Battery maintainer help

Wow. Thanks for the great information. Very helpful. One question I still have is: If I will primarily be using the maintainer for winter storage does it really matter if the maintainer is "recommended" for batteries up to 120Ah (while my batteries are 232Ah)? My understanding is that this recommendation is simply due to how long it will take to charge the battery. Even a maintainer recommended for batteries of 50Ah will still fully top-up a 232Ah battery but will just be slower (which I am fine with as I am mostly looking at long-term storage in my garage over the winter).

Group 31 johnson controls Wal Mart battery. 110 amp hours @20-hours rated

One salvaged transformer type wall wart. Unregulated 18-volts open circuit.

800-ma rated. Connected to battery. Maintainted battery at 13.62 volts. 4/5 amp.

This will give you some idea of how little amperage is needed to maintain a disconnected battery.

Older higher antimony batteries may cosume more float amperage due to negative plate antimony migration. But these batteries would be noticeable consumers of distilled water during everday use.

Connect the battery tender to fully charged, 100% fully charged batteries. The voltage of the battery tender should never sag less than it's nameplate voltage rating or there is a problem and you need to find out what it is. Be sure to note if the tender is temperarure compensated and if it is, float voltage values will adjust up or down for very cold or very warm days.

The most common error I see is when folks connect a voltage float device to batteries that are not 100% charged.

I leave my batteries on a "really working" SMART MODE CONVERTER/CHARGER unit in my trailer all the time when sitting at home. These working smart mode unit really take care of your batteries for you.

I would become very knowledgeable how your batteries work and watch and maintain them. The batteries is your trailer life-line and will last many years if properly maintained.

If your Trailer on-board converter/charger is the single mode type unit that only puts out 13.6VDC then this will require you to keep an constant watch on your battery fluids as 13.6VDC will tend to boil out battery fluids over time. Once the battery fluid level drops below the cell cores then the battery will start building crud on them and eventually short between the cores. When this happens it is usually game over for the battery.

Also keep in mind that a fully charged battery will do quite well when completely disconnected at one of the battery terminals when in storage mode. They will hold their charge for very long periods of time even in the winter months. Here again you would want to monitor them and put back on charge occasionally to keep them topped off.

Parasitic drains from installed trailer appliances and devices electronics boards left connected to your trailer battery setup can drain your batteries rather quickly sometimes in just a few days time. You need to be mindful of what parasitic drains you have in your trailer.

The big rule of thumb for me was to never let my batteries drop below their 50% charge state which is pretty close to only 12.0VDC. When camping off the power grid my number one priority is watch my battery DC VOLTAGE with an inside mounted monitor digital meter setup. It takes planning to know what you operate when camping off the power grid and the game plan is to make it until the next morning with what you have and then recharge the batteries back up to at least their 90% charge state each so you can do this all over again for the next day/night run off the batteries.

You just can't show up at the off road camp sites and expect it all to work for you... It usually gets dark on you around 10PM at night when you first do this haha...

Camping in your back yard has a lot of merit sometimes learning how things work battery wise.

We enjoy our many camping trips off the power grid over the years the best...

Just some of my thoughts here...
Roy Ken

westend wrote:
Best procedure is to fully charge the batteries with your RV's converter or a charger. The maintainer can then be used to float the batteries.

This.

Get a name brand fully automatic charger of at least 2 amp capacity.
If they are anywhere near to a full charge, it should be able to top them up.

Leaving the RV plugged in is an option but the onboard systems often are not good enough for really long term use like that. You could just plug the RV in for a couple of days every month though.

I would not get in a position where it needs to be "topped up" unless you boondock. If you are storing it where you have access to AC to use the maintainter while the batteries are still in the trailer, just get a dog bone to convert the RV shore power plug down to a standard 110 house plug and keep the trailer plugged in all the time, than in the warm season it is always full and being maintained by the built in converter/charger in the trailer. For winter take the batteries out of the trailer, Canadian winters will crack them and permanently damage them. Store the batteries on a maintainer in an above freezing location for the winter.

I hook a marine multi stage charger directly to my battery.
bumpy

Best procedure is to fully charge the batteries with your RV's converter or a charger. The maintainer can then be used to float the batteries.