Hey there guys, I am in the process of putting together a dual hub motor build. I am stuck on which battery setup to get, and not getting much feedback on my build thread. Right now it’s between just getting a prebuilt 10s2p like Jason’s SPACE Cell or Torqueboards pack. Or building my own Lipo/8650/26650 battery pack to fit the setup I am going for just right. I want it to be slim, I don’t mind if it’s long, but i’d like the batteries to be around 1.0-1.2 in (30mm) or less in thickness. The size of the SPACE cell looks about right, but If i can get away with a few less goodies, make it thinner and save some money I will put in the effort. The main thing holding me back from just buying one of these packs is a concern voiced by Lever that I may experience some cutoff with these cells on his dual hub motors in high acceleration. He is also working on a new pack I guess, so maybe it’s best to wait for that? Unless there is a custom, thin 12s pack that I am not finding? I will buy it immediately, so if you’re selling let me know!
i would go the 18650 route do to it being the safest, lipos can explode and really cant take any damage. 18650’s are in a metal can that can take some damage in both physical and electrical situations. also cells like samsung dont explode or shoot fire no matter what you do to them.
right now im building my own 18650 battery using battery sleds used in vapes because they can take the high current.
this lets me recharge them on 18650 cell chargers like the nitecore d4 and i can remove any cell i want at anytime to check to make sure its still good. little more labour intensive but gives you piece of mind.
Right on, thanks for the info. I was watching some videos on those Samsung cell tests when I was trying to get my bearings on all the differences, and best suppliers. They look pretty redundantly safe.
So you’re going to take out like 30 some cells individually every time you charge, or will you have some balance charger solution for when they’re all installed in the pack as well?
im gonna get a 6 bay charger and just charge them 6 at a time, shouldnt take that long.
I’d buy 5 of them Are you building a 10s or 12s pack? How are you planning on putting it together? I’d be interested in seeing some rough dimensions.
its gonna be using these sleds http://www.brimstonevapeco.com/product-p/slim-dual-18650.htm
im gonna solder solid copper to each contact and put it all in to a box under my board. size wise it will be shorter then the space cell because no bms.
I am contemplating a similar Dilemma myself. I have 12 10000mah cells sitting on my desk in front of me and I’m wondering if I should make a 10S or 12S battery?
Make a 12s! We need more people figuring out the best possible configurations to keep them sized to the board. I would love to see a little writeup.
Is BMS not necessary with that configuration?
I’ve been building my packs(18650) with no bms,and they seem to be working just fine. I’m guessing they don’t get the full charge but must be close to full. The last 8s3p set up cost me just over $60, and some time.
My first build was 6s2p using 18650’s that was six months ago is still working. It has about a 4 mile range with a top speed on 22mph. The packs were made with used batteries that I took out of my cordless drill that is about 3-4 yrs old. I believe all batteries were Samsung. I’ve been using a smart charger that I got on line that was specifically used for lithiun ion batteries.
a bms is never necessary but it is a nice safety feature. as long as you have balance leads and watch your voltage on the ride your safe.
Where did you guys read that the Samsung are safer? I can’t find any info saying that. Some have a high discharge rate but can’t find anything that says they are less likely to burn up than other li-ion when abused :over charged, over discharged, or banged.
Why seal the cells up so there’s no way to check and balance them!? Bulk charging without knowing what the cells voltages are is asking for trouble and really frowned on. Even if you had some gaps to get some prongs around each cell you could at least check them periodically and do some balancing with a modified phone charger or some resistors to discharge. Otherwise if you’re charging to full capacity at 4.2…danger. Maybe at least only charge to 4.15 or 4.10. Some people would freak if they saw unmonitored cells like that. I’m building a huge 48 cell 12s pack without a bms or balance leads but plan to still balance in the ways I mentioned above. Also relying on the esc low voltage cut-off. And with such a huge pack I’ll likely only charge to 4.1 and it will last much longer
im going by samsungs in house test and just general reviews.
and no one runs it where they cant balance, any 18650 battery made here is made with a bms or balance leads.
I can’t find those Samsung safety claims.
The guy above is going without anything to monitor
its on the datasheet for the cells
Here’s a sheet for the Lg hg2 cells. The tests are on the last page. They’re similar and showing doing just as well. I’ve never heard of a li-ion cell for sale that was considered safer.
But after looking at both these…they’re safer than I though.
I think that regardless of the brand, all lithium batteries should be considered dangerous and treated with respect.
If you are using the VESC, divide 8600 by your motor KV and that will give you the max voltage you should use. Of course this isn’t some golden rule just a general guide.
@AbrownMN If you are going to power hubs you will want some amperage for initial take off and acceleration unless you will be installing a VESC. The VESC can make a weak pack work by limiting the current draw but, in my opinion, it is a big compromise. Go as big as you can with your battery pack and you will not need to put the VESC into “nanny mode”.
Board looks nice Chaka… I want one