Electrical Issue

[RLHAMILTON]

Have 2011 Berkshire 390RB. All batteries are less than a year old. Have no trouble starting coach at all. However, after setting overnight when turn ignition and start coach, get a low battery warning for approx. 2 minutes while coach is running. After the 2 minutes the warning stops and reading is 14.1 or 14.2 volts. Just took back to repair shop and had batteries pulled, tested, re-installed, and tested-all OK.

Only think I can think of is possibly bad transfer switch. Any other ideas? Thanks.

[dogsgocamping]

Has noting to do with the transfer switch. Modern alternators wait for the voltage to stabilize so as not to burn themselves out. They send current in bursts to bring the battery voltage up in a controlled fashion. Once the load is safe for it, it will run in a state to maintain the batteries. Alternators are not designed to charge batteries, just maintain them. I'm not saying they don't charge batteries, just that they will last a lot longer if they are only required to maintain them.

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[tmmar]

The low battery warning happens on startup because the engine heaters are drawing power from the batteries
Once the engine warms, the heaters stop drawing power and the message no longer appears. You can also prevent the message from appearing NY plugging the block heater in for 20 minutes prior to starting the engine. If you do that you should not get the low battery message

[KennyGolub]

I had the same problem last fall. Took it to Freightliner in Canton Ohio and the found both chassis batteries were bad (under 2 yrs old).

I'm not sure the converter charges the chassis batteries, so this winter, I turn off the master switch for the chassis batteries and keep a battery tender on them.

[ccupton]

Had same problem on 38a. Added ghost switch that when plugged in after the house batteries are charged it auto switches to engine batteries. When they are charged it switches back to house batteries. It also works with my solar system.


Chris & Carol
2016 Berkshire 38A
2014 Honda CRV

[I-RV]

Originally Posted by tmmar

The low battery warning happens on startup because the engine heaters are drawing power from the batteries
Once the engine warms, the heaters stop drawing power and the message no longer appears. You can also prevent the message from appearing NY plugging the block heater in for 20 minutes prior to starting the engine. If you do that you should not get the low battery message

X2 - Have had that issue for years. I got real excited when it first happened and dealer even replaced the alternator. This has been addressed many times in the forum and you should not get worried about it as long as the Low Voltage warning disappears in a few minutes.
Hank

[SeaDog]

Glow plugs continue to draw high amps for several minutes after a cold engine starts which accounts for the low voltage warning (some draw as high as 300 amps) after an engine has been run or plugged in for a few hours they are either not needed to start or are only on for a short period.

[RLHAMILTON]

Appreciate the responses. Safe travels to everyone!

[RKNOLA]

ours does the same thing. (Sometimes the only thing really low are the sales numbers of the guy selling batteries! Buyer Beware!!)
Good Luck!
Karen

[edgewant]

I have the same thing going on but I don't think it has to do with engine heaters or glow plugs. I sit and watch the volt meter cycle and it continues to cycle from low to high voltage and the warning is dsiplayed until the air systems are pressurized and the pressure relief valve pops. Only then does the volt meter stay in the proper range and the low battery voltage warning goes away. I believe either the chassis air compressor or air dryer are drawing the voltage causing the low reading.

[edgewant]

Cummins 6.7L doesn't have glow plugs but uses a grid heater. Thats the coil like graphic on the dash display. You're supposed to wait until that coil light goes out before attempting a start. It means the grid heater has heated to temperature and is ready for engine start. So no glow plugs and the grid heater no longer drawing current is why I think the low battery warning is triggered by the chassis air system drawing current.