FLA Battery Charge Voltage Question

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397001#Comment_397001

Not sure if they will honor anything. Worth a shot, but for what I can find, the Trojan L16H-AC carries a 1 year warranty. And I am now out past 1 year. It began to show these signs in the 14th month.

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397003#Comment_397003

That is correct. The dealer / distributor did a load test. Discharged it at 25 amps for 385 minutes. Returned it to me fully charged and all cells SG in spec. I know they were in the Acid (I assume testing SG but possibly not temps) because my caps where backwards per their numbers.

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397004#Comment_397004

The hottest spot on the battery was in one area. The battery itself ranged from 34.2*C at the hottest spot of a few square inches near the top on both sides on the (+) side of the battery to 29.5*C at the farthest other end. I fairly certain it is not the cables. I moved all the batteries around and moved all the cables around. So if it was the battery, the issue would be showing up on anther battery AND I think the connection point would have been the hottest, it was not , But I will run the bank under some sustained load and take a temp reading of all connects to be sure.

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397005#Comment_397005

So "Boiling Dry" is when one has the risk of meltdown / fire? But as long as there is liquid in the cell it will not be a problem? Not that I plan to leave it this way, just curious.

MrM1 · April 2019

Here is what I plan to do:

I have full documentation of maintenance
will also document / photo graph the temps
write Trojan and see what they will do. I doubt anything as the battery is beyond warranty
replace the battery.
my dealer recently received about 100 Trojan 235Ah batteries "slightly used" at a really good price. After load testing will have them pull me a few good ones that seem volt balance. Parallel those 2 together to get the AHs up and series connect them with my existing 435Ah L16s.
Ill use these batteries sacrificially setting charge voltages to the correct voltages for the OTHER batteries/cells as long at the "new" batteries are not over charging or heating up.
Run them until they die and repeat until my bank gives up.
then replace the bank

That's about all I can afford to do right now. would that work?

mcgivor · April 2019

A few years ago I went through a very similar experience here is the link to what I did, it's a long read, but it did extend the life to some degree https://forum.solar-electric.com/discussion/351467/water-treatment-for-over-sulfation#latest

Tecnodave · April 2019

I would not recommend mixing different batteries in a string. It will fail. I find it rather surprising that Trojan has only a 1 year warranty. I am using a 13, almost 14 year old set of Rolls Surette S-530 L-16 batteries.Shipped out June 26, 2005. I contacted Rolls with only a question as to how old these batteries were. They did not ask where I purchased them, they opened a support ticket, shortly I got a call from Rolls support and Steve Higgins at Rolls shared much information even after I told him I had bought the batteries at scrap price...$20.00....on the way to the recycle center! He told me that they (Rolls) used infrared cameras to see the hot spots. He also asked what s.g. I maintained and advised me to set voltages down a bit as well broken in batteries such as mine do not need such a high s.g. He stated that I was doing something right and I told him I had worked at Alaska Husky Battery in Anchorage Alaska, He knew the owner. Directly due to Steve Higgins support I advised my current customer to consider the Rolls batteries to replace his set of D-8 AGM Interstate batteries, My customer didn't want to spend that kind of money, He asked me to recommend someone else to advise him on this. I referred him to sales at NAWS, the answers he got lined up directly with mine and he ordered the S-550 L-16 and the MagnaSine MS-2024 that I recommended, good job NAWS, my customer is happy, I'm happy, I have one more extended service maintaince contract and a very happy customer. Rolls warranty on this product is 2 years unconditional and 7 years pro rated. I know that I will get 20 years from the Rolls set, not sure about my other set, Interstate (Johnson Controls) living that long. Interstate will not answer questions from me as they are out of warranty. Even person to person at the warehouse where I bought them.......Interstate Battery in Salinas, CA......even when I asked the person who sold them to me.......quote "you got your life out of them" interstate has gone seriously down in the last 5 years, I no longer recommend them. They are a automobile battery company! I always thought Trojan support was good but your fiasco seems to prove otherwise.

david

MrM1 · April 2019

I did just notice from the spec sheet that the distrubutor only not discharge the battery very long. According to spec, at 25amps the battery is supposed to be good for 935 minutes not the 385 minutes they tested for. So does their test really tell me much about the condition of the battery?

