How to dissasemble then reassemble odd forklift type batteries?

softdown

Got a "deal" on eight of these used 8 volt batteries. http://www.amertekspt.com/proddetail.php?prod=4LMS-450 Each battery weighs 270 pounds. Four 2 volt cells with 25 plates/cell...so they are a hybrid starter/traction type battery. Each cell weighs about 60 pounds. Very expensive when new at over $1100 per 270 pound battery.

I have 32 two volt cells. 25 cells show 1.9 volts(when warm) or better. Seven cells are bad...S.G. is water and voltage runs from 1.7 - .5. I think there is a good chance that cells showing less than 1 volt are shorted out and a safety hazard. There are three such cells. Thus explaining why the user had to replace them. Did they have to replace them all? Good question.

The cases are made of durable plastic and each cell has four lugs instead of two. Separating 2 volt cells from the 8 volt battery looks like a daunting chore. On my side: I can probably lift 200 pounds if need be.
                                                                 Have a big, strong engine hoist
                                                                 Have an old, hard to start forklift
                                                                 All I have is time.

http://www.amertekspt.com/proddetail.php?prod=4LMS-450

I'd say more but lengthy posts tend to get overlooked in my experience. Like...re-assembly as 2 volt cells. Use 1/0 or 2/0 or flattened 1" copper pipe?

BB.

Not sure if this is how your battery bus bars are removed and replaced. In heavily accented Mandarin:

https://www.youtube.com/watch?v=u8oiMoP5A1E

There are a lot of other videos on how to change cells in forklift batteries if you follow the youtube link above.

Member John P measured up some 10 foot lengths of various sizes/types of copper pipe for resistance... You can compare those to the resistance of copper cable and get a rough equavalence:

http://forum.solar-electric.com/discussion/comment/108378#Comment_108378

http://www.interfacebus.com/AWG-table-of-different-wire-gauge-resistance.html


-Bill

softdown

Thanks BB....a lot of terrific data there. Looks pretty easy to yank out bad cells. The youtube link led to me battery chemicals...which I am going to try with almost nothing to lose. I'll try to inform the board of the results though results will not be obtained for several weeks. I am always working on a dozen projects. Little of this, little of that.

A big one is a nuclear fall-out shelter if [... we do not really go into politics here. -Bill B. moderator].

softdown

Looks like a 7/8" drill bit should "core out" the lead connection on each battery post. Does anybody know of a good drill bit type for this job? Metal drilling bits would remove more lead than I would like. Considering a "flat head" wood bit.

Looked like they used "lead sticks" to fill the lead back in with a propane torch. The video is good but speaking in Chinese did not help. Wonder what those "lead sticks" are called.

Here is a fascinating chart of the electrical conductivity of various metals. Many surprises in  there. Lead is only 7% conductive....for example. That is why good solder was called "silver solder". I doubt there is much silver in the vast majority of readily available solders. Silver is 105% conductive....rated as the best....even better than copper.

http://www.kp44.org/electric/ElectricalConductivityOfMaterials.php

jonr

Maybe a slot drill and then lead solder sticks.

I always find it odd how alloys can have low conductivity.  For example, 70% copper might have 5% of the conductivity of pure copper.

BB.

Ideally, I would think you want eutectic tin lead solder sticks:

http://btsolders.com/P_stick.htm

If you cannot get that, then tin lead solder (correct typo) sticks used for body repair should work OK:

http://www.eastwood.com/body-soldering-sticks-10-pack.html

Tin/Lead solder has a lower melting point vs pure lead... I would want my "solder" to melt at a lower temperature than the posts (so that they do not melt down into the inside of the battery cell). Although, one You Tube I found did have them melting the posts of a new cell first, then adding solder on a second/third pass.

I did not see anyone using any type of flux--If you do, try to use a non-corrosive flux (avoid some "plumbing" type fluxes--Use flux made for electrical connections). (maybe using corrosive flux is not going to make much difference on a flooded cell lead acid battery with all of the electrolyte around--But I would try to use non-corrosive flux).

-Bill

mrfixit

I used a 7/8" or maybe 1" hole saw to drill mine out. Tried soldering the replacement in but didn't get a good joint, so ended up just drilling and tapping the post for a 5/16" stainless steel bolt and used cable between the cells.
So far so good.
Be very careful if you try to solder the post with a torch, make sure of no charge or discharge beforehand and fan out the cell adequately.

BB.

And that the cell is nearly full (little airspace for explosive gasses).

