Trojan batteries

Re Trojan charging voltage. AFAICS Trojan don't give different recommendations for different use cases. However the big market for T105s is floor cleaners for offices, hospitals etc. The pattern of use for these is typically a nightly deep discharge followed by a few hours recharge for the next night's use. In some cases like big hospitals they are in constant use just recharging when flat, like fork lift trucks. I believe the 14.8V is for these conditions I.e. constant deep cycle and rapid recharge. Battery life is a secondary consideration. In a typical boat use case without such intensive cycling and with more concern over life I am sure the more normal 14.2/14.4V (or even down to 13.8 as an absolute minimum if you dont mind it being slow) would be fine, even preferable. It is much more in line with the construction and s.g. of the battery.
 
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GrahamM376 said:
Sealed lead acid in some cases means you can't get the caps off without removing labels but some of them still have a vent hole so are not truly sealed.
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All SLA (as opposed to sealed maintenance free wet batteries) have vents with pressure relief valves in. A slight positive pressure is an essential aid to the recombination behaviour. You will not find any that have permanently open vents, nor will you find any that don't have vents that will open with overpressure of a few p.s.i. except Optima and Cyclon that vent at much higher pressure.

Sealed maintenance free wet batteries all vent without deliberate positive pressure but there will be something in the vent to reduce explosion risk and spillage risk, typically a porous disc of ceramic or sintered polypropylene/polythene.
 
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Plevier said:
Re Trojan charging voltage. AFAICS Trojan don't give different recommendations for different use cases. However the big market for T105s is floor cleaners for offices, hospitals etc. The pattern of use for these is typically a nightly deep discharge followed by a few hours recharge for the next night's use. In some cases like big hospitals they are in constant use just recharging when flat, like fork lift trucks. I believe the 14.8V is for these conditions I.e. constant deep cycle and rapid recharge. Battery life is a secondary consideration. In a typical boat use case without such intensive cycling and with more concern over life I am sure the more normal 14.2/14.4V (or even down to 13.8 as an absolute minimum if you dont mind it being slow) would be fine, even preferable. It is much more in line with the construction and s.g. of the battery.
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Interesting, thanks.

So on a cruising boat reliant on solar & wind, would it be worse to charge high with a good chance of getting up near 100% every day or a bit lower and risk not getting near a full charge each day?
Is that even a question which can be answered?
 
GHA said:
Interesting, thanks.

So on a cruising boat reliant on solar & wind, would it be worse to charge high with a good chance of getting up near 100% every day or a bit lower and risk not getting near a full charge each day?
Is that even a question which can be answered?
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Difficult!
I have very limited knowledge of wind and solar systems as opposed to mains and generator.
However as more batteries are damaged by undercharge than overcharge, particularly in boats and cars, if you are reliant on an uncertain source, get as much as you can when it's there is my instinct.
Always keep lead acid batteries as fully charged as possible is the basic rule.
Of course even Trojan aren't saying apply 14.8 up to full charge. If you continue that voltage above (say) 90% state of charge you will get lots of gassing and water loss. The controller must reduce the voltage when the current falls to a certain level, indicating that you have reached that state of charge.
 
Plevier said:
Re Trojan charging voltage. AFAICS Trojan don't give different recommendations for different use cases. However the big market for T105s is floor cleaners for offices, hospitals etc. The pattern of use for these is typically a nightly deep discharge followed by a few hours recharge for the next night's use. In some cases like big hospitals they are in constant use just recharging when flat, like fork lift trucks. I believe the 14.8V is for these conditions I.e. constant deep cycle and rapid recharge. Battery life is a secondary consideration. In a typical boat use case without such intensive cycling and with more concern over life I am sure the more normal 14.2/14.4V (or even down to 13.8 as an absolute minimum if you dont mind it being slow) would be fine, even preferable. It is much more in line with the construction and s.g. of the battery.
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I think that 14.8V suits my own system with solar/wind and occ. generator. Fairly long gaps between periods on shorepower.