Dave Angelini · April 2019

It tells me they do not know what they are doing if they do not test to specification.

mcnutt13579 · April 2019

One point of contention here. We have a customer with a very large single string of Solar Ones. Which we consider top of the line. About 10 years old they had a failure in watering that caused one cell to go dry and it was junked. Solar One instructed us to just put a new single cell in. So far it is working well. And it is a hard working battery. So replacing a cell in a string is sometimes allowed. Just confer with the manufacturer before you do it.

https://forum.solar-electric.com/discussion/comment/397019#Comment_397019

Estragon · April 2019

One thing you might try (only if you're a somewhat unusual combination of adventurous and very careful) is to try to see if you can mechanically dislodge a possible source of the presumed short.

It's a really long shot, but maybe a slim chance there's a little piece of flaked off plate which should normally have fallen to a collection space at the bottom of the cell has instead become stuck between plates. A good EQ that gets the cell bubbling vigorously might dislodge it, or maybe some other sort of stirring, such as removing/replacing acid more forcefully than normal with hydrometer to sort of blast the upper portion of plates? Obviouly, proper personal protection gear is essential.

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397018#Comment_397018

Interesting. Reading most of this now. Read the thread too. So it worked for you in a Sulfated (?) condition? Does Sulfation of a cell cause that cell to increase in heat when charging and also not allow that cell to accept full voltage when charging?

Tecnodave · April 2019

Mcnutt,

I agree with you on that. It is acceptable to replace one only battery in a set. It does not allways work but it is worth doing. I have done that. Replaced a 1 year old L-16 in a matched set. I made sure that the new one was in the same state of charge when I put it in the string then did several e.g.'s. To force a balance. It worked out well. I would not do it and walk away without monotoring for at least several cycles. I was referring to using two GC-2 batteries to replace a failed L-16, I have done that as a patch until I could secure an identical replacement. The GC-2' were undercharged by the time I got the replacement L-16 and needed to rebalance whole set. They lasted another 6 years so not bad. A Crown L-16 will not work in a set of Trojans L-16's , too different. Seen that done, it failed miserably. I replaced entire set to recover system.

Estragon · April 2019

It seems to me a sulfated battery/cell may heat and gas a bit more, but likely the whole cell (not a hotspot).

AFAIK, a sign of sulfation is the voltage rises quickly under charge, and falls quickly under discharge. Your problem one is rising less slowly under charge though, right?

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397041#Comment_397041

Problem seems to be several fold:

In float at 27.2v there is only a .02v per battery difference from battery to battery
At 28.5v charge the imbalance goes to 0.4v difference between the one battery and the other 3 (which are all measuring almost the same voltage within 0.03v)
At 31.6v charge the imbalance goes up to 0.65v difference between the one battery and the other 3 (which are all measuring almost the same voltage still within 0.03v). So at 31.6v charge the suspect battery is at about 7.46 While the other 3 batteries are at around 8.08-8.12v. So the higher voltage I use, the greater the voltage gap becomes
Also, the suspect cell (there may actually be 2 cells) are using NO water where as all other 10 cells are using water at a pretty good rate.
There seems to be very little to no gassing taking place in the suspect cells
Today at 100% charged the suspect cell was at 1.243 where all other cells were at 1.280 plus
There is the hot spot that is hottest at the top of the suspect cell. That whole battery is quite a bit warmer than the other batteries. It's hottest spot is 31*C today where at the other 3 are under 28*C

I may try to set the charger at a very low 28.3v tomorrow for all charge phases, and charge all day and monitor the voltage and heat and see at the end of the day if the SG has risen any better. Might be I can charge the batteries at a very minimum volts and hi current for a while

mcgivor · April 2019

https://forum.solar-electric.com/discussion/comment/397035#Comment_397035

The water treatment is a last resort when there is nothing to loose, as described in the pdf attached to post 1 of the linked thread.

Before considering such action I would suggest agitation of the battery to dislodge any possible deposits that may be lodged on top or between the plates, which should be in the well at the bottom. A turkey baster can be used to squirt electrolyte between the plates to help agitation. There is belief that the reason batteries in forklifts last so long despite such high demand is attributed in part to the fact they are constantly agitated, unlike in stationary applications.

Isolating and charging the single 6V battery would be far better than damaging all the other cells in the process.

