Battery Adapters Revisted (Kobalt 24v and possibly others)

[tw05]

As some of you might have noticed Lowes has been selling Kobalt 24 volt batteries starting at $10 (started a week ago I think). By chance I came across a seller on eBay selling Kobalt 24v battery adapters. He (or she) makes them using a 3D printer. I am in no way affiliated with the seller and have not purchased an adapter. I did message the seller for more information about making more if there was demand. I am also giving the seller the link to this thread.

http://www.ebay.com/itm/191988179405

In theory battery adapters could help re-purpose old tools that now have worn out Ni-cad batteries. You could even buy a tool from a different company and mount a battery adapter on it to use with your current line up. One could even hook up 2 24 Volt batteries in series to make a 40 plus volt battery. There are way too many possibilities to list.

I am in no way an authority on electronics. I just tinker at home with my own stuff so maybe some more experienced members can chime in. I currently use one of my Lithium tool batteries rigged up with a home made battery adapter to run my old roomba.

I hope the seller will join in here as they were open to the idea of engineering different solutions (maybe adapters for other brands?). I am sure it is cost/time dependent.

 

[tw05]

Pictures from the eBay listing:

 

[6PTsocket]

Just how far over the original voltage the motor was designed for do you think you can go? At some point you are going to let out the magic smoke.


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[Infinia]

yikes sorry there is much more complexity than attaching 2 wires to a 24V battery.
are the spade terminals designed for this purpose?
cell balance leads, charging solution?

I am in no way affiliated with the seller and have not purchased an adapter. I did message the seller for more information about making more if there was demand. I am also giving the seller the link to this thread.

sure thing bub
3d printer will travel

 

[tw05]

Just how far over the original voltage the motor was designed for do you think you can go? At some point you are going to let out the magic smoke.


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I was wondering the same thing. I was going to try this on older tools first that I don't care as much about. Kobalt 24 volt batteries have one extra cell compared to most other brands that use "20 volt" batteries.

 

[tw05]

yikes sorry there is much more complexity than attaching 2 wires to a 24V battery.
are the spade terminals designed for this purpose?
cell balance leads, charging solution?


sure thing bub
3d printer will travel

Charging would probably be done using a Kobalt charger. What I am more curious about is the possibility of interchanging batteries across 18 volt/ 20 volt max line ups. Has anyone actually done this? The only similar item I have seen is the Dewalt DCA1820:

http://www.dewalt.com/products/acce...chargers/batteries/18v-to-20v-adapter/dca1820

 

[Infinia]

Li Ion 18650 cells are 3.7 Vdc nominal , ~4.1 volts fully charged & plus zero load.
even if yer a battery expert don't buy these, or if you were you wouldnt need a prompt.
come on folks the terminals can get hot and melt crappy 3D plastics. this stuff isn't easy as appears

 

[6PTsocket]

I was wondering the same thing. I was going to try this on older tools first that I don't care as much about. Kobalt 24 volt batteries have one extra cell compared to most other brands that use "20 volt" batteries.

That would not be a problem but he was talking about putting batteries in series. People have been making lithium replacements for nicads for all kinds of stuff for a long time. As long as you have the appropriate charger for the lithiums, it is not a bad thing. They are a lot fussier and sometimes need individual cell monitoring, minimum and maximum and maximum cutoff on the state of charge . If they go too low they can be ruined. If they are overcharged they can catch fire.

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[kctyphoon]

yikes sorry there is much more complexity than attaching 2 wires to a 24V battery.
are the spade terminals designed for this purpose?
cell balance leads, charging solution?


sure thing bub
3d printer will travel

All of that is in the battery already. All he's doing is making a snap in power source just like Milwaukee, Dewalt, Bosch, Makita, and Ridgid already does for their stuff..