-Bill

softdown

BB. said:

Ideally, I would think you want eutectic tin lead solder sticks:

http://btsolders.com/P_stick.htm

If you cannot get that, then tin lead solar sticks used for body repair should work OK:

http://www.eastwood.com/body-soldering-sticks-10-pack.html

Tin/Lead solder has a lower melting point vs pure lead... I would want my "solder" to melt at a lower temperature than the posts (so that they do not melt down into the inside of the battery cell). Although, one You Tube I found did have them melting the posts of a new cell first, then adding solder on a second/third pass.

I did not see anyone using any type of flux--If you do, try to use a non-corrosive flux (avoid some "plumbing" type fluxes--Use flux made for electrical connections). (maybe using corrosive flux is not going to make much difference on a flooded cell lead acid battery with all of the electrolyte around--But I would try to use non-corrosive flux).

-Bill

The first link is good for information but I found no way to look at prices etc. Indeed....their other pages did not open for me.

I did luck out and find a pound of 63% tin and and 37% lead by a name brand. Last pound they had.

Tin is 15% conductive. Lead is 7% conductive.

Thanks for the advice from all concerned.

BTW.....flattened 3/4" copper pipe is the "cats meow" for connections with excellent conductivity. Beats even the big cables with the needed lugs pretty soundly. 1" copper pipe gets pretty expensive.

BB.

Here is a vendor that has multiple places across the US with pricing (don't know anything about website/company) and sells different alloy mixes:

https://rotometals.com/solder/

-Bill

mike95490

softdown said:

... Silver is 105% conductive....rated as the best....even better than copper.

There is only 100%.
Silver is the best electrical conductor simple metal. It's also a great thermal conductor. 
I think copper is next best in both categorys  (diamond is best thermal conductor)

softdown

mike95490 said:

softdown said:

... Silver is 105% conductive....rated as the best....even better than copper.

There is only 100%.
Silver is the best electrical conductor simple metal. It's also a great thermal conductor. 
I think copper is next best in both categorys  (diamond is best thermal conductor)

You did not read their reasoning. Copper is the standard. Silver is a little better. Thanks for you elucidating your math skills though.

MGar

Copper and a Roll form tap into the post with carbon conductive paste?
I know a 10-24 works at 6 in lbs. So make sure it NC...

softdown

MGar said:

Copper and a Roll form tap into the post with carbon conductive paste?
I know a 10-24 works at 6 in lbs. So make sure it NC...

Thanks for the idea about the paste....that stuff is pretty expensive. Over $200 for a pint.

softdown

Little follow up now that I just replaced a 2 volt cell. WD-40 works extremely well for lubricating the sides of the battery cells. I was able to simply use my back instead of a hydraulic lift on ~65 pound cells. Last year an engine hoist was needed on some cells. A hay hook with a dull tip is ideal for lifting a cell. The initial strain of stubborn cells lowered the angle of my hay hook to ~~12 degrees which prevents it from punching a hole in the battery top.

You need to leave the drill bit in the center of the hole saw and drill in a rotating circular motion. This allows the debris to remove itself and allows needed clearance for re-assembly. Measure the thickness of the connective lugs and place tape on the hole saw bit so that you drill to the proper distance. My lugs are ~.520 thick for example.

An 8 amp drill worked considerably better than an ~ 5.5 amp drill. Takes a very good hole saw ~ 1 1/8".

Making a corner cell substitute for an in-line cell is pretty easy to do. Just stare at it for a minute and the solution will come to you. My cells have four connective bars instead of two which creates significant work.

The new cell was bubbling within minutes of connectivity. Bad cells do not bubble so I think I did OK. We'll know tomorrow.

You will need a lot of odds and ends like pry bars and files and hammers. Have a decent assortment of tools handy.

On a scale of 1-10, I would rate the difficulty of this chore at an ~7. Of course this means nothing at all except to let the reader know that this is not an exceptionally easy thing to do after everything is considered.

Wear eye protection.

Arp

Is anybody knows where can I get a replacement cell for my forklift battery? 

BB.

Welcome to the forum Arp,

Best I can suggest is to go back to your battery supplier and see if they can get cells (from the original battery manufacturer)... I don't know how standardized the cells are (if there is any standardization).

-Bill

softdown

Should have info stamped on the iron case with the info they will need. I might try for 3 quotes - if possible.

softdown

Have you tried (equalizing) very high voltage for two hours? I figured out a jerry rigged way to do it - forklift batteries are super robust.