I base this on 3 things:

Trojan specs.
Under ideal test conditions a T105 should cycle from 50% - 100% around 1200 times. I couldn't get exact details of the test procedure from Trojan Tech. support but was led to believe that it went along these lines:

Temp stabilised initially to 25C and load applied at C20 rate until battery reduced to 50% charge before immediate rapid recharge to 100%

I didn't get detail on fail criteria but was told that recharge followed their recommended profile:
1) Voltage rises steadily to reach 14.1V by time battery is at approx. 91% charge
2) Voltage remains at 14.1V until 95% charged.
3) Voltage rises to 14.7V - 16.7V until battery reaches 100% charge.

I'm ignoring current just now and only quoting voltage.


Internet article

I can't find the link but remember reading a report written by a guy who used solar panels and T105s to live off-grid. He indicated that his battery life increased significantly after he started to follow Trojan's suggested charging profile. He'd only been going up to 14.2-14.3V for years before trying 14.8V

Own experience (limited to one system)
My own batteries pretty much level out around 85%-88% when using solar and setting max. 14.3V. Charge rate tapers off quickly and excess solar power is effectively thrown away. Increasing to 14.7V gets around this and avoids waste of solar power and nothing is dumped until batteries get close to 100%. Measurements taken from SmartGauge and temp. corrected SG plus estimated Amps in/out.

So my batteries never get much over 86% unless I bump voltage setting to 14.8V. No idea about longevity but battery capacity appears fine after 3 years use and no need for equalisation yet and all SG values remain very similar.


I can see that 14.8V will cause gassing and accelerate plate corrosion. However, Trojan's own test procedure appears to regularly reach 14.8V for last part of charge cyle and I assumed that they would optimise the test to give largest number of charge/discharge cycles.

I accept that I'll be lucky to achieve half the life Trojan's tests predict.

Any thoughts about this vs. your comments regarding lower charging voltage, especially wrt Trojan's recommended charge profile quoted above?
 
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Plevier said:
Difficult!
I have very limited knowledge of wind and solar systems as opposed to mains and generator.
However as more batteries are damaged by undercharge than overcharge, particularly in boats and cars, if you are reliant on an uncertain source, get as much as you can when it's there is my instinct.
Always keep lead acid batteries as fully charged as possible is the basic rule.
Of course even Trojan aren't saying apply 14.8 up to full charge. If you continue that voltage above (say) 90% state of charge you will get lots of gassing and water loss. The controller must reduce the voltage when the current falls to a certain level, indicating that you have reached that state of charge.
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Sorry, just spotted your reply above. It sounds as if you are saying that 14.8V may be the way to go when away from shore power/ generator most of the time. I think that this is pretty much as I expected.

"Of course even Trojan aren't saying apply 14.8 up to full charge."
Actually, Trojan's profile seems to do just that and voltage only rises to 14.8V between 95% - 100% state of charge (unless I'm not reading their specs. correctly).
 
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Mistroma said:
Sorry, just spotted your reply above. It sounds as if you are saying that 14.8V may be the way to go when away from shore power/ generator most of the time. I think that this is pretty much as I expected.

"Of course even Trojan aren't saying apply 14.8 up to full charge."
Actually, Trojan's profile seems to do just that and voltage only rises to 14.8V between 95% - 100% state of charge (unless I'm not reading their specs. correctly).
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What solar regulators are you using? Mine don't have facility to vary the output voltage. When charging via shore power, unfortunately many battery chargers have a timed charge before dropping to float regardless of the state of the batteries, how does one overcome this except by turning the charger off when it drops to float and then on again for another timed period?
 
Mistroma

I'm very surprised if your capacity sticks at those levels with 14.2V applied. Normally one would expect anything over 13.8 to bring a battery of this type up to pretty much full charge, albeit slowly. Increasing voltage increases current but not the actual charge rate; the extra current goes as gassing and heating and charge efficiency nosedives. Admittedly in a regular cycling situation one would benefit from supplementing this with occasional equalisation charges at 14.8 or above, but not after every cycle.

My concern over the regular use of sustained 14.8 is, as you suggest, accelerated plate corrosion and gassing. However the T105s are built for a tough life. Try this regime on a typical "leisure" battery and its life would be shortened dramatically.

