Chassis battery problem

Ronscomm · 03-05-2020, 01:10 PM

I am looking for some feedback on our Motorcraft chassis battery. We purchased our 2019 Redhawk in October 2018. It was used quite a bit between then and April 2019. While sitting at home in April-May, it would often need a jump to start. By November, it needed a jump to start, even after just turning off the engine. Ford replaced the battery under warranty. Now, the new battery seems to have a drain. The RV has been sitting in a campground since February 1 and we watch movies using the radio/sound system.

Here are some voltage diagnostics:
2/26 2 p.m. resting after charging - 12.58
2/26 5:30 p.m. - 12.34
2/26 Evening - 3 hr. movie
2/27 2 p.m. 12.08
2/27 Evening - 3 hr. movie
2/28 5 p.m. 11.82

Some questions:
Is the drop from 12.58 to 12.34 in 3-1/2 hours without using the sound system typical? If not, what could be happening?
Is the drain from watching a movie typical?
Is it typical to have to charge the battery or run the engine to start it when sitting for a period of time?

Thank you in advance for any feedback.

EA37TS · 03-05-2020, 01:20 PM

If you are plugged into shore power the chassis and house batteries should be charging and if not there may be a problem with the battery isolation relay (BIRD).

Is your DVD player connected to the chassis battery or the house battery?

Ronscomm · 03-05-2020, 03:27 PM

The DVD player is part of the radio/sound system. So, it is connected to the chassis battery.

Shore power does not charge the chassis battery, as far as I know.

Bullitt6283 · 03-05-2020, 03:30 PM

Are you using the dashboard-mounted 12 volt sockets for anything?

They are typically connected to the chassis battery.
.

Ronscomm · 03-05-2020, 05:53 PM

No, we don't have anything plugged in.

Greg58 · 03-05-2020, 07:31 PM

All rv's I've ever dealt with have a power converter to run 12v lights, exhaust fan and even the furnace fan are 12v. The converter also has a charger circuit for your battery, it sounds like your converter has a problem. I had to replace the converter on a previous TT that failed. The converter is usually close to the breaker panel, probably behind it. I have no experience with motor coaches but everything that uses power should run through the converter when plugged in to AC.

RetiredOne · 03-05-2020, 07:44 PM

Quote:

Originally Posted by Ronscomm

By November, it needed a jump to start, even after just turning off the engine. Ford replaced the battery under warranty. Now, the new battery seems to have a drain. The RV has been sitting in a campground since February 1 and we watch movies using the radio/sound system.

Question, did that new battery ever discharge all the way down between November and February? There is always a parasitic drain on these batteries, and they can be run down if left uncharged for a month or so.

Do you charge it up while it's sitting in the campground regularly, either by running the engine or a trickle charger. The converter doesn't charge the chassis battery when plugged into shore power on the Redhawk.

Do you know what the condition was of the replacement battery from Ford? What is the date on it?

RetiredOne · 03-05-2020, 07:48 PM

Quote:

Originally Posted by Ronscomm

Here are some voltage diagnostics:
2/26 2 p.m. resting after charging - 12.58
2/26 5:30 p.m. - 12.34
2/26 Evening - 3 hr. movie
2/27 2 p.m. 12.08
2/27 Evening - 3 hr. movie
2/28 5 p.m. 11.82

If you're regularly letting that battery run into the 11's on voltage, you are hurting it. Here's a reference chart:

MikeUSNRet · 03-05-2020, 08:08 PM

The easy solution for this problem is the installation of a Trik-L-Start. Works well on my Redhawk. Keeps the chassis battery fully charged when you are plugged into shore power. Inexpensive and very easy install.

Bullitt6283 · 03-06-2020, 08:56 AM

Like mine, some coaches do not charge the chassis battery when the engine is not running, even though the coach is plugged into shore power and the house battery is being charged.
Like MikeUSNRet, I installed a Trik-L-Start to solve the problem.

To answer your other question, I would not have assumed the dash sound system would pull the chassis battery down so fast. Perhaps there's another drain on the system. Putting an ammeter in series with the battery and pulling one fuse at a time may help find the culprit.
.

Ronscomm · 03-07-2020, 06:58 PM

Thanks for the Trik-L-Start suggestion. I'll look into it.

Armyman97 · 03-07-2020, 08:55 PM

Ours is a 2018. our battery only lasted 1 year from purchase and I feel that it was used as dealership display model so the battery was constantly worn below capacity. Replaced battery and installed The Trik-L-Start and no problems so far.

