Trickle charge or solar.

[Postman94]

Good afternoon everyone. I am looking for some guidance with what Is the best option for maintaining charge on my 2 12v batteries. I have plenty of friends who take there batteries out and have them trickle charge between trips. Others, who charge them via solar without ever having to remove them from the trailer. What is the best option and what products are you using for either? Thank you for your input

[dsol]

Do not use a trickle charger unless it is a battery maintainer or float charger that cuts off when they are full. Same with a solar charger. If you keep a constant charge on your batteries you will eventually reduce capacity as water can ever so slightly boil out.

In an ideal situation you will top off your batteries at least monthly but once full you stop charging.

[franktafl]

Since there are usually vampire loads that kill your battery, I used a solar panel to keep a charge on my batteries. Get a decent regulator that will shut the charging process off when the batteries are charged.

[ewarnerusa]

I love the solar I installed on our unit, so I am a fan of recommending solar. But it is a bit of a go big or go home technology. A puny little panel from the hardware store isn't going to get you much of anything. Not worth the investment to me or trustworthy enough if you're just worried about keeping a full battery full. If your motivation is how to keep a full battery full in between trips, I would say a battery disconnect switch will address that in a more user-friendly manner than taking batteries out and putting them on a trickle charger. Reconnect on a periodic basis (monthly maybe?) and plug your shore power cable in to let the onboard converter charge the batteries back up over a day or 2. Unplug, re-establish battery disconnect, and let it sit again.

Solar becomes a worthy project if you're getting into how to use your unit off-grid and not run out of battery power.

[persistent]

There are several good ways to store lead acid batteries. Removing them is not need in most cases.

Lead acid batteries must be stored fully charged for long service life. Fully charged means 14 to 18 hours on a high quality charger like the one in your RV.

What ever method you chose, maintain water level and fully recharge before terminal voltage drops below 12.4 volts.

Monitor battery terminal voltage until you know how long it lasts. Monitor water level until you know how much is consumed and how fast. Battery charging and battery maintaining consumes water. High ambient temperatures may also consume water.

Methods:

Remove the cables from one battery bank post.
Fully charged and completely disconnected flooded cell lead acid batteries may last 6 months. Fully charged and disconnected AGM batteries may last for 12 months.

Switch off battery disconnect located near the battery. It must disconnect everything like removing a cable.
Same storage times as removing a cable above.

Switch off entry door 12 volt system disconnect.
Fully charged and disconnected may last 1 week to 3 weeks. Typically everything is not disconnected. Parasitic draw remains.

Use a battery maintainer. Modern high quality RV chargers and high quality battery maintainers work the same to maintain batteries. Modern high quality solar controllers also do the same thing.

Long term optimum maintenance battery terminal voltage is 13.2 volts. 13.6 is a little high. More water will be consumed.

14.4 volts is too high. Water consumption in flooded cells will be high. AGM cells will vent. Water lost from AGM cells cannot be replaced. Capacity loss in permanent.

Each of these methods have advantages and disadvantages.