Community Forums

SBScouter · 10-27-2012, 09:15 AM

We found the chassis battery totally discharged on the Scout last weekend, after it sat parked for a couple of weeks. We tried to use the Start Boost switch to start the engine for the first time, but it didn't work. We tried pushing it to the Start side and starting, and we tried holding if down for a count of five seconds. We could hear what we thought was the solenoid clicking in the battery compartment every time. But no go. The battery checked OK, just fully discharged. So a couple of questions about Start Boost. Should it work with a fully discharged chassis battery? How can you check to see if it is working properly without waiting until you have a weak or dead chassis battery? Do you have to hold the Start Boost switch down to start (ours is a toggle that springs back to the standard position when you're not holding it down) or should just pushing and releasing get the job done? On a related issue, should our chassis battery charge if we're plugged into 110, 15 amp shore power? Posts on this topic say some do and some don't, partly depending on what year the coach is. Is there a way to check to see if it is or isn't charging?

texkayaker · 10-27-2012, 09:32 AM

You do have to hold down on the start boost switch when engage the starter. To check if your chassis battery is being charged while plugged in use a volt meter to check the battery volts before plugging in and after you plug in check again. If it is charging the volts will be higher while plugged in.

wa8yxm · 10-27-2012, 11:24 AM

I will second that, Press and hold the boost switch, Count to five and start the coach WHILE HOLDING THE SWITCH,, Continue to hold it for a five count after starting, then release.

On my coach it works for the generator too, but you have to hold it longer after starting (Till the ATS TSes)

docj · 10-27-2012, 11:31 AM

If your chassis batteries are extremely discharged or shorted then putting the house batteries in parallel with them (which is what happens when the switch is in the START position) may not be enough to get the rig started. It's like what happens when you connect jumper cables to a really dead battery on your car; sometimes you have to sit for a while while the battery gets some energy from the car doing the jumping.

The difference is that in that case there is an alternator actively supplying energy to the dead battery and your engine. In the case of the START switch you are simply sharing energy from another set of batteries. If that energy is being "sucked away" into a dead or shorted battery, you may still not be able to start the MH.

vsheetz · 10-27-2012, 11:47 AM

Quote:

Originally Posted by docj

If your chassis batteries are extremely discharged or shorted then putting the house batteries in parallel with them (which is what happens when the switch is in the START position) may not be enough to get the rig started. It's like what happens when you connect jumper cables to a really dead battery on your car; sometimes you have to sit for a while while the battery gets some energy from the car doing the jumping.

The difference is that in that case there is an alternator actively supplying energy to the dead battery and your engine. In the case of the START switch you are simply sharing energy from another set of batteries. If that energy is being "sucked away" into a dead or shorted battery, you may still not be able to start the MH.

Agree - if the chassis battery is way depleted, then hold the boost switch for awhile and then try to start the engine.

tropical36 · 10-28-2012, 09:28 AM

Quote:

Originally Posted by SBScouter

We found the chassis battery totally discharged on the Scout last weekend, after it sat parked for a couple of weeks. We tried to use the Start Boost switch to start the engine for the first time, but it didn't work. We tried pushing it to the Start side and starting, and we tried holding if down for a count of five seconds. We could hear what we thought was the solenoid clicking in the battery compartment every time. But no go. The battery checked OK, just fully discharged. So a couple of questions about Start Boost. Should it work with a fully discharged chassis battery? How can you check to see if it is working properly without waiting until you have a weak or dead chassis battery? Do you have to hold the Start Boost switch down to start (ours is a toggle that springs back to the standard position when you're not holding it down) or should just pushing and releasing get the job done? On a related issue, should our chassis battery charge if we're plugged into 110, 15 amp shore power? Posts on this topic say some do and some don't, partly depending on what year the coach is. Is there a way to check to see if it is or isn't charging?

Your coach batteries would have to have sufficient power to overcome a severely discharged chassis battery, but for the most part should have worked. When the chassis or coach batteries are down a little you can try separate voltage readings of each with and without your battery boost for comparisons. My system has a time delay on drop out, so holding it down isn't necessary for the first 30secs or so. As for the charging of both systems with the converter, you can again take voltage readings and recording each reading over a period of charging to see what's taking place. Mine charges the coach batteries first and then the chassis at a pre-determined level, so relatively speaking, if both read exactly the same voltage, then the chassis battery is being charged.

SBScouter · 10-28-2012, 05:21 PM

We appreciate the suggestions for checking what's going on with both the Start Boost and the shore power charging. We bought a multimeter today and have started working our way through the testing procedures. Happy RVing!

clyon51 · 10-28-2012, 05:50 PM

Quote:

Originally Posted by SBScouter

We appreciate the suggestions for checking what's going on with both the Start Boost and the shore power charging. We bought a multimeter today and have started working our way through the testing procedures. Happy RVing!

When you find out your chassis battery is not charged on shore power (I'm that confident) I highly recommend one of these. A snap to install then forget about it.

http://www.lslproducts.com/TLSPage.html

John...