Trojan Industrial batteries not working

NorthGuy

Re: Trojan Industrial batteries not working

jeffkruse wrote: »

My opinion, get a good hydrometer from this site. Measure the voltage of the entire bank frequently to make sure it’s what you expect, don’t trust the charge controller just yet. If you set for 62V EQ what is at the bank?

When I start EQ, there's a 30A current. My cables drop 0.3V/100A, so there should be about 0.1 difference with the Inverter setting, but when I measure, I cannot really tell because voltage goes back and forth about 0.1 all the time. I measured at different situations. Sometimes, the voltage the Inverter show is a little bit off (sometimes by 0.2, may be rarely 0.3) in either direction. But I cannot fix that - Inverter runs the show.

jeffkruse wrote: »

Durring EQ the bubbling should be like water boiling at a low/medium boil.

Mine probably looks like a low boil, but that's really hard to quantify.

jeffkruse wrote: »

Up your voltages and EQ @64V (after a good absorb) until no more change in SG, monitor temps and stop if they get to warm. If your SG stops changing for an hour then that is as high as you can get.

Thank you. I'll try that. However, I need to run this idea by Trojan first, not to void the warranty.

westbranch

Re: Trojan Industrial batteries not working

NG, do you have a DC clamp on amp meter? so you can check what the amperage is at each cell as you are charging?

BB.

Re: Trojan Industrial batteries not working

NorthGuy wrote: »

I'm building my off-grid system. I bought 8 Trojan IND13-6V batteries, one string, 673AH.

In this case, a clamp meter won't show any difference because he has one series string of batteries--current will be the same into each battery. Measuring voltages of each cell/battery (and even wiring drops) will show if everything is balanced or not...

-Bill

vtmaps

Re: Trojan Industrial batteries not working

Blackcherry04 wrote: »

There is a web site that has pictures of battery plates with all the different kinds damage. There was one that showed the damage from the trapping of hydrogen / oxygen. As usual I couldn't find the site.

Here's the picture:
http://forum.solar-electric.com/showthread.php?15475

--vtMaps

NorthGuy

Re: Trojan Industrial batteries not working

BB. wrote: »

In this case, a clamp meter won't show any difference because he has one series string of batteries--current will be the same into each battery. Measuring voltages of each cell/battery (and even wiring drops) will show if everything is balanced or not...

I don't have a DC clamp.

I did measure voltage drop on cables during bulk stage at 90A. It is about 12mV for a cable, except that one shorter cable at the far end of the bank drops only 7 mV.

Assuming cables are the same, the equal voltage drop over each cable shows that the current is the same.

or

Assuming that the current is the same, the equal voltage drop over each cable shows that the cables are the same (or that contacts are good).

In short, I didn't find any significant difference between batteries and between connections.

BB.

Re: Trojan Industrial batteries not working

Yep--all sounds good... You are looking for loose connections, corroded cables, and shorted/open cells when measuring voltage drop (you can use identical lengths of cable as a current shut to estimate current differences between parallel strings).

-Bill

garlmike

Re: Trojan Industrial batteries not working

First read in to the very old battery info found at:http://www.powerstream.com/1922/battery_1922_WITTE/battery_WITTE.htm#toc

if you order battery's they will ask you where you live: They will add More Acid if you live in Colder climate, and Less Acid if you live in Hot Climate. mine are 1.285+ and some are 1.300.

IMHO

your battery will Not last long if you use more than 20% and they are above 15 degrees C. see http://www.mpoweruk.com/life.htm
they last the longest at <15 degrees C and a 10% DOD, only problem is the overall cost and storage space. And they have Less ah than rating.

actual load you are pulling try to keep it down to 5% or less of ah (C/20). 673/20=33 amps x 48 volts is 1615 watts, I hope you don't have a amp hog electric stove!
as they suck over 3000 watts.

