Replacement Battery Help/Choices/Opinions

[thundercloud]

So my 2008 Bigfoot has had 2 Trojan T-105 Plus 6 volt batteries since new (starting their 10th year of service). My current electrical system consists of a Xantrex XADC60 charger/converter (3-stage) and 200 watts of solar with a mppt charge controller. I keep the camper plugged into shore power all the times when not in use. I replenish the water in the batteries twice a year (once before seasonal use and once when we put it away for the winter) using distilled water.

I have not seen any performance loss in the batteries throughout the years of use. So I have a few question to ask so I can make some informed decisions on replacing the batteries.

1.) How can I test the batteries to see what the state of charge is or how can I perform a capacity test?
2.) Should I replace the current set with the same Trojan T-105 Plus since I got such great performance out of them?
3.) Is there an advantage to going with an AGM battery set up like the Lifeline GPL-4CT besides the ability to not have to maintain water levels? Would I see even more life out of these vs. my current setup?

Thank you in advance for your imput and just to let you know I am not interested in lithium battery opinions as they are way over price and not in my budget.

Thanks again,

David

[thundercloud]

work2much wrote:

Personally I would invest in a battery monitor (for any system) and do your own load test. Charge them up fully, put a load on them and see how many Amp hours the provide until you get to your low voltage shut off. ~12v rested. New these batteries should deliver 100 AH or so for the pair to 50% SOC. (12v) If you are close the batteries are still good to go. Even if they only give you 80AH there is still life left. It would be odd for the batteries to be working fine one day and quit the next.

I do have somewhat of a battery monitor from my solar charge controller. It gives current battery voltage along with amps charging and amps of the solar panels. I will plan on doing a load test after our trip to Zion NP next week and get a better feel for life left in the batteries. Thank you for your help and suggestions.

[work2much]

thundercloud wrote:

work2much wrote:


:h Why replace them if they are still providing the same performance?

Well I am going to continue to use them until they die. We live in an area that the nearest Trojan dealer is 60 miles away. I did contact that dealer and he does keep the T-105's in stocks for $162.00 ea. I am just a little nervous about them crapping out on a trip but I am sure they would give me a sign that they are starting to fail.....right?

Typically they will just start losing capacity. Battery life is more a function of cycles and maintenance than time. It sounds like you have a decent maintenance schedule and keep them topped off when not being used. It could be the total number of cycles may not be that high even though you have had them 10 years. Especially if you didn't regular deeply discharge them or only used them for vacations.

Personally I would invest in a battery monitor (for any system) and do your own load test. Charge them up fully, put a load on them and see how many Amp hours the provide until you get to your low voltage shut off. ~12v rested. New these batteries should deliver 100 AH or so for the pair to 50% SOC. (12v) If you are close the batteries are still good to go. Even if they only give you 80AH there is still life left. It would be odd for the batteries to be working fine one day and quit the next.

[thundercloud]

work2much wrote:


:h Why replace them if they are still providing the same performance?

Well I am going to continue to use them until they die. We live in an area that the nearest Trojan dealer is 60 miles away. I did contact that dealer and he does keep the T-105's in stocks for $162.00 ea. I am just a little nervous about them crapping out on a trip but I am sure they would give me a sign that they are starting to fail.....right?

[time2roll]

+1 Why replace them at all? Use them hard and use them up. When the lights go dim just get new batteries.

[work2much]

thundercloud wrote:


I have not seen any performance loss in the batteries throughout the years of use. So I have a few question to ask so I can make some informed decisions on replacing the batteries.



David

:h Why replace them if they are still providing the same performance?

[ticki2]

Kayteg1 wrote:
The solar tester measure CA or CCA, what is in close relation to capacity.
So it will not give you exact number, but comparing % of CA to label CA you can predict capacity.
For golf cart battery choice who is better to ask than golf cart service center?
That is what I did years ago and Trojan at the time was having very poor CS, so dealers did not deal with them.
That is when I went to buy Sam's batteries, they were $46 a piece about 13 years ago and I was still using them on 11th year.
Now listening to our politicians, inflation is minimal, so you still should buy batteries for about $50, right?

As far as I know deep cycle batteries do not give or label CA or CCA ratings so how are you comparing their percentage to AH or energy capacity ?

[Kayteg1]

The solar tester measure CA or CCA, what is in close relation to capacity.
So it will not give you exact number, but comparing % of CA to label CA you can predict capacity.
For golf cart battery choice who is better to ask than golf cart service center?
That is what I did years ago and Trojan at the time was having very poor CS, so dealers did not deal with them.
That is when I went to buy Sam's batteries, they were $46 a piece about 13 years ago and I was still using them on 11th year.
Now listening to our politicians, inflation is minimal, so you still should buy batteries for about $50, right?

[thundercloud]

So I am leaning more towards replacing the batteries with the same Trojan T-105's and add a watering system if height allows. It's hard to beat the performance I have received from the current set up and to just AGM's at twice the cost. I think the main reason I have had such great performance out of the current setup is my depth of discharge (DOD) has never really gone below 70%.

Thanks everyone for your imput and helping me make an informed decision on my next battery purchase.

[HMS_Beagle]

The only way to capacity test a battery is to capacity test it. That involves putting a known load on it and measuring the time to discharge. This is a device that does just that. It will test at discharge rates up to around 8A by itself, or much higher with the accessory load, but 8A is a realistic test for most RV use.

[ticki2]

Kayteg1 wrote:

New technology is amazing. After decades of dealing with load tester, this gizmo tells you actual capacity.
I wonder why with huge solar system you keep your camper plug in?
Something is not doing good charging job if you have to add water so often.
Solar battery tester
Battery choice is always a dilemma.
Having several cars, for TC I just use car battery. In the past I bought cheap golf-cart batteries from Sam's and they lasted me over 10 years. But I had top-end inverter/charger and remember adding water every 5 years.

Looking at the discrption of that tester it measures CCA only even for deep cycle batteries . It does not appear to measure AH capacity .

[cewillis]

thundercloud wrote:
So my 2008 Bigfoot has had 2 Trojan T-105 Plus 6 volt batteries since new (starting their 10th year of service).

That's great. I thought it outstanding that I got 10 years out of my 4 big AGMs -- and it was.
If your electrical usage is modest, it would be hard not to continue with the same batteries.

[OutdoorAddict]

I have the Flowrite watering system and it really adds no height to the batteries. It works great, I hook it up to distilled water about once every two months and top the batteries off. I was looking at AGM batteries, but after a lot of research, for my application, I believe that flooded batteries will work better in the long run than AGM. Good luck

[thundercloud]

Kayteg1 wrote:

I wonder why with huge solar system you keep your camper plug in?
Something is not doing good charging job if you have to add water so often.

When we are not using the camper it sits under our carport so the solar panels don't get any sun. It only gets a small amount of de-ionized water 2x per year. I don't think that is overly excessive. Initially Trojan wants you to check water monthly and fill if low until you find your maintenance schedule.

[thundercloud]

Kayteg1 wrote:

I wonder why with huge solar system you keep your camper plug in?
Something is not doing good charging job if you have to add water so often.

When we are not using the camper it sits under our carport so the solar panels don't get and sun.