Recovering fork lift battery

Tecnodave

One of my customers has neglected to properly maintain their Caterpilar Fork Lift battery. The Fork lift was moved to a new location and the charger was plugged into the wrong voltage damaging it and the battery has been left sitting since November '18, plates were  exposed and voltage is about 31.44  volts, about 4 gallons of distilled water was added to submerge moss guards,    battery is manufactured by CD Technologies, don't have exact model number, but twin to this forklift has a Yuasa 36 volt 1140 a.h. @6 hour rate battery, flooded lead acid,  Big charger is CD Technology Ferroresonant charger 240/480 volt 3 phase. Rated 375 amps at 46 volts. It is wired 240 3 phase and was plugged into 480 volt 3 phase. It burned out the primary windings of the control transformer. The main transformers are energised by the control logic driving a 3 phase relay so they had no power and were not damaged. I have found a control logic transformer and repaired the big charger but it is in shop where we have 240/480 power, 
Normal charge rate for that forklift using that charger is 190-225 amps, charger is automatic and will not charge a battery that low in voltage,  unfortunately the fork lift is miles away now so I need to implement a charging scheme to prevent further damage to this >2500$ battery. 

To that end I am using 12 volt automotive chargers on each 1/3 of battery, too small, but the only thing I have to work with. I have 1 at 40 amps, modern logic control and 3 at 10 amps ,all old basic chargers,
The 40 amp charger is logic controlled and stays in desulfate mode at 2.2 amps until the three 10 amp chargers tickle the battery a bit then with power cycling it comes up to 40 amps. 
 I have only 4 chargers total so I need to improvise and charge only 6 cells at a time. All 4 chargers in parallel on each group of 6 cells nets about 60-70 amps for about 36-48 hours has brought battery from 11.4 volts to 12.6  volts for each of  2 of the 3 groups of 6 cells, I've just started the third set of 6 cells, they are the weakest ones at 11.2 volts and they are slow to come up in voltage. Im focusing on getting the s.g.'s out of the toilet first, so only charging each group of 6 cells to about 12.8 volts or so.

I have talked  the general manager into buying a Lestronic 36 volt 25 amp charger I found on flee bay for $99. to speed up the process. This manager can reach into his pocket and squeeze the quarter so hard the eagle screams then he squeezes the nickle so hard the buffalo takes a shit in his pocket, to give you an idea of what I am dealing with on that end. I have a week into this allready, only an hour or so to set up and chart but need to monitor to be sure I don't damage this further. I need to get the battery up to 30-40 percent charge so it can be driven to transport truck and bring it to big charger. I have only 120 volts 30 amps service where forklift is now.

Any suggestions from anyone who has worked with such a battery?  Please no YouTube instant experts, this is big industrial!  big,big bucks!  Caterpilar wants $4500 to install new battery.

FYI,  forklift batteries often do not have a 20 hour rate, 6 hour rate is used as that is an average day for an industrial forklift.
This forklift is a modern computer controlled logic based and does recognize the battery but will not engage drive electronics at that low a voltage.
I think that 1140 a.h. at 6 hours translates to about 2000 a.h. at 20 hours approximately 

Estragon

What's the low cutoff on the big charger?  There isn't much energy at voltage under ~11v, so if the cutoff is reasonable it shouldn't take long with the little chargers to get voltage above the big chargers cutoff.

I've done this by using a little 6/12v dumb charger to get a 48v bank above my Outback LBCO (~42v IIRC).  It only took a few minutes to get the inverter/charger to boot and get charging.

Dave Angelini

Cut your potential loss and bill them now. Bad batteries are bad batteries.

Tecnodave

Estragon,
the battery has never been  at this low of state of charge before, the forklift slows down by computer control when it gets low. It lets you know that it needs attention. Caterpilar pays attention to details like that. I started with only the shop charger, an automated 2 amp, 10 amp , 40 amp boost, 200 amp cranking charger, it took a long time to get it out of the 2.2 amp desulfate mode., I had to add as much non regulated current to get the big charger to output 40 amps, unfortunately it times out after some unknown hours because it's a car charger, I have no idea how many amp hours I have put in. It looks better every time I look. I'll probably have the 36 volt charger by Tuesday, it's totally manual with only a timer to control charging, no smarts. What concerns me the most is unbalancing the cells. Charging them 6 at a time. 

