Winterizing Coach battery in/out

[pokergeist]

Originally Posted by hoppers4

Yes, you can use the power port (cigarette lighter) on the dash. On my Greyhawk this port is always hot and feeds directly to the battery (fused of course). ...

Similar situation with the Seneca with no shore power. I have a small solar panel connected to the cigarette lighter port.

[hoppers4]

Originally Posted by pokergeist

Similar situation with the Seneca with no shore power. I have a small solar panel connected to the cigarette lighter port.

Excellent way to go with no shore power!

[ljh684]

Originally Posted by pokergeist

I've since switched to Lithium (LiFePO4) which is way easier for me to maintain properly.

Lithium has a very different charge profile from lead acid, requiring changes to the microprocessor-controlled charging circuit for proper charging and float. I have a switchable 800 milliamp trickle charger (lead acid or LiFePO4) for the lithium powersports batteries, as well as a "normal" 1.25A charger for wet lead acid and AGM powersports batteries.

Did you change out the Progressive Dynamics power converter in your rig to the Lithium version (PD 4500L series)? Or did you leave a power converter with a lead acid charge controller in place, and just switch the coach battery to LiFePO4? If the latter, I wonder how using a converter with a lead acid charging circuit on a lithium battery has affected your battery life, if at all.

I'm getting ready to switch out the stock wet lead acid for AGM, but didn't consider lithium as I thought it would require changing out the power converter, too. Also not sure how the BIM would ever properly handle lithium on the coach side and lead acid on the chassis side, since it probably just connects the two batteries in parallel when sensing a charging voltage.

[Imazman]

Originally Posted by cherv

If you have aux. Start button to left of steering wheel chassis batt is connected to coach batt. And should be charged by converter

I do have a button under steering wheel and I recall it is used if chassis battery dies, the button with allow me to start vehicle using coach battery. So my question is...
Do I have to push the button under dash to get the shore power to charge the chassis battery or is it always connected? I assume I have to push it....otherwise why push it when vehicle is dead?

[ljh684]

Originally Posted by Imazman

Do I have to push the button under dash to get the shore power to charge the chassis battery or is it always connected? I assume I have to push it....otherwise why push it when vehicle is dead?

If the circuit was just a switch that energized a solenoid to connect the batteries together, then yes, you would be correct.

However, some Jayco Class C units apparently have a very fancy Battery Isolation Manager (BIM) by Precision Circuits (link to user manual):

https://www.precisioncircuitsinc.com...nager-RevF.pdf

that contains a voltage sensing circuit which will connect the coach & chassis batteries if a "charge voltage" is present. A normal lead acid battery sits at about 12.6-12.7 volts. A charger applies 13.5 or more volts. So the 00-10021-000 Battery Isolation Manager is a bit more than a simple low current dash switch which energizes a solenoid to connect the two batteries in parallel.

If you have a Battery Isolation Manager different from the 00-10021-000 Precision Circuits unit in your rig, you have to get the part number and read the manual to see what "smart BIM" features your BIM may provide.

[pokergeist]

Originally Posted by ljh684

Lithium has a very different charge profile from lead acid, requiring changes to the microprocessor-controlled charging circuit for proper charging and float. I have a switchable 800 milliamp trickle charger (lead acid or LiFePO4) for the lithium powersports batteries, as well as a "normal" 1.25A charger for wet lead acid and AGM powersports batteries.

Did you change out the Progressive Dynamics power converter in your rig to the Lithium version (PD 4500L series)? Or did you leave a power converter with a lead acid charge controller in place, and just switch the coach battery to LiFePO4? If the latter, I wonder how using a converter with a lead acid charging circuit on a lithium battery has affected your battery life, if at all.

I'm getting ready to switch out the stock wet lead acid for AGM, but didn't consider lithium as I thought it would require changing out the power converter, too. Also not sure how the BIM would ever properly handle lithium on the coach side and lead acid on the chassis side, since it probably just connects the two batteries in parallel when sensing a charging voltage.

This might be appropriate for another thread ... also, please pardon the excessive detail - a bit extra for the folks starting to consider LFP. Also, if I'm wrong about something, someone will let me know!

The simpler CC/CV charge profile is the reason I went with LFP. We camp sporadically so the coach spends way too much time in a storage lot with no AC power. The only time the LA batteries got a good absorption charge was when we were camping with shore power or I yanked them out for a good charge in the garage. With LFP I can run the generator or engine (class-c FL) to boost the LFPs. They're happy wherever I stop, preferably between 12.8 and 13.2V. Above that and the LFPs will just charge the chassis batteries when they drop to 12.6V. I share your concerns about the BIM and want to get more data on everything.