Ideally is a giant battery pack and use only 10% DOD and keep temp to 5-15 degrees C and charge it once a week. Or have more than one giant battery and be using one and charging the other. I would like to skip the battery'$$ and use some other source of storage.

maybe just measure the ohms after its rested for a few hours I got one on ebay.ca for around 100 bucks its a "Cen-Tech" 12v.
search for "BRAND NEW DIGITAL BATTERY ANALYZER" sold by NORTHSTAR AUTOMOTIVE its on sale for less than 100 bucks!
I just measured the new battery (when i got them) (3x2 volt cells) and wrote it down.(give idea of cells ohms) wish they had a 2 volt or 24 volt models.

Also measure each cell voltage they should be within .04 volts, please correct me if I'm off on that number. The ohms will drop as battery gets charged and change as it cools. Its easy to learn. just press the ok twice.
and a simple de-sulphate will work as your battery may have sat too long without being charged, (then it takes a long time). The Ohm test will tell you.

just trying to help...

Rybren

Re: Trojan Industrial batteries not working

NorthGuy wrote: »

I don't have a DC clamp.

NorthGuy, I get the impression that you're somewhere up here in Kanukistan. If so, and you're near Ottawa, I can lend you my clamp meter.

Jerry

NorthGuy

Re: Trojan Industrial batteries not working

Rybren wrote: »

NorthGuy, I get the impression that you're somewhere up here in Kanukistan. If so, and you're near Ottawa, I can lend you my clamp meter.

Thank you, Jerry.

No I'm thousands miles away, in Northern Alberta.

Rybren

Re: Trojan Industrial batteries not working

Just a tad too far away to swing by and pick it up after work

NorthGuy

Re: Trojan Industrial batteries not working

Hi,

Trojan had a conference with engineers to discuss my batteries, and what they're telling me is that the batteries are sulphated and stratified, possibly beyond repair. They recommend doing 10-hour equalizations at 64V every day until SG gets to 1.260. If it does, batteries will function Ok. If it doesn't they're ruined.

They say that such a bad state of my batteries is because I didn't do "Initial Boost Charge" at the beginning. It's in their Manual, which they didn't give to me and I didn't even know it existed even though I downloaded all the documents from their site that I could. They only sent this manual to me by email on January 3.

The "Initial Boost Charge" has two alternative methods: first is essentially the same as equalization, second is constant current at 3% of capacity until voltage stops increasing.

I had no way of knowing that, so I just did a regular charge, put batteries on float, and then measured SG, which averaged 1.219. I though that was low, so I filled their tech support form right away asking whether to equalize or not (haven't received a response until over a month later, and the response didn't mention any boost charge neither).

They said that I shouldn't known about Initial Boost Charge because it needs to be applied to all batteries.

I have two questions:

1. Has anyone heard of this Initial Boost Charge?

2. Is that possible that the lack of this single charge would completely ruin the batteries in three months even though I did regular charging and equalizations later?

Blackcherry04

Re: Trojan Industrial batteries not working

NorthGuy, a " Commissioning Charge " is whats it generally called here, has been well talked about many times. It's the first thing you do when you put a set of batteries in service. If you start out in the hole, you'll always be in one. The SG is your " Constant " when all else fails it the one place you can return to and know where your SOC is. You know your plates are clean and you are at 100%

By not returning the SG back to it's original point the sulfate had hardened and crystallized and will be hard to recombine. Can it be done ?? Maybe, you can make better than they are. You seemed to think you still had good capacity. Time will tell, If they are 80 % you may never know the difference.

jeffkruse

Re: Trojan Industrial batteries not working

IMO I think that is BS. Sure, it's recomened to do a short EQ when you first get your batteries but the first few proper charges you do should be engough. I would be very upset with the responce you got.

NorthGuy

Re: Trojan Industrial batteries not working

Just wanted to update this story. It's always sad to read posts about a problem when you do not know how it ends.

I managed to elevate SG to 1.26 (this is exact spec) with a 10-hr equalization at 64V, followed by 6-hr of the same next day. So there there's no sulphation or anything of that sort.

