Battery Maintainer

[marudnick]

We have a 2019 Sunstar 29VE, which has three lead acid batteries. This is our first winter owning the RV. We were told that we should have a battery maintainer on the batteries to keep them healthy over the winter. Since the RV is at a storage facility, we need a solar maintainer.

Does anyone have any product recommendations?

Thanks.

[l1v3fr33ord1]

marudnick-

A healthy battery, fully-charged and disconnected, will last the Winter. Charge them, disconnect them, and be done with it.

Disconnect by removing the ground leads from both battery banks (chassis and house). If your coach has a Magnum inverter in the house battery system, follow the Magnum instructions for the procedure.

[marudnick]

I’m not going to disconnect them. They aren’t easy to access and I’m not crazy about taking them out. I’d like to have a trickle charge running on them. I heard about solar battery maintainers and thought someone on this forum might have suggestions.
Thanks.

[Bobn1957]

Just plug it in with a good extension cord and let the built-in converter maintain the batteries, for the cassis battery or batteries use a good three-stage charger to maintain them.

[DavidM]

Here is a page of solar battery tenders on Amazon, some of which are waterproof- https://www.amazon.com/s?k=solar+bat...ss_ts-a-p_2_16

If your MH is outside, try to orient it facing south and just put the solar panel on the dash facing south and upwards. Run the charging cord to the batteries or maybe you can find a cigarette lighter that is powered by the coach battery, but see the effect of parasitic loads below as you would have to leave the store/use switch on to do that.

Flooded cell batteries self discharge at 2-3% per month. In our climate where winter storage is for 6 months my batteries would be down perhaps 20%. All of the sulfate produced is sitting there for all of that time, sloughing off and ultimately shorting the plates.

AGM batteries self discharge at much lower rates and should be ok without maintenance. Lithium batteries even more so.

All if this presumes no parasitic loads slowly bringing the batteries down. I would measure those loads if any and choose your panel size accordingly, ie if you have a 1/4 amp parasitic draw, which is 6 amp hours each day, I would look for a 30 watt or larger solar panel tender to keep up. Better still, disconnect your battery's negative lead and wire the solar output directly to the battery terminals to avoid the parasitic draw.

David

[gmellison]

I had a solar battery maintainer and it helped my dual 6v wet batteries last over 10 years on my old Minnie Winnie.

https://m.northerntool.com/shop/tool...8565_200328565

It’d work on 12v as well, just how you wire it up. I installed a plug in dual bank maintainer on my new 29v since I have power where I store it. I was a big fan of the old solar maintainer. My house batteries were always topped off and ready to go.

[johnevans3]

I have two 12v batteries on my 2106FBS. It is stored out in the open with no shore power access available, so got a 20 watt solar panel with controller from eBay. Not a highly efficient panel/controller but adequate for the job. Plugged it in to the Zamp solar SAE plug on the side of the trailer with a reverse polarity adapter. Turned the battery cutoff switch off so no power draw and am keeping the batteries topped off. Been checking it every week for a month now and all is good. Very happy with this simple and inexpensive (around $50) approach. I’ve tested the batteries by putting a load on them for about 10 minutes to make sure that my voltage is good and not being a false reading from a “surface” charge.

[71_340]

I used a cheap solar charger from Harborfreight to maintain the chassis battery on our previous RV and it worked great (I just placed it on the dash board). I think you will need two, one for your chassis and one for the two house batteries.

https://www.harborfreight.com/15-wat...SABEgJ9Z_D_BwE

[powercat_ras]

I would have thought that the 29VE is like all Vistas and has 2 12V coach batteries and 1 12V chassis battery under the entry step, and that all you do to access is to release the latch and slide the step out about 1" then lift it up and off.

You can take drain on the coach batteries down to near zero by operating the chassis battey disconnect switch. Once you do that the only drain is the step control board.

I believe your model has no chassis disconnect switch. There will be a slight drain from the constant battery connection on the dash radio and the Engine Control module.

I'd plan on going to your RV in storage about every 60 days and connecting the coach battery switch, start the RV and let it run 15 minutes, and run the Onan generator for 15 minutes. This will replenish the batteries and will also make the engine and generator last longer. Incrementally, tou can also drive the coach around the storage lot and re-park it to minimize tire flat spotting and to exercise the transmission and drive train.

[marudnick]

Randy, Thanks for your comments. First, you are correct that we have 2 house and 1 chassis batteries. We also have a battery disconnect switch, which I flip whenever we leave the rig for any length of time. We actually planned something very similar to what you suggest. Each month we are going to take the rig for a drive somewhere nearby, have lunch and run the generator while we are parked. However, I didn’t think that was enough and thought we also needed a trickle charge to keep the batteries charged. You’re suggesting that we don’t need the charger?
Thanks.

[powercat_ras]

First of all, do you realize that whenever you flip the battery disconnect switch, it shuts off your refrigerator/freezer? You should not be flipping off the battery disconnect switch when you leave your rig, if you are using the refrigerator.

With the disconnect switch set to off, if you have started with charged batteries, your coach battery will still be well above 50 % remaining after 60 days, and the chassis battery will also be well above 50 %. If you drive the rig every 60 days the chassis battery will stay charged.

A small solar panel charger on the chassis battery is not a bad idea but in my opinion you'll be fine without if you exercise every 1-2 months. The only place you can connect it is right on the chassis battery, so it involves taking up the step which you said you did not want to do. There's no easy connection point inside the RV as built. However, you can put a 12 volt power outlet in the rig and run 14 gauge wire for it to the chassis battery thru a 10 or 15 amp fuse then you can just put the small solar panel charger in the front window and plug it into the added chassis battery power outlet. I did this on mine. I put the chassis battery power outlet on the floor next to the door near the step well on my Vista.

[marudnick]

I flip the battery disconnect switch when we are finished traveling and are storing the RV, for a week, a month or longer.

Thanks for the reply.