What really surprises me is Trojan's suggested regime dropping straight from 14.8V to 13.2V, the latter being a long term float voltage barely enough to maintain charge. As T105s are unlikely ever to see long term float, I would have anticipated a 14.8/13.8 regime, switching at some charge current level. If you want to live dangerously and use 14.8 up to full charge, how do you determine when full charge state is reached?

(Looking at your more detailed description of Trojan's ideal test regime, I see in fact they limit voltage to 14.1 until 95% SOC, then go to 14.8, that's very different from just 14.8/13.2! In effect they are carrying out the main recharge at a much more normal voltage then giving a boost/equalisation final charge which will be fairly short. It approximates to a traditional constant current rather than constant voltage charge cycle.)

I think there is a play off here between cycling performance and life in years. Undercharging when cycling is very damaging in a relatively short term, overcharging (unless really insane) takes a long time to show up, maybe longer than the cycle life limit if the battery is cycling regularly. If the recharge time is limited, you have to use a high voltage despite its drawbacks. I guess a liveaboard scenario relying as much as possible on solar/wind fits into this category.
 
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GrahamM376 said:
What solar regulators are you using? Mine don't have facility to vary the output voltage. When charging via shore power, unfortunately many battery chargers have a timed charge before dropping to float regardless of the state of the batteries, how does one overcome this except by turning the charger off when it drops to float and then on again for another timed period?
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I have a Marlec HRDi regulator for both wind & solar. It allows me to monitor amps from wind or solar at any time and also keeps a running total of amps. The display shows amps generated and amps going to the battery. I can also alter the max. charge voltage per cell and the default is 2.4v. The regulator was effectively throwing away energy at the default setting. Increasing it to 14.7V causes the PWM regulator to continue putting a charge into the battery.

The batteries rarely get to 100% on solar alone and the regulator doesn't often get to the float phase. You can find more detail on the boat's setup in my profile.
 
Plevier said:
Mistroma

I'm very surprised if your capacity sticks at those levels with 14.2V applied. Normally one would expect anything over 13.8 to bring a battery of this type up to pretty much full charge, albeit slowly. Increasing voltage increases current but not the actual charge rate; the extra current goes as gassing and heating and charge efficiency nosedives. Admittedly in a regular cycling situation one would benefit from supplementing this with occasional equalisation charges at 14.8 or above, but not after every cycle.

My concern over the regular use of sustained 14.8 is, as you suggest, accelerated plate corrosion and gassing. However the T105s are built for a tough life. Try this regime on a typical "leisure" battery and its life would be shortened dramatically.

What really surprises me is Trojan's suggested regime dropping straight from 14.8V to 13.2V, the latter being a long term float voltage barely enough to maintain charge. As T105s are unlikely ever to see long term float, I would have anticipated a 14.8/13.8 regime, switching at some charge current level. If you want to live dangerously and use 14.8 up to full charge, how do you determine when full charge state is reached?

(Looking at your more detailed description of Trojan's ideal test regime, I see in fact they limit voltage to 14.1 until 95% SOC, then go to 14.8, that's very different from just 14.8/13.2! In effect they are carrying out the main recharge at a much more normal voltage then giving a boost/equalisation final charge which will be fairly short. It approximates to a traditional constant current rather than constant voltage charge cycle.)

I think there is a play off here between cycling performance and life in years. Undercharging when cycling is very damaging in a relatively short term, overcharging (unless really insane) takes a long time to show up, maybe longer than the cycle life limit if the battery is cycling regularly. If the recharge time is limited, you have to use a high voltage despite its drawbacks. I guess a liveaboard scenario relying as much as possible on solar/wind fits into this category.
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The key point is "albeit slowly". I don't think we disagree on the basics but I'm off-grid most of the time and there are a limited number of daylight hours. This means that I'm focussed on getting charge back in as quickly as possible. My regulator decides to dump charge too early at a 14.4V setting.

It may be the balance I have between consumption and power generation and things might be different if I had 2 or 3 times number of solar panels. The charging profile actually follows Trojan's published profile reasonably closely. It is probably more by accident than design. I have a nominal 450Ah capacity and panels only put out 10-11 Amps at most. Voltage rises quite slowly and is around 14.4V most of the time, only rising to 14.7V when batteries get above 90%.

