Recovering fork lift battery
Tecnodave
Registered Users Posts: 418 ✭✭✭✭
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 $4500 to install new battery.
FYI, forklift batteries often do not have a 20 hour rate, 6 hour rate is used as that is an average day for an industrial forklift.
This forklift is a modern computer controlled logic based and does recognize the battery but will not engage drive electronics at that low a voltage.
I think that 1140 a.h. at 6 hours translates to about 2000 a.h. at 20 hours approximately
Normal charge rate for that forklift using that charger is 190-225 amps, charger is automatic and will not charge a battery that low in voltage, unfortunately the fork lift is miles away now so I need to implement a charging scheme to prevent further damage to this >2500$ 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
2 Classic 150, 2 Kid, 5 arrays 7.5 kw total 2ea. 2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200, 2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Exeltech XP-1100, 2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or LiFePO4,
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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.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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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...
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.
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
I'm sure it's too late to help, glad you got it sorted out, wonder how much equalizing until the SG maxes out?
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
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.
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.
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
L16's from Americas most trusted deep cycle battery since 1926 weigh in near 120 pounds. It is my preferred battery.
https://www.usbattery.com/products/2-volt-batteries/us-re-l162v-xc2/
Good job Dave! It sounds like you are breaking the retirement rule on this bank
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Kind of like the difference of a Tesla with a bank of thousands of "flashlight" battery size cells vs a forklift that has 12-24 cells where each cell may weigh upwards of 200 lbs apiece.
They are both possible engineering solutions and each has its own pluses and minuses.
The Tesla is the "high tech" solution when put into a car... The forklift batteries are the low tech solution when weight/size/configuration are less of an issue.
For small battery banks, a single 6 or 12 volt battery can have enough stored energy for the task.
For large battery banks, you can get 4 volt (2 cell) or 2 volt (single cells) and put them in series. The large single cells help keep weight manageable when installing your system (i.e., a 12 volt @ 100 AH battery is about the same weight/size as a 6 volt @ 200 AH battery or a 2 volt @ 600 AH cell (technically a battery is a group of series/parallel connected cells).
For a mythical 24 volt @ 600 AH battery bank, you can have:
- 2x 12 volt @ 100 AH batteries in series times 6 parallel strings (6x100AH=600AH) or a 24 volt @ 600 AH with 72 cells (2 series * 6 parallel * 6 cells per battery = 72 cells).
- 4x 6 volt @ 200 AH batteries in series * 3 parallel strings = same capacity and 36 cells (4 series * 3 parallel * 3 cells per battery)
- 12 x 2 volt @ 600 AH batteries in series and only 1 string = same capacity and 12 cells (12 series * 1 parallel * 1 cell per batt)
In the above example, each battery (or 2 volt cell) stores the same amount of energy. But a large single cell allows you to avoid parallel strings and 1/6th the number of cells to water and many fewer electrical connections.-Bill
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
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