I copied this from the Red Power Magazine Community forum. In case someone was in the market for a ..... 

http://www.batterytender.com/

(quote) I though I would relay a story to you concerning my experience with battery maintaners. I know this subject was covered not to long ago. I have about 30 BATTERY TENDERS PLUS for my tractors and trucks I bought them over a 12 year period. Well 2 of them went Kaput. I emailed the company Told them about them dying and explained that I had no idea when I bought them . I boxed them up and sent them back along with a $30 check to cover diagnostics. Bingo a week later I receive 2 brand new ones in the mail. I believe these things are over $50 now. Deltran is the manufacturer .These things really work good I have had batterys last 5-6 years hooked up with Battery Tenders Great service with a great product Really refreshing!

retento, I belong to a Christian motorcycle association and a very large number of the members use battery tendrs on the bikes.  So..........guess what?  Now I do too.  I had used them on a couple of pieces of my construction equipment since they were diesels and required a lot juice to get them going in the mornings when it was cold.  By the time the glow plugs cycle a few times and you still have to SPIN the motor over to get it going, the batteries take a beating.  Battery tenders save the day from lost time, down time, man power being wasted and the list goes on.  Battery tenders are a great device and I really like them.

Thanks for posting the article, UDAMAN!!!!!

deranger

I've been using float chargers for several years. I have a few classic cars, trailer LQ and boat batteries, and a tractor that are not used during the winter months. I initially purchased a Napa charger that worked well, but as my needs increased, I purchased several of the inexpensive Harbor Freight models. One has failed over the years, but the rest have worked well. At less than $8 ea., I can afford a failure now and then.

These chargers are certainly not "the best". I am a full believer in you usually get what you pay for. All I can say is that they work, and if you need multiple units, affordable.

They are much more convenient, than running around once a month with a full sized battery charger. With their usage, my batteries are long lasting and always ready for service.

Gard

Our truck gets very little use in the winter  with dual batteries under the hood I protect it with the Deltran charger also.  

I installed it permently under the hood and ran the plug out next to the block heater.

Works like a charm.

Here's a link or three on RV batteries.....

http://www.explorerrv.com/articles/RVBatteries101.pdf

http://www.progressivedyn.com/battery_manage_101.html

http://www.batteryuniversity.com/parttwo-35.htm

With all the batteries that are on the market today, why buy a battery that you got to add water to all the time???  Every battery I replace, I try to replace it with a AGM battery.

http://www.zbattery.com/AGM-vs-Gel-Cell-sealed-lead-acid-batteries

http://www.apexbattery.com/faq-seleacba.html

What they look like in the inside...

 http://www.users.bigpond.com/solarbbq/batteriesrejuvenating.htm

This is where I buy....

http://www.batterymart.com/c-deep-cycle-marine-batteries.html

Is your LQ plugged in all the time too?  If so you should not have to use your batteries you can turn them off at the selector switch.  Your converter will run everything from shore power. This will keep your batteries off the charging circuit all the time and occasionally you can flip them on to ensure they are fully charged which will aid them in surviving the freezing temps.

Have you checked your water levels lately?

http://janwp.com/mm5/merchant.mvc?Screen=SFNT&Store_Code=JANWP

My most interesting find was what I learned about the converters installed in most RV's.

The standard converter used does not maintain a battery properly.  Most will supply a level of charging that will overcharge and run a battery dry in weeks.

Even a trickle charger is not a good method. Believe it or not it will run a battery dry in time.

A interactive charging system will sense battery condition and act accordingly in three ways.

Boost (Rapid recharge), Normal and Storage in storage a good system will at intervals raise up and apply a large charge for a short time to apply a desulfation process this process clears built up sulfur from the lead plates.

This site offers a neat add on product for progressive dynamics converters that do not have charge monitoring capabilities.

http://www.progressivedyn.com/prod_details/charge_wizard.html