Hi, I need help deciding on cells. I found a guy who will spot weld the battery pack for me, now I just have to decide on the cells. I will use a single Flipsky 6374 motor with 85mm Wheels and Flipsky VESC 4.2. I can’t decide between: A) 10s3p config. with Molicel INR18650-P26A 2600mAh- 35A (115 € for the cells) B) 10s2p with Samsung INR21700-40T 4000mAh - 35A (144 €)
To say truth i dont know the answer) Im planning to build battery too and im thinking on 21700 40T, as 2p cpnfig. But again, i dont know what is better choice.
Well i feel better that someone has the same dilemma, but that doesn’t really help Maybe someone will chime in who has some experience with the Molicels. I bet the Samsungs are more reliable, and what not, better size to energy ratio,… But the Molicels are so dam “cheap”
You should make SURE the person welding the battery knows what they are doing, and knows it needs to be a high-vibration battery.
Do you have photos of their past work?
He got recommend to me by a Friend who is into RC stuff. I’m pretty sure he knows what he is doing. But thanks for the tip!
I’ve been comparing these, recently. Well actually it was the Molicell P26A (18650) vs. Molicell M42A (21700). As Samsung cells don’t exist in the UK at the moment, well not ones we trust anyway.
I’m making a 4P pack, but I figure the numbers will help inform your choice.
Which does make your two packs (cells) weigh nearly identical 1.38kg vs 1.33kg.
21700s have it by a pinch.
Current capability, both 35A, but you get 3 of them! 105 Amps vs, 70 Amps.
Although you might not need the max current, charging/discharging Li-ion gently extends it’s usable life, so more cells means less strain on each.
Space - Damn you 21700s, I wish I could fit 4P of you in this enclosure, we’d go so far together.
For me this is a tie finish, I have 48 of each next to me, I would love the extra range of the bigger cells, but this isn’t for free, we’re carrying the extra weight, and paying the extra cash too.
Probably best to choose whichever packages better on your board, as a stealthy enclosure design tips the balance pretty quick.
Molicell P26A are good cells, and in ready supply at the moment, which is more than I can say for Samsung.
I don’t think space is as much of a difference as you think, here’s 20% of your pack in each flavour:
Similar footprint, and 15% less height than 21700s
I just realized that the Molicel INR21700-P42A 4000mAh - 45A are in stock again on NKON.nl. And now I’m considering:
A) 10s3p Pack mad from Molicel INR18650-P26A 2600mAh- 35A (115 € ) 10s3p = 7.8 Ah, 36V 105A; 288Wh so 28 km aprox.
B) 10s2p Pack made from Molicel INR21700-P42A 4000mAh - 45A (123,87 €) 10s2p = 8000 mAh, 36 V 90 A; 288 Wh
so basically the same range for the same money. I get that its better to demand 30A from a B.pack capable of 105A than from one capable of 90A. But is there something else to consider? What about voltage sag and longevity of the batteries? Which ones will charge faster? Can someone suggest where to get a good charger and what too look for in a charger? I prefer safety and longevity to speed of charging.
Haha, same batteries as me (4200mAh), I couldn’t decide so I bought both
Sag should be reduced and longevity increased by sharing the load between more cells.
Theoretically 18650 should be healthier for longer (as we are working at a lower ‘C’) all other chemical effects being the same.
Also these could be charged quicker, as your charger current is split between more cells (C * Parallels). Although longevity of batteries is very directly related to charging current, so always better to charge slow.
I went with a Wate Charger, and have been pleasantly surprised (although it does have a noisy fan, that helps me know when it’s done) https://www.aliexpress.com/store/3113065.
Mine’s 4 Amp for a 4P. So 1Amp per Cell charging current, but that could be faster but I’m not in a hurry.
Thanks for the tip! So if i decide 10s3p, I should go for a 3 A 36 V charger? Any advice on the charging port? Is some type better than another?
For 2A/3A charging current the 2.1 mm / 2.5 mm are more then enough.
The biggest battle is waterproofing them when not in use. I don’t really like any of their options for that.
Their DC & RCA options are at about their limit of current capacity, so not ideal. And Anderson’s are too big and exposed.
The GX-16 looks nice, but they give you the wrong end from the picture, as the esk8 should have the female (socket), and the charger the male (pins). This is just best practice to make your ride safer.
So XLR (if you have the space), or XT60 (if you fancy a waterproofing challenge).
Or like me, cut off their connector and find your own one that has a waterproofing cap, but then I do love myself a good connector.
Or like Skitzor says. It’s only 3A. So a little DC jack will be fine.
This is what many longboards seem to use.
and they’re cheap to replace. CNlinko or so is 10-15 euro / pc. You’ll have 10-15 of the 2.1/2.5’s for that money
No, you need a 42V charger, which are commonly mislabeled as “36V” chargers. The problem is that 43.8V chargers are also commonly mislabeled as “36V” chargers. So if the seller cant tell you the actual cutoff voltage, then don’t buy from that seller.
Thx, that is some information you can’t get just anywhere! Much appreciated!
Hi, can anyone chime in if this looks like a good charger? Ma battery pack is a 10s3p pack made from Molicel P26M (cont. current 25 A)
Yeah it looks fine.
It looks like my Wate model I bought from Aliexpress