Progress Report on Used T-1275s

I hope your T-1275s work out well. As seen above, I have mine working properly after some initial nursing.

I get 12.1v for the 50% mark confirmed by the Trimetric AH count and my notion of how many AH is "full" depending on the temperature and from my last load test where I got 270AH for the pair. It has checked out a couple of times now while camping, so I am confident in the numbers. I don't think I have their resting voltages when full---I have them on a Float once they are charged up or else they are down some while camping.

I treat them as though they are the same as my 6s for charging them and they do seem to need the Equalize (15.7v) shot after being brought to Full at 14.8v with the VEC1093DBD. I'd be lost without that charger. You can do it with a manual charger if you can stay there and monitor it. The VEC you can let it do E it by itself so handy for letting it run overnight or while away from the house.

I use a $5 hydrometer, but it is the long glass tube with a bobber in it, not one of the fat plastic stupid things I can never get to work right. It is accurate enough for my purposes.

Lately I have them banked with my two pair of 6s in a three-12s in parallel configuration with the loads and charging going to the outside ends. I know about using buss bars and links to balance three 12s better, but haven't got that far yet. Plus I keep changing my set-up so the wiring is always messy. :) I might go back to a four and two split when going back to using solar this Spring.

I've one battery that sat on the Ctek US7002 for 8 hours yesterday, to 14.4V. Let it sit overnight, took a Voltage reading this morning, 12.76V. Battery 2 charged over night also, 10:30pm to 6:30 AM, will let it sit all day, and see what I get for a voltage reading for it sometime this afternoon.

I looked inside after 8 hours of charging, all cells, no smoke coming off of them, just the tiniest of bubbles, .4 or .5mm or less in diameter, streaming up very slowly to the surface of the electrolyte.

I have to figure out how I am going to meet Trojans charging specs to get it charged at 14.8V, not 14.4, to get them truly topped off and at 100% charge. Is it really necessary, as Mena661 says to get these to 14.8 with a 10 amp + charger, to really get them to work right?

Trojan Battery manual as here says 15.5 Volts to Equalize charge these batteries, at 1 to 3% of the C/20 rating, 1.5 to 4.5 amps for a T1275. Yikes! Don't do that while hooked up to electrical on your RV. Disconnect completely.

Trojan battery Users Guide

High antimony deep cycle batteries are kind of a different beast than automotive batteries in their charging requirements.

So what does your voltage on these batteries read now with a 50% SOC? And Specific Gravity?

My two T1275's were bestowed to me today, so I suppose I need to process them with some equalizing first doing a 50% SOC. Voltages were 12.64 and 12.62, after sitting around 4 weeks. Specific gravity per cell to be determined soon. August 2011 build date for the batteries, no telling when they went into service.

MEXICOWANDERER wrote:
Batteryman jargon is TROPIC BLEND Mena.

You can test individual batteries when in series but it's going to take a meter and some extra help. Check the voltage across EACH six volt battery.

Same if you discharge a hodge podge together. Determine which battery battery slumps worse in a series configuration. Do that by checking voltage INDIVIDUALLY after being discharged and left to sit for several hours. I do not like batteries different than .15 volts charged or discharged.

How can you do that while camping? You can't leave them to sit for hours. And if you are home you can do them all separately in slow time, so no need to leave them connected.

While camping with a series parallel hodge-podge, all you can do is run the batts up and down till it's over, then go home and do what ya gotta do.

Batteryman jargon is TROPIC BLEND Mena.

You can test individual batteries when in series but it's going to take a meter and some extra help. Check the voltage across EACH six volt battery.

Same if you discharge a hodge podge together. Determine which battery battery slumps worse in a series configuration. Do that by checking voltage INDIVIDUALLY after being discharged and left to sit for several hours. I do not like batteries different than .15 volts charged or discharged.

The trade-offs for higher and lower SG for different battery applications is covered neatly in the last half of this

http://www.engineersedge.com/battery/specific_gravity_battery.htm

ktmrfs wrote:

what's interesting is that the Trojan "solar energy" batteries, which have claimed much higher cycle life (2-4X) than the regular trojans have

a) noticeaby lower initial SG spec than "regular" deep discharge counterpart batteries, about 1.26 IIRC
b) A corresponding decrease in AH spec's for the same weight. (As I would expect given the lower initial SG)

So, like so many things it's a tradeoff, what do you value most? Long life, or more AH/lower initial cost.

More AH for me. As far as long life, I'll be happy if they last 5 years. Though considering how they're babied (7%C charging, 1 cycle per month max at 50% SOC or higher, equalized once a year, top charged once a month, always on float unless the IOTA cuts out because it can't handle high temps), I think they'll last longer than that.

MEXICOWANDERER wrote:
I Live and learn. That's too danged hot in my opinion for temps in excess of 50F. These knotheads will do anything to boost apparent specifications to please the sales department. I am have been running 1.260 in my 2-volt cells.

The part that has hardened sulfation will always have low gravity and in turn really hampers CCA (biggest restriction = total limit of amperage). By establishing a "true" baseline for your gravity BFL13 I have a better picture of what's going on. The missing test link is a 20 hour test.

But, hey, if you flip the switch and the lights go on, what more can a person ask for?

Should I ask for summer blend on the next go round?

Glad to see the work and effort to get them back in shape seems to have paid off. Hopefully with your good care they will last a while.

Mex, I did a rough load test at first in August and it came to about 250AH or 83% of 300AH rating for the pair. That confirmed the golf car shop's version from June when they got 86% using their funny timed way of testing where they want better than 100 minutes or whatever they do. The batts then sat outside on a pallet until I came along in August.

I did a proper 10 hour 20hr rate test in October and got 9 hours to get to about 50% (12.1v Trojan spec and 1.175SG) the Trimetric showed that was 270AH or 90% of 300 for the pair.

I did not test them individually. I imagine Batt 4 is better than Batt 1 but I use them in parallel so that was how I tested them.

--BTW, Mex, do you still think with the latest figures that these would be harmful to my 6s to have them in parallel for a few days in a row while camping? I would prefer to have one big bank than the two for that. I separate them when on Float at home.