days.

Today was no different. This dealer had blown up our batteries for both winters they had our RV in their shop to work on it. Winters in Alaska are brutal, so you either have to remove your cabin batteries or you have to make darn sure nothing is putting a load on them. There is this thing called a battery disconnect. Our Coachmen Leprechaun had survived an especially bad winter with just this switch turned off. This switch cuts the voltage drain on the batteries. This also helps prevent their exploding.

So, after the first winter we were told they had blown up our cabin batteries which had been two 6 volt Interstate batteries. Instead of cleaning the battery trays and treating them with enamel that resists corrosion, they just threw the batteries in there and hoped we wouldn’t notice. Smelled battery acid on the whole trip. Complained. They had a mechanic clean the tray with baking soda and paint the tray with enamel.

The next winter, while it was in their shop for some indepth work, they blew them up again. (sigh). How much of a dumbass do you have to be? Forgive me. I digress.

Unfortunately, we had to leave everything as is for evidence reasons in the court case. So, we really didn’t get a good look at what was actually in there. Pulling the batteries out, we found they had installed two different sized batteries. We went to Batteries Plus and discussed this issue in detail. Very dangerous to put two different sizes in there. One looked like an RV battery while the other looked like a car battery. Duh.

So, the first step was to really really clean the battery trays with baking soda, then I treated them with RustOleum. This picture shows the results of that work and also shows the new batteries installed in parallel.

In parallel means the positive connections (red) are connected together between the two batteries by a large cable.  It also means the black terminals are connected by a jumper cable. The cables that jumper them should be heavy duty. That way, when one battery runs out of juice, the other one takes over. You can see the heavy red cable in this picture.

You can see the parallel connection here. You can also see how much I cleaned up the battery tray and coated it with Rustoleum to stop any corrosion or rust from continuing to eat away at the battery tray. It looks pretty good now.

Here’s a simple line diagram to show you what a set of 12 volt batteries look like in parallel.

You can also see the battery clamp that needs to be there to avoid jostling the batteries around during travel.

The engine batteries were still in good shape, so we just cleaned any battery acid residue off of them and put some vaseline on the battery cable terminals and posts on the batteries. We also put vaseline on the posts and cables of the cabin batteries to avoid any further oxidation or corrosion from forming. (I like to use an old artist’s paintbrush for this or q-tips)

Before doing any of the battery install, we had to remember a couple of things:

Turn off all power to the battery compartment. Switch off the main power to the bus and pull all circuit breakers in the breaker panel inside the bus.

Ours is a diesel pusher, and this is located in the engine compartment door.

To ensure you don’t get a zap (shock) from the batteries themselves, hook up the red connections (positive) first then the black connections (grounds) next.

Test your connections with a meter before starting any work to make sure there is no residual voltage. Since we did not know what was working and what wasn’t, it was just an extra safety step for us.

Converters/Inverters and how they can make you a little crazy if you don’t understand how they work.

Magnum Energy Power Converter Unit

Note:  Although your RV may not have exactly the same brand of voltage converter and inverter that ours does, it will work in a very similar way.

After plugging the RV into the outlet on our garage (called shoreline plugging), we got a little too anxious to start checking things out. This is where you have to be patient and let the batteries charge up. We have a Magnum Energy converter/inverter that does a lot of things but the main thing it does is take 12 vdc power and convert it to cabin power, such as 115 VAC.

It also performs some very important functions that we had really never investigated before. We had often had inverter problems with this RV, so we were interested in troubleshooting this part of it to make sure it wasn’t just “operator error.”

Turns out the indications we saw on the control panel were the results of operator error (or at least that is how it panned out as we went along.)

The converter also performs a very detailed function of charging your cabin batteries to make sure they maintain an exact level of voltage DC and also to make sure they are charged correctly.

When we first hooked up to shoreline power, we found the lights were very dim and nothing in the cabin would maintain power levels long enough. For example, we could turn the TV on, but then it would drop off.

We also tried it by running the generator, but with the same results.

We went online and found the manual for our power converter/inverter after narrowing it down to the box. We could hear it clicking when it was attempting to convert DC to AC.

We were also getting a strange light on our control panel inside the coach that we had never seen before. We kept getting an intermittent, flashing red FAULT light. After reading about the converter, we found this would be normal if the batteries were not yet up to the optimum voltage. We were also getting a BULK light on our control panel that we did not recognize. I cannot stand not to know what stuff like that means, so I started digging through the manual and found out this is normal.

I had vaguely seen this Magnum control panel before, but I had no earthly idea what it did. The Coachmen owner’s manual said absolutely nothing about this.

When you start charging the batteries, you will probably get a FAULT light once every 4 seconds until your batteries are bulk charged to a certain level. While this is happening, you will also see a BULK light.

The next stage is the ABSORB stage. The charge is kept at the BULK charge stage and will back off if it is too hot.

After ABSORB, comes the FLOAT stage. The charge voltage is reduced to a constant maintenance voltage that the converter can handle.

So, your converter not only protects the circuits in your RV and shuts itself off if the voltage is not at the right level for your cabin’s components. Once the voltage is optimum for conversion to AC, the converter then sends the correct voltage to your cabin functions.

So, unlike when you install a battery in your car, for example, you don’t just throw it in and go for an RV. You have to let your RV’s converter/inverter figure it all out.

In my next chapter, we’ll tackle the case of the “Missing Mudflap” and what to do about it. (the dealership returned our RV without its signature mudflap)

You can see the mudflap that says “Sportscoach” at the bottom of this photo. This was mysteriously missing from our coach when we got it back from the dealer. We will talk about what to do about that when I come back.

See you next time!