When I charge them, SG still doesn't go up. After full charge, depending of the depth of the cycle, the SG is anywhere between 1.19 and 1.23.

The best idea would be to increase absorption voltage, and many people suggest that, however Trojan support is against this. They only allow 59.6 (at the very last resort 60V). At these voltages, even long absorption does not elevate SG significantly.

I can put SG back up with another equalization at 64V, but it takes 10 hours again.

I contacted the dealer and told him that I want to return the batteries back.

BB.

Re: Trojan Industrial batteries not working

If the batteries are not gassing excessively or too hot--I am not sure why not try to crank the Absorb Voltage higher. Of course, this also depends on the battery bank temperature (cold batteries needing higher charging voltages, etc.). Of course there is the limitations of charge controllers and inverters that may not like to work at elevated charging voltages.

Based on what "they" are telling you right now, these batteries are not good for solar power (not enough time on charging during the day to reach >90% SOC with just solar power--especially during winter).

Have you asked the T. Engineers exactly what battery(ies) they would recommend for solar? And why, this particular battery appears to not be suitable (there are different additives/plate alloys that can be added to change certain properties--Some appear to impede quick charging at reasonable voltages).

-Bill

Blackcherry04

Re: Trojan Industrial batteries not working

I think Bill hit it right on the head. The Trojan IND13-6V is a forklift battery without the metal case. They probably would work, but if Trojan is going to hold you to their voltages, then your doing the right thing if you can return them. There is no reason why you can't make them work if they can get the right charge. I know a few people who used " Mining Car Batteries " as they called them ( depends where they stole them ...lol ) they all had a hard time charging them.

Most of them have a 5 year and 1500 cycle life, IF ( big IF ) they are pulled to 80% dod and charged back in one full cycle, no half cycles or or opportunity charging, as that shortens their life according to their warranty.

NorthGuy

Re: Trojan Industrial batteries not working

BB. wrote: »

Based on what "they" are telling you right now, these batteries are not good for solar power (not enough time on charging during the day to reach >90% SOC with just solar power--especially during winter).

That would be my assessment too. Even if it's possible to make these batteries work, this wouldn't be for solar applications.

BB. wrote: »

Have you asked the T. Engineers exactly what battery(ies) they would recommend for solar? And why, this particular battery appears to not be suitable (there are different additives/plate alloys that can be added to change certain properties--Some appear to impede quick charging at reasonable voltages).

Their marketing materials are very clear about this:

Trojan’s Industrial line of flooded deep-cycle batteries
is designed for 1,500 cycles at 80 percent depth of 
discharge and is specifically engineered to withstand the 
rigorous conditions of renewable energy applications 
including extreme temperatures, remote locations and 
the intermittent nature of solar power generation. These 
batteries are designed to be cycled regularly and are 
engineered to perform optimally under conditions where 
the batteries are in a partial state of charge (not fully 
charged or discharged every day); a common occurrence 
in renewable energy applications due to the varying 
levels of irradiance, temperature, and available sun hours.

and

The Industrial line is engineered specifically to support renewable energy systems with large daily loads 
where the batteries are cycled regularly. These high amp-hour capacity batteries are ideal for use in large 
off-grid photovolataic (PV) systems, off-grid hybrid PV systems, grid-tied PV systems with battery backup, 
smart grid peak shifting systems and a variety of other applications.

I think my batteries are somehow defective because they do not fit these discriptions.

Vic

Re: Trojan Industrial batteries not working

NorthGuy,

Based on your " Absorption Time " Thread, looks like you are contemplating increasing the average DOD of these batts. And, that seems to be one important aspect of their design as noted in the first Code paragraph you copied into the post, just above ( ..."designed to be cycled regularly ... ").

And Bc . 04, these batts may well be much like the Forklift batteries, BUT it is said that the target SG is 1.260, NOT 1277 - 1.280 that is usually seen in Forklift batts.

