Chassis battery charging?

Want a B

Senior Member
Joined
Oct 29, 2019
Messages
110
Location
Indiana
Brand: Born Free
Model: Built for Two
Coach Year: 2009
Chassis year: 2008

Does the chassis battery get charged/maintain when the coach is connected to shore power?

If yes, what would be a good test to confirm?

I was thinking the answer was yes. BUT.

I have a voltage meter plugged into the chassis cigarette lighter socket. Voltage meter I installed has a ON/OFF switch because the chassis cigarette socket is hot when the ignition switch is off. Voltage meter also powers the GPS, TPMS and Dash Cam. I turn the voltage meter switch off when I turn the ignition switch off.

I turn the voltage meter ON before turning the engine ignition switch on. I've notice that the longer the Coach sits between usage the lower the voltage meter reads. Makes me think the chassis battery is NOT being charged when the coach is connected to shore power.
 
Most often, the answer is "no". Most (but not all) rigs isolate the chassis and the coach except when the engine is running.

You can easily correct this by installing a Trik-L-Start.
 
Or just take it for a spin regularly. That has the added advantage of circulating all fluids, warming up tires, belts and hoses, lubricating seals, burning rust and dust off brakes... It may also allow a developing mechanical problem to surface so it doesn’t spoil a trip.

I shoot for every couple of weeks, but it’s gone as long as a month between uses. Our major shopping is 30 miles away, so a round trip gives it a nice workout.
 
Or just take it for a spin regularly. That has the added advantage of circulating all fluids, warming up tires, belts and hoses, lubricating seals, burning rust and dust off brakes... It may also allow a developing mechanical problem to surface so it doesn’t spoil a trip.

I shoot for every couple of weeks, but it’s gone as long as a month between uses. Our major shopping is 30 miles away, so a round trip gives it a nice workout.

If you are talking about a 30 mile trip, then Jon's advice is good. Note, however, that starting an engine without bringing it up to full operating temperature does much more harm than good. Lots of people start their rigs and idle them for a few minutes. This is nowhere near adequate, especially for a diesel. Modern diesels may NEVER get up to operating speed via idling, and can take a long time even when driving under load. This is why Sprinters (for example) have auxiliary heaters--the engines are just too efficient to get hot without a significant load for a significant period of time.

If you are not going to commit to a good long drive, best to let it sleep.
 
If you are talking about a 30 mile trip, then Jon's advice is good. Note, however, that starting an engine without bringing it up to full operating temperature does much more harm than good. Lots of people start their rigs and idle them for a few minutes. This is nowhere near adequate, especially for a diesel. Modern diesels may NEVER get up to operating speed via idling, and can take a long time even when driving under load. This is why Sprinters (for example) have auxiliary heaters--the engines are just too efficient to get hot without a significant load for a significant period of time.

If you are not going to commit to a good long drive, best to let it sleep.


I will add to this a bit from living in a cold climate. In the winter here in Minnesota it is very common to take a very long time to get the engine to operating temperature, even at highway speed and sometimes the exhaust never even completely dries out. If you can see vapor coming out of the tailipipe immediately at the pipe, you likely are condensing in the exhaust.


Personally, and based on looking at oil quality at changes and such, I prefer to leave a "put up" vehicle unstarted for that time if at all possible in climates like ours.


Of course, around here, if you venture out in the winter you will almost certainly give the vehicle a dose of salt most times which will sit on it until spring.


If the battery can't be charged though shore power, as others have said, a trickle start is a good idea.
 
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In the interest of having to add more gizmos, replacing the separator/isolator with one of these two way charger relays might be a way to go.

https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A

It has time delays to prevent surging and also has a low current draw, 175ma when combined, 15ma when open.

It has only a 120 amp continuous rating but as either battery can be set up as the primary those amps do not count as the alt cable is mounted to the same post. I'm pretty sure that there is a heavy duty version for those needing more current flow.

Price runs in the $70+ range at Wally and Amazon.

I've had mine for a few months now and it works quite splendidly. One caveat is that it will mess with measuring on a battery monitor as there is now another path to ground not going through the shunt while the batteries are combined.

MY batteries are all flooded L/A. I'm thinking it will also work fine for a flooded/AGM mixed scenario(I could be wrong, there is precedent). Lithium batteries, by their nature, would be a no go, I would think.
 
My 2020 Wonder RTB didn't charge the motor battery since Triple E said that Ford wouldn't allow them to modify the electrical system. I used a Xantrex unit (like the Ultr TRIK-L-start but it was close to $400.00. and it keeps the batteries both charged (AGM). and I wouldn't be without it. My unit is pugged in for 4-6 months. It is also extremely easy to install. If you need more info - ask. Oh yes I contacted Ford and they said that they didn't care if I installed one as long as I didn't screw up the wiring - no problem. GO FOR IT.
 
Most often, the answer is "no". Most (but not all) rigs isolate the chassis and the coach except when the engine is running.

You can easily correct this by installing a Trik-L-Start.

That is what I ended up doing. Coach is connect to shore power. Extension cord run under the coach and up though the engine compartment to power the battery maintainer.
 
The unit I installed worked automatically. I didn't have to remember to plug in a extra power cord or hook it up to the starting battery. As soon as I pugged in the coach circuit it went to work. I found that more trustworthy as it was -14.C the other night (C= cold, Canadian or Celsius. I plan on having my unit plugged in till early May and I don't have to worry about $400.00+ for starting batteries.
 
The unit I installed worked automatically. I didn't have to remember to plug in a extra power cord or hook it up to the starting battery. As soon as I pugged in the coach circuit it went to work. I found that more trustworthy as it was -14.C the other night (C= cold, Canadian or Celsius. I plan on having my unit plugged in till early May and I don't have to worry about $400.00+ for starting batteries.

I spent $35.
 

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