The temperature difference noted is not excessive, sulfation usually renders the cell inactive, the current still has to pass through for the other cells but cannot break down the crystals into solution, bridging of the plates by deposits will cause similar symptoms by providing a path around the plates.

MrM1 · April 2019

Will agitate in the morning. Seems like I don't have a lot of options.

In the case of a replacement battery, so it is not ideal to parallel 2 smaller GC2 batteries together (even though using 215-220Ah would be very close to my current 435Ah L16s)? Is that due to resistance of different makes and models? In the case of the 2 GC2 batteries I would not be concerned about destroying the GC2 batteries, They would be sacrificial. I am only interested in keeping the bank up and running AND keeping the other 3 L16s charging at the right voltages / current / etc.

And while not ideal, would it be better to replace it with a new single same L16H-AC Trojan 435Ah

What is the best way to not replace the whole bank? My hope was 3-5 years. I am at 18 months so far.

I also still plan to reach out to Trojan, But I am not hopeful based on any warranty info I can find on this battery.

mcgivor · April 2019

Replacement wit GC would probably be better than nothing, it's tricky because of unknown capacity of both existing and replacement whichever way you go.

Estragon · April 2019

IMHO, there will likely be an initial difference in resistance between old and new batteries no matter what is used as a replacement. That said, replacing with an identical battery is likely to be closer, and more likely to converge with old in terms of best charging regime. If too different, neither is likely to get ideal charging, leading to reduced lifespan on both new and old.

Replacing with GC2 would work in a pinch to get/stay lit if getting an identical replacement takes a while, but I'd avoid doing it longer term.

MrM1 · April 2019

Ok I did try agitating the suspect battery pretty vigorously and aggressively. Rocked side to side, back and forth and tapped the bottom of the battery on the ground in an attempt to dislodge anything that might be causing a short.

Electrolyte turned almost black. Had to wait 12 hours for it to clear enough to get an SG reading. Connected the battery back into the bank, And tried a very light charge at 29.6v for just a few minutes. Still this 1 battery is reading 0.5-0.6v below the other batteries in charge (all 4 batteries in the bank are at 100% charged).

I did not wait long enough for heat to start building up again, but This voltage unbalance between batteries still being the same as before agitating indicates to me there is still some kind of problem ?? Short? Maybe? One Cell Sulfated?

So at any rate I have decided to proceed with the Water Treatment. Nothing to lose here.

MrM1 · April 2019

I did figure out a way to EQ Charge a single 6v Battery while it is in a 24v battery bank WtihOut EQ charging the other batteries.

Tell me if this is a bad idea? It does require a very programmable charge - I have the Conext SW Inverter Charger

Start by charging the whole 24v bank to fully charged
Replace the battery I want to EQ charge with a fully charged Sacrificial Battery (in my case I have 2 6v GC2 batteries to parallel into the bank keeping this sacrificial battery at the same Ah as the rest of the bank)
Now discharge the bank 10-20% with the sacrificially battery installed.
Now the 3 batteries are at 80% while the 1 battery I want to EQ is at 100%
Re-Install the battery I want to EQ into the bank
Set the charger to FLOAT charge only AND set the charge amps to as low as possible (in my case I have the float charge voltage set to 27.9v )
Start the Charger in FLOAT skipping Bulk and Absorb. Using Float gives me full control of the voltage without the charger turning off or charger changing the voltage
Tweak the Float voltage until the 1 battery that needs EQ and is at 100% is charging at EQ voltage (Trojan 8.1v for the battery which is 32.4v for a 24v bank).
Because the other batteries are discharged to 80%, they are charging at 6.6v per battery or not even float voltage for a 24v bank, but the 1 battery I want to EQ is charging at 8.1v which is EQ voltage. The charger will hold this all day.
Monitor the voltages at each battery regularly and Keep an eye on my temps on the 1 battery that is charging at EQ voltage. Heat probe connected. Started at 22.3C now up to 24.5C after 1 hour of EQ charging (ambient temp is 65*F)
Once the I am done EQing the one battery, IF the others are not back up to 100% charge (unlikely) Re-Install the discharged Sacrificial GC2 battery and charge the bank until the other batteries are charge and then remove the sacrificial battery.