 

[Derek420]

Charging would probably be done using a Kobalt charger. What I am more curious about is the possibility of interchanging batteries across 18 volt/ 20 volt max line ups. Has anyone actually done this? The only similar item I have seen is the Dewalt DCA1820:

http://www.dewalt.com/products/acce...chargers/batteries/18v-to-20v-adapter/dca1820

The 18v and 20v are the same it's just a marketing scam/strategy. Both are 20v without load and 18 with, check out a Lowes add or it might be menards but it has fine print stating that and I checked my 18v makita with my multi meter and sure enough 18, They have the same amount of cells and the new dewault flex volts have a sliding contact switch that just engages more cells when hooked up to a 40v and to be able to be shipped by airplane also so it's a smart design. I would guy a dumb adapter because its so easy to rebuild old nicad batteries just go to HF with 20% off coupon and buy one of their cheapo ones take it apart and solder them up with wire and take them together in the right formation and bingo, much cheaper than buying cells online. To rebuild lithium packs some say you can't well BS you just get the cells for laptops but the right ones and Viola same as above. I've done it and some say you gotta have a good soldering iron, nope my 3m from Wally did it fine. The HF wiegh less but work fine I don't care about mah numbers or amps on nicad but do on lithium as it's not same. Cost $10 to rebuild nicad with HF and notice no difference other than weight.

 

[Teenager with old tools]

The motor will handle the volts I'm not sure the wiring and circuitry is ideal for it


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[6PTsocket]

The 18v and 20v are the same it's just a marketing scam/strategy. Both are 20v without load and 18 with, check out a Lowes add or it might be menards but it has fine print stating that and I checked my 18v makita with my multi meter and sure enough 18, They have the same amount of cells and the new dewault flex volts have a sliding contact switch that just engages more cells when hooked up to a 40v and to be able to be shipped by airplane also so it's a smart design. I would guy a dumb adapter because its so easy to rebuild old nicad batteries just go to HF with 20% off coupon and buy one of their cheapo ones take it apart and solder them up with wire and take them together in the right formation and bingo, much cheaper than buying cells online. To rebuild lithium packs some say you can't well BS you just get the cells for laptops but the right ones and Viola same as above. I've done it and some say you gotta have a good soldering iron, nope my 3m from Wally did it fine. The HF wiegh less but work fine I don't care about mah numbers or amps on nicad but do on lithium as it's not same. Cost $10 to rebuild nicad with HF and notice no difference other than weight.

Mah is capacity. If you don't care about run time, that is your preference. Others might be willing to spend a couple of more bucks to not have their batteries live on the charger. I recently spent four bucks a cell for Tenergy, a brand with good reviews, for 2200 mah NiCds They just had a half price sale. They are available with or without tabs. There is also the matter of reliability. If you go with NiMh which has other drawbacks, you can get as much as 5 amp hrs in a sub C. What is the capacity of a HF sub C. I never looked into it. I suspect they don't say.

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[6PTsocket]

All of that is in the battery already. All he's doing is making a snap in power source just like Milwaukee, Dewalt, Bosch, Makita, and Ridgid already does for their stuff..

Yes there is built in cell protection but lithium charge requirements are different. That is why you cannot use the same charger unless it it is built to handle both chemistries. The 3.7 volt lithium in your phone has four contacts even though it contains only one cell. Not everything is always internal.

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[Jamie V]

I'd be interested in one for M18 Milwaukee batteries so I can put them in my kids power wheels. Maybe with some thicker wires or studs for ring terminals.

 

[Infinia]

kctyphoon;6124760]All of that is in the battery already.

what is 'that'?
no , look at the connectors there are many more leads on a Li Ion battery pack compared to NiCd. these are for cell balance.
the 2 high current connections need to be rated for high current for a specified temperature rise after wear and tear E.g. many insertions. Lets see how he staked in the connector spade and source / make-up of the metal spade. Every battery pack is custom some have better cells, protections than others, sadly there are no standard connectors for these packs just like lap-tops but no built in smarts.. I'm afraid one guy with a 3D printer in his apt. doesn't make an all purpose adapter or engineered solution. buyer beware.

 

[mburko]

Mitchell Burko here. I designed the Kobalt battery mount for a client. He is using it on a portable lighting product. Seemed like a useful item and offered it for sale on ebay. I have sold 6 so far. Not a big demand item.

Power tools are a more demanding use than his lamp assemblies. tw05 discussed powering his Roomba with Li-on packs. That seems like a good match.

I will address concerns I read in this thread.

Wire and terminals:
The terminals are TE Faston brand #2-293041-1. They are common in automotive applications. They are the spade to the 1/4" Faston series. Often used in 10 or even 15 amp circuits. This terminal accepts 28 to 17 ga wire. For 14 to 18 ga wire the part number is 170153-2 or 42098-1. I purchase them from DigiKey.com.

As the holder is offered on ebay they have 12 inch long 18ga wires crimped in. Not soldered, crimped. Current rating of 10A is a comfortable number for short wires of 0 to 24 inch. Solder the wire to the terminal and you will have lower losses in the terminal.

