Shore Power Battery Maintenance

DNC · 04-13-2020, 09:52 PM

My 2016 Journey has six 6V AGM deep cycle batteries and two 12 volt maintenance free chassis batteries. The battery isolation manager (BIM) monitors battery voltage in both coach and chassis batteries and connects the two together whenever it senses a charging voltage. Once the batteries have reached a float charge state for one hour, the BIM isolates the batteries to prevent overcharging and to prevent electrical draw on one system from depleting the other battery. It seems to me that it would be a great system for keeping the batteries charged when the unit is in storage.

But, my Owner's Manual says the two best defenses against sulfating and insufficient charge are to (1) turn off the coach battery disconnect switch when the coach is in storage and (2) check and if necessary recharge once a month. Then it says "NOTE: Do not leave the shoreline plugged in during storage...".

Anyone know why it is recommended not to leave the shoreline plugged in during long term storage?

Jim_HiTek · 04-14-2020, 10:05 AM

Because there's always the danger of overcharging...and the batteries boiling. Not as much of a worry with today's modern multi-stage converters but people do strange things to their RVs so the instruction manual tries to keep that in mind.

Easiest way to store an RV in my opinion is to just disconnect the battery grounds. I always keep a pair of gloves and a wrench in the battery compartment just for this. Takes all of 5 minutes.

DNC · 04-14-2020, 10:11 AM

Thanks Jim. That's good info. I just bought my Journey and it's in like new condition so I'd like to keep it that way. I got all of the manuals that came with it when it was new (according to the dealership). They are very good, but not all of my questions were answered reading the manuals. I like to hear others opinions and experience. I appreciate your reply.

Jim_HiTek · 04-14-2020, 10:44 AM

I see that they offer a 100 watt solar panel on the roof as an option for your model and year. Do you have that? I'd be interesting in knowing how it does on a sunny day, when unplugged from shore power of course. Also would be interesting to know if it charges BOTH battery banks...I've a feeling it would only charge the chassis batts as 100 watts is only 7.2 amps. And that's only in direct strong sunshine.

Any chance you're interested in discovering that too? If so, measure the voltage across each bank. If it's 13+ volts, than that bank is charging.

Morich · 04-14-2020, 12:15 PM

To make it quick and easy to disconnect the battery ground , I like to add a switch and there are lots of different types to fit different battery layouts. This is an easy one to just add to the battery p[oast and then put the wire on the end:
https://www.google.com/search?q=batt...hrome&ie=UTF-8
This is a different type that can be mounted through a panel so that we don't need to even open the box, but I always want to look at my batteries for cleaning and water, anyway.
https://www.walmart.com/ip/ATV-RV-Wa...xoCIa4QAvD_BwE
Lots of options to while away some downtime as we are not likely to be getting out much for a few months, at least.

Winterbagoal · 04-14-2020, 02:33 PM

OP, you might want to check the battery manufacturer's specs for % self discharge/month, before you decide which route to take. If they typically self discharge more than 10% per month, you might be better off leaving the rig plugged into shore power. You could also see what they suggest for maintaining their products over longer periods of inactivity. They will have recommendations for that, as well.
A coach as new as yours will have a very good converter/charger that should keep them in good shape, without the addition of any extra hardware or bother. AGM batteries are also less prone to sulfation, by design.
Just a thought.

DNC · 04-14-2020, 05:11 PM

I do have the 100 watt solar panel and the owner's manual says that anytime either the coach or chassis batteries charge level falls below 80%, they are charged. And the battery isolation manager (BIM) monitors battery voltage in both coach and chassis batteries and connects the two together whenever it senses a charging voltage.

DNC · 04-14-2020, 05:15 PM

Richard

My coach has a switch for disconnecting the chassis batteries and one for disconnecting the coach batteries. I've asked Nicholas at Winnebago why the owners manual says its better to check the battery charge status once a month and only charge them then if needed rather than keep it plugged in to shore power. Have yet to receive his explanation, but will post his answer if and when I receive it.

DNC · 04-14-2020, 05:21 PM

Winterbagoal

The manual recommends checking and charging the batteries once a month if the charge falls below 80%. And it says "NOTE: Do not leave the shoreline plugged in during storage...". What I'm wanting to know is why they say not to leave it plugged in during storage. I could understand not wanting to leave it plugged in if it was in an unvented garage (which mine is) if the batteries were lead acid batteries. But the coach batteries are AGM. The chassis batteries are maintenance free batteries, but I guess they can still give off fumes whenever they are charging and that would be a reason for not keeping it plugged in if in an enclosed garage.

Wyatt · 04-14-2020, 07:09 PM

Like Jim said, it depends on your system for charging. Ours has a three stage charger, and we leave it on shoreline power when stored at home. It maintains the coach batteries as needed, without overcharging (float charge).
It also will charge the starter battery, I just need to turn the ignition key to the FIRST position, not when it actually turns on the dash, and so every week of so I do that to also recharge the starter battery.

DNC · 04-15-2020, 07:37 PM

Nicholas at Winnebago sent me the following reply.

"The reasoning for that is if the isolation manager or the charger fails it could over charge the batteries and damage them. With it being in storage you would not know because you are not able to be checking the monitors daily. That is why we recommend to keep unplugged in storage."

Wyatt · 04-15-2020, 07:46 PM

Quote:

Originally Posted by DNC

Nicholas at Winnebago sent me the following reply.

"The reasoning for that is if the isolation manager or the charger fails it could over charge the batteries and damage them. With it being in storage you would not know because you are not able to be checking the monitors daily. That is why we recommend to keep unplugged in storage."

Hi Dennis,

Well, technically, mine’s never in “storage” because it’s in my driveway, and I’m always working on it.

But that seems to be a specious reason for not keeping it charging. I think they’re playing it awful safe, as in “we told you not to do that” defense. Sort of like saying don’t run your generator when you’re not in your RV because something might go wrong. Something can always go wrong. What if you’re alseep on shoreline power? Who’s watching the gauges then?..

DNC · 04-15-2020, 08:17 PM

Wyatt:

I agree. I have mine parked in an enclosed garage at my house and I'm in and out of the garage several times a week so I could probably just leave it plugged in.