Only problem, is amps/current. I have to have the current going into the bank high enough or the volts drop below the SW Float setting AND below EQ voltage at the battery I am trying to EQ. So I have to have at least 28 amps going into the bank. And perhaps that is a lot of amps into a battery that is already fully charged? Will that higher current going in hurt the one battery that is already full charge? Or is the system just passing that current onto the other batteries (because the fully charge battery will not receive anymore current) ??? The voltage is staying correct, but the current is higher than I'd like. Usually in an EQ charge, Current into the bank is around 10-18 amps.

Is there a problem with this method ?

jonr · April 2019

As far as I know, there is no issue with removing all of the electrolyte, agitating and flushing thoroughly with distilled water and then refilling with fresh electrolyte of the same SG (as what was removed).

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397108#Comment_397108

Thanks jonr, good to know. Can you look above and comment on my EQ charging idea too? (may how posted the idea while you were posting)

MrM1 · April 2019

Water Treatment Results after 1 hour:

Did not have the nerve or space to store the acid, so I only lowered it in the one cell to 1.135

After 1 hour of EQ that cell is up to 1.200. So the process is working.

mcgivor · April 2019

Follow the instructions carefully, the SG needs to be lowered to near pure water, the rationale is, the sulfation crystals will disolve more readily into pure water than into an acid. This is a slow process of reducing SG, as it rises, withdraw some more acid, then add more water, to maintain a close to water reading until it rises no further, only then do you replace the acid withdrawn, previously to achieve the desired SG, or use new clean electrolyte. Should the SG rise above desired limits, withdraw acid and add water.

The key to the process is to maintain a higher voltage, as close to EQ as possible, in a series string this may mean placing loads on the remaining batteries to drag their voltage down, incandescent or halogen headlights work well as a sacrificial load. The withdrawn acid can be stored in the bottles the distilled water came in, any excess can be neutralized with baking soda if needed.

When I did this process the plates foamed with excitement with the near pure water, the ultimate result was I got additional life from an otherwise dead cell , having said that, it may be an isolated case, hense the last resort.....nothing to lose.

BB. · April 2019

Current wise, EQ is typically 2.5 to 5.0% of cell AH capacity. However, you should never do this without monitoring the battery(ies). You can overheat the battery bank.

Less than 2% rate of charge, the battery bank is less likely to overheat during extended "EQ".

-Bill

MrM1 · April 2019

Thanks for the encouragement and detail instructions @mcgivor . so far so good. I am seeing "gassing" from this one cell like I have not see in a long time. in 2 hours it has went from 1135 up to 1200. So I am optimistic. I plan to reduce the acid in this cell and add water again and continue to EQ.

MrM1 · April 2019

https://forum.solar-electric.com/discussion/comment/397115#Comment_397115

Thanks Bill. I am monitoring very closely. I had to leave for a few hours and totally turned all charging off and (and of course no loads too). 2% of my bank would be 8.7amps. I am having to use 25 amps in the process I described above. Is this hurting the full battery that is running at EQ voltage? I figure it is already "damaged" so I guess it really is a mute point.

mcgivor · April 2019

As @BB. said watch the temperature but I wouldn't be too concerned with current, it needs current to do the work, it's definitely a hands on exercise which requires constant monitoring.

MrM1 · April 2019

OK ... 2 things have happened in first agitating the battery yesterday and now doing the early stages of the water treatment process

The heat has either moved or is gone from the suspect low cell. I just used an Infrared Thermometer (temp gun) to check the electrolyte temps with the caps off the 3 cells and doing an EQ charge, the cell that had the lowest temp is my suspect cell that had been running the highest case temp before agitation. So perhaps I dis lodged some material that may have been shorting it ???
With only the first reduction in SG in that suspect cell to a low 1.135 state, after 3.5 hrs of charging, the SG in that cell has risen to 1.228. So thus far things are working better than expected.
All the 3 cells in this one battery are still gassing vigorously, and the SG in the suspect cell is still rising. (the other 2 cells are both at full SG - 1.290 - and are not rising at all)
When the SG stops rising, I will lower the SG down in the one suspect cell to 1.100, Add water and start again and see where it goes from there.

But at this early stage I am optimistic. A friend from the local battery store is bring me new electrolyte to add when done to bring the cell back up to just below spec

FLA Battery Charge Voltage Question

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