Power Tool Battery Rebuild DIY

You Asked,

Is it possible to purchase cells and cases to rebuild as a DIY project?

My Answer,

Firstly, thank you for the order of 3 Craftsman Lithium batteries. I will get them packed up and out in tomorrows mail.

Secondly, I get most of my cases from the customers when they need an upgrade or rebuild. It is better for them to send me their cases to make sure I can fill their orders.

I do buy recycled cases from a variety of entities and rebuild them for direct sales.

I do buy cells wholesale to rebuild with.

Cells are available for DIY if a person feels they have the ability to do the rebuild.

I operate a complete battery lab with all the necessary equipment to get the job done. The equipment alone costs tens of thousands of dollars and a person would have to have a big need for rebuilt batteries to justify a DIY operation.

There is also a large learning curve to properly rebuild batteries alone with the computerized equipment to test with.

The Lithium Ion batteries you have purchased have an inherent danger factor in the cells that requires a computer within the battery to control the balance of all cells. The computer will shut down the battery or charging event if there is any fault withing the pack. If misused, the cells will explode and could possibly ruin your day.

I would discourage you from rebuilding unless you have been properly trained in the chemistry of these power units. I rework a large number of batteries that customers made an attempt to rebuild.

With that said, It would not be me that would dictate to talented individuals to not learn about the industry.

Thank you for asking,

Ernie

Rebuilt tool battery charging hints

You Asked.

When did you rebuild this battery and how long will it hold a full charge?

My answer,

Hi,

I rebuilt the battery in the recent past. It does not have a sticker on it so that means it has not been inventoried as stock yet.

As a matter of information only, a battery built with sub c cells by nature will lose
approximately 1% of its voltage in 24 hrs. Conceivably in a 30 day time period the battery, rebuilt, or brand new, will lose approximately 30% of its charge.

This knowledge is very important to me when I hear from someone that their battery is in excellent condition with little use on it as it sets around most of the time. All batteries have to be maintained to survive. A ni-CD battery will become useless if not maintained after the initial charge takes place.

Thank you for your interest.

Ernie

Upgrading Milwaukee M18 XC power tool battery

You asked,

Can you rebuild this pack with larger capacity cells, yet retain the BMS and mounting point so I can still be attached to the weed eater as well as the factory charger?

My Answer,

Interesting question.

If you have a M18 XC battery the capacity should be rated at 2.8ah. The ratings are not linear and to acheive listed capacity you have to fudge the numbers. Nevertheless the output is what it is regardless at how you play with it.

Your battery has a double stack, or (10) ten cells rated at 1.4ah giving you a total of 2.8ah. If we can find a good cell of 3.0ah rated output you could conceivably increase your run time by 100%. But in the real world with pack losses in multiple bus connections, ambient and operation temperature, tool condition, fudge factors, etc, the mathematically reality is lost.

The answer to your question is, Yes we can increase the capacity by changing the cells.

The questions I have is; Will the circuit board take the extra heat without shutting down the pack, as they are designed to do, and would that cause you a problem to let the pack cool down, or could we install a fan as some high voltage batteries have to help it cool.

The last question I have is, how much would you want to spend? I love doing these things but there are always consequences that have to be understood. It is similar to our racing program where we had to ask, How fast do we want to go and how much do we have to spend? We called it "Cubic Dollars".

Keep in touch, I would love to work with you.

Thank you,

Ernie

Craftsman Li-Ion 19.2v power tool batteries

I have purchased a sizable number of Craftsman 19.2v Li Ion tool batteries that have never been in a tool.

It seems that there was probably a manufacturing glitch  that rendered all these new batteries into unusable fodder.

After receiving the first order I disassembled each battery to analyze the problem. In every case there were a series of bloated cells that were subjected to high voltage, heat or both.

In some cases the pressure in the cells vented fluids into the pack corroding those metal parts that were exposed. Those cells that were not effected were as new, testing to 4.2v each. There were not many in each pack and none in some. There was random bursting of the cells position and that leads to no obvious conclusion as to a specific cause.

Nevertheless, I have assembled a number of those battery packs with existing cells or in some cases new cells and tested them thoroughly, not only with test equipment but in actual tool tests. The performance is exceptional.

I might state that some circuit boards were damaged in the event of question and there is no hope for repair on them.

I have placed one of these rebuilt batteries in my eBay store and have many more available.

This is a great chance to get as close to a new battery as is available at a reduced cost. I am asking $65.00 each for the completely warrantied battery pack.

Who rebuilds power tool batteries? We do !

REBUILDING IS RECYCLING

I have been asked often as to whether I rebuild as a hobby or business.

The answer is neither.

 I am a retired contractor that has more time on my hands than needed.

 I built my small State of the Art, battery lab years ago to supply my own needs in the construction industry.

I have produced many hundreds of rebuilds for a wide variety of users.

I do not strive to rebuild every battery in the world and am very comfortable to work with a select client base that appreciates the quality and personal availability I offer.

Also, being Eco Friendly is a most important thought provoking theme right now.