N G, if you could trade in these batteries for full credit on something more appropriate for your (or any RE user), then you should be well ahead. Charging batteries with a very capable RE (+ Grid) system should not be a constant, daily preoccupation. Life is far too short. We all are looking for solutions when it comes to batteries, not constant continuing problems and worry.

However, since them mention that these batts are
" ... These
batteries are designed to be cycled regularly and are engineered to perform optimally under conditions where
the batteries are in a partial state of charge (not fully charged or discharged every day); a common occurrence
in renewable energy applications ... ".
Perhaps trying to get them fully recharged only every 5 days or so might work. BUT, since they dictate charge voltages so low that they are not fully charged unless you do an EQ, they do seem too specialized for almost any RE application, IMHO.

Trade them in, if you can.

Am certain that you mentioned that you are using Batt Temp Sensor on the Schneider system, and it is shared among all chargers, so that should NOT be a problem ... Have you confirmed that the Chargers are actually Temp Comping the charge V? Believe that you did say "yes" before. Am just too lazy to re-read this thread. Give 'em %ell. Good Luck, Vic

NorthGuy

Re: Trojan Industrial batteries not working

Vic wrote: »

Based on your " Absorption Time " Thread, looks like you are contemplating increasing the average DOD of these batts. And, that seems to be one important aspect of their design as noted in the first Code paragraph you copied into the post, just above ( ..."designed to be cycled regularly ... ").

My intended use was cycling every day - Bulk and a little bit of Absorption - then full charge every week. That would be very efficient.

The problem is with that full charge. Seems to take prohibitively long. I found a document where Trojan compares these batteries to Surrettes in multi-month experiment. I that experiment they were charging for 16 hours daily. If 5-6 hours of bulk, then there must be 10-11 hours of absorption. Why would they do that? Nowehere on the Earth the sun shines for 16 hours. Then I thought that may be the behaviour that I see is not because the batteries are defective, but, sort of, by design.

I thought that if I return these batteries and get new ones, then I need to learn the lesson and get batteries that wouldn't be designed for long absorption times. Hence, I decided to ask what absorption times are good for other batteries, and started the "Absorption Time" thread.

Vic wrote: »

Am certain that you mentioned that you are using Batt Temp Sensor on the Schneider system, and it is shared among all chargers, so that should NOT be a problem ... Have you confirmed that the Chargers are actually Temp Comping the charge V? Believe that you did say "yes" before. Am just too lazy to re-read this thread.

Sure. That one work very well for all the CC and the inverter.

Vic wrote: »

Good Luck, Vic

Thanks for the support.

Blackcherry04

Re: Trojan Industrial batteries not working

Vic wrote: »

And Bc . 04, these batts may well be much like the Forklift batteries, BUT it is said that the target SG is 1.260, NOT 1277 - 1.280 that is usually seen in Forklift batts.

I don't remember mentioning SG, but it's a good point. Maybe if they were 1.277 - 1.280 they'd work better. They are just not the right kind of batteries for RE in the north lands..

NorthGuy

Re: Trojan Industrial batteries not working

Blackcherry04 wrote: »

I think Bill hit it right on the head. The Trojan IND13-6V is a forklift battery without the metal case. They probably would work, but if Trojan is going to hold you to their voltages, then your doing the right thing if you can return them. There is no reason why you can't make them work if they can get the right charge. I know a few people who used " Mining Car Batteries " as they called them ( depends where they stole them ...lol ) they all had a hard time charging them.

That could be exactly right. It's possible that they didn't really do a special design, but just took forklift batteries. And all the voltage settings are not from the design team, but simply copied from smaller batteris, such as L16-RE, or even from Surrettes. Then different Trojan guys simply read the specs and tell me not to go far from them.

However, if I want to return them, it's best not to go against their words.