I'm more likely to undercharge than overcharge and bought T105s to meet a specific requirement. I could get longer life from them by not using them but that would defeat the object. So I have accepted that I need use them in a way that will destroy them, but do it in an acceptable timeframe.

I'd agree with the comment about a 13.2V float voltage being a bit low. I followed Trojan's recommendation one winter an found that it wasn't really good enough for solar over winter. My remote monitoring system doesn't draw much but it was enough to take out more than the panel was putting in each day. Increasing the voltage to 13.8V solved the problem. I think that 13.2V might just be OK on mains power but won't manage on solar, it needs just a little more to put back small overnight loss.
 
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Mistroma said:
I have a Marlec HRDi regulator for both wind & solar.
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Just had a look at the Marlec spec., unfortunately, it won't do. I have 200w of solar and the Aerogen has it's own regulator and dump resistor, I think it works differently to the Rutland.
I'll have a look around and see if any others allow the output voltage to be adjusted.
 
Mistroma said:
It may be the balance I have between consumption and power generation and things might be different if I had 2 or 3 times number of solar panels. The charging profile actually follows Trojan's published profile reasonably closely. It is probably more by accident than design. I have a nominal 450Ah capacity and panels only put out 10-11 Amps at most. Voltage rises quite slowly and is around 14.4V most of the time, only rising to 14.7V when batteries get above 90%.
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So only about 2.5% charge current! Your daily consumption must be very low. Surprised you ever get to 14.7V. Maybe it's a function of the way your solar regulator works, I've already admitted to little knowledge of solar gear. Anyway it sounds as though you have arrived at a solution that works for you.
On a mains or generator system I'd want to charge these with at least 10% current capability but not be above 14.4V for long.
 
GrahamM376 said:
Just had a look at the Marlec spec., unfortunately, it won't do. I have 200w of solar and the Aerogen has it's own regulator and dump resistor, I think it works differently to the Rutland.
I'll have a look around and see if any others allow the output voltage to be adjusted.
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Yes, the 160W limit on solar is an issue for me, I'm thinking of adding an extra panel but that would go over the limit. I am short of room so might add a small one.

I do like the display on the HRDi though, you can immediately see if current coming in from wind/solar is going into the batteries or being dumped. I suppose I could have fitted ammeters before and after a controller if it didn't have this function. It helped a lot when tweaking settings to make the most of wind/solar.
 
Plevier said:
So only about 2.5% charge current! Your daily consumption must be very low. Surprised you ever get to 14.7V. Maybe it's a function of the way your solar regulator works, I've already admitted to little knowledge of solar gear. Anyway it sounds as though you have arrived at a solution that works for you.
On a mains or generator system I'd want to charge these with at least 10% current capability but not be above 14.4V for long.
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Yes, it is quite a tiny charge going in. It's a bit complex to explain but I have a mix of engine, wind, solar and small generator. I can sometimes get the batteries up to 100% mid-summer even at anchor for several days. However, that only happens when it's very sunny, not too hot and I've been stingy with power use. I usually have to run the generator 1-2 hours every 3 days just to get back to 85%-88% and mains charger is then set to 14.7V. If I motor somewhere then I usually manage to get to 100% or close to it (based on SmartGauge with backup SG checks from time to time). I do have problems when temp. gets above 35-38C as fridge consumption jumps a lot (no surprise).

I'm on mains power at start and end of season and do almost what you suggest. I tweak the 40A mains charger to give 14.2/13.6 as it is left on 24x7.

Sorry for the thread drift, but it does relate to use of T105s in real life so might be of interest to OP.
 
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Mistroma said:
Yes, it is quite a tiny charge going in. It's a bit complex to explain but I have a mix of engine, wind, solar and small generator. I can sometimes get the batteries up to 100% mid-summer even at anchor for several days. However, that only happens when it's very sunny, not too hot and I've been stingy with power use. I usually have to run the generator 1-2 hours every 3 days just to get back to 85%-88% and mains charger is then set to 14.7V. If I motor somewhere then I usually manage to get to 100% or close to it (based on SmartGauge with backup SG checks from time to time). I do have problems when temp. gets above 35-38C as fridge consumption jumps a lot (no surprise).