The LA batteries like to be at a high state-of-charge, and suffer degradation when over discharged. The LFPs have low self discharge. But if they were to drop below 10V due to parasitic loads, the integrated BMS would take them off-line until a charge voltage is applied - with little or no degradation.

I did order the PD4590LICSV but won't install it until I sort out the BIM situation - a new model from Precision Circuits (not the Li version Battle Born sells) or maybe a Victron DC-to-DC Converter. I don't want to hammer my chassis batteries with 14.4V every time. For the moment I can put the PD Charge Wizard in temporary Boost mode (14.4V) for faster charging of the LFPs. But again, I don't run the LFPs full up other than for occasional equalization or prep for boondocking. I hope to get a few hundred extra cycles out of them by staying a bit under voltage. So to answer your question: the latter - a drop-in replacement thus far.

The new charge module doesn't provide a constant current (CC) mode per se unless you count the 90A limit which leaves me charging at roughly 22.5%C max, which I'm good with. I don't anticipate needing a pre-charge/recovery phase at 1-5%C - if so, I'll disconnect and throw the Noco LFP charger or my 12VDC UPS (LFP+SMPS) on them. I'm curious to see how the LFP charge module behaves - whether it stays at 14.4V or does some smart load sensing and voltage adjustment.

I'll also add that Battle Born's support was good before the sale and two guys from BB are active on the Airstream forum. Progressive Dynamics was also quick to answer my questions. And I have a good source for the Li Charge Module ($252 delivered).

[ljh684]

Originally Posted by pokergeist

This might be appropriate for another thread ... also, please pardon the excessive detail - a bit extra for the folks starting to consider LFP.

Yeah, useful detail but we kind of got away from the original thread topic of winterizing and more onto the topic of a full conversion of all coach & chassis charging and float systems from lead acid to lithium

Not sure if you need to modify the chassis alternator and generator circuitry, too, for a Lithium coach + Lithium chassis battery. If you do end up with a full conversion, might be worthwhile starting a separate thread to discuss the parts needed and the process.

[Bluesky46]

Everyone seems to have a slightly different opinion on this issue. I have a 2012 Greyhawk 31SS If I park it for over a momth with no shorepwer or battery tender connected, both coach and engine batteries will be dead in a month. If I plug in shore power it will keep the house battery charged irrregardless of how I have the battery disconnect, so I leave it in the off position. This will not keep my engine battery charged, I have to use a separate battery tender for that.

[cherv]

Hi, your unit is a 2012, ours is a 2019 so the electronics has changed i 7 yrs, but not positive all we were given by tech. Support that our unit charges both coach and chassis batt.

[Sunflake]

I have always left our 2016 Jayflight 27 BHS plugged in all winter. We didn’t use it at all this year and this fall I unplugged overnight to see how the batteries were. Next morning they were dead. Pulled the caps off and found out they were both extremely low on water and were ruined. What ever you decide to do check them once in a while for water level!

[cherv]

We have a 2019 coach jayco class c. Keep it plugged in with disconnect switch on. Checked both coach and chassis battery yesterday with meter, both fully charged, no issue.

[Imazman]

@cherv Thanks for the info throughout this thread. I am sending back the trickle charger santa brought and will just leave the motorhome plugged in and let it charge both batteries too. I have a unrelated question for you but will post it in an new thread titled Garmin 600 series...hope to hear from you there

[cherv]

What yr is your coach? May not have that charging feature. Not sure when jayco started to install that converter feature. Contact tech. Support with your vin#. (motorizedservice@jayco.com) please let us know how you made out....

[Imazman]

Originally Posted by cherv

What yr is your coach? May not have that charging feature. Not sure when jayco started to install that converter feature. Contact tech. Support with your vin#. (motorizedservice@jayco.com) please let us know how you made out....

Looks like I'm keeping the trickle charger :-(. The coach has been plugged the past month and it's been almost 1 month since I started up the motorhome so I figured I would start it up. Put the key in and the key wouldn't turn! Not even to the Accessory. Tried the auxillary button under dash, which when pressed I heard a solenoid click and the the dash computer turned on and the key was able to turn to accessory. Tried to start it, it tried but didn't...the auxillary battery couldn't start it. I hooked up a charger and charged the battery. It started fine there after.

