Battery voltage

[Memphisbobby]

Was wondering why on my cs 3953 the voltage differs from shore to engine power.
Engine off I get about
13.1 on chasis
12.9 on house
Engine on
14.0 on chasis
13.9 on house

I just do not know enough yet about this complex electrical system.
Or plumbing, ac, water, etc.
Thanks for all the help I get by reading this forum

[LJowdy]

Probably because your alternator is charging your batteries at 14.7 volts which is normal

[C.Martin]

Anything above around 12.6v (sitting idle, no load) is coming from somewhere...

The chassis...Alternator, Small Solar panel on the roof.

The house...Inverter Charger (Shore or Generator), possibly aftermarket SOLAR.

Then the trick...the two can be joined together by the bi-directional relay when certain conditions are met.

Extra reading, if interested.

http://www.intellitec.com/assets/pdf...-00362-000.pdf

[Skip426]

Your shore power readings indicate the charging system that operates when on shore power is in float or minimum charge mode. To avoid overcharging that would result in electrolyte loss from the battery cells.
With the engine started , the chassis battery has been drawn down by the load of the starter and the alternator is running a higher charge rate to build the battery back up.
I see nothing unusual about your readings , are you having a specific problem ?
If you turn on a number of interior lights in the coach , the shore power charging system should , ramp up to cover the added load.
For more info visit this site.

The 12volt Side of Life (Part 1)

[Memphisbobby]

Thanks to all for the replies. Skip, I am not having a specific problem, just was curious about the difference. Since I left my lights on the first night out I am a little anxious about batteries and such. No fun having to get a boost on day number 2.

[Skip426]

The 0.1 /0.2 volt difference , could just be from the length of the charge wire to the batteries ; and shouldn't be a problem.
You say you had to get a boost ?
Isn't your coach equipped with a " Boost " or "Emergency Start " button on the dash ?

There are many links in the " Sticky " posts in the top of the list in the Newmar owners forums , that can help you understand your coach's systems.
Look at " Quick Mods and Easy Fixes 1,2 & 3 " for information on all things Newmar.

[Memphisbobby]

Yes it does have a battery boost button. May I just used it wrong but I pushed it and it did not help.
Held it down to start but still nothing. Looking back maybe I should have held it down for a while to let it charge up some.

[Skip426]

There may be an issue with where the boost switch gets it's power . If the switch needs power from the chassis battery and it was totally dead , then you'd have no operation of the interconnect relay.

[Memphisbobby]

If I remember correctly the panel above the door showed about 8.5 volts on the chassis battery.so that is dead dead

[palehorse89]

Originally Posted by Memphisbobby

If I remember correctly the panel above the door showed about 8.5 volts on the chassis battery.so that is dead dead

If it were mine, Plug it in and let the batteries charge up, and if no shore power, start the genset and run it for a couple of hours to put a charge back in those batteries. Trying to charge them all with the engine's alternator will put a big load on it and it will really get hot........and this will take the life right out of it...........

[Skip426]

Originally Posted by Memphisbobby

If I remember correctly the panel above the door showed about 8.5 volts on the chassis battery.so that is dead dead

That could easily have been dead enough ; that the interconnect wouldn't work.
Anything below 11volts will shut down a lot of systems .
BTW: I carry a set of jumper cables , long enough to reach from the coach batteries to my toad ( my batteries are behind the right rear wheels ) so I can jump start the toad without unhooking it , or vice versa. But on the coach all the batteries are on one tray so easier ; unless both sets of batteries were dead; to join the banks together, with the cables.

[Memphisbobby]

Skip, I do now

[Skip426]

Originally Posted by Memphisbobby

Skip, I do now

Safe travels.

[dc3carl]

I always use the Battery Boost switch to gang the house and chassis batteries together on engine start. If we are not plugged into shore power, I bring the generator on-line before starting the chassis engine. Induction heaters can put a significant load on the chassis electrical system until temperature is reached so I hold the Boost switch until the induction heater stops cycling.
Happy travels!