I'm on mains power at start and end of season and do almost what you suggest. I tweak the 40A mains charger to give 14.2/13.6 as it is left on 24x7.

Sorry for the thread drift, but it does relate to use of T105s in real life so might be of interest to OP.
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I have a similar setup to you except 2 banks of 2 Trojan T125s which have the same base area as the T105s but a bit taller more capacity and, 200w solar. Have 2 regs, one to each bank. In Algarve sun Jan & Feb, had no problem getting the batteries to 100% (the NASAs actually show 105% when full on float then drop to 100% when charge stops) with the fridge running 24/7. Only difference to normal usage was we had computers and TV running off yard mains plus the luxury of microwave, elec kettle & toaster:)
 
Mistroma said:
...............
Trojan specs.
Under ideal test conditions a T105 should cycle from 50% - 100% around 1200 times. I couldn't get exact details of the test procedure from Trojan Tech. support but was led to believe that it went along these lines:
...............
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I have higher figures for the number of cycles verses depth of discharge, received in an email from Trojan's technical support in 2013.
20% 4000 cycles
30% 2667
40% 2000
50% 1600
60% 1333
70% 1143
80% 1000
100% 800

Less important than a good charging regime;
I find it interesting that if you use these figures to calculate life time amp-hours available at a fixed discharge rate, you get an almost flat line. So the theoretical cost per Ah over the life of of a T105 has little relation to the depth of discharge.

EG.
For the 11.25A discharge rate, the datasheet states that the capacity is 225Ah.
Using the figures above;
Discharge by 20% yields 4000 cycles.
Life time capacity = 20% * 225Ah * 4000 = 180000Ah
Discharge by 80% yields 1000 cycles.
Life time capacity = 80% * 225Ah * 1000 = 180000Ah

If you do the same calculations with the cycle figures from the datasheet which are lower you get 135000Ah.

What this calculation doesn't take into account is the reduction of capacity with cycles. If the 1st discharge cycle has a capacity of 225Ah then the 1000th cycle with have a lower capacity. But, if the % loss of capacity per cycle is the same for all discharge rates (and I accept this is a big but), then depth of discharge has little effect on battery life.

However, rate of discharge has a big effect on life time capacity of T105s because the capacity reduces with increasing discharge rate.
Capacity @ 11.25A rate is 225Ah
Capacity @ 20.7A rate is 207Ah.

It is often stated in these forums that we should limit the depth of discharge to increase battery life when planning new installations or replacements.
For a T105 battery bank, limiting depth of discharge will increase battery life; not because the depth of discharge is reduced but because the rate of discharge will also be lower.
As a result I'd suggest using the rate of discharge as a basis for life/capacity calculations of T105s.

I haven't tried to apply this to other batteries.

Theory aside, the T105s I fitted last year have behaved well. I hope it will be quite a few years before I have to replace them.
 
Interesting figures from JohnGC. I found Trojan tech. dept. very helpful and they sent me data to compare their 6V & 12V range. The 6V figures were pretty close to their published figures for T105. The figures they gave JohnGC shows many more cycles. I have to wonder why they don't put these figures in their marketing literature. Manufacturers usually make the test procedure show their product in best possible light.

Capacity figures seem similar to published datasheet. I worked out a couple of years ago that my T105s would give 470Ah because my current draw tended to be much lower than the C20 rate. There are peaks when fridge, pumps etc. kick in at the same time, but these should be relatively infrequent. However, I have little real control over the average base rate without replacing inefficient kit or turning items off. These two options are the ones I tackle anyway in order to cut daily Ah usage. Adding more T105s would dilute the effect of my average current draw and give 720Ah from nominal 675Ah capacity. Weight and lack of space prevented me fitting 6xT105s to achieve this capacity.

I suspect that most people tackle the problem in the same way, fit largest bank you can, install more efficient kit and keep usage to a minimum. It is worth knowing about increased capacity from lower current draw but I doubt many people are able to influence the peaks and troughs. It might be of interest to OP as he's thinking of going from 220Ah to 450Ah and should see more of an increase than he might have expected.

Of course Trojan also state that you won't get 225Ah initially. It slowly builds up over the first 50 cycles (I think that's the figure) hits 225Ah for while and then drops off steadily as the battery ages.
 
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