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 > Trojan T-1275 Trouble

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MakerMK

IN

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Posted: 01/09/19 11:50am Link  |  Quote  |  Print  |  Notify Moderator

Newbie here.

I have a travel trailer that has a Trojan T-1275 battery that is around three years old. The camper spends most of it's time in a pole barn hooked up to a couple of 100 watt solar panels and a Schneider charge/load controller. I check the water level when I think about it (I know, it should be on a schedule) and the last time I checked it was about 1/8" below the top of the plates and the charge level was low. I topped the cells off with distilled water and gave it a couple of days to recharge.

Well, it didn't recharge. I initially thought I must have ruined the battery by letting it get low, but after checking the wiring of my solar system I discovered a bad connection. A much better problem to have than a dead battery! I moved the camper to a source of AC power and let the camper's system (not the Schneider) charge the battery. The next day I took hydrometer readings and they were still deep in the red/recharge zone. I let it charge for another day and there was no change.

I decided to take a voltage reading, so I disconnected the battery and let it sit overnight. When I checked it, it read 13.1 volts! I grabbed the hydrometer again and the readings were all still in the red/recharge zone. I suspected the hydrometer so I checked it with plain water and it read 1.0, or more precisely the water level was at the point where 1.0 would be if the scale went that far.

What the heck? I'm no battery guru, but this seems crazy! Do any of you folks have an explanation for this? I'm at a loss.

BFL13

Victoria, BC

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Posted: 01/09/19 12:04pm Link  |  Quote  |  Print  |  Notify Moderator

I had a pair of T-1275s in a past set-up. Great batteries for RVing!

What you need is to charge the battery at 14.8v or so to get the SG up. I suspect the charger you had them on was only a 13.x voltage charger.

Right now you have the acid at the bottom of the battery giving you that 13.1 volts, and the hydrometer is not getting at it. You need proper "gassing voltage" to get the electrolyte mixed from bottom to top.

Make sure the solar controller's high set point is 14.8 volts too, or else it will happen again.


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Chris Bryant

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Posted: 01/09/19 12:39pm Link  |  Quote  |  Print  |  Notify Moderator

The built in system will not charge that well at all


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Lwiddis

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Posted: 01/09/19 12:57pm Link  |  Quote  |  Print  |  Notify Moderator

T1275s will be my next battery purchase. Nothing but good reports.


2015 Winnebago 2101DS TT & Tahoe LTZ, 300 watts WindyNation solar-parallel & MPPT, Trojan T-125s. TALL flagpole for US flag. Prefer USFS, COE, BLM, NPS, TVA, USF&WS, state & county camps. Bicyclist! 14 year Army vet - 11B40 then 11A - old MOS 1542 & 1560.


2112

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Posted: 01/09/19 01:24pm Link  |  Quote  |  Print  |  Notify Moderator

Read Equalizing


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theoldwizard1

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Posted: 01/09/19 03:47pm Link  |  Quote  |  Print  |  Notify Moderator

Trojan charging specs are different than any other flooded lead acid battery.

I do not know of ANY off-the-shelf battery charger that will do the 14.8/13.5/16.2 Bulk/Float/Equalize that Trojan recommends.

You can do it "manually" with a decent 30V, 10A lab power supply that has both constant voltage and constant current, but it is a pain.

BFL13

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Posted: 01/09/19 04:00pm Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

Trojan charging specs are different than any other flooded lead acid battery.

I do not know of ANY off-the-shelf battery charger that will do the 14.8/13.5/16.2 Bulk/Float/Equalize that Trojan recommends.

You can do it "manually" with a decent 30V, 10A lab power supply that has both constant voltage and constant current, but it is a pain.


Yes you do. I have posted before about this one that is adjustable from 13 to 16.5 volts. Works great. Not very costly either! You can get these LKs in various amp "sizes" from 35 to 120 amps.

https://www.boatandrvaccessories.com/pro........er-converter-battery-charger-w-led-light

theoldwizard1

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Posted: 01/09/19 04:50pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

I have posted before about this one that is adjustable from 13 to 16.5 volts. Works great. Not very costly either! You can get these LKs in various amp "sizes" from 35 to 120 amps.

Powermax LK Series manual

These instructions are not very clear to me.

[image]


Quote:

ADJUSTING FIXED VOLTAGE : The unit is on the three stage charging mode firstly. 1. move the switch A to "Adjust Fixed Voltage", move switch B gently to adjust voltage from 13~16.5V, and get a fixed output voltage. 2. make sure the voltage as 14.6V, move the switch A to " Three stage charging", then the unit back to standard “Three Stage Charging”, run 14.6V almost 0.5 hour, 13.6V almost 12 hours and then to 13.2V. The voltage value of 3 stage charging will be changed with fixed voltage changed when the unit on “Three stage charging”.


Switch A appears in fact to be a switch. Switch B appears to be a small adjustable resistor.

How does changing the "Boost" (Bulk) voltage setting affect the "Normal" (Float) setting ? Also, this charger does NOT have an Equalization mode.

BFL13

Victoria, BC

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Posted: 01/09/19 05:13pm Link  |  Quote  |  Print  |  Notify Moderator

Yes it is sort of complicated till you do it in real life. Switch A makes it a typical three stage converter and if you monkey with the pot with the switch set to the left, it will change all three voltages at once. You can restore that to original though.

The real benefit is as a singe voltage manual charger with switch A to the right, set to any voltage you like with the pot B.

This means you can set it to say 14.8 and leave it there till the battery is charged, then drop that voltage to 13.6 or whatever float voltage you want and leave it there. Or when the batts are done at 14.8 just switch A back to the left and it will be in three stage and do that float voltage.

You can equalize by first charging the batts at 14.8 till full, then crank the voltage up to 16.2 and do your equalize, then crank the voltage back to whatever.

It is a pain to use a little screw driver in that hole B to change the voltage, but you don't have to do it often. I much prefer the model with the pot knob on top you can just dial around, but those models cost way more for the privilege.

You really need a voltmeter you can see while operating this thing and an ammeter too if you are trying to tell when your AGMs are down to accepting 0.5a per 100AH of battery after charging at that chosen single voltage using pot B that matches your AGM battery specs for charging. I have my Trimetric for that. You can get by with other meters though.

It is no worse operating an LK like those than setting voltages with an inverter/charger that has fancy options. the big thing is that you can match your charging to the specs of any battery you might have and they vary a lot. Even AGMs have all different levels of charging voltages.

MakerMK

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Posted: 01/09/19 05:29pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks for the responses! More would be welcome too.

The Schneider controller is configurable to the Trojan battery profile. And I think that I did that correctly, although it might be a good idea to double check. But I did have that problem with the solar panel connector that wasn't letting the battery charge. So I've decided to try the Schneider again, but instead of powering it with the solar panels I'll feed it with an adjustable power supply set at the same voltage that the solar panels provided. BFL13, you make a good point about the electrolyte being different at the top than the bottom. That sure explains the difference between the voltmeter and hydrometer readings that I was seeing. I plan to do an equalization charge in the hope that that will mix things up a bit.

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