They are retained in my housing just as in an automotive connector block. A latch tab in the terminal catches on the housing to prevent pull back.

The housing is made of PLA. It has a relatively low melting point. It softens at about 140C. It is runny at 220C. Not for HOT applications.

Happy to answer questions. Post em.

Will add information in subsequent posts.

Thank you for reading, Mitch

 

[mburko]

Mitch again:
How many terminals does a Li-on powered device need? Depends on a few things. The Kobalt pack has 3 terminals. 1 terminal each for Power and Ground.

The 3rd terminal has typically be a temperature sensor. A charger or tool could be set to shutdown if the pack get "hot".

The Kobalt pack is of the new Smart type. I have yet to learn what is made available on that 3rd pin. Could be a data line to report many parameters of the pack, control the chip in the pack, or just provide temperature as before.

The Power and Ground terminals need only handle the current of the thing it is powering. I chose moderate capacity power terminals. This holder is NOT made for 40A loads.

Attached is the mfgrs drawings of the terminals for the thicker gauge wire. The drawing for the thinner gauge wire was too big to upload.

Later, Mitch

 

[mburko]

Mitch again:

A shameless promotion that belongs in a different thread.

There is another thing I dreamed up in my "apt". Well actually at work while trying to cut brass tubing with a Dremel.

Attached picture is a Dremel 4000 holder that clamps in a vise. Search ebay for DH-4000V to learn more.

Regards, Leonardo DaVinci wana-be

 

[mburko]

Opps. Was so focused on my battery thingy that I forgot to thank the guy that invited me.

tw05: Thank you so very much for introducing my battery holder to the group. The comments are enlightening. it might even be useful to someone here. At the very least some folks got thinking and writing about this generation of portable power, what it can do and what it cannot do.

Thank you, Mitch

 

[purduephotog]

Opps. Was so focused on my battery thingy that I forgot to thank the guy that invited me.

tw05: Thank you so very much for introducing my battery holder to the group. The comments are enlightening. it might even be useful to someone here. At the very least some folks got thinking and writing about this generation of portable power, what it can do and what it cannot do.

Thank you, Mitch

Too awesome.

I don't get out much but today I hit Lowe's and saw said battery. I had just been designing a 24v lighting and was going to run 18v via buck boost... But really not liking the idea of having to deal individual cells. So this battery... And price... Got me excited.

After spending hours looking for adapters I find this thread with exactly what I needed on one of my favorite forums.

You made my birthday great

 

[guy48065]

yikes sorry there is much more complexity than attaching 2 wires to a 24V battery.
are the spade terminals designed for this purpose?
cell balance leads, charging solution?

I opened up a Dewalt 24V pack to replace a couple shorted cells and found a battery maintenance module inside the pack, with a wire to each cell. This approach makes sense to me.
Aren't all lithium batteries like that or do some have the balancing circuit in the charger itself?

 

[Infinia]

I opened up a Dewalt 24V pack to replace a couple shorted cells and found a battery maintenance module inside the pack, with a wire to each cell. This approach makes sense to me.
Aren't all lithium batteries like that or do some have the balancing circuit in the charger itself?

that's the $60K question about using multi pack adapters isn't it, they don't have set standards. I'm pretty sure the best BMS are in the chargers themselves, similar to Hobby packs / charger technology. My main concern is reliability of the high current connectors. That 'stuff gets hot when it doesn't fit or gets worn out. Printed plastics is known to melt at much lower temps than industrial moldings, causing further fitment problems. There is a lot more engineering in there than 1st glance.

 

[purduephotog]

Well I've taken apart many a battery. All multi packs sold by reliable vendors (laptop and tool, not counting HF because I haven't gutted one of their lithiums yet) have BMS circuits. The lowes battery does too although I couldn't immediately locate the chip that is central to it. I'll finish removing the potting at some point.

The charger actually had me worried. It's adult but it sounds exactly like my dumb SLA charger. So opening this guy up and measuring what it puts out will be interesting.

The cells have balance wires to top off and bypass during charging. I also saw 2 or 3 thermal fuses under the potting.

If the battery is designed to be discharged hard the connections will hold. My application ain't draw more than 1a, which is well under 0.5C so I should get nearly full capacity. My cells were with good on and codes. My guess is these are bottom of the barrel rejected cells and that's why said pack is so cheap.