Chassis Batteries won't charge from shore power

[Tom Chace]

I may have asked this before----

What would be the leading candidate for the lack of charging of my chassis batteries when hooked up to shore power?

Thank You all for your responses

Tom

[Edward Buker]

Tom,

Please list your coach so we have some idea what configuration you might have. The chassis batteries need a system of their own to charge them while on shore power and not all coaches had a separate charging system installed. There are several versions, the simplest being an Echo charger which couples the house and chassis batteries based on voltage levels in order to maintain the chassis battery charge level with up to 15amps of charging capability. Looks like this.

http://www.amazon.com/Xantrex-82-0123-01-Echo-Charge-Systems/dp/B0016G8RT8

Later Ed

[David Handley]

Since I'm a newer owner, I hesitate to respond to these questions because of the rookie "syndrome", but after I first got my coach (equipped with a factory provided echo charger), I was not getting a charge to the chassis batteries when connected to 120V at my storage facility.  I was in the habit of placing the coach battery disconnect switch to OFF despite the 120V connection in those circumstances.  By coincidence I discovered that leaving the coach disconnect switch ON allowed the echo charger to do it's job and now my chassis batteries remain fully charged.  Weird, but it worked.

[Tom Chace]

I seem to forget to add the coach specs

1999 Beaver Montery
300 Cat

It does have an echo charger (original) looks like

I am going to the coach with a volt meter to check input and output

Tom

[Edward Buker]

Tom,

You should be seeing around 13.8V or a bit more volts on the house batteries, the Echo charger should have a solid green light on (not blinking) and the chassis batteries should have maybe 13V to 13.5V on them. Even 12.8V on the chassis batteries would be enough if fully charged.

Later Ed

[Frank Towle]

Don't forget about the in-line fuse from Echo to each battery.   

Also, ended up replacing my Echo with http://www.lslproducts.net/TLSPage.html as the Echo would not stay operating.

[Fred Brooks]

                  Hi Tom,

     The Echo charger has 2 yellow fuse holders. The red wire with the yellow stripe is the one that charges the chassis battery. It is not unusual for the inline 15amp sfe fuse to blow for varius reasons. The most common reason is the coach was sitting in covered storage for a long time and the chassis battery has discharged. When the Echo charger finally has the resourses to charge, The demand from the discharged chassis battery exceeds the 15amp fuse. To avoid this from happening, always start the engine first (use boost if necessary) so the alternator has first shot at putting a charge back in the chassis battery. Regards, Fred

[David T. Richelderfer]

Fred - You mean start the generator, not the coach engine?  When the batteries are low and the coach engine is started, then the demand for charging power on the engine's alternator will overheat the alternator, ultimately reducing its service life - yes?

[Fred Brooks]

             Dave,

      All we are trying to do is get a "surface charge" on the chassis batteries so the Echo charger doesn't latch on to low batteries. A 160 amp alternator can handle a low battery for a few minutes, then turn the engine off and start the gen or plug into shore power. The echo charger is more of a maintenance device. Regards, Fred

[David T. Richelderfer]

ahhh, okay.  The last part of the sentence was not clear in your first post - "can handle a low battery for a few minutes, then turn the engine off and start the gen or plug into shore power."  Got it...

[Edward Buker]

Fred, Dave,

I have not experienced the fuse blowing issue with the Echo Charger but Fred has a lot of experience and has come across this problem. I had very low charge in my chassis batteries due to a failed Echo Charger (corrosion), replaced it, and measured the current being supplied to the essentially dead battery set by the new Echo Charger. It was under 10 amps, current limiting is built into the circuitry, and the charger put out no heat under these conditions. It took several days but the unit fully charged the chassis set with no issues as designed.

If you check the fuses and they are fine then do not be concerned about the Echo Charger charging low batteries, it will just take some time with the coach plugged in.

If the house batteries are fully charged and the chassis batteries are low the engine alternator will handle bringing those batteries back up but not the larger house set when they are low, especially if the chassis batteries are also low. Most every large diesel truck has a pair of chassis batteries and the alternator is sized to handle that kind of load. The alternator has protection circuitry built in it, that de-rates the current output with temperature rise, but heavy loads like a dead house set can be the devil to an alternator. The devil will do it in eventually...

Later Ed

[David T. Richelderfer]

I think I will stick to the often mentioned plan to simply run the generator for an hour or so to charge up low batteries.  My guess is if the batteries have enough poop to start the coach engine, then they have more than enough to start the generator.  I believe the power boost button works for starting both the generator and coach engine, so why even start the coach engine in this situation?

[Edward Buker]

The thing to remember about the Echo Charger is it is not a power supply, it simple regulates the amount of current coming from the house set to the chassis set. It watches voltage levels and passes current based on that value. If it was not for water and corrosion issues you probably could not kill one of these given it has an easy job to do...

Later Ed