Actually, the batteries charge pretty well with these low voltages, and at the end of a regular charge they're probably at 95% SOC. SG is low - 1.19, but SOC cannot be that low. When I equalize from this state to 100% SOC in 10 hours, it's only 180AH in, and most of that is heat and bubbling. Even if half of that is real charging, it's only 90AH. If they're at 100% SOC after equalizing then they most have been at least 90% before. If they were at 60% SOC before, they couldn't have gone to 100% SOC after only 90AH were added.

So, I get 95% SOC batteries with very low SG. Most of the acid is between plates, most of the water is around. Just a little bit of bubbling and mixing and everything would be Ok. If thse are indeed forklift batteries, then the forklift charger would have a "constant current" phase at the end. An hour or two at 30A would probably do the trick. But, Xantrex family will not go above 64V, and, even at this voltage, the current keeps at 30A few minutes then quickly falls to 20A. So, I would have to do it for 10 hours to get good SG.

Something is not right.

NorthGuy

Re: Trojan Industrial batteries not working

Blackcherry04 wrote: »

They are just not the right kind of batteries for RE in the north lands..

It's possible they have some additives to work well at high temperatures. They ofthen mention temperature in the marketing brochures. They installed them in India where heat would be the problem. May be they simply don't work below 30C.

Blackcherry04

Re: Trojan Industrial batteries not working

NorthGuy wrote: »

That could be exactly right. It's possible that they didn't really do a special design, but just took forklift batteries. And all the voltage settings are not from the design team, but simply copied from smaller batteris, such as L16-RE, or even from Surrettes. Then different Trojan guys simply read the specs and tell me not to go far from them.

However, if I want to return them, it's best not to go against their words.

Actually, the batteries charge pretty well with these low voltages, and at the end of a regular charge they're probably at 95% SOC. SG is low - 1.19, but SOC cannot be that low. When I equalize from this state to 100% SOC in 10 hours, it's only 180AH in, and most of that is heat and bubbling. Even if half of that is real charging, it's only 90AH. If they're at 100% SOC after equalizing then they most have been at least 90% before. If they were at 60% SOC before, they couldn't have gone to 100% SOC after only 90AH were added.

So, I get 95% SOC batteries with very low SG. Most of the acid is between plates, most of the water is around. Just a little bit of bubbling and mixing and everything would be Ok. If thse are indeed forklift batteries, then the forklift charger would have a "constant current" phase at the end. An hour or two at 30A would probably do the trick. But, Xantrex family will not go above 64V, and, even at this voltage, the current keeps at 30A few minutes then quickly falls to 20A. So, I would have to do it for 10 hours to get good SG.

Something is not right.

I have been buying Trojans for years, they are set up ( Factory Guys ) at every Industrial Show I attend. 5 years ago they never mentioned the RE market. Now all of a sudden they can't talk enough about it. They have taken the same product and tried to bend it around the RE market. Like you said, the charging profile we use is just not right for some of these batteries. In a few years we'll see Battery Chemistry more tailored for the RE Market.

I am going to test some Lead / Selenium batteries for a company this year. I have no clue how they'll work, I can't afford to many mistakes.

Blackcherry04

Re: Trojan Industrial batteries not working

NorthGuy wrote: »

It's possible they have some additives to work well at high temperatures. They ofthen mention temperature in the marketing brochures. They installed them in India where heat would be the problem. May be they simply don't work below 30C.

I have no clue. I am sure if you could talk to a engineer at Trojan they could tell you. You have to remember, batteries are a cost to you, In a Business batteries are a cost, but they are to cost of doing business, 3-4 years may be acceptable to them and it wouldn't be to you. In the few sets I have Leased, the first 3 years cover the replacement cost and the last 2 years are the profit minus the Maintenance cost.

NorthGuy

Re: Trojan Industrial batteries not working

While waiting for response from the dealer, I've done a lot of thinking and reading about battery function and chemistry.

I realized that there are two separate processes - electrochemical reaction and electrolyte stirring, and for successfull charge I need to complete both. So, I decided to evaluate which of these processes are going bad in my batteries.

