Battery adapters - words of caution

[armalites]

Battery adapters are mentioned fairly often on here, I've used a cheap generic unit to run new Dewalt batteries on one old Dewalt unit that wasn't worth replacing and it works fine.

I suspect it all depends on which brands your are converting too/from.

So to the story,

Youngest bought all eldest's old Ryobi kit and he only a couple of decent size batteries and they just don't last like my Dewalt ones do. We bought a Dewalt to Ryobi adapter and it works fine and the grinder runs much better with the Dewalt battery. I had always stressed that he shouldn't run them till they are absolutely dead because the way the protection is done in Dewalt and Ryobi is different. This week he was grinding some bits for his tractor and borrowed a couple of my batteries. Flattened the first so put it on charge. He must have forgot what I said about not nrunning them completely dead because the seocnd battery does not charge now. I'd tried all the usual, brief spike to get enough power to make it charge. I opened it up to have a look and found that 3 out of the 5 banks of cells are down as low as 0.5V. I'll try and get some charge into those banks with a bench PSU

There is no doubt that it was running the Dewalt battery on the Ryobi grinder and running totally dead that's killed it so it's something to be aware of if using an adapter.

Since this happened we've order a non genuine Ryobi battery and I have to say for the £22 it cost it's very nice, not sure if it really is 6ah but the reality is I'm looking at a £50 doorstop Dewalt battery at the moment.

I am fully aware I can fix my Dewalt with some new cells but I'm going to try and charge the individual banks in situ with a current/voltage controlled supply first

If you are using battery adapters, remember why you are using them and use them with caution. I had always been someone who did not want multiple battery platforms but sadly sometimes it's the only way. I am sure many of you use them all the time and have no issues but it's not a coincidence that a battery I've run with no issues for 4 years suddenly dies after running on a battery adapter.

 

[eLuSiVeMiTe]

Battery adapters are mentioned fairly often on here, I've used a cheap generic unit to run new Dewalt batteries on one old Dewalt unit that wasn't worth replacing and it works fine.

I suspect it all depends on which brands your are converting too/from.

So to the story,

Youngest bought all eldest's old Ryobi kit and he only a couple of decent size batteries and they just don't last like my Dewalt ones do. We bought a Dewalt to Ryobi adapter and it works fine and the grinder runs much better with the Dewalt battery. I had always stressed that he shouldn't run them till they are absolutely dead because the way the protection is done in Dewalt and Ryobi is different. This week he was grinding some bits for his tractor and borrowed a couple of my batteries. Flattened the first so put it on charge. He must have forgot what I said about not nrunning them completely dead because the seocnd battery does not charge now. I'd tried all the usual, brief spike to get enough power to make it charge. I opened it up to have a look and found that 3 out of the 5 banks of cells are down as low as 0.5V. I suspect it's done for but I'm waiting for a new bench power supply to arrive so I can try and get some charge into the dead banks.

There is no doubt that it was running the Dewalt battery on the Ryobi grinder and running totally dead that's killed it so it's something to be aware of if using an adapter.

Since this happened we've order a non genuine Ryobi battery and I have to say for the £22 it cost it's very nice, not sure if it really is 6ah but the reality is I'm looking at a £50 doorstop Dewalt battery at the moment.

I am fully aware I can fix my Dewalt with some new cells but I'm going to try and charge the individual banks in situ with a current/voltage controlled supply first

If you are using battery adapters, remember why you are using them and use them with caution. I had always been someone who did not want multiple battery platforms but sadly sometimes it's the only way. I am sure many of you use them all the time and have no issues but it's not a coincidence that a battery I've run with no issues for 4 years suddenly dies after running on a battery adapter.

DeWalt protection is in the battery. Might just have been coincidence. Touch wood I'm still running batteries from 2017 with no issues.

I use adapters for old nicad DeWalt. Hammer drill and recip saw.

Avoid ones with usb power. They will fully discharge a battery if it's left on the tool overnight.

 

[Kram]

Dont blame the adaptors for firstly, poor quality protection in the original battery, and incorrect use by the user.
I have some lipo 5A packs that have zero built in protection. Ive been using them with tools since 2015 and still running well.

. I'd tried all the usual, brief spike to get enough power to make it charge. I opened it up to have a look and found that 3 out of the 5 banks of cells are down as low as 0.5V. I suspect it's done for but I'm waiting for a new bench power supply to arrive so I can try and get some charge into the dead banks.

Doing this requires a lot of care and could easily cause a delayed fire if done wrong. If you dont know your way around lithium battery tech I suggest replacing with a genuine battery and scrapping this one.

 

[armalites]

Dont blame the adaptors for firstly, poor quality protection in the original battery, and incorrect use by the user.
I have some lipo 5A packs that have zero built in protection. Ive been using them with tools since 2015 and still running well.


Doing this requires a lot of care and could easily cause a delayed fire if done wrong. If you dont know your way around lithium battery tech I suggest replacing with a genuine battery and scrapping this one.

It was mostly down to the user which is annoying as I had stressed many times not to run them totally dead. I didn't specifically blame the adapter in my post but it's something people need to be aware of given different brands do stuff differently. If the battery had been swapped when it was down to one LED then I'm sure it would still be fine. Most/all battery adapters simply tap into the positive and negative so any communication between tool and battery is most likely not there. The Dewalt battery does have built protection but given a Dewalt battery has 8 connections and a Dewalt tool has 4 then it's easy to understand how just connecting to the positive and negative could be an issue. Ryobi tools are famed for the fact they can still use the original Ni-cad batteries so they clearly don't communicate with the batteries in the same way a Dewalt tool does

I've played with/replaced quite a few Li-Ion cells and I understand the risks.

Often the reasons for using an adapter are, your brand doesn't do the tool you want, you don't want multiple platforms or you can't afford to buy new batteries.

I have no issues chalking it up to experience and buy a new battery but the reality is we could have just bought a couple generic Ryobi batteries for the cost of a Dewalt hence the words of caution.

 

[Kram]

A properly designed battery should not delegate per cell under/over voltage protection to the tool and very little communication is needed. I'd disagree its a bad design of the Dewalt. It may be the battery uses a signal to tell the tool it should cut out, but if a bad connection of failure happens in the tool, it could kill the battery or create a fire risk.

Its not like we are talking about cheap far easten tools/batteries. Branded stuff costs a huge premium!

It implies the battery does not have a mosfet on the output to save a few pence, but does it have a thermal fuse or sensor?

Reminds me that the Lidl Parkside batterys in 2020 or so, started saying "Now includes balance charging" on the box, as a Unique Selling Point. I bloody well hope so because charging series cells without balancing can overcharge, and that is a very real fire risk. Mine were all bought before this change on the box.

 

[armalites]

A properly designed battery should not delegate per cell under/over voltage protection to the tool and very little communication is needed. I'd disagree its a bad design of the Dewalt. It may be the battery uses a signal to tell the tool it should cut out, but if a bad connection of failure happens in the tool, it could kill the battery or create a fire risk.

Totally agree, a properly designed battery used in it's intended location should not pose any risk which brings us back to the reason for this thread.

From what I've read the circuit board in a Dewalt battery is only charging protection with balance connections and temperature sensing whereas the circuit board in a Ryobi battery is a totally different beast. I think this is where the issue lies, the Ryobi tool just needs to see a +ve and -ve because their batteries do there own control which is why the batteries are able to backwards compatible(probably also why the tools are cheap and batteries are expensive) but the Dewalt tool is in charge of looking after the battery from a usage point of view.