Trojan batteries question

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Falling Star

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My boat has a bank of four 6 volt T105's as the domestic supply. I don't know how old these are but I suspect 10 years or more.

I do keep them topped up but they seem to get through a lot of water. Also the tops of the casings have a slight upwards bulge. We are invariably connected to a mains supply so don't rely on the batteries as such.

They are permanently on trickle charge by a smart charger. Hence they never get flat but I suspect they are at the end of their life.

My question is, would there be a safety risk? Could old batteries catch fire or will they remain in this charged but "dead" state indefinitely?
 
I am on my second set of 4 x T105s. The first set came with the boat. They have a reputation of needing frequent water top ups, as you have experienced. I do not leave my new ones on charge when away from the boat. The longest they have been left is 3 x months and they charged back to full successfully. I think you increase the risk of some sort of damage with consequences like fire if you leave the batteries connected. The T105s are designed for deep discharge. Also, use a hydrometer to monitor battery charge, similar to the link below. The battery casings are not supposed to be bulged. I would recommend that you don't keep the batteries on charge constantly, it is not needed but could be hazardous, more so on older batteries.

How to check a solar battery's state of charge
 
Falling Star said:
My question is, would there be a safety risk? Could old batteries catch fire or will they remain in this charged but "dead" state indefinitely?
Click to expand...

I would personally be changing those as soon as possible. Do you have a CO alarm? Many of those also usefully pick up hydrogen from knackered batteries.
 
Falling Star said:
We are invariably connected to a mains supply so don't rely on the batteries as such.

They are permanently on trickle charge by a smart charger.
Click to expand...

Could be wrong, but I get the impression that your are living onboard, while hooked up to shore power? In other words, there are also loads on the 12V system, while batteries are being charged?
If so, I would be concerned about the smartness ot the charger. Is it clever enough to remain on float voltage, despite the parallel loads? If it often goes into bulk charging mode that could perhaps explain the high water consumption. A voltage reading would confirm.
 
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The only time I have seen batteries with bulging cases is because the vents were blocked. It's not easy to imagine any another reason whatever their age, although being physically restrained with too much force might well do something similar, I guess. :unsure:

Richard
 
I have 6 x T105s, which are now about 10 years old and still going strong. They last a lot longer than mere mortal batteries.

The bulges sound a bit worrying though.
 
At 10 years old, I would expect them to be a bout time expired. Deformed cases could be through overheating and excessive water loss most likely due to overcharging, which can be as damaging as undercharging. Leaving permanently on trickle charge not a good idea. Suggest you cycle the batteries and just charge when necessary, which will give an indication of their state. Check each cell with hydrometer.
 
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We don't live onboard. I would prefer not to have the batteries on permanent trickle charge but found that they go flat quite quickly if just left. I guess this is probably another indication that they are stuffed.

If I do let them get flat, then when I put the charger on the battery monitor indicates that they are taking 35 amps charge initially. Seems a lot to me and more worrying. Hence I have not been letting them discharge.

The vents are clear and they are fixed firmly but not in an excessive way.

I will have to bite the bullet and buy some new ones. I have used battery megastore before so will probably try them.

Thanks to everyone for your suggestions.
 
That’s what happened to my first set, no idea how old they were. I also over cooked them and found the cells quite dry one day. Advice on here was clear, no need to leave on all the time.
They should be replaced.
Look the batteries up on Google and get the data sheet, self discharge rates is info you need.
 
Leaving batteries on a shore power charger indefinitely is unlikely to be good for your batteries. To some extend it may depend on the level of sophistication of the charger. If the batteries are not being discharged everyday then they dont go through a charge cycle that will elevate the voltage to stop sulphation. Some chargers can be set to do a monthly de-sulphation cycle where the batteries are taken up to 16.2v (in the case of T105s) for a few hours.
 
Falling Star said:
I will have to bite the bullet and buy some new ones. I have used battery megastore before so will probably try them.
Click to expand...

Worth trying Tayna for a price as well but, if you're not living aboard or using for long stays, do you need Trojans? Much cheaper batteries around if just weekend and holiday use and a small solar panel will keep them charged ready for weekend use.
 
Given my ability to trash even Trojans in <4 years as a liveaboard, I would just go for medium-cheapo AGM now (they have come down in price a lot lately). Much less hassle than flooded
 
Falling Star said:
I will have to bite the bullet and buy some new ones.
Click to expand...
Replacing FLA batteries after 10+ years is not what I would call bite the bullet.
Having enjoyed them for twice the lifetime that can be reasonably expected is more like it.
And the Trojan quality had a lot to see with that, I believe.
If anything, that suggests to stick with them.
 
pcatterall said:
before changing it may be worth checking that there are no 'hidden loads' when you leave the boat. Could there be some drain explaining why the go flat so quickly when left. Better to find out before fitting new ones?
Click to expand...
I think that's a very wise suggestion. My Trojans are 10 years old and I can leave them for 3 months without them dropping below 12v. If you have a current leak, it could be causing other problems (such as damaging your prop or heat exchanger).
 
Bobc said:
I think that's a very wise suggestion. My Trojans are 10 years old and I can leave them for 3 months without them dropping below 12v. If you have a current leak, it could be causing other problems (such as damaging your prop or heat exchanger).
Click to expand...
Like Bobc I can leave a boat for several months without significant loss of voltage. Having just replaced my old lead acid batteries with new fangled AGM, I hope this continues to be the case when I next step onboard. Says man who is beginning to feel like Ron Weasley in the Dark Hallows listening to the radio.
 
Water usage during the summer has been relatively low until last year when one cell failed and another looked a bit dodgy. I replaced the whole set of 4 T105s in mid. summer.

Average water usage during the summer (living at anchor on solar):
  • 1.3 - 1.4mls per cell per day in 2013
  • 1.5 - 1.6mls per cell per day in 2016
By mid. 2019 2 batteries were still using exactly the same amount as in 2016

However, usage on the other two had increased
  • 5 - 5.8mls per cell per day (One cell then stopped using any water for approx. 2 months)
  • 4 - 4.5mls per cell per day (Until one cell suddenly dropped to 1.0 SG)
I usually get voltage up to 14.8V each day using solar in peak summer or generator/engine in morning and then solar. Batteries are usually at 100% on most days (based on temp. corrected SG and SmartGauge readings).

The information above seems to indicate that 1-2mls per cell per day wouldn't be unusual for batteries charged to 100% and 14.8V each day.
4-6mls per cell per day probably indicates batteries are a bit long in the tooth.

I hope that's of some interest, even though it really only applies to my setup.


Winter charging
My T105s couldn't be left uncharged over winter as discharge rate was too high in the relatively warm weather. I worked out the discharge rate using data supplied by Trojan and decided a float charge from a 65W solar was safer. My new MPPT regulator is more sophisticated and has a large number of settings.

Configuration isn't ideal as I set voltages a little higher because there's little sunshine in December/January, probably not quite enough to keep up with self-discharge.

13.8V Boost Charge each morning for 90 minutes
13.4V Float Charge
14.5V Equal Charge for 2 hours on 28th of each month and then float

In a normal year I'd only need to add 30ml per cell and batteries would be 98-100% SOC in mid. April. However, not so good as I might not return until April 2021 due to Covid-19. I'm arranging for solar to be disconnected and covered with mains connected for a few days every month until autumn/winter.
 
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