Batteries do relatively good on the electromechanical reaction. After deep (70% DOD) discharge, it takes 5.5 hours of absorption time to complete the reaction. Even after 2.5 hours, it's already 95% done and after 4 hours, it's 99% done. That's not very much dependent on absorption voltage.

Stirring is going way worse. To completely stirr the batteries, I need 10 hours at 64V to get full SG. During this process, the terminal current becomes 16A, so I need 160AH to completely stirr. At 62V, terminal current is 10A, so I would need 160AH/10A = 16 hours at 62V. When I tried, that's exactly how it was - 17 hours to full SG. At 60V, terminal current is 4A. Using the same logic I would need 40 hours at 60V. I didn't try for that long, but this may be right. At 58V, with 3A terminal current, it would take over 50 hours.

So, the problem with my batteries is stirring. I can charge even at low voltages, but it won't stirr the electrolyte in any reasonable amount of time. I think that's mostly because the batteries are vey tall - 2 feet - the tallest on solar market.

I probably should abandon the idea of complete stirring. I know I can stirr to SG of 1.245 (compared to 1.260 full) in 4 hours at 64V. I cannot go with less voltage, because even at 62V it'll be 7 hours instead of 4!

I can do 4 hours of charging (which will take me to 99% SOC), then apply 64V for 4 hours, which will stirr them to SG of 1.245. This is 8 hours of absorption. That's definitely too long.

Or, I can take Bill's advise and increase absorption voltage to 64V. This will combine these two processes, doing both stirring and charging at the same time. In my mind, 4 hours of absorption at 64V should both bring SOC to 99% and SG to 1.245 (within 0.015 of full SG). 4 hours absorption is not great, but acceptable.

I have two questions:

1. Trojan manual recommends doing full charge once a week/10 days. Would it be considered a full charge if it reaches SOC of 99% (in a sense of electrochemical reaction) and stirr electrolyte to 1.245 level? Or is it likely not to be enough so that chronic sulphation/stratification will develop with time?

2. Can absorbing at 64V (vs 56.4-58.8V recommended by Trojan and 60V stated as a max by their enineers) cause any harm to batteries except over-heating?

westbranch

Re: Trojan Industrial batteries not working

NG, I'm prone to believe that the truth to your question lies in the amount of water you will have to add.

hth

Vic

Re: Trojan Industrial batteries not working

Hi NorthGuy,

Had previously wondered if perhaps diffusion might help allow the SG to "equalize" if the batteries were allowed to sit for a day, just resting. Know that many folks are concerned about Stratification, but had wondered if in your testing that you had tried something like this.

EQing does raise temps of the batts, but in my experience the temp rise for the banks here, lasting 2 hours raised the electrolyte temp by a couple of degrees C (above the temp at end of Abs) at a nominal 63.4-ish temp comped V. 64 V for four hours might well raise temps a few more degrees C.

One downside of EQing is the plate corrosion that goes along with the breakdown of the water into Hydrogen, and particularly the generation of Oxygen. It is all a balance.

The main banks here are also TALL -- 24.75 " overall, including the Flag terminals. The Jar is about 22 or so inches. BUT, these Surrettes must have greater L and W dimensions for the Jar, which should lower the impeadance presented to the electrolyte in trying to mix completly during a normal Absorption at nominal suggested V. The Vabs for these banks runs in the low 58s -- about 58.2 - 58.4 for normal recharges. There appears to be NO problem whatsoever in mixing at this Vabs range in one to about four hours (absolute maximum) of Absorption. The electrolyte is 1.265 SG.

Hope that the Dealer will allow full trade-in for something that meets your needs. GOOD LUCK! Vic

NorthGuy

Re: Trojan Industrial batteries not working

westbranch wrote: »

NG, I'm prone to believe that the truth to your question lies in the amount of water you will have to add.

It's hard to tell if I use good amount of water or not. Each cell contains 7.7 liters of electrolyte. Based on the level of water I would guess I probably used 0.7 liters from a cell. But last two months I had lots of cycling and 5 very long equalizations. Don't know if that's enough or too much.