Dave, 
Im retired, don't need a lot of income, everything is paid off and I like to tinker, this customer has been mine exclusively for 20 years and I am paid well there, with lots of extra privileges. I was just gifted a 20 foot shipping containers from them.  They make it worth my while to be persistent . They are a used shipping container dealer, repurposing them and building anything you want out of them. Offices, shops, solar stations, etc., just built a solar shed for an Dual Outback Radian system with huge AGM battery set as specified by a local contractor, it's at Felton in the Santa Cruz Mountains, built to code, it had double doors in the side with panic hardware as specified by building dept, fully insulated with finished walls inside, climate controlled,  didn't ask the price, it was built to specs from a 20 foot hi cube shipping container to house huge solar system way off the grid. My own solar system is on/in a 40 foot hi cube shipping container that also is my main tinker shop bought from them for $1200, it's worth a quick 5400 here as a bare container.

My main battery set are Rolls Surette S-530 L-16's salvaged on the way to recyclers. They were at 0.05 volts for the set. They now test as new. Shipped out the door at Rolls June 26, 2005, verified by Steve Higging at Rolls. That recovery took 30 days of slow tickling to get them to 24 volts, been using them for 7 years now. Bought the whole failed solar system for $800  with a Trace SW4024, 26 Sharp NE-170 panels as new,and Trace C-40 and C-60 controllers with burnt FET's, and other misselany,  all the panels are in use and the SW was sold in a moment of weakness for $1950...

DickyDck

Learn something new every day, didn't know you could recover batteries after they were dead, good reading.

softdown

Interesting - I'll try to remember to respond when I get back. Tired and on the road with lack of sleep right now...

Tecnodave

I have recovered this battery. It took several weeks of persistence to do it. I 4 ea. used old all manual 12 volt automotive chargers to charge each 6 cell bank, providing 60-70 amps for 2 days at a time, then moving to the next bank and repeating the procudure, I charted each run, watching the s.g. Of each cell . This is way below the recommended charge current of 221 amps, but the forklift charger had been damaged by plugging into 480 volt three phase while wired for 240 volt three phase. I repaired the CD Technologies Ferro resonant charger , but it's computer controlled logic would not charge that dead of battery. I got the whole battery up to 34 volts, then connected a 36 volt 20 amp Lister golf cart charger across all cells. I am continuing to charge it at that level as it will not go over e.q. Voltage at that charge rate, I'm putting voltage on it to steadily burn off the sulfates and restore the battery to full status. I'm not using the CD Tecno charger as it is computer controlled, I'd rather use old school "dumb" charger to do this. The computer controlled chargers have too many limits built in to do this.

Tecnodave

There is more intrest here than I expected so here is how I recovered my Rolls Surette set from 0.05 volts and s.g. so low I could not read it.

Portions of this are copied from an email sent to Hot Rod.

There is some background first as to how I arrived at this solution.

Tons of expereince with FLA batteries, as a teen I spent time at Alaska Husky Battery in Anchorage,Alaska building arctic  batteries for the sub zero climate there. 

We used "string chargers"  AKA "tungar bulb chargers"  which impressed a very high voltage at a very limited current to form new batteries. The "Tungar bulb" is a mercury vapor bulb much like a streetlamp bulb but has a diode rectifier with a "dunce cap" converting the AC to pulsing limited current to the battery. This provides positive polarity thus preventing reverse polarizing a cell. Also the high initial voltage will "burn off" any sulfation. The batteries were conditioned with this pulsing DC until cells came up to 1.7-1.9 volts per cell, only then was full charge attempted as all cells will be forced to correct polarity. Our chargers were powered by 240 vac, isolated by a transformer and the DC output was 180 volts DC but very limited current so when connected will fall down in voltage to the voltage of the battery.

Tungar bulbs are history and I built my own using a transformer , a single diode, (I need the pulsing of the half wave rectifier to create the voltage pulses) and current limited by a bank of incandescent lamp bulbs, common 120 volt 100 watt bulbs, 12 or so ganged in parallel to control current, screwing in bulbs to get the desired 6 amps or so of current. So I am applying 80 volts pulsating DC with a very limited current to recondition the batteries.

Move forward a bunch of years and solar panels have the very same limited current, high voltage as did the Tungar bulbs and my homemade facsimile of the string charger.

I picked up my Rolls-Surette batteries on the way to the scrap yard, asking price was $20.00......well core on these are $30-70 each so I didn't blink, bought them as possible cores at worst,  they looked new but were dead with only 0.05 volts on the set of four. 

