Battery thoughts - resting voltage for Trojan T105's

[GrumpyDad]

I've been using a pair of trojan T105's for several years, and I bought them used, so I have no idea how old they are. They are working fine, but, I'm always wondering.

After a full charge, wired in series, and letting them sit 24h with no draw they sit at a resting voltage of 12.8v, which seems low to me. I know automotive batteries will sit at a higher resting voltage.

I have no specific reason to suspect these batteries are bad. Anyone with a newer set of Trojans or other 6V golf cart style batteries want to chime in?

[Mustang65]

12.6 volts is a full charge. Batteries on FLOAT will be around 13.2 - 13.4, give or take a few. My original Interstate batteries (replaced with T145 6 volt batteries) sat by my work bench for 5+ years before being recycled earlier this year. They would charge once a week while home, would drop to a 12.8 Volts and sit there for a few months until I returned home, still at 12.8 volts. The resting voltage finally dropped to 12.4.... 12.1.... and then the next time I looked they were at 10.something. Recycled at this point.

An old battery will hold a charge, but what you will see on an older battery is that the Ah's available will drop as time goes on. An example of this is in the battery test I did a few years ago on the Interstate batteries. I contacted Trojan support and asked how they perform an Ah test on the batteries. They gave me the info I needed (tests used by the industry as a norm).

The results are here: THE RESULTS ARE IN (Battery Test)



You will notice that your batteries are not supplying power (without shore power) for the same length of time as they did when you first installed them. Trojan uses a date code and it is on the top of each battery that they make. Unfortunitally you have no idea as to if these batteries were properly cared for before you received them. Just keep the battery water level just below the ring in each cell area. Use only distilled water to refill

Good Luck

Don

My Registry

RVing with SOLAR

[Screwby]

Our everwise Mustang beat me to it, but, my 6v batteries wired in series read 12.8 at full charge. Like Mustang said above, my solar system floats mine around 13.2 otherwise.

[GrumpyDad]

I'm always impressed with the speed and quality of Don (Mustang's) posts. Thanks guys. Guess unless I feel like the capacity is lower, I should stop worrying about this voltage.

I am planning on getting one of those DROK battery monitors that have been mentioned, so I guess I can see how many watts I'm using before the voltage drops.

No solar in my setup yet.

[Screwby]

Originally Posted by GrumpyDad

I'm always impressed with the speed and quality of Don (Mustang's) posts. Thanks guys. Guess unless I feel like the capacity is lower, I should stop worrying about this voltage.

I am planning on getting one of those DROK battery monitors that have been mentioned, so I guess I can see how many watts I'm using before the voltage drops.

No solar in my setup yet.

Yet....lol...drink the koolaid, it’s delicious

[Artsville]

I have a question for those with 2 6v batts. Did you upgrade your converter charger so that you can bulk mode at 14.6 or so volts? I doubt my wyco will ever switch into bulk and certainly not at the voltage. Also have read that these batteries really like 14.6v or so to really become fully charged. Can someone fill in the details on this scenario? I am about to switch over as I mostly dry camp.

[Screwby]

It’s been a few years since I installed my Renogy system so forgive me if I’m vague. If I remember right, I went into the menu to set the parameters and the smart controller took over from there. I’m sure there was a call or two to their awesome CS department along the way so I was sure it was set up correctly.

[Artsville]

What if no solar hooked up did you upgrade your trailer converter. I have a portable solar panel and i know it runs with good sun at like 14.4 volts on trailer. Since mine is portable when i am at home or hookups i was thinking a better converter for battery life and full charge.

[Mustang65]

Originally Posted by Artsville

Since mine is portable when i am at home or hookups i was thinking a better converter for battery life and full charge.

Renogy has a good 30 amp, which at the current time is cheaper than the lower amp units.

The TT's battery charge controller and the SOLAR charge controller work fine together.
Don

My Registry

RVing with SOLAR

[bdreinv]

Might consider 40 amp controller. We did a 30 MPPT and are limited to 300 watts of solar. One thing solar people seem to want more panels! Thanks