DeWalt Li-Ion battery pack and chargers

[wptski]

Got two different DeWalt kits, one with 2Ah batteries with 2A charger and another kit with 4Ah batteries with a 4A charger. Didn't dawn on me about the difference right away. They do have some of these new batteries that they call Smart batteries with Bluetooth connection with an app but I don't have or need that. I wondered what happens if a 2Ah battery pack is charged on the 4A charger. It seems they aren't that Smart as DeWalt just told me that it will charge twice as fast or at 2C! Not too good for battery life, hey? Unless the guy I talked was wrong as he did spend lots of time looking that up, coming back to me several times.

I could probably rig a connection up to test this myself.

 

[SilverFox]

Hello Bill,

While not ideal I don't think it is a problem.

If you put the 2Ah battery in the 4A charger, the first part of the charge will go a little faster but as the voltage rises the current will drop off and you will be back to a more normal charge rate. The main issue may come from the charge termination. Your 2 Ah batteries may not end up fully charged if the charger termination is based on some ratio of the current. For example if the charge is terminated when the current drops to 0.1 of the maximum charge rate, that would terminate the charge of the 4A charger when the charge current drops below 0.4 amps where the 2A charger would terminate at below 0.2 amps.

There are a couple of ways to check this out. You can charge the 2Ah pack on the 4A charger, let it rest, then measure its open circuit voltage. Use it a little, then charge it on the 2Ah charger and see if there is a difference.

Another thing you can try is to monitor the voltage of the battery as it is being charged. Comparing the voltage profiles from the different chargers may help visualize what is going on.

Tom

 

[wptski]

Tom, it's been a while, hey?

Looking a bit closer at the battery connections, two are marked B+ and B- but there are six more that are probably controls. I do know that it monitors battery temperature for one. One is marked ID and I'm guessing that the charger adjusts knowing the size of the installed battery. Since there are eight contacts measuring the voltage during charging would mean making up eight jumpers, don't know if I'm up to the task.:tired:

 

[SilverFox]

Hello Bill,

Aren't you retired? What else are you going to do... :devil:

You may just be able to hook up to the B+ and B- and get an idea for the whole pack.

Tom

 

[wptski]

Yep, going on eight years this April.

Yeah, they could be for tool control only or that might at least tell me if it does indeed use a battery ID to function. I did make two leads for B+/- just used two male spade terminals and tinned the other end just for clipping leads. The other six are narrower or half the width.

Just looked it up, my old Schultz charger will do five Li-Ion cells.

 

[wptski]

Nope! Won't charge with just B+/- connected. I'm too curious about this and have the needed parts to make up some jumpers over the weekend, I hope!

 

[wptski]

It wouldn't charge with all eight contacts connected with jumper wires. I guess a bit of added resistance it didn't like and all checked less than one ohm. Oh well....

 

[SilverFox]

Hello Bill,

Is it possible to take the charger apart so you can measure voltage during charging but not have to interfere with the battery/charger connection?

Tom

 

[wptski]

Hello Bill,

Is it possible to take the charger apart so you can measure voltage during charging but not have to interfere with the battery/charger connection?

Tom

A good idea! I didn't notice if they have tamper-proof Torx screws as they do on their battery packs. I was also thinking about measuring the input current as the 2A charger draws .7A AC and the 4A charger draws 1.5A AC.

Just looked, T15 Torx screws in a one inch deep hole with very shallow heads. Got two out but the other two are in crooked and I can't get a bite on them. I'll think about drilling the heads off tonight.:thinking:

 

[wptski]

The reason the screws had shallow heads were indeed tamper-proof just two were better! I used a 1/32" drill to undo the tamper-proof. I was worried that all the battery contacts might be soldered right to a PCB but they aren't so I can measure current with a clamp meter/probe. I run down my 2Ah battery a bit more tomorrow and test it.

 

[wptski]

It was charging at 4A on a 2Ah battery so I stopped it and used the 2A charger which I'll use from now on. Nowhere does it state that charging at 2C is good for a Li-Ion battery/cell. They use 3.6V cells also.

 

[NoNotAgain]

It was charging at 4A on a 2Ah battery so I stopped it and used the 2A charger which I'll use from now on. Nowhere does it state that charging at 2C is good for a Li-Ion battery/cell. They use 3.6V cells also.

Sounds like Black & Decker/DeWalt doesn't do too much right these days.

