cant keep engine battery charged

[2005 Southwind]

I always keep connected to shore power but after a few days the engine battery is dead. I thought the power converter was spose to keep batteries charged? I have a charger on it now but would like to have it function like it is spose to. Where do i start looking to fix it? Any help would be appreciated.

thanks

[Mark and Dale Bruss]

Not all systems charge the engine battery with the converter,

 

You could install a battery combiner to allow the converter to charge the engine battery as well as the house battery.

 

You do not want to just connect the two batteries to the converter.

[Clay L]

What kind of motor home do you have? That may determine how to answer your question.

[skp51443]

If nothing is broken then adding a battery minder to the engine battery is probably the easy way to go.

 

You might want to look for what is drawing the battery down so quickly too, it is often an overlooked light or other device that is powered off the engine battery and not the RV battery that is the culprit. We had that issue with a compartment light that didn't go out when the door was closed and was not an easy find.

[Devilishjim]

Or it may just be a bad battery but if not do as Stanley says.

[BrianT]

A battery maintainer is nice. I have one for my truck now and like having it connected when I'm not using the truck much. I have some issues with some of the chassis electrical draining the batteries. If I ran the truck every day, it would not be an issue as it would recharge the batteries when it ran. But there are times when it sits for months without running at all. It's a pain pulling the battery terminals. So the maintainer is how I've chosen to deal with the issues.

 

I do also pull a couple of fuses when I know it's going to sit for a while, one of which runs stuff like interior lights and other stuff that works when the ignition key is off.

 

I think the battery maintainer I bought was something like $20 or $25 at Walmart. Doesn't take a whole lot.

[Guest ticat900]

Or it may just be a bad battery but if not do as Stanley says.

agreed may be a bad battery and a batt minder works well as long as there is not a large unknown power draw.If so this needs to be fixed before a battery minder will suffice

My last diesel pusher MH I just ran a simple 10G charge wire from the house batterys and it worked just fine

[oldjohnt]

My RV's (nor the many I have owned) current electrical configuration does not charge the engine battery when its plugged into shore power, ONLY my house batteries. Of course, a person could easily wire it so that takes place. However, if it were mine, I would find and fix the problem before throwing a battery tender at it or configuring your Converter/Charger to charge the engine battery if its not already so connected. It's possible your battery may be bad (many shops test them for free) or else there's a parasitic drain which is discharging it when the RV is parked. Such could be some sort of a glove box light or an interior light that isn't turning off as it should. I would start with testing the battery itself, then look for the parasitic drain, then re wire or add a tender but only if necessary as that (discharge) shouldn't take place if the battery is okay and all else is well.

 

John T

[Jimalberta]

I agree with fixing the problem. Your battery should not drain that fast. My MH can easily sit for a month or more and starts right up. Engine batteries do not get charged while on shore power.

[moisheh]

Many motorhomes DO charge the chassis batteries when on shore power. There are many different systems. Our Dynasty uses one form Intellitec. that is very complex and expensive. Our Bounder DP has a simple system. There are special devices that will allow your chassis batteries to receive a small charge from your convertor or inverter. Depending on your RV many items may run off your chassis batteries when parked..

[BrianT]

Sure it's better to fix the problem if you can. But if you can't, or it's going to be a while before you can get it done, it's definitely cheaper to stick a battery maintainer on than buying a new battery (or batteries) a couple of times a year and definitely handier than disconnecting. Just sayin'...

[steved44]

Our bus was not set up to charge the chassis batteries on shore power so we but an AMP-L-Start on it and now it works great.

http://www.rvupgradestore.com/15-Amp-Starting-Battery-Charger-Maintainer-p/amp-l-start.htm Steve

[Kirk W]

The first thing to do is to determine what the problem actually is. It could be a bad battery, or some sort of phantom load draining it, or even failure of the alternator to charge the battery properly. I suggest that you start by checking your battery for proper electrolyte levels, if it is one that can be serviced. Low levels in the battery will severely limit the amount of charge the battery can take and will destroy the battery fairly quickly. Once the electrolyte is known to be at proper levels, charge it up fully and then lift the battery cables. Use a good digital meter and check the voltage after the battery has had a couple of hours to rest and record it. Then wait 24 hours and do this again. Compare the readings that you get to those from these battery charge level charts to see just where you stand. If the battery discharges rapidly with cables lifted, you then know that your battery is defective. If it does not, then I suggest you also have it load tested, which most battery shops will do for you at not charge.

 

If the battery is good then the next thing you need to do is to determine what is causing that much discharge as that is far too rapidly for it to be normal. This can be done by connecting one battery cable and then your amp meter between the other cable and the battery post. You then see what the current reading is and begin to pull 12V fuses while watching for a major drop in current flow to locate the circuit that has the problem.

 

As others have said, very few motorhomes are connected for the OEM converter to keep the battery properly charged but one of the float chargers will do the job, as long as the discharge rate is low enough. Most such devices only supply 1-2a so you can't have any large current loads.