Vic wrote: »

Had previously wondered if perhaps diffusion might help allow the SG to "equalize" if the batteries were allowed to sit for a day, just resting. Know that many folks are concerned about Stratification, but had wondered if in your testing that you had tried something like this.

I tried to let them stand (or float) for 24 hours. This, perhaps, increased SG by 0.005. But I cannot really do that once I'm off grid.

Vic wrote: »

EQing does raise temps of the batts, but in my experience the temp rise for the banks here, lasting 2 hours raised the electrolyte temp by a couple of degrees C (above the temp at end of Abs) at a nominal 63.4-ish temp comped V. 64 V for four hours might well raise temps a few more degrees C.

It does. 10 hours of equalization at 64V bring the temperatrure up by 5-6C. But that's not as much as I get during bulk charge at 100A (which is 14% of C20). At bulk, the temperature goes up 1 to 2C every hour.

Vic wrote: »

One downside of EQing is the plate corrosion that goes along with the breakdown of the water into Hydrogen, and particularly the generation of Oxygen. It is all a balance.

Then, if the purpose is to generate a certain amount of bubbles, it shouldn't really matter if that's done in 4 hours at high voltage or 20 hours at low voltage, as soon as the amount of bubbling is the same.

Vic wrote: »

The main banks here are also TALL -- 24.75 " overall, including the Flag terminals. The Jar is about 22 or so inches. BUT, these Surrettes must have greater L and W dimensions for the Jar, which should lower the impeadance presented to the electrolyte in trying to mix completly during a normal Absorption at nominal suggested V. The Vabs for these banks runs in the low 58s -- about 58.2 - 58.4 for normal recharges. There appears to be NO problem whatsoever in mixing at this Vabs range in one to about four hours (absolute maximum) of Absorption. The electrolyte is 1.265 SG.

Surrettes have long history of RE batteries. They had time to figure things out. For Trojan, this is something new, so it may not work. I still cannot figure out if my batteries are defective, or it's simply such a bad design.

solar_dave

Re: Trojan Industrial batteries not working

Didn't I read someplace that adding a small air pump and tubing to help with the stirring was possible? Wouldn't that cure all these stratification issues on these really tall batteries and make the Absorb cycle more effective.

BB.

Re: Trojan Industrial batteries not working

Some links to various threads and information:

BB. wrote: »

This article is behind a pay wall:

Effects of Electrolyte Stratification on Performances of Flood Lead-Acid Batteries

Abstract
The electrolyte stratification in the charge/discharge of lead-acid cells was monitored by a sensor of specific gravity and an in situ electrochemical scan technique was used to measure the current distribution directly on the plates in the rest state. A simulated cell was set up to study the electrochemical behavior of lead-acid batteries with electrolyte stratification. The active mass (AM) in the lower part is discharged in preference to that in the upper part. During recharging, however, the AM in the upper part is more easily charged. The more concentrated the solution, the finer the formed AM becomes. Two mechanisms of sulfation have been proposed. For the batteries often at rest or in the discharge state at very low current, the sulfation occurs in the lower part of the plates, but for the batteries in continual cycles at a high current, it often appears in the upper part.

And there are other studies:

Dependence of Lead Acid Battery Performance on Electrolyte ...

The above appeared to discuss some of the same types of testing that John P did at his work and published here (mixing of electrolyte).

Anyway--It appears that the electrolyte will stratify on its own accord... My guess is that the bubbles from charging and even the heat from charging/discharging helps mix the electrolyte (and the discharge heat helps very cold battery performance--mixing cools the plates and reduces cold weather performance)...

In the end, flooded cell lead acid batteries want discharge from the bottom and recharge at the top--Certainly not ideal. And I would suggest that very light loads and charging currents are not helpful for long battery life.

-Bill

PS: Member "John P" tests on pumping air to mix/agitate electrolyte in storage batteries. The setup and test results are in this thread:

Air pumps for better battery charging

-Bill