I was a former user of the Black & Decker Professional line of tools before B&D formed a spin off named DeWalt. Back then NiCad was it for the rechargeable line.

Milwaukee Tools lithium batteries, be it 12 or 18 volts can all use the same charger. The 1812 charger has a slot for the 12 volt batteries be it 1.8, 2.0 or the 3.0 amp versions and the 2.0, 2.8, 4.0 and 5.0 amp 18 volt batteries. Milwaukee regulates the charge in the battery circuitry board and only uses 4 contacts.

 

[wptski]

Sounds like Black & Decker/DeWalt doesn't do too much right these days.

I was a former user of the Black & Decker Professional line of tools before B&D formed a spin off named DeWalt. Back then NiCad was it for the rechargeable line.

Milwaukee Tools lithium batteries, be it 12 or 18 volts can all use the same charger. The 1812 charger has a slot for the 12 volt batteries be it 1.8, 2.0 or the 3.0 amp versions and the 2.0, 2.8, 4.0 and 5.0 amp 18 volt batteries. Milwaukee regulates the charge in the battery circuitry board and only uses 4 contacts.

Funny, this very thing about Milwaukee came up in another forum. If you look at the PDF for Red whatever charger, it lists a thirty minute charge on the 2Ah battery which means they are doing the same thing. The PDF isn't on my tablet here but IIRC, it was a 3.1A output charger.

 

[NoNotAgain]

Funny, this very thing about Milwaukee came up in another forum. If you look at the PDF for Red whatever charger, it lists a thirty minute charge on the 2Ah battery which means they are doing the same thing. The PDF isn't on my tablet here but IIRC, it was a 3.1A output charger.

Like I said though, Milwaukee regulates there charging in the battery via the pcb.

I've only got two of the 18 volt 2 amp hr batteries. They charge in about 25 minutes to just under 20 volts. The batteries don't get warm.

My 4 amp hr batteries get used hard. When I was building my deck, I was driving 3 1/2 screws as fast as I could locate my lay out lines and pull the trigger. I was getting 150-175 screws per charge. I was driving the screws into pt 2x6 treated boards to 1.2 ounces per foot. This lumber is very wet to drive fasteners into.

Off topic, I've got a great lumber yard I deal with, Virginia Frame. They introduced me to the company, Cox Lumber that does all their pressure treated lumber.

The Milwaukee batteries are easy to open, just two long and two short tamper proof screws. They use Sanyo lithium manganese 2200 mah rated cells in most packs. I've yet to have a battery go bad, knocking on wood.

 

[wptski]

Like I said though, Milwaukee regulates there charging in the battery via the pcb.

I've only got two of the 18 volt 2 amp hr batteries. They charge in about 25 minutes to just under 20 volts. The batteries don't get warm.

My 4 amp hr batteries get used hard. When I was building my deck, I was driving 3 1/2 screws as fast as I could locate my lay out lines and pull the trigger. I was getting 150-175 screws per charge. I was driving the screws into pt 2x6 treated boards to 1.2 ounces per foot. This lumber is very wet to drive fasteners into.

Off topic, I've got a great lumber yard I deal with, Virginia Frame. They introduced me to the company, Cox Lumber that does all their pressure treated lumber.

The Milwaukee batteries are easy to open, just two long and two short tamper proof screws. They use Sanyo lithium manganese 2200 mah rated cells in most packs. I've yet to have a battery go bad, knocking on wood.

Look below here. Their Milwaukee 48-59-1801 charger, output is 3.1A charges a 48-11-1815 which is a 2Ah battery in thirty minutes which means what? Of course, >1C rate. Any time, anything charges in less than an hour is automatically >1C.

[URL=http://smg.photobucket.com/user/wptski/media/Specs.jpg.html][/URL]

 

[Pui]

No such thing as current regulation inside the battery. It will take whatever the charger has to give. These are not smart chargers, will put out one current regardless of voltage or capacity.
Makita has the 2.6, 3.5 (older, not made anymore) and the 9Ah chargers. The last one will charge a 3Ah battery in 20 minutes, has a fan. Thats exactly 3c charge rate. Modern cells can easily take 2c, 3c and even 4c with cooling. 1.5Ah batteries charged on the 9Ah charger take just 9-10 min to charge. Thats 6c for you. They dont get hot and still last for years, but use exclusively Sony Vtc4 and Vtc5. Older packs use the Sony Konion Vx cells, even those seem to take the 9Ah current without problem.

