Community Forums

fla tom · 01-24-2019, 09:10 PM

Our coach will be 4 years old this June (2015 Cornerstone). The house and chassis batteries are all seemingly working like champs,but all this talk in other threads about needing new batteries (on newer coaches than ours) how does one determine the time to replace batteries without waiting for utter failure?

ArkansasRomr · 01-24-2019, 10:05 PM

Proper maintenance when not using the batteries can determine whether they last several years or just a couple.

The bottom line is a little routine maintenance and recharging a discharged battery as soon as possible will extend the life of the battery. RV batteries can and should last 5 to7 years, rather than 1 to 2 years.

ArkansasRomr

brobox · 01-25-2019, 04:45 AM

Tom you keep yours plugged in a well maintain and should get a few more years out of your batteries. I still use the old fashion method. I unplug, turn what I normally use at night on for 4 hours while on battery power. If the batteries are still holding a good charge, the are not weak and good for another season. If they fall below 12v they are getting weak.

I know others use sophisticated battery meters that will tell you everything, I still use the KISS method. In the "old days" we had to used a volt meter on the batteries, checking every hour. An inside volt meter is a move up for me.

twinboat · 01-25-2019, 05:43 AM

Quote:

Originally Posted by brobox

Tom you keep yours plugged in a well maintain and should get a few more years out of your batteries. I still use the old fashion method. I unplug, turn what I normally use at night on for 4 hours while on battery power. If the batteries are still holding a good charge, the are not weak and good for another season. If they fall below 12v they are getting weak.

I know others use sophisticated battery meters that will tell you everything, I still use the KISS method. In the "old days" we had to used a volt meter on the batteries, checking every hour. An inside volt meter is a move up for me.

That is probably the best way of testing batteries.

" Battery testers " test high draw, short term capacity. Great for cranking batteries.

Deep cycle batteries are designed for low amp draw, long duration use. A measured & timed test, sort of like what you do, is a more accurate way to test them.

oneknight · 01-25-2019, 07:09 AM

Quote:

Originally Posted by brobox

An inside volt meter is a move up for me.

In my previous Monaco, I put a pair of these on the dash.

I'll add them to the Aspire someday. Either in the center dash, or the panel above the door. They mount with a single 1/4" hole.
Lascar 1200 voltmeter

xtechgeek · 01-25-2019, 07:50 AM

I just replaced my house batteries on my 2013 Entegra Cornerstone. I keep the RV stored indoors / plugged in when not in use, and I thought I would have gotten a little more life out of them. I purchased the coach new in April of 2014 so they only lasted 4.5 years. Turns out my Magnum Inverter settings were not absorb charging long enough (set to 2.5 hrs) even though they were setup for the correct float, absorb, and equalize voltages. This caused a bit of walk down and shortened my battery life. Lifeline technical manual states to absorb charge until current flow is <0.5% (4.4 A) of Battery Bank capacity (880Ah).

Shout out to Mark from Centex Batteries for helping me get my Lifeline batteries setup.

Gary.Jones · 01-25-2019, 08:49 AM

I think that you make that decision based on the decay in performance of the house bank from new to older. I bought my 2015 Anthem in March of 2015 and in 2016, spent 10-12 days in Quartzsite at the first annual Gathering of Entegra coaches/owners. My house batteries were easily able to support our needs (television, general lights, AquaHot 450D running all night, and some exterior lights all night during BLM's Quiet Hours (10:00 pm to 6:00 am). That is where I developed my standard boondocking procedure: Run Onan for 2 hours every night before bedtime, and 2 hours every morning when first getting up, and then any time we needed to run high amperage appliances during the daytime (lunch and dinner) for as long as we needed the appliance in use. Using that logic, I easily was able to honor quiet hours from 10 to 6 and support all my creature comforts in the coach.

Another issue was did you "equalize" AGM batteries or did you not "equalize" batteries? I never did in the 3 years that I owned the coach. Although PJ at Entegra recommended "Equalizing" the house batteries, the manufacturer clearly recommended against the process as the process used by Entegra and recommended by PJ departed very far from the process that is recommended for AGM batteries (kinda appropriate for flooded, but not for AGM batteries). I had several calls with the Discover Battery company engineers, and with various technical people, and all confirmed that the process used by Magnum and recommended by PJ did not conform to their guidelines or recommendations. So, I never did it.

However during my third winter at Quartzsite at the Gathering, my house battery bank was not strong enough to get me through the night without the AGS starting the Onan. So, I was at the point of giving "equalizing" a try with the AGMs on board even though the manufacturer recommended against it. However, for other reasons, we decided to trade up to our Cornerstone. When I turned in my coach, my first "weakness" listed on my list to the dealer was that the batteries be replaced or properly "equalized" using the proper procedure. If I had kept it, I would have done that process anyway to see if it would have helped.

So, unless you spend some significant time off the power grid boondocking, shore power keeps your house battery banks "looking good" when they are not. Along with other suggestions, my suggestion is spend 4 days boondocking somewhere and you will get a clear idea of the status of your battery bank.

Gary

tom chelbana · 01-25-2019, 09:46 AM

Te best way to test batteries is to check each battery separately with a load tester. Can be purchased at Harbor Freight for less then 50$. Get the 100 AMP tester and use a digital volt meter. I mark all batteries and then record reading with the date so you can trace how the batteries are doing after retesting them. Each time batteries are below 50% the battery live is shortened. Load testing batteries isn't difficult but will leave that part to another irv2 member to do or goggle.

twinboat · 01-25-2019, 10:25 AM

Testing deep cycle batteries with a cheap HF tester isn't showing anything but cranking amps. A useless test of deep cycle batteries, except to see when they are totally shot.

Even a major AGM, deep cycle battery manufacture, Lifeline, recommends a measured amp draw until FULLY discharged, while recording the time it takes.

As far as the 50% rule ?

Every time you discharge a battery, even 10%, you have shortened its life. There is a finite number of cycles in a deep cycle battery.

A deep cycle battery is like a a box of energy. Everytime you use some of it, and put it back ( charge it ), its like you have added a bit of sand to the box. That leaves less energy the very next time.

Draw it down to 50% and add a cup of sand, draw it down to 80% add 2 cups.
If you only draw it down 25%, you only add 1/2 cup.

Leave it sitting discharged is like slowly pouring sand in it. Keep them at 100% for long storage life.

Download the technical manual from Lifeline Battery for lots of factual information. Most of it pertanens to all deep cycle batteries.

Here is a screenshot.