[Wrknrvr]

If you nave a DC clamp on amp meter then clamp it around the positive battery cable. Now see how many amps it is using. Then pull one fuse at a time and that will find what circuit has the problem on it when the amps drop. Then follow that circuit as for what the problem is. While you have the meter, clamp it on the charge line to the battery and see that your alternator is putting out the proper amps at the proper voltage.

This after you do the basic's and checking the battery.

[rv-voyager]

Our radio operates on the motor battery, when listening to xm it would drain the battery. I bought a trickle charger, and plugged-it to the outside AC plug total cost $17.95

[Jimalberta]

Kirk, its been many years since I have seen an engine battery that you could check the electrolyte on. First thing I would do is drive the MH to a good battery place and have it load tested. They can hook up a small power supply to the coach while this is happening so that you dont lose power to the engine computer. Then look for a parastic drain......they can help with that as well.

[Kirk W]

Kirk, its been many years since I have seen an engine battery that you could check the electrolyte on.

They do still exist, but I don't believe that any of the OEM batteries are today. Either way, if they have that type then levels should be checked.

 

[Guest ticat900]

I always keep connected to shore power but after a few days the engine battery is dead. I thought the power converter was spose to keep batteries charged? I have a charger on it now but would like to have it function like it is spose to. Where do i start looking to fix it? Any help would be appreciated.

thanks

Some Diesel pusher MH do from the factory with a chassis batt charge system but most have a battery tender installed. Dead after a few days means possible excessive draw and or useage or just at the end of its life. You sometimes would be surprized what the factory runs off the chassis battery that you assumed was just house. For example on my diesel pusher I have the main entry electronic door lock system that runs off the chassis batterys and so do the seats so even when my disconnect switch is off the seats and door locks are still active

Installing a battery minder system should solve your problems but I would have the chassis battery load tested also. Your alternater is obviously working fine or it(battery) would have been dead when you arrived at your destination.Like \I said earlier you could run a 10 gauge wire from house batt to chassis batt instead of the trickle type charger

[Kirk W]

For example on my diesel pusher I have the main entry electronic door lock system that runs off the chassis batterys and so do the seats so even when my disconnect switch is off the seats and door locks are still active

That doesn't surprise me as most coaches I am familiar with tie anything needed in order to drive the RV to the chassis battery system. If you are able to drive the RV with the coach battery disconnect open, it is better that way. We didn't have an electric door lock but ours did have the power seats and the automatic step supplied from the chassis battery as well as the light under the engine cover.

[Guest ticat900]

kirk. Its not a surprize to me either.My point was sometimes chassis batterys actually control more stuff than one realizes when sitting still that's used both on the road and while sitting

sounds like in this case as its not a diesel pusher and most likely a simple converter/single battery system that the battery is most likely getting weak + he left something on that's drawing it down faster than normal

[Kirk W]

kirk. Its not a surprize to me either.My point was sometimes chassis batterys actually control more stuff than one realizes when sitting still that's used both on the road and while sitting

That is entirely possible and some things are not connected through the battery isolator either. Although it is just guessing at this point, I tend to suspect the battery but only based upon a feeling, since we can't tell based upon what little we know.

[mickhoss]

Next time you stop the vehicle after driving for a reasonable distance remove the earth lead from the start battery, then check if any thing that normally works doesent with the start battery disconnected, then you will know there are items draining the start battery battery and you may want to rewire these things to the house batteries.

 

If after sitting for a number of days the start battery is flat it probably needs replacing.

just check that the top of the battery is not damp and dusty and leaking voltage through the battery hold down clamp. ( ive been caught by that one)

 

mick

[Honorman]

If nothing is broken then adding a battery minder to the engine battery is probably the easy way to go.

 

You might want to look for what is drawing the battery down so quickly too, it is often an overlooked light or other device that is powered off the engine battery and not the RV battery that is the culprit. We had that issue with a compartment light that didn't go out when the door was closed and was not an easy find.

_________________________________________________________________________________________________________

I keep a battery minder on the house and chassis battery's (dead converter, and I don't get to use it enough right now to buy the smart charger)

[Keelandb]

I had a problem with the starting battery of my Jayco Greyhawk going down within about a month of being parked. Rather than putting a battery minder on it I followed the suggestion of the repair people at the RV dealership. They suggested that I put a shut-off switch on the battery. When I park for more than overnight I lift the hood and pull the switch lever up to disconnect the battery. I have had that setup for over two years and lots of miles on the RV with no problem or drained starting battery. To start the RV just lift the hood and push the lever back down.

 

I agree that finding the parasitic load is better, but it that is too difficult then try the shut-off switch that can be purchased at many auto parts stores.

[mscans]

I had a minor problem with the chassis battery running down when parked even when plugged in. As others mentioned, the battery doe not charge under these conditions. I installed a Trik-L-Start ( http://www.lslproducts.net/TLSPage.html ) system that also allows the chassis battery the benefit of correct charging as the converter was a 4 way system. With this in place the chassis battery was able to see the improved charging effect.

 

This system has status lights so it lets you know what it is doing as well.

 

Good luck and happy camping!