Chassis Battery Voltage

[Rick 2005 Dolphin 5376]

Good morning all.
A little background. 2005 Dolphin 5376, W24. A few months ago my Chassis Battery exploded while I was trying to start the engine. It was a 5 old year old battery. After all the clean up and new battery installed, everything works and I can assume for this moment nothing was damaged.
This morning I checked the battery voltage at the control panel. House Batteries 13.7v Chassis 11.7v.
I checked voltage at the Interconnect Solenoid and get 13.7 out of each pole. One going to the coach batteries and the other, the chassis.
When starting the engine, the dash displays 14.7volts.
The control center reports 13.7 house and 14.7 chassis.
I would think that I should have darn near the same volts between chassis and house when just on shore power and engine off.
Clues, suggestions?

As an addendum:

The first attempt to start the engine that day, the battery appeared dead.
I then pressed the "Emergency Start" button on the dash and tried again to start it. It was then that the battery blew up.
Is there a relay or fuse that the "Emergency Start" button is connected to?
I checked all the fuses under the top dash panel and are all good.
I'm about to install a battery tender to keep the chassis battery topped of as the only time, currently, the chassis battery is being charged is with the engine running.
Help is greatly appreciated

[Arch Hoagland]

Wow I'll bet that was a mess to clean up!! Do you remember what brand of battery it was that blew up?

Can't help you on what the voltages should be.

[Skip426]

From the info in your post it looks like the alternator isn't charging the coach batteries either.

Engine running ; chassis battery 14.7 , coach 13.7. They should be the same there too.

Is the interconnect solenoid/relay in a BCC ? ( Battery Control Center )

Could you post a picture of it's location ?

[tmw188]

Rick I’ll check mine while running and give you a call while doing so maybe tomorrow or Tuesday.

[Rick 2005 Dolphin 5376]

Originally Posted by Arch Hoagland

Wow I'll bet that was a mess to clean up!! Do you remember what brand of battery it was that blew up?

Can't help you on what the voltages should be.

We were on the road and I had to stop at WalMart for a replacement.

[Rick 2005 Dolphin 5376]

Originally Posted by Skip426

From the info in your post it looks like the alternator isn't charging the coach batteries either.

Engine running ; chassis battery 14.7 , coach 13.7. They should be the same there too.

Is the interconnect solenoid/relay in a BCC ? ( Battery Control Center )

Could you post a picture of it's location ?

The alternator charges both sides of the system. If I run it long enough they both balance.

The BCC to the right of the interconnect. It has 6 black boxes, and a bigger black box. (breakers) on it. If you reach behind each little box you'll find a reset button

[Rick 2005 Dolphin 5376]

The Battery Tender has been on since noon Sunday the 16th. Today were are at 13.7, both sides and the tender is in green mode.

[TTTman]

TTTman here my first post reply so hopefully I wont mess this up. If I do flogg me like I deserve it! Background Electricians mate Chief Nuc Submarines. The chassis battery blowing up or at least overheating is not an extremely rare occurence. Remember we have alternators that put out from 75 all the way up to 145 amps or more , so if we believe we have a battery problem it pays to give it quick attention. My 02 holiday rambler blew up a shorted cell chassis battery 2 months ago. so a shorted cell or cell reversal will quickly lead to excessive heat and then excessive gassing (Heat and a pungent acid smell will be present) and possibly an explosion. I do not believe the chassis battery gets charged by the inverter/charger so the chassis batteries being a different voltage is not unusual, although after running a while and both being in good condition the readings should equalize while running. A fully charged lead acid battery will read approximately 12.8 volts and will go up to 13.8 volts following an equalizing charge. When we see voltages like 14.2 what we are really seeing is alternator output or battery charger output.what I call the charging source voltage. The 13.7 both sides tells you that the house batteries on the inverter charger and the chassis battery in green mode (on the battery tender)are both fully charged! I hope that makes some sense.

[TTTman]

I couldn't remember the whole post so i had to go back and read it. With shore power on and the engine running the dash will show motor alternator voltage output. The house panel should show the same reading for chassis battery voltage and the house batteries will show battery charger output voltage from shore power supplied inverter charger. I think my terminology is wrong calling the ac power converter an inverter. I think I will correct myself. an inverter is usually used in large diesel coaches to change dc power to ac 110 while running, in class a gassers we use a converter to change shore power 110 volt ac to dc 12 volt to supply dc loads and charge the house batteries. no 110 volt while driving unless the generator is running! TTTman

[tmw188]

Originally Posted by TTTman

I couldn't remember the whole post so i had to go back and read it. With shore power on and the engine running the dash will show motor alternator voltage output. The house panel should show the same reading for chassis battery voltage and the house batteries will show battery charger output voltage from shore power supplied inverter charger. I think my terminology is wrong calling the ac power converter an inverter. I think I will correct myself. an inverter is usually used in large diesel coaches to change dc power to ac 110 while running, in class a gassers we use a converter to change shore power 110 volt ac to dc 12 volt to supply dc loads and charge the house batteries. no 110 volt while driving unless the generator is running! TTTman

I have an inverter in my 05 gasser.

[Rick 2005 Dolphin 5376]

TTTman, no flogging required, thanks for all the info. I haven't messed with it for a week and I still believe the cable is suspect.
Currently the chassis battery is being maintained by the battery tender at 13.0v steady.

[TTTman]

TMW188, thanks for that note, I moved from a diesel pusher to a 2002 gas holiday rambler and was wondering if all gas rigs had converters instead of inverters. I hate to give out bad info but the differences in coaches makes a mistake easy to make. wish I had an inverter in mine just to have ac for small fans ect. while on the road.

[tmw188]

I often watch tv in the coach when working on things...no generator needed.