Storage between trips--do you leave on shore power?

[JonMN]

Greetings from Minnesota! I am lucky enough to be able to store my Class B in a spot with power available.

Would you disconnect the coach battery or leave it on shore power where it will be maintained. This is our first RV, so on a bit of a learning curve.

It's a 2022 Coachmen Beyond with AGM battery. Xantrex I/C.

[@Michael]

I leave my Coachmen Beyond/Crossfit plugged in and powered up all winter. I run the generator an hour every month to keep the gas in the carb fresh.

I'm also in MN.

[Rocinante]

If you have lead-acid coach batteries, I would leave the coach plugged into 15-amp power and leave the power turned on in the coach so it can maintain charge from shore power. You don't need to leave anything on in the coach besides the main disconnect - no lights, no heater, etc.

If you have lithium coach batteries, I would use the main disconnect switch because they don't lose power over time as long as the coach isn't drawing any juice (beware phantom draws - if there are any you should actually disconnect the batteries), and because they don't like to be charged if they are below freezing.

In either case, I would also use that shore power and a battery tender device to maintain charge in the engine battery.

[avanti]

AGM batteries don’t self-discharge appreciably, either. Typically less than 2% per month. Leaving them disconnected over the winter is just fine. Just make sure they are really fully-disconnected and are fully-charged when you put the van to sleep.

[jrobe]

If you have shore power, there is absolutely no reason not to keep the van plugged in.

[avanti]

Originally Posted by jrobe

If you have shore power, there is absolutely no reason not to keep the van plugged in.

Ummm...
I don't know. Having everything deep asleep, unpowered and passive adds a certain peace of mind--at least I find it so. When nothing is happening, there is less that can go wrong. I do not hesitate to plug in when there is value. But when there isn't, I MUCH prefer not doing so.

[Davydd]

I've had lithium ion batteries since 2014 in Minnesota so I had to have shore power when they had to be kept over -4F with the batteries I had at the time even if I disconnected them to last over the winter season. Shore power kept them warm with battery heaters outside. Now I have a heated garage but could store them outside with my new van that says the lithium ion batteries can withstand -40F. I haven't seen any specs for lithium ion that say that except Valence batteries.

I couldn't remove batteries if I had to but can now as another option. My first lithium ion batteries in a 16 module block were under the van in an iron cage and I think weighed 500 lbs. in total so I wouldn't be capable of doing it. This was the installation.

[booster]

I do a sort of in between way as the van has access to power and is stored at home. I will leave it plugged in for about a week or until it shows very low 0 to .1 amp on the monitor, which is as low as it goes for our 440 amp AGM bank. Then I will unplug it for a month or so. I usually run the charge down to 80% and then recharge and repeat the process.



Very easy to do as I am in that garage a lot for other stuff I am working on.

[mumkin]

If you have solar, it would keep the battery up.

Don't forget your starter battery. You will need to maintain that battery too. Promasters come with a manual disconnect on the negative that can be used. Not sure what the Transit has. I always just disconnected my rigs when stored, but there is also the option of a trickle charger if you have access to power.

[avanti]

In our Legend (with 440AH AGM), I had it built with a master cutoff switch that disconnects everything except the solar panel and the Trik-L-Start. Since I park outside, the small solar panel keeps all batteries topped-off, but the van is otherwise inert.

Our new rig is more complex for two reasons: (1) the house battery is lithium, which doesn't like to stay fully-charged; and (2) the Victron solar charger is tightly integrated with the rest of the electrical system, so "just powering the solar" is not so simple. I am not certain exactly what the best storage configuration will prove to be--The Victron stuff is too complex to fully-understand without getting my hands on it. I will learn as I go. As we have discussed in the past, I will need a plan for the infrequent sub-zero F temperatures I may encounter while in storage. I will plug in when possible if this is anticipated, but may have to rely on automation and remote access occasionally. The large house battery will get me through short frigid snaps, perhaps with remote start as a last resort.

[JonMN]

Hey, thanks very much all for the replies. It's great to find an active Class B forum. Expect a few more questions in the near future!!

PS: DavyDD--where was the shop in your photo?

[booster]

Originally Posted by mumkin

If you have solar, it would keep the battery up.

Don't forget your starter battery. You will need to maintain that battery too. Promasters come with a manual disconnect on the negative that can be used. Not sure what the Transit has. I always just disconnected my rigs when stored, but there is also the option of a trickle charger if you have access to power.

Also be sure to check how your solar controller controls the charging. Some controllers do a full, timed, absorption charge every day, usually in the 4 hour range, which can be harmful to already full batteries. The controller should look at the battery voltage and go right to float if the batteries do not need and absorption charge.

[Punkinhead]

Originally Posted by avanti

Our new rig is more complex for two reasons: (1) the house battery is lithium, which doesn't like to stay fully-charged;

I'm wondering about this too. We have indoor storage with access to a 20 amp circuit. We could leave it plugged in all the time but I'm not sure that's a great idea for the lithium.

[Davydd]

If you have a second alternator I can guarantee you will not keep lithium batteries at 60% SOC like the experts have espoused. You will arrive every night at 100% SOC in a campground and overnight you might go down to at most 70% SOC in an all electric van with heavy electrical use. With a second alternator you will recharge those batteries back to 100% in less than an hour driving. If you don't have a second alternator you might have to drive 4 - 6 hours the next day in a Sprinter.

