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Is it a bad idea to convert a newish 3s pack to 4s?


#1

ive been using my board for the past couple of months, Im wanting to upgrade to an 8s set up just for more power and speed.
I am currently using 2 3s packs in series they have had around 15 cycles on them, is it ok to buy a new single cell to that pack or is it a bad idea, but since my packs are not that old :confused:
@barajabali
@lowGuido
@longhairedboy
and any one else any thoughts?


#2

buy a single cell from hobbyking that matches the specs of your batteries and then put 15 cycles on it. now you should be able to add it to your 3s pack.

Might not be the most elegant or precise method, but should work. Should.

Don’t forget aluminum solder.


#3

ahhhhhh thats a great idea didnt think of that hahaha just time consuming tho
why the aluminium solder?


#4

Typical lipo cells use aluminum tabs because they usually crimp the cells together. You will need aluminum solder if you plan to join your existing lipo to a Hobbyking single cell. How I made my lipo packs slimmer!


#5

Trying to add a cell to your existing packs will not only be a lot of hassle moving either the blk or red power wire, replacing the balance harness with a 4s harness and trying to solder aluminum tabs. And good luck finding a single cell that matches your packs cells in capacity, C-Rating and internal resistance.
My advise to you is don’t go there.
I think a better option would be to sell your 3s packs on the forum market place and just buy 2 new matching 4s packs like the zippy flight max 8000mah


#6

you can buy a single cell…
but its probably more cost effective to just buy bigger battery packs and be done with it.


#7

or i could just go with a 9s set up with a extra pack?


#8

That sounds like the best option


#9

are there many bms choices out there for 9s?


#10

Yes. Battery supports.com is pretty good


#11

Using a BMS with Lipos is also a great idea and eliminates the need for low voltage alarms as well as the hassle of using expensive balance chargers.
Just stay with known quality BMS choices like bestech and battery supports. And choose a BMS with a high enough continuous amp rating to allow discharging through the BMS. And Check the low voltage setting on the BMