Diesel pusher electrical starting prob[ems

[Ed_Manifold]

Approx.3 weeks ago I went to start my motorhome and the batteries seemed dead with nothing from the switch so I hit aux. start and it started right up. My motorhome is a 2002 Phaeton with the 3126 Cat. The motorhome is parked at home so it is always plugged-in. I have heard and read that a plugged in motorhome does not charge the starting batteries but in the almost 14 years it has never had this problem. I installed trickle chargers on the starting batteries and in a couple of days the batteries showed fully charged and continue to do so each time I re-plug the trickle chargers in. On March 1st I pulled the motorhome up on the level and finished getting ready to leave for Las Vegas Nascar. We finally got in to leave tuned the key to start and nothing, now remember 2 hours before It started when I moved it to my level driveway. I went ahead and started with the aux start switch and went on my trip. This occurrence happened several times during our trip. When we got to Las Vegas I checked the batteries for corrosion and to make sure the terminals were all tight. When I started the motorhome to move it and hook-up the jeep it started fine with using the regular starting batteries. One half hour later ready to leave I turned the key switch and nothing, so I started the engine with the aux start. This occurrence happened a couple more times on the way home. The batteries are Cat Batteries that are maintenance free that I replaced approx. 4 plus years ago, I used the Cat batteries because that's what came in the motorhome. Please help me with suggestions as to what's wrong.

[Ivylog]

Have someone watch your head lights the next time this happens. If they go out when you try and start (without the boost) you have a battery problem. If they stay on you have a switching problem.

My two Interstate group 31 starting batteries went 11 years BUT I found the caps under the hard plastic top (maintenance free) and added a little water every couple of years.

[ricelake922]

This happened to me three times when I had just turned off the coach to get coffee. It was the solenoid which a friend smacked while I turned the key. Coach started. Will be getting that fixedin the spring when it is out of storage.

[YC_1]

Four year old starting batteries are shot. Since you put a charger on the terminals themselves it is unlikely the cables or connections are at fault.

Batteries are not bought, they are just rented. Save yourself a lot of grief and install new ones. Take pictures of the cables before removing them. Then while you have them out disconnect the second bank and clean every connection and reconnect. Do not just retighten them. Take them off and clean them shiny bright.

[Mandalay_Parr]

Sounds like your chassis batteries need to be replaced.

[fourmat]

like others have said first thing to do is have batteries load tested 4 years is not old but not new either. If all cks good then its time to find some type of draw that will have to be pretty heavy to draw them down in a couple of hours When you turn the key on and it does not start do you have all dash lights and headlights or are all circuits dead?

[rgatijnet1]

Also you want to make sure that your battery connections are all tight and clean. Even a bad connection will allow a small amount of current, from a trickle charger, to get through and charge your batteries. But when you try to start the coach, it needs a LOT of current and a poor connection can fail.

[Ivylog]

I would start by making sure something is not turned on drawing your batteries down. Remove both positive terminals for a spark when you touch one of them back. Even the cheap Harbor freight meters I have a 10 AM setting.which you could use to check the amount which should be 1-2 amps.

[rdmike]

Ed Manifold wrote:
Thank-you gatorcg; You're right I have not tried a stress test because I don't know how. Any Ideas where to get this done?

Definately sounds like batteries. A truck shop will have a tester to check CCA under load. Sometimes a battery just goes south. Replace them both.

[Ed_Manifold]

Thank-you gatorcg; You're right I have not tried a stress test because I don't know how. Any Ideas where to get this done?

[gatorcq]

When was the last time you had the batteries checked out?
By the way, starting a any diesel with Qty 2 1000 cold cranking amps. As soon as one goes south then you are in trouble. By the way, I reread your post, not once did you perform stress test on your batteries.