 

[wptski]

No such thing as current regulation inside the battery. It will take whatever the charger has to give. These are not smart chargers, will put out one current regardless of voltage or capacity.
Makita has the 2.6, 3.5 (older, not made anymore) and the 9Ah chargers. The last one will charge a 3Ah battery in 20 minutes, has a fan. Thats exactly 3c charge rate. Modern cells can easily take 2c, 3c and even 4c with cooling. 1.5Ah batteries charged on the 9Ah charger take just 9-10 min to charge. Thats 6c for you. They dont get hot and still last for years, but use exclusively Sony Vtc4 and Vtc5. Older packs use the Sony Konion Vx cells, even those seem to take the 9Ah current without problem.

Please provide a valid link stating that charging over 1C is good to do. PowerStream suggests 0.2C-0.7C charging rate. Why would DeWalt have two different Li-Ion 20V Max chargers if only one is needed?

The following specs for those cells don't see to agree with what you said.

VTC4 specs: https://cdn.shopify.com/s/files/1/0674/3651/files/Sony_VTC4.pdf?838

VTC5 specs: https://cdn.shopify.com/s/files/1/0674/3651/files/Sony_VTC5.pdf?837

 

[Pui]

Dont buy Powerstream then. 0.2-0.7c charge rate reminds me of the early 2000'.
Sony suggests 2.5c for Vtc5. For 2P packs that can double. So they are pushing it a bit with the 9A charger, but Makita packs seem to last. My oldest one is certainly well over 500 cycles and still goes like theres no tomorrow.

To answer your question, the 2A Dewalt charger is probably intended for 5s packs, the 4A one is for 5s2p. I would personally just use the 4A one for everything. Cells nowadays are cheap enough to not worry about them lasting a decade, they will degrade even if left at storage charge in the freezer. So better use them hard and when weak, buy new technology.
Theres a couple of guys with some Nicad battery tools at my site. Everyone else and their dog use fast chargers and huge capacity packs, doing loads of work before needing a recharge. The Nicad guys are at the store charging their packs 5 times a day. F that. Dont be those guys

 

[wptski]

Dont buy Powerstream then. 0.2-0.7c charge rate reminds me of the early 2000'.
Sony suggests 2.5c for Vtc5. For 2P packs that can double. So they are pushing it a bit with the 9A charger, but Makita packs seem to last. My oldest one is certainly well over 500 cycles and still goes like theres no tomorrow.

To answer your question, the 2A Dewalt charger is probably intended for 5s packs, the 4A one is for 5s2p. I would personally just use the 4A one for everything. Cells nowadays are cheap enough to not worry about them lasting a decade, they will degrade even if left at storage charge in the freezer. So better use them hard and when weak, buy new technology.
Theres a couple of guys with some Nicad battery tools at my site. Everyone else and their dog use fast chargers and huge capacity packs, doing loads of work before needing a recharge. The Nicad guys are at the store charging their packs 5 times a day. F that. Dont be those guys

Where are you getting Sony suggests 2.5C from? Their specs are 1C for a VTC5 clearly states 2.5A which is 1C. This isn't about what you and your boys are doing, it's about what manufacturers suggests. You think Sony doesn't know what they are talking about?

 

[Pui]

Sony knows what they are talking about. But do you think Makita just decided to ignore the datasheets and charge the cells at whatever they feel like without first getting the thumbs up from Sony? Sony would have stopped supplying them long ago if that. The 1c reccomended current is probably already a compromise between cell life vs charge speed, and 0.5c is even better. 0.2 for overnight charge is probably best. But doubling the reccomended charging rate most likely introduces an insignificant amount of additional degradation, thats unavoidable anyway. It doesnt mean squat in real life.
And remember these datasheets are for the end user, that can choose to charge them with anything from a dumpcharge from another battery, a homemade or a cheap chinese copy of a chinese copy of a chinese charger, and given this, no manufacturer will say "yes of course Jim, our cells will take 5A current but make sure you have a good extinguisher". Theyll play it safe and state 1c max. Manufacturers that buy millions of cells, are probably getting a sheet with different values.

Bottom line is, you worry about nothing. 4A charge for a 4Ah pack is 1c anyway. For a 2Ah is 2c. Keep the cells cool and its fine. Its not the high charge or discharge current that kills the cell, its mostly heat. Fast cell degradation starts at 70-85°C, not at high currents.