My small company will promote a positive image by offering optional products which are Eco Friendly.

These products not only portray a good image to my customers but also help increase my companies moral by showing that I am doing my part to help the enviroment.

Please explore my store for some exciting new Eco Friendly products. These products will help to make choices and have you thinking that Eco Friendly is not only good for the enviroment but good for your moral.

All Eco Friendly products will be marked with the Green Earth logo and the little battery pointing the way.

We hope you enjoy your visit to my store and if you have any questions please feel free to contact me.

Thank you for your interest,

Ernie

Makita tool battery charger options

YOU ASKED,

What would you recomend for an optional battery charger for a Makita LXT with a bad chip?

MY ANSWER.

I believe that Makita has probably taken care of the discussed problems with there new production but we will never know. Also the fact that there is a device to reset the chip is possibly a figment of someones imagination. I hope it is true but who knows.

 

As a re builder I am very cautious not to mislead my customers about the possibility to rebuild their batteries without a disclaimer. It is possible to change out cells but that does not constitute a rebuild if it can not be charged.

 

The type of charger you need is obviously one designed for Li-Ion batteries and offers at least two parameters of protection. I prefer a third parameter but it is not mandatory.

 

1. Protection from overcharge.

 

2. Protection from undercharge.

 

3. Protection from heat buildup. (Optional) 

No chargers, even the OEM makita will balance cells within the pack. They only detect unbalance. If a cell is bad the charger shuts down. If that happens the only recourse is to find that cell and replace it with another that matches the rest of the pack.

 

The charger I will recomend has the ability to balance individual cells for optimum performance but will not make a bad cell work again.

 

With that said, I will list the charger I like, to replace your OEM unit.

 

This charger is on sale right now and goes off sale on 9/10/11.

 

http://www.all-battery.com/tenergytb6b-charger-combo-90263.aspx

 

Remember, I am a battery rebuilder and share information for the possibility of future interaction in my small business.

Power tool battery compatibility and rebuild responsibility

I rebuilt a Dewalt battery from a customer in Pennsylvania who was preparing to re roof a large historical barn. His interest was to make sure he had enough batteries available to minimise his accent and decent from the roof 60' from the ground.

He shipped me his case and I rebuilt it to OEM spec and shipped it back to him. Within a few days he emailed me that he could not charge the new rebuild. Dewalt produced a fairly common battery for their tools and rebuilds are straight forward.

He asked if he could ship it back but I suggested that I would rebuild another pack for him and quickly get it to him allowing him to return the other back at his convenience. If that was the end of the story I would not have posted these details. He emailed me when he received the new rebuild that he could not charge either battery.

I reminded him that as far as I knew, Dewalt had only used two NI-CD chemistry's in there battery history and unless he had a "Univolt" system he should be getting the job done. The battery he sent me was not for a univolt system so I assumed that was not possible.

The next day he notified me that he had communicated with Dewalt and they sent him to their factory rep for suggestions.

The following is his report.

Ernie,

I went to a nearby shop to get help on my charging problem.

Suffice to say, this guy knows his batteries. What he told me, and showed to me, made everything clear: First of all, there is no amount of rewiring...or any other modifications, that can make your 2300-mAh batteries charge on any of my chargers. All of my chargers were built and sold in the days of 1300-mAh and 2000-mAh (max capacity) batteries. The reason they will not charge is because my old chargers run a short diagnostic to determine if the batteries have any problems (dead-shorts and/or open or damaged cells). The 2300-mAh batteries you use in your packs have an internal impedance which is simply out-of-tolerance for my chargers. Therefore, no amount of rewiring is going to correct the problem.  Besides, there is only one way to wire these 12 sub-C cells in order to get 14.4 volts. And, by the way, Mr. Lyons complemented you on the quality of your work. He was impressed with your welding and the cell arrangement.  So, bottom line, there is no way that these two rebuilt packs can be recharged with any of my old chargers...because they were not built to the original specifications of the old DW9091 and B&D 97152 batteries. Lyons then showed me that the Dewalt DW9116 charger will charge all of my batteries; my old ones and both of the batteries you have rebuilt. The DW9116 has the largest acceptable test range, so it will charge everything from 1300-mAh to 2400-mAh batteries. Incidentally, your DC9310 charger also has a rather wide acceptability range, but Lyons thinks it may not go all the way down to the impedance of the 1100-mAh cells B&D originally used.  This knowledge cost me $56.85...$33.63 for a new-old-stock DW9116 charger and $20 for taking apart your second rebuilt battery, checking the construction, and putting it back together, and PA sales tax.

So now I have what I need to get started on the barn (which we are planning to start tomorrow morning). Since I am not particularly happy in having to spend $107.12 (for the first rebuilt battery, new charger, consultation, and extra postage) for one battery, I would like you to let me know how much I owe you for the second rebuild, I'll Paypal you the payment, and we can call it knowledge gained.

 

Lance

 

The moral to this story is, "If you are looking for new parts or updating old systems ask all the questions you can think of".  before ordering.