Did some volt meter readings on chassis battery...
- when charging ~14.1
- just after disconnecting charger 12.5
- 10 minutes later 12.0
- 10 minutes later 11.8

This whole time my coach was plugged in so it is safe to say my motorhome doesn't charge both batteries :-(. So I hooked up my trickle charger by plugging it into a 120v outlet inside the coach and then plugged the DC output of the trickle charger into the chassis cigarette lighter and the measured the chassis battery after 10 minutes and it read 12.2 volts. So when I unplug the trickle charger 10 minutes later it does down to 11.8. So know I know three things
A) My RV doesn't charge both batteries
B) I can charge my RV via cigarette lighter
C) Something is drawing on Chassis battery!

So investigating C a little, I noticed when I turn off engine the top rear driverside brake light has three LED very dimmly lit for about a minute after the engine is turned off. I also correlated that to a very high pitched sound coming from the engine compartment and after about a minute of turning off the engine I hear a click and the high pitched noise stops...and that is when the tail light dimmness goes out. Also when I just go in or out of the chassis door, the dash computer does on and so does this brake light dimmness issue...and after about a minute they do out. Finally, I have noticed the middle rear driverside brake light has a fourth of it filled up with water and three LEDs that are submersed in water are not working.

I'm not really sure what it all means short of getting this into either Jayco or Mercedes-Benz to fix the issue...I'm guessing Jayco since they must rewire the rear brake lighting that Mercedes-Benz provides on their Sprinter chassis.

Well anyway, I'm starting to get a little down about my motorhome because I feel like I'm always taking it in to get something fixed...paying out of my pocket and hoping I get reimburse each time..so far...
- Furnace stops working after a few hours (random problem so could not get fixed)
- Metal support for black tank falling off (reimbursed by Jayco)
- Refridgerator stopped working (paid by Norcold)
- Hot water on propane didn't work (out of pocket, need to submit to Jayco)
- Recall (out of pocket, need to submit to Jayco)
- Tail-light has water (new issue, awaiting repair)
- Draw on chassis battery (retest after tail light is fixed)

Someone please tell me these issues will stop soon. My Kodiac TT by Dutchman was issue free (albeit no engine and generator, so less to go wrong).

Well here's to 2019 🍾...hope it is issue free!

[pokergeist]

Did you take a voltage reading of the house batteries? If the house batteries won't allow the charge voltage to rise to or above 13.3V, the battery isolation manager (BIM) won't connect the battery sets and pass the charge voltage to the chassis batteries.

[Imazman]

Originally Posted by pokergeist

Did you take a voltage reading of the house batteries? If the house batteries won't allow the charge voltage to rise to or above 13.3V, the battery isolation manager (BIM) won't connect the battery sets and pass the charge voltage to the chassis batteries.

No I didn't, good to know thank you. I will measure that tomorrow. I looked for a BIM near the coach battery but I only saw that shown in the pic which I don't think is a BIM.

[MikeUSNRet]

That is the battery disconnect latching relay. I haven't found my BIM yet either. Had to put a battery tender on my chassis battery.

[Imazman]

Originally Posted by pokergeist

Did you take a voltage reading of the house batteries? If the house batteries won't allow the charge voltage to rise to or above 13.3V, the battery isolation manager (BIM) won't connect the battery sets and pass the charge voltage to the chassis batteries.

I disconnected my chassis tender, left my coach plugged into house, and measured the coach battery...it only measured 12.6V. So does this mean my coach battery is bad?

[cherv]

I don't think so, however if you unplug the shore power for a day see what the coach batt. Reads. This will tell you if batt is holding a charge.

[pokergeist]

Originally Posted by Imazman

I disconnected my chassis tender, left my coach plugged into house, and measured the coach battery...it only measured 12.6V. So does this mean my coach battery is bad?

If the battery was at 12.6V after being charged for a while, and was still charging, your battery could be sulfated and due for reconditioning (a good absorption change followed by equalization or desulfating phases).

A couple of things could cause the low voltage - a current limiting (or limited) charger could be dropping the voltage to stay within its programmed current parameters. Excess current draw or a leak to ground from your 12V system would pull down the voltage, Extra resistance due to loose or corroded connections or a bad cable would drop the voltage in proportion to the current load.

Please keep in mind that these are not all things that are wrong with your coach, but rather a variety of possible causes, any one of which could cause the low voltage symptom. As noted above, battery condition can be assessed by observing the voltage after charging.

I recommend borrowing a clamp-on ammeter to see where the current (and how much) is flowing. If current is flowing from your charger then out to the coach, then your battery isn't the culprit.

Here's a reference for 3-stage charging that shows the absorption charge at 14.5V, and the float charge at 13.6V, so theoretically, a charger sufficient for your system should get close to those voltages.