That 60% not 100% may be an ideal but a cycle as ARV says is 100% down to 20% where they have set a cutoff. The number of cycles for my batteries are rated at 4,000 life cycles. So in storage I remained plugged in as I use the van as my kitchen and bathroom in my man cave as I like to call my heated garage. Mostly it is not in use so I may experience one cycle every 6+ days in battery use and that is a number of days I probably would say as a minimum. So 4,000 x 6 = 24,000 days / 365 days = a theoretical 65+ years which you know is only theory but you will never keep a Class B that long anyway, and yes, I suspect an efficiency drop off but I didn't detect that in 6 years with my first lithium van. Who knows how many years you can stretch out a battery life if you can maintain 60% SOC. Oh and some say 2,000 cycles or maybe just 30+ years.

How does ARV manage cycles in storage with shore power? Once it reaches 100% SOC plugged in to shore power charging ceases until it drops to a pre-determined SOC and then starts charging again up to 100%. I know it doesn't go down to 20%. Last week I checked it at 54% but I am not out at my garage every day. It is not a concern considering that 65 year number and having two lithium battery vans for 8 years with no perceived drop off. I have a 30A service in my garage but I usually plug in to a more convenient 20A circuit with one of those adapter plugs. There a no issues in doing so. It just recharges slower which again theoretically extends the life of the batteries.

PS. JonMN, that battery installation was at Advanced RV. Note the jack underneath. They were not lifting but just guiding to the bolt holes. My new van has 4 individual type 27 battery cases inside under my bed now that I could theoretically handle.

[avanti]

Originally Posted by Davydd

If you have a second alternator I can guarantee you will not keep lithium batteries at 60% SOC like the experts have espoused. You will arrive every night at 100% SOC in a campground and overnight you might go down to at most 70% SOC in an all electric van with heavy electrical use. With a second alternator you will recharge those batteries back to 100% in less than an hour driving.

Well, I certainly hope that all of this is true.

However, I don't see any of it as an excuse to abuse the battery needlessly. The fully-programmable automation system that is designed into our new rig should be able to handle all cases optimally. I anticipate implementing a "mode" that, when selected, tells the system to keep the battery at 60% rather than 100%. The Transit has four user-defined toggle switches on the driver's console. Picture one of them labelled "Going Home". Flipping this switch on the last day of a trip will enter "60% charge mode" (and possibly do other things as well). That way, we will arrive home ready for optimal storage.

And if that fails, there can be an "in storage" mode, which would automatically drain a too-full battery to 60%. It could do this by turning on some convenient load until the target SOC is reached. It would start with something useful (such as running the battery heater if it is cold, or keeping the van on-line), and fall back to neutral operations (such as running the Espar glycol heating coil). This is all quite easy given the right infrastructure. It is actually a pretty good example of how a modern automation system can be much more than a glitzy stunt.

I understand your "65 years" argument. However, there are many ways to abuse a battery (both intentional and inadvertent). The damage is often cumulative, and I would rather "save" the battery abuse for the unavoidable cases and the inevitable screwups, rather than building it into the normal operational regimen.

[BillsPaseo]

We use ours year round, so it stays plugged in when parked at home, with the thermostat set to 47 degrees (Truma-Combi set to EL-1, fan on Eco). No winterizing. If we get a really cold spell, I turn on the tank heaters as well.

[avanti]

Originally Posted by BillsPaseo

We use ours year round, so it stays plugged in when parked at home,

That sounds like the best solution.

[BillsPaseo]

Originally Posted by avanti

That sounds like the best solution.

Thanks! Doing this is also very good for preventing mold growth inside the van - a huge issue here in the PNW for vehicles left parked outside for long periods of time. The combination of high humidity in the winter, and day/night temperature swings cause condensation on any metal or glass surfaces, and then mold starts to grow. Having the furnace on and air circulating stops the condensation from forming.

[JonMN]

Thanks all--I really appreciate the useful replies on this forum. I will keep plugged in until I get out again. To paraphrase an old saying . . . "All charged up and nowhere to go!" (Until January, when we make our first trip to Florida.)

[ks@yvr]

I see you have a Ford Transit based van. The Ford transit van has a bit of parasitic draw on the automotive battery and if not run every 4-6 weeks, disconnected or put on a trickle charger it will run down the automotive battery over an extended period of time. The cellular link with Ford for remote start, location etc. is one draw, there is some solenoids that seem to cycle is another draw, plus who knows what else. I found my Transit has a draw, although it has not run the battery flat has lost charge in the winter to where the truck starts but you can tell the battery is not fully charged.

On the Transit forums there are several threads on dead automotive starter batteries from vehicles sitting over 4-6 weeks. I hard wired a small trickle charger to my automotive battery and keep that plugged in if I am leaving the van for an extended period of time. This has worked for me. At least this way my automotive battery is always ready to go when I am.

My lithium house batteries I just turn off the main disconnect but my battery bank is big enough that it just doesn’t seem to have any noticeable battery loss between van runs whether on or off. My lithium batteries have a temperature sensitive BMS and will not accept charge if the batteries are too cold.