House/chassis battery issue

[ramsaymike]

I have a 2007 Coachmen Concord DS275 and discovered that the only way to charge the chassis batteries is by the alternator. Shore power charges house batteries only. This is a real issue for me as the engine cracking speed is critical in starting the 6L Ford diesel. I also have a solar system but it too is house only. I would like to be able to use the solar charging as needed to keep the chassis batteries fully charged. The battery interconnect solenoid would seem to be what I need to use but when I activate it (apply 12v) the headlights turn on which greatly reduces the charging efficiency. Any ideas appreciated.

[time2roll]

11.7 volts resting is considered dead. That low in 10 days has an unusually high parasite drain or the battery is shot. Not sure what size you need but for superior "cracking" power consider an AGM such as Odyssey.

[Chum_lee]

In this format, there is nothing more I can do/say to help you.

Chum lee

[ramsaymike]

The problem I am dealing concerns the cracking speed of the motor. This is a 6L Ford diesel and it needs to developed sufficient pressure before it lets the engine start. THe faster the crank speed the faster the start. Even using the battery interconnect button does not help much. Of course, it can be fixed but as a work around it seems that having a fully charged battery does make a difference. There could well be a problem with some sort of unknown current draw - the battery was at 11.7V after 10 days or so. This 2007 unit is new to me. Also I should add that 120ac is not available where it is stored. It has 340 watts of solar.

[Chum_lee]

ramsaymike wrote:
I have a 2007 Coachmen Concord DS275 and discovered that the only way to charge the chassis batteries is by the alternator. Shore power charges house batteries only. This is a real issue for me as the engine cracking speed is critical in starting the 6L Ford diesel. I also have a solar system but it too is house only. I would like to be able to use the solar charging as needed to keep the chassis batteries fully charged. The battery interconnect solenoid would seem to be what I need to use but when I activate it (apply 12v) the headlights turn on which greatly reduces the charging efficiency. Any ideas appreciated.

IMO, what you are experiencing is completely normal and it is how most Class A/B/C gas MH's are wired from the factory. The chassis manufacturer (Ford/Chevrolet/Mercedes/etc.) designs/builds the chassis including the charging system which NORMALLY charges the engine (chassis) battery. The coach battery(s) are charged by the MH builders system. (It is often interlocked to the chassis batteries when the engine is running) For my Class A gasser, the easiest way to charge the chassis battery is to use a separate automotive type 12 volt charger (I use a 10 amp charger) which is plugged into a 120 volt outlet inside the MH. You must run the generator or be plugged into shore power to do this. IMO this is the easiest/safest/cheapest way to charge the chassis battery without causing other issues. You can manually hold down the house/chassis battery interconnect switch, but that is NOT what it is designed to do. IMO, charging deep cycle and automotive batteries together with the same charger is not a good idea and can result in failing to get all the batteries fully charged or cause some to be overcharged. The house/chassis batteries are often of different age/chemistry/voltage and don't like co-operating with each other when charging.

You could also use a separate charger connected to a 12/120 volt inverter which is powered by your solar system.

Chum lee

[time2roll]

+1 for Trik-L-Start. Solar on my trailer has kept my truck battery charged for years now.
No issues, no downside.

[ajriding]

I would not bother with trying to connect the chassis batt to the house batt for this.
I assume this is a motorhome?
There should be an over-ride button so you can self-jump start by connecting the house battery to chassis battery when starting so the starter motor has power from both, but maybe not.
I assume you are storing the motorhome for long periods is why you need to charge the chassis batt?
The easiest way is to put a 5 or 10 watt solar charger on the dash and plug into a DC outlet. You need the outlet that is connected to the battery (has a battery icon) not the one connected to the ignition (has no power when key is off).
If the windshield faces the sun at anytime then this will work.
i had one on a E350, I think it was only 5 watts, and it did the job. It actually put in all 18 volts, but never was a problem for 10 years because 5 watts is so little, but one that puts out 13.x is preferred.
or, as others have said, if you are plugged in anyway, then just put a small trickle charger on it, you can plug into the DC outlet also, so no need to pop the hood.

[BFL13]

On solar no converter, it would be intermittent, but that would be ok as long as you got some sunshine now and again while in storage.

I also have a connector I rigged up using two 12v plugs so I plug one into the TV set's socket (on house) and the other into the dash cig lighter socket (on engine). Had to do some meter work to get their polarities right on the joining wires between plugs since they don't mark them pos and neg.

[ramsaymike]

This is essentially what I had in mind by using the battery interconnect solenoid. I think the Trik-L-Start looks like a good install and forget solution....

[lane_hog]

On our Winnebago, I ran a positive wire from the house battery compartment to the engine compartment... Only connected it when in storage so it could benefit from the solar panel.

The proper way would have been to put diodes in-line to prevent pulling the coach batteries down to whatever the starter battery was at... we scrapped the Winnebago before I got around to that.

[ramsaymike]

Anyone know of a source for the Trik-L-Start in Canada???

[RJsfishin]

just connect the positives together thru a toggle switch on the dash gives me manual control for charging either direction, and from either source

[Bobbo]

I put a Trik-L-Start on my 2007 Class C (when I had one). Problem solved.

BFL13 wrote:
ISTR reading on here that there is a trick to the trickle start?

It only works when one set of batts is higher voltage or some such?

When the RV is plugged in to shore power, the converter/charger will be putting out AT LEAST 13.2v. Again, problem solved. (And, the Trik-L-Start only lets power flow one direction. Set to charge the chassis battery, it won't pull power FROM the chassis battery.)

BFL13 wrote:
Says here battery disconnect must be "on" (meaning "closed"? who knows???

That means the house battery must be charging from the converter/charger.

[BFL13]

ISTR reading on here that there is a trick to the trickle start?

It only works when one set of batts is higher voltage or some such? So there could be a scenario it doesn't do what you want? I completely forget what that was about - except it worried me so I don't have one. Maybe a false alarm here, don't know.

Somebody will know whatever that was about----
EDIT--

Engine batt must be 1/2 volt lower than house to let any current flow from house. Says here battery disconnect must be "on" (meaning "closed"? who knows??? )

https://winnebagoind.com/resources/service/pdfs/2006-04%20Trik-L-Start.pdf

[ramsaymike]

Thanks for the ideas. I like the look of the Trik-L-Start. I should be able to simply install it across the interconnect solenoid - I think. Sounds ideal to me as I will always have active solar charging every day and can just let it keep the starting batteries charged.

[BFL13]

Very common problem. You can charge/maintain the engine batt with its own little charger or parallel the engine batt with the house batts to charge/maintain them all with the converter.

I use a 2a charger that stays at 13.4 volts forever when it is plugged in. It came with two sets of wires. One with clamps and one with a 12v plug. I use it inside the Class C by plugging the charger's 120v plug into a receptacle and plug the 12v into the dash cig lighter socket. That keeps the engine batt at 13.4v.

There are lots of other ways to get it done.