I’m trying to rebuild my Dyson DC16’s battery pack with new + stronger cells and I think I need 18650 of a very specific chemistry.
I’m saying this as the battery pack consists of just 6 x 18650 in series with no balancing circuit whatsoever. As I’d like to keep using the original charger I need 18650s that stay balanced on their own. I read somewhere, that there is a certain type of 18650s that have that property.
Could you please hint me at what battery type/chemistry I need to look for?
The labels of the batteries in the current pack are labeled “SE US18650VT” and the whole pack is rated at 21.6V and 1080mAh. Sadly I couldn’t find any information on it.
I’d love to get a long run time so 3000+mAh cells would be awesome.
They look like Sony high drain cells… I would replace them with Samsung 30Q or Sony VTC6, both very reliable high drain cells. Not sure about the effect on lack of balancing, but they shouldn’t be major problems if you buy from the same batch.
If Dyson originally designed it without a balance charger, then any high-drain IMR cell will probably be fine.
If you can find out what the maximum discharge current was for the original cells that will help you narrow it down a bit, but even if you go highest current cells you could get a increase in capacity with something like a Sony VTC4A.
Thats crazy, I never have seen a Lithium OEM battery without balancing like that before! I had the same batteries in another stick vacuum, they measure about 1.2ah only. I checked the Max draw and it was only about 5amps at 25v, So i replaced it with 30q’s and it ran for 2.5 times longer :).
While its apart I would recommend to get a balance cable and attach it somewhere out of the way, that way you can occasional check the cells and balance charge if required. If you put the vacuum away at storage votages 3.3 to 3.9v The batteries will outlast the machine!
thanks for the replies so far, but I really do think I need to get a specific type of chemistry.
I agree that they should be high drain cells again, but there are definitely different chemistries in that category as well.
So far I never had to deal with battery chemistry and could just select them based on capacity/performance.
I already googled quite a bit and what I found so far is that one needs to use a balancing circuit to charge 18650 in series, or have a secret/old 18650 chemistry, which somehow supposedly makes them auto balance themselves.
First off, I would NOT recommend rebuilding this pack. Much, much too dangerous.
There is so much you and I do not know about this sort of thing. I have a saying that I have to keep repeating to myself all the time. Often times,
“I know enough to get myself in trouble, but not enough to keep myself out of trouble”
This could be one of those times for you.
Several years ago, certain drill pack manufacturers built packs with no balancing circuits. They had poor results, and did away with them. Lots of failures and poor performance. Those packs used a special, older technology cell from Sony that are called “konion” cells.
Here are some pics of an older Ridgid 18V tool pack battery that used some of those konion cells. Ridgid got a bad rep because of them and inproved their packs. Makita did likewise.
Old Ridgid
Here is an old Ridgid next to a newer Ridgid with the balancing leads and circuit, and an old Makita next to a newer Makita.
Here is a link to a discussion of Sony “konion” cells from 8 years ago. Whether what is talked about is true and accurate, I can not verify.
