Community Forums

Persistent · 11-14-2018, 08:18 PM

There are multiple threads about overwinter care of batteries. This one is a little old but the issue is the same.
Batteries properly cared for will last more than a decade. Deviating from the required care will shorten the life. Deviate a lot and they will deteriorate a lot.
Lead acid battery voltage must stay above 12.4 v to prevent accumulation of sulfate on the plates. Short periods below 12.4 cause little to no accumulation. Small amounts of sulfate can be removed by fast charging. Large amount are permanent.
Lead acid batteries in discharged state will freeze causing mechanical damage to the plates. The lower the temperature, the fuller the charge must be. I use 12.7 volts as my minimum for southern Wisconsin.
Over charging will "boil" off water. Leaving a constant voltage converter/charger on all winter can loss of water in flooded cell batteries and venting of sealed batteries (GEL and AGM). Water can be added to flooded cell batteries. Water cannot be added to sealed cell batteries. If water in flooded cells drop below the plates, permanent damage result. The longer it is low, the more the damage. Sealed cells vent, permanently damaging the battery. More venting means more damage.
My Kodiak Cub converter maintains 13.6 volts. That will cause boiling and venting over long periods. I shut off the batteries when connected to shore power for more than 1 day. I monitor the voltage periodically turn them on for 1 day when they drop below 12.7 volts.
Flooded cell batteries need to be "stirred" periodically by overcharging them briefly so they "boil". Not stirring cause damage to one end of the plates.
There are 4 stage converter/chargers. They monitor and properly maintain the battery voltage including brief high rate charging periodically. If you are going to leave shore power on with batteries connected for long periods, this is the best solution. I think there are battery maintainers that do this as well.
If you leave the battery connected overwinter without something maintaining the voltage the batteries will be "flat" and permanently damaged in the spring. The are "always on" devices in every TT or Motor Home. They will fully discharge the batteries in a few weeks.
If you leave the battery disconnected overwinter the battery will probably have low voltage and be accumulating significant sulfate on the plates. They may also have frozen and mechanically damaged plates.
This of course applies to all lead acid batteries. It includes lawn tractors, automotive, aircraft, RV's, and toys. The fact that a lot of people "do it" does not change physics. Choose a method and bear the costs.

Regards,
Paul Bristol

cimplexsound · 11-15-2018, 07:32 AM

Keeping it plugged in is a really good idea.

1979 Dodge Tioga Class C 24 foot. 1987 Fleetwood Bounder 34 Foot.

Whitewolf · 11-29-2018, 06:10 PM

I'm in the plug in crowd. I cover her plug her in and plug in the 'sonic thingies' as Slapshoot said. Also throw some dryer sheets in various places. I have 2 6V batteries that I leave in, and have not had a problem so far.

Persistent · 11-30-2018, 08:53 AM

I was working on a battery relocation project when I got my magnifying glasses out and read the charging specs on my Interstate AGM batteries. It said 13.6 volt float charge was good. So why did I see signs of venting the sealed batteries? The converter/charger on my Dutchmen Kodiak Cub was providing a 13.6 volt float charge. Theoretically I could leave the battery on charge all winter without damage.
I recently confirmed my Dutchmen Kodiak Cub came with a 40 amp 3 stage fast charger. I did not discover this by reading an instruction manual. I discovered it while using a digital battery voltage monitor. (Not the one on the Cub control panel.) When the furnace switched on, the voltage jumped to 14.5 volts. My guess is the venting occurred when the converter jumped to fast charge when various appliances ran.

So now I advocate leaving TT's plugged in over winter. Of course you should first measure the float voltage of your charger and check the manufacturer's specs for your batteries. You should also monitor fluid levels periodically, more often to begin with, less often as you verify water consumption.

PS: Certain 6 volt golf cart battery voltage specs published by the manufacture were too high and were later lowered. I don't remember the manufacturer or the model years. I saw it somewhere on iRV2.

Regards,
Paul Bristol