Trapper2020 · 03-08-2020, 07:26 AM

The inverter is a large draw on the battery. When dry camping and not recharging daily we turn off the inverter. Main use for inverter is power for the TVs. The switch is right inside the door with the others. We also added a second battery to the bank which helped a lot. Like others have stated I use a trickle charger on all batteries while in storage. Good luck

Grumpy · 03-08-2020, 08:00 AM

Quote:

Originally Posted by Ronscomm

The DVD player is part of the radio/sound system. So, it is connected to the chassis battery.

Shore power does not charge the chassis battery, as far as I know.

Unless they changed their system the radio should run off of either/or chassis and house depending on whether the ignition is off or on.

Florida Ranger · 03-08-2020, 09:34 AM

Grumpy,,,will this be true for a 2018 Greyhawk that the in dash radio runs off the chassis battery and the house battery, depending on position of ignition key ?

Camper_bob · 03-09-2020, 07:48 AM

Quote:

Originally Posted by Grumpy

Unless they changed their system the radio should run off of either/or chassis and house depending on whether the ignition is off or on.

Quote:

Originally Posted by Florida Ranger

Grumpy,,,will this be true for a 2018 Greyhawk that the in dash radio runs off the chassis battery and the house battery, depending on position of ignition key ?

This was my understanding as well. I'm not sure though, never verified it, but I assumed there was a relay that would power the dash unit from the house battery with the ignition off. You know what they say about "Assumption" though...

You could disconnect the negative side of the chassis battery and try to fire up the radio? That should tell you for sure...

Pretty much everything in the house should run off the house battery by design. The last thing you (and the designers) want is to be stranded with a dead chassis battery. Basically, the only things that should be drawing on the chassis battery are the normally chassis related functions. This is where the relay for the dash unit comes into play. This would normally be powered by the chassis battery, but the designers know that you need to be able to run that equipment while stopped. But if the ignition is off, the dash unit shouldn't be drawing on the chassis battery.

At least that was my understanding...

Added: It is HIGHLY unlikely your unit came from the factory with the relay and wiring necessary to charge the chassis battery from shore power (Trik-L-Start or Amp-L-Start). If you equip this to your coach (which I did), the chassis battery will only get a charge once the house battery has been completely charged by the converter/charger using shore/generator power. This is not true in the other direction though; your house battery will receive a charge from the alternator on the motor.

If I were you, I would have my chassis battery tested (load test) at a local auto-part outlet, and install a Trik-L-Start. Replace the battery if necessary with an AGM or Gel battery. If your coach is plugged in or running on generator power, your chassis battery will be maintained, and will be able to fight the parasitic draws that could kill it while it's sitting for long periods.

Bullitt6283 · 03-09-2020, 05:23 PM

At least Part of the in-dash entertainment system runs off the chassis battery.

Today I turned off the house battery "salesman switch" (because I dropped the shore power cord) and started up the engine to move the Greyhawk up the driveway. The rear-view camera started up all by itself. Turned itself off too when I was done.

Another thing.... Jayco sent me some wiring diagrams. The one I attached here shows a pair of diodes. I am assuming that the function of the diodes is to assure power to the entertainment system and the LP detector regardless of the source.
.

Grumpy · 03-09-2020, 06:52 PM

Quote:

Originally Posted by Bullitt6283

. The one I attached here shows a pair of diodes. I am assuming that the function of the diodes is to assure power to the entertainment system and the LP detector regardless of the source.
.

So things are the still the same....

Florida Ranger · 03-09-2020, 07:21 PM

If is wired this way in a 2016 Greyhawk,,hopefully it is the same in a 2018 model. Thanks very much for both of your reply’s it really does help..

pconroy · 03-09-2020, 07:31 PM

Yeah - chiming in. If you're using the DVD player in the headunit (in the dash) it's pulling from the Ford/chassis/engine battery.

Those discharge rates seem a bit high - but we never use our Jensen to play DVDs. We've got a dedicated DVD player connected to the inverter and thus pulls from the house battery.

But perhaps that headunit just sucks a lot of power.
You should be able to pull the specs for the unit from the Internet.

In our case, when I kill the chassis battery, it's because I forgot to pull out things from the accessory sockets. Then I have to use the aux battery switch to get things running.

In lieu of a Trick-l-start, I've been just dragging along my old Schumacher Battery Charger. I plug that into an extension cord and connect it to the engine battery. That's been working fine.

You may also like: