Look what I found in the recycle bin

See, there’s gold in them yar bins!

Just yesterday in the same bin as the Ryobi 40v, i recovered 2 - 18v Ridgid packs. But they are NOT compatible with my 18v Ridgid. The packs were made in Germany and contain Sony cells. Never seen them before in a Ridgid.
I will post a picture later

I think HD threw it away. Just one more reason to look forward to Pittsburgh.

In each picture the German pack is on the left, my compatible pack is on the right.





Notice there is NO sophisticated balancing circuit in the German pack. I suppose it is possible that it is in the charger or the tool itself.

If you would like to know where the recycle bins are, do a Google search of the 800 number on battery packs. :slight_smile:

Man, that pack is scary. I gotta watch out for that in my future Ridged battery acquisitions. Thank you for sharing dchomak.

vuanhquoc wrote:

they have free battery packs at Home Depot? where can i find them?

The bins are usually in the front of the store near the Customer Service desk. Most stores frown on people pulling packs out of them. I've been asked if I needed any help several times while digging. So you need a good excuse like your contact lens fell out.

Usually confuses them since I wear glasses.

If there is not balance harness then the pack will not be balanced. A balance harness taps the connection between EACH pair of series cells, plus BAT+ and BAT-. Normally the BMS in a battery pack would have the harness directly attached to it.


All of the simple 3 cell, 12V Li-ion packs I have seen work that way. My 12V Ridgid is and when I upgraded to a 6 cell 12V bat pack it had a BMS in the pack.

IMA4, no need to worry, the German pack will not fit your Ridgid. :wink:

Oops, I didn’t understand what I was looking at from the original pic. I agree, BMS in the charger. FWIW, BMS on battery is safer IMO (I’m sure we all realize that).

You have 10 cells in series, you would need at least 11 connections to the charger if the BMS was in it.

Yes, I think so too.
In fact I believe that some packs will actually “Brick” themselves when something goes wrong. I saw a reference on the internet once on how to un-brick a Makita pack, but it was removed. There seems to be very little info on the subject.

That is right, but that pic is of the German 5 cell Ridgid. Sorry, I switched which cell I was talking about.
You are correct, the 40V Ryobi is 2P10S and the BMS is in the pack.
And it’s a mother. As the series cell count goes up, with all the necessary connections between the pack and the charger, it makes more and more sense to include the BMS circuit in the pack. Safety issues aside.

Can you check on that Ridgid pack if there are balance leads going to each cell?
I recently opened a Makita pack found in the bin and found 10 Sony 1600mAh (5S2P) green cells like yours (US18650V). Can you confirm you have the same cells on the following pack pack please?

I noticed on my Makita pack that there is no balancing circuit and no balance leads! I think I know why but I want to see if your pack is the same…

There are no balance leads to each cell on the German Ridgid.



And that pack was made in 2012

That’s very interesting. It seems that these sony cells are self balancing. I did a few tests and if you charge them to 4.2V they’ll come down to 4.12V after a few hours. If you charge them to 4.1V they stay at 4.1V.
I believe that this is the reason why they don’t need balancing leads.

Interesting indeed. Thanks for the info.

lagman wrote:
That’s very interesting. It seems that these sony cells are self balancing. I did a few tests and if you charge them to 4.2V they’ll come down to 4.12V after a few hours. If you charge them to 4.1V they stay at 4.1V.

I believe that this is the reason why they don’t need balancing leads.

Hey guy. Please don't trust those any cell to be self balancing with other cells. You have a case were all you cells happen to be about the same condition at this time. A balancing circuit is for when a cell or cells start to deteriorate faster than the others in the pack.

I’m just experimenting, not trusting anything or doing unsafe things. :slight_smile:
But how do you explain the fact that the makita pack I got doesn’t have balancing leads? For a 5S lithium pack it really is a must… Unless the cells self balance. :slight_smile:

Some cells are more disposed to this kind of treatment than others. Remember, NiMH and NiCad cells were not balanced - and it’s not because they don’t get out of balance. With a hardy enough cell I think the normal strategy is to overcharge the whole pack in series and let the excess burn off as heat. A123 M1 cells (a LiFe chemistry cell) can be charged in that fashion.

I can't. Seems crazy to me. Of course, some laptops lacked adequate safety features until some hurt people. Those cells don't appear to have any protection circuits on them. Makes no sense to me, but I admit that I'm no expert by any means.

I didn't mean to imply you were doing anything dangerous or wrong.

I’m… not really sure that you’re correct about the laptop safety features thing. When I think of laptops that hurt people I think of modern machines which did incorporate BMS’s. Sony has been in the news once or twice in recent years, and it wasn’t due to a lack of BMS.

That said, low-drain cells cannot be treated in the way I describe. The only lithium chemistry cells I’ve heard can be treated this way in the past were the A123 stuff, and they are both extremely high drain and extremely hardy. (approximately: 50C pulse discharge, 30C continuous discharge, 4C charge) I can only guess that Sony’s IMR chemistry is starting to catch up enough where they can be treated in a similar way. If not, the designers of that powertool pack are grossly negligent of course…

Well, those 2 German packs had all 5 cells in each pack sitting at exactly 4.01V. They are 2 year old packs and probably cycled many times. We now know that they are not balanced charged. How else can they all be the same unless they self balance?
I just learned something today.

Remember the issue in serial batteries is not whether cells are balanced - it is whether it is safe for the cells to pass current between cells when there is an active circuit.

For example, in a 2 cell light with lithium primaries in series, if one of the cells drains faster than the other cell, then the lower voltage primary cell may start taking on too much voltage from the better cell during use - when it may not be safe to do so. Same thing with a rechargeable cell that is not in good condition within a group of cells in a series battery, especially when a charge is being applied.