Judging Deep Cycleability by weight per capacity ratio

It's been decades since I had a traitorous spy in Trojan engineering.

It depends on the thickness of the positive plates and the density of the paste. You can ask Trojan a question that may or may not raise their "PROPRIETARY INFO!" hackles.

ARE THE SAME PLATES USED IN THE T-105 AND T-1275?"

A phone call to Sata Fe Springs, CA. is inexpensive.

If they answer the question with "No" then the 1275 plates are going to be slightly thicker.

Ultra-high density plate paste is extremely expensive. I do not know this guaranteed but I can only assume Trojan reserves the high-priced-spread for the industrial battery line. The dollar per amp hour and calculated by weight is a clue to what an industrial battery consists of, material wise.

But this is quibbling the point...

The 1275 is a different animal than the 31

More antimony and denser plates make re-learning trends & tendencies a must.

The voltage/gassing point will be different as will float voltage value.

Charge acceptance will be different a whole new world.

Learn to fine-tune float voltage. Exactly enough watts to not allow gravity to degrade over time.

All flooded batteries tend to have a weak sister cell. Find it right off the bat.

landyacht318 wrote:
Now, it is no secret that the group 24/27/31 sizes are not built anywhere nearly as burly as the T-105's.

It's probably not correct to take that statement at face value without supporting qualifiers.

Comparing equivalent volumetric sizes of true deep cycle Group 24/27/31 12 volt batteries to true deep cycle Golf Cart 6 volt batteries might reveal that:

Since an equivalent case-volume size 12 volt battery has to supply only 1/2 the current per cell that an equivalent case-volume size 6 volt battery does per cell, the 12 volt version can, and must, be built with less density per cell (12 volt = 6 skinny cells, 6 volt = 3 fat cells). HOWEVER, the less dense per cell 12 volt version will last the same length of time as the more dense per cell 6 volt version because the 12 volt version consumes itself, over time, only one-half as fast due to supplying only one-half of the current per cell on average over time.

I'm talking grass roots basics here - which are difficult for us to prove or take advantage of because finding a non-AGM 12 volt equivalent to the common non-AGM T-105 is so difficult. It would be necessary to step into the AGM battery world - in order to compare 6 volt and 12 volt deep cycle version lifetimes - so as to demonstrate equivalency of 6 low-burliness cells supplying one-half the current (per cell) to 3 high-burliness cells supplying twice the current (per cell).

I think for acid starvation potential, you should compare their volumes vs their weights instead of their AHs.

My T-1275s have their caps in a V shape but ISTR Niner showed a photo of his with a different caps layout. No idea if that means anything.
They might come with various post type options too, don't know.

$175 seems a good price to me. Up here they want that for a single 6. Two 6s would be 232AH and two T-1275s is 300AH.

The T-1275 is listed at 82Lbs, not 84 as I originally posted, I will edit the OP.

I found the SCS225 and the T-1275 both cost 175$ at my nearest distributor with the t-1275 having a 3$ higher core charge

I do have nearly 200 watts of solar, and the screwy31(USbattery) which is about to fail, has about 465 cycles on it, in 19 months. I do not think this is bad. In terms of cycles per dollar the screwy31 has been a better value than all previous batteries, but it also got much more attention and massaging.

However the screwy31 recharging requirements are rather extreme. If it is not top charged daily at high voltages, upto 15.3v, Specific gravity tanks quickly and performance, (voltage held under load) is horrible. And EQ cycles are required every 2 to 3 weeks even when top charging daily.

I'm hoping Trojan's are less demanding in this respect. Mex in the past has called flooded 31's acid starved. Trojan's 31 weighs 2 lbs more than USbattery's 31, so perhaps Trojan's 31 would still be petulant.

Fitting a T-1275 where the screwy31 currently resides is going to be a very tight fit. The screwy31 barely fits. The tray can be lowered with more effort than most would employ to achieve, but the tray is currently compromised and needs attention anyway.

My main curiosity in this thread is the plate thickness, if it can be determined by weight. Trojan lists CCA ratings for its 24/27/31 group sizes but does not bother with CCA ratings on the t-1275.

SCS, superior cycling series, in comparison to what, standard dual purpose marine batteries? That is not such a high bar to jump over.

I'm hoping the T1275 is on another level compared to the 24/27/31 group sizes. As the price is the same, I'd be a fool to not try and fit the T-1275 instead of another 31 compromise.

This is an interesting link.

http://www.pbase.com/mainecruising/deep_cycle_battery

The t-1275 is also called a J150 but this model has different handles. that extend beyond the case where the t-1275 does not.

He calls the 24/27/31 'pseudo deep cycles" at 600 LAB cycles to 50% DOD
He says both the t-105, J150 are rated at 1200 Lab cycles to 50% DOD

Same price but 50% more rated LAB cycles? Sign me up.

Bottom line is, I want a true deep cycle battery, and I do not think that is possible in a 12v format in the 24/27/31 size, no matter the labelling on the battery. I will go through the effort of fitting the T-1275, even though shaving off a handle of an SCS 225 would be easier.

USbattery31 and trojan's 31 might very well be superior to any other flooded group31 available that has a 'deep cycle' claim, but can they compare to a battery that was designed around cycling in the first place?

Does the weight/AH ratio of the T-1275 place it firmly in the true deep cycle camp like the t-105, or is it somewhere in between T-105 and the SCS 24/27/31?

I thought my T-1275s weighed 82lbs each, but didn't look it up just now.

My previously enjoyed T-1275s (made in 2011) are still in good shape since I restored them two years ago after they were in a golf car.

I expect the T-1275 would be a good candidate to replace the 31, but it will have its own personality of course.

They do act differently from my 6s in how they react to loads (Niner mentioned this too ISTR) The T-1275 takes loads with a voltage drop like you would expect (not as big a drop as the 6s), but when the load is removed the voltage bounce back is sort of relaxed coming back up, taking longer than it does with 6s. This might worry you at first, but it is normal.

They don't use much water. I kind of like my T-1275s and have come to trust them, which is the main thing- you want a battery you can trust.

Take a look at the scs150, this is a grp 24 105 AH 12 that Trojan makes.

Just curious what you found the T1275s cost were... I really want to do two battery banks of 1275s one on the trailer tongue and the other one in the bed of my truck. I have two separate uses for more batteries being camping and emergency radio comms setups.

When camping I will be able to combine the two battery banks to give me around 600Ahs of capacity.

Battery size and weight is not a problem for my setups...

Roy Ken

Do you already have a solar system?

I don't think that you will require as large of battery capacity after installing a solar system, because in part the 35 AH that you use daily to run just the CO meter, propane leak detector, and refrigerator will be in part supplied directly from the sun, not the battery.

I used a 85 pound 12 volt battery in a personal lift at my work. It came with a group 31 battery at around 50 pounds, but was replaced with a L5 battery (I think - it was over 15 years ago). That battery lasted a long time. IT was a 1 person manlift that went straight up, no drive motor, just up and gravity down. All aluminum, it was pretty light.

Good luck finding new batteries. Trojan is a good brand. They make many 12 volt batteries. I sometime wonder if the 'HC' version of the 12 volt group 27 battery is good or not. To get the higher capacity, did they install larger plates with less room below the bottom of the plates to accumulate junk - before the junk shorts out one of the cells?

I have heard that the T-105 and T-125 have the same case, yet the T-125 weight is about 8 pounds more. They both are rated at 75 amps for 105 or 125 minutes respectively (in the name). The T-125 has about 250 AH. Yet I guess that it might have larger plates that allow less 'junk' below them, leading to a reported shorter battery life.

Fred.