Ryobi 18V lithium battery pinout?

[SamTexas]

Does any know what the two contact points in the middle of the battery is for? Is it the charging ports? I don't have the charger so I can't check.
Thanks.

(No, I'm not asking about the 3 contact points on the vertical column.)

 

[Electroddy]

The lithium packs have a BMS. The two contacts are for the charger diagnostic circuitry. And possibly to turn the FETs on to allow charging. I am NOT an expert, but I have the same pack open awaiting some new cells.

 

[SamTexas]

Thank you Electroddy. I'm no expert either, just horsing around with these BMSs.

I'm guessing here based on what you said, so please correct me if I'm wrong: So charging is done at the + and - contact points on the vertical column. But for that to happen, the two middle contact points must be shorted. Right?

I have removed the batteries and soldered wires to the battery contact points. Now I can make the capacity of that battery as big as I want. Just tried 5s4p with LiCo (not LiMn), 8Ah capacity. Now I want to charge through the Ryobi's BMS.

View attachment 1

 

[SamTexas]

I'm still needing help. Anyone out there with a charger for this battery? Can you please measure the voltage of the middle two contact points as well as the voltage between the + and - contact points on the vertical column, while the battery is being charged of course.

I need to charge the battery, the have the proper power source (21.0V or higher). I just don't know where the contact points should be?

Obviously I could just guess but I really don't want to ruin the BMS. Thanks.

 

[Electroddy]

Sam; I get a 1.7V A/C not D/C on the two small middle contacts. 20.2 on the main contacts. I believe the third vertical contact is for voltage sense for the BMS just not certain


UPDATE: 20.55 End of charge on the main contacts.

 

[SamTexas]

Thank you Electroddy.

You're right about the third vertical contact point. It's directly connected to the negative end of the pack (pin #1 on my above picture). The voltage difference between it and pin#1 is zero when the battery is at rest, and some mVs when the battery is discharging.

So we now know that the charging points are the same as the discharging points.

I have no idea what to do with the 1.7V A/C on the 2 middle contact points.

Thanks again.

Edit to add: This Ryobi BMS consumes power even when the battery is at rest. 0.222mA, or 4mW at 18.5V nominal. The good thing is that it draws power from all 5 cells so no imbalance is created.

 

[Electroddy]

This Ryobi BMS consumes power even when the battery is at rest. 0.222mA, or 4mW at 18.5V nominal. The good thing is that it draws power from all 5 cells so no imbalance is created.


Thanks for that tip. It's good to know IF I ever need to store my packs. I use the tools so much, I'm probably charging one of my three packs daily if not more . I'll probably kill them with use LOOONG before they go dead from sitting .

 

[Xanda2260]

Thread resurrection!
I'm trying to replace my dead ryobi nicd cells with a lipo pack (5s, 2.2ah) and am wondering if there'sany chance of getting my lithium charger to charge it. Anyone know what these two centre contacts actually do? Any way to know if the charger will bulk charge the pack?
If I can't do it that way, I'll just use a lipo charger, but it would be nice
Any help appreciated

Ta
Alex

 

[bluovalguy]

Thread resurrection!
I'm trying to replace my dead ryobi nicd cells with a lipo pack (5s, 2.2ah) and am wondering if there'sany chance of getting my lithium charger to charge it. Anyone know what these two centre contacts actually do? Any way to know if the charger will bulk charge the pack?
If I can't do it that way, I'll just use a lipo charger, but it would be nice
Any help appreciated

Ta
Alex

The newest Li batteries only have one middle contact (the one on the left looking at the charger.) One of my dual chemistry chargers only has that left connection, and the other two have both. I haven't pulled the BMS off to confirm, but it must go to the temp sensor. Also, the front terminal on the main post is shorted to some degree to activate the battery for charging at +/- (otherwise it only delivers partial voltage.)