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

Ten years of good service from the Trojans is terrific!

1) you need a true battery capacity tester to see what the capacity of the battery is, such as the West Mountain Radio CBA IV. The testers that automotive battery stores have is typically a high current test, not a capacity test (for starting currents). You can do your own rudimentary test by running a known load until you reach a discharged state, for example 5 amps for 20 hours would be 100 AH. 2) Why not, if you are happy with them?3) With your maintenance regimen, I doubt you will get longer life from Lifeline or other AGM. Their main advantage is lower self discharge rates, and higher charge/discharge rates (lower internal resistance). Their main disadvantage is intolerance to operation at a partial state of charge. If you don't mind the watering and outgassing of the Trojans, they are far cheaper.

Thanks Jon for the info. If I do replace with the same batteries I would get a Hydrolink Watering System or a Flowrite System to make watering easier. My issue with such a system is one cost and two clearance issues with the stock battery box. Has anyone had experience with either one of the watering systems?

thundercloud wrote:2.) Should I replace the current set with the same Trojan T-105 Plus since I got such great performance out of them?Trojan T105 batteries are hard to beat ! If you are looking to save a buck, get the regular Trojan T105 batteries or check the GC2 batteries at either Costco or Sams. They may have a little less power, but they coast a lot less !thundercloud wrote: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?You will not get any additional life out of AGM. Well maintained (regularly cleaned and watered) "flooded" batteries are still the best bang for the buck !

I just replaced my cheap wm batteries ( that lasted 10 yea rd BTW ) with two T105's . Thy give me the most AH for the space available .

Replacement Battery Help/Choices/Opinions | Good Sam Community

Lwiddis
Explorer II
Mar 18, 2018
Ten years of good service from the Trojans is terrific!
HMS_Beagle
Explorer
Mar 18, 2018
1) you need a true battery capacity tester to see what the capacity of the battery is, such as the West Mountain Radio CBA IV. The testers that automotive battery stores have is typically a high current test, not a capacity test (for starting currents). You can do your own rudimentary test by running a known load until you reach a discharged state, for example 5 amps for 20 hours would be 100 AH.
2) Why not, if you are happy with them?
3) With your maintenance regimen, I doubt you will get longer life from Lifeline or other AGM. Their main advantage is lower self discharge rates, and higher charge/discharge rates (lower internal resistance). Their main disadvantage is intolerance to operation at a partial state of charge. If you don't mind the watering and outgassing of the Trojans, they are far cheaper.
thundercloud
Explorer
Mar 18, 2018
Thanks Jon for the info. If I do replace with the same batteries I would get a Hydrolink Watering System or a Flowrite System to make watering easier. My issue with such a system is one cost and two clearance issues with the stock battery box. Has anyone had experience with either one of the watering systems?
theoldwizard1
Explorer II
Mar 19, 2018
thundercloud wrote:

2.) Should I replace the current set with the same Trojan T-105 Plus since I got such great performance out of them?

Trojan T105 batteries are hard to beat ! If you are looking to save a buck, get the regular Trojan T105 batteries or check the GC2 batteries at either Costco or Sams. They may have a little less power, but they coast a lot less !

thundercloud wrote:
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?

You will not get any additional life out of AGM. Well maintained (regularly cleaned and watered) "flooded" batteries are still the best bang for the buck !
ticki2
Explorer
Mar 19, 2018
I just replaced my cheap wm batteries ( that lasted 10 yea rd BTW ) with two T105's . Thy give me the most AH for the space available .
Kayteg1
Explorer II
Mar 19, 2018

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.
thundercloud
Explorer
Mar 19, 2018
My major limitations on battery replacements is the small battery compartment from Bigfoot. So I am not sure if the Costco 6 volts would work.
thundercloud
Explorer
Mar 19, 2018
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.
thundercloud
Explorer
Mar 19, 2018
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.
OutdoorAddict
Explorer
Mar 20, 2018
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