Chassis battery question.

Sal · September 30, 2017

Hi all, we have a 2004 Damon daybreak class a motorhome with a F450 chassis. We kept it in a storage lot for a few weeks and when we came back to it today all of the batteries were dead the chassis battery as well as the coach battery. We were able to get a jump from a good Samaritan who also happen to be somewhat of an RV expert and informed us that the battery in our chassis was not meant for an RV, in his words it was a car battery. I'm OK with buying a new battery that's better manufactured to support our RV, but what kind of battery is that?

What do you all suggest?

Thank you !

Orvil Hazelton · September 30, 2017

You really have two problems to address: 1) what type of starting battery is required on your particular Ford F-53 Chassis. If you do indeed have an improper battery installed you're going to have to ascertain what size and model is correct. Starting batteries are quite different from your house, or chassis batteries. Be sure to check your owners manual for the proper model. 2) your next challenge is to stop the drain on your batteries while in storage. If you have an exterior AC plug available you can purchase an inexpensive battery minder to maintain the desired charge. I recommend a 3 stage charger for a longer battery life. If no electrical service is available where you store your rig, I would then recommend the installation of a blade type battery disconnect. This will hold back the inevitable "phantom leaks" so prevalent in our modern RVs. I wish you well, my friend. As always, oRV

Kirk W · September 30, 2017

Let me add a bit to what Orv has already told you. I'd look first at the battery for the chassis, then the house. You have two separate 12V-dc electrical systems in addition to the 120V-ac that comes from shore power. The one for the chassis is the same as would exist for any truck or car, but with the ability to tie to the one for the coach, but when the engine is not running, the two systems should be isolated from each other unless there is some problem in the system. If you are not the original owner, it is possible that a previous owner made changes but that isn't probable, so let's assume that it is working as it should. An easy way to test this is to remove the negative battery cable from the coach battery so it isn't connected, then with the chassis battery charged but the engine off, try the interior lights or water pump to see if they work. If as normal, they should not but when you start the engine they should then work, then not work again if you shut the engine off. Once you know that you can move forward to address the two batteries as separate problems.

Typical batteries are wet cell meaning that they have liquid in each cell and that level must be maintained by adding distilled to each cell as needed. Your chassis battery quite likely is a maintenance free one, but if it has removable caps on each cell you should check to be sure that each one has liquid and that you can't see the tops of the cells above that liquid. If you can, the battery may be damaged but I would first add distilled water to bring them to the proper level just to see if that helps. If your battery is old, it may just be failing from old age. Once you know that the electrolyte level is proper, I would charge it up and then take it to a battery shop and ask them to load test it. Most such shops will do this for free as they often sell batteries when the test fails. A failing battery will discharge while sitting unused even though it has no current drawn from it. If the battery is good, then we look for a way to prevent discharging.

The coach battery is, or should be a deep cycle battery such as are used for power golf carts and similar vehicles. They are constructed quite differently from the chassis, starting battery because they are used differently and require different standards. Those batteries will need to have proper electrolyte levels also and they also can be load tested and although the standard for that test is different than the chassis battery, your local battery shop should know how to check both. You should be able to at least partially recharge the coach battery by plugging the shore power cord in for a day or two.

One question is, did you just buy this RV or have you owned it and so know the history of the batteries? If you recently purchased the RV, there is a strong possibility that both of your batteries were near death when you bought the RV.

Sal · September 30, 2017

We bought it a month or so ago and have used it for only one short outing.

Youve both given me a lot of homework! Thank you! I'll get started and hopefully in the meantime it will start when we go to take it out this after noon.

Ray,IN · October 5, 2017

Locate the code stamped into the battery case, then phone a battery store that sells that brand and ask when the battery was made. Depending on age and brand, it may be covered by a pro-rated warranty. A pickup truck battery is only different from an automobile battery by amp-hours available. I assume your MH has a gas engine, as it would require 2 batteries to reliably start a diesel engine . Your owners manual states the required minimum battery size.