I connected 4 Siemens SM-55 solar panels in series (84 volts at 3.15 amps) in series to the dead 4 batteries in series with only a series disaster fuse of 10 amps quick blow for safety. The batteries slowly formed and raised in voltage, until at day 30 they were at 24.0 volts. One day of rest they were still at 24.0 volts and the s.g. was still low. I then reprogrammed one of my beta kid controllers to be totally manually controlled and put some power to them, 30 amps at 30 volts, recommended equalization voltage for these cells, and proceeded to "burn off sulfation" until batteries were at 1.265 s.g. across all cells. The kid is operating in "bulk mode" through programming, I don't need the smarts at this point, I want a totally dumb power source that will not time out.  Full recovery as tested by my Snap-On MT-540  battery,alternator load tester. It has a fully adjustable carbon pile to load batteries to 120 amps at 36 volts. These batteries were shipped out the door at Rolls-Surette on June, 26, 2005,  youngsters at 14 years old. On the advise given me by Steve Higgins at Rolls I run the s.g. on these well worn in batteries at 1.260 as Steve has told me batteries this well formed do not need as high as s.g. batteries as new ones. They are the backbone of my solar system today, not bad for $20.00?  I have done this high voltage, throttled current technique many times and this is how I recovered the forklift batteries. The Caterpilar forklifts (2, one good, one spare parts, earlier model, not computer controlled) came to me "dead" for cheap as it would not move despite good voltage on the battery, it was highly sulfated from continuous failing to charge to 1.265 s.g. and had several cells that I had to connect to with jumpers to "wake up" again using high voltage, throttled current technique, took two months of spare minutes at a time to regain full capacity. I now have a modern computer controlled fork lift for a few hundred bucks! And some time tinkering.

Picture is Beta Kid equalizing the Rolls-Surette S-530's in bulk charge mode!  MidNite said to beta test the hell out of them, I did...LOL...they did not expect this!  I think outside the box! Kid did not overheat but notice the orange "over" lamp is lit, current maxed out! 

I equalized every day for a week until had the s.g. where I wanted it

The panels used with the Kid to e.q. The Surette batteries were 6 ea Sharp NE-170 connected 2S3P at 72 volts in to Kid controller 

Photowhit

A realistic conversion from 6 hr rate to 20hr rate is about 130%. When I received my forklift battery I was told it could charge at 15% of the 20hr rate, it will take a bit ore than that when below 70%  SOC. But of course it's a GB battery and they over ate their 20hr rate, and I was using my derived capacity of 660 ah vs 800 ah (510hr at 6 hr rate).

I'm sure it's too late to help, glad you got it sorted out, wonder how much equalizing until the SG maxes out?

BB.

About 9 years ago, we had a member from Hawaii that had good luck with getting old forklift batteries going again... Frequently, he would get 36 volt batteries, and cut out the bad cells down to a 24 volt battery and run the heck out of them.

For anyway interested, here is user "adas" posts and threads:

https://forum.solar-electric.com/profile/adas

And how quickly a person who knows what he is doing can change out a forklift battery cell (it is a little scary watching the video in the thread below):

https://forum.solar-electric.com/discussion/351114/how-to-dissasemble-then-reassemble-odd-forklift-type-batteries

-Bill

Tecnodave

I've been using the Surette set for 6 years since recovering them. I'm still charging the best forklift battery with the 20 amp charger, I don't think it will go up to 48 volts, that would be my top limit of voltage for a 36 volt battery. 2.667 v.p.c.
When I can get the forklift moved to the charger I will use the CD Tecno charger in e.q. Mode to finish up, currently the forklift is close but I can't plug it in just right now.

Its all about watching the battery and its reaction to the charging profile and reading voltage cell by cell and charting the s.g. And doing some calculations as to rate of change.

I did not change the acid in any of these batteries.

Tecnodave

BB, 

Thanks for that lead, I'm still learning, being born in the backwoods of Alaska on a homestead has given me this desire to repurpose abandoned tossed out items. 

DickyDck

BB. said:

About 9 years ago, we had a member from Hawaii that had good luck with getting old forklift batteries going again... Frequently, he would get 36 volt batteries, and cut out the bad cells down to a 24 volt battery and run the heck out of them.

For anyway interested, here is user "adas" posts and threads:

https://forum.solar-electric.com/profile/adas

And how quickly a person who knows what he is doing can change out a forklift battery cell (it is a little scary watching the video in the thread below):

https://forum.solar-electric.com/discussion/351114/how-to-dissasemble-then-reassemble-odd-forklift-type-batteries

-Bill

I watched that video, however since I speak Cantonese and not Mandarin I don't know what they are saying, or if they are saying what it is they are doing anyway but could you tell me what they are doing and to what effect? I mean physically I can see what they are doing, but what is it doing to the battery bank and allowing to happen? 

BB.

Many larger forklift batteries are just a collection of 2 volt cells in a steel box.

If you have a bad cell, this is how you can pull the cell and replace it by drilling out the bus bars and soldering them back in.

The video was just a quick example of the operation.

-Bill

DickyDck

Ahhhhh! ok so the term "Cell" in this scenario is actually a physically large size but low volt battery in a big ass string of batteries. got it! Since you all were talking about this, I was looking up forklift batteries and they are a viable option for a big cost effective solar batt bank. Would it be beneficial to have a bunch of 2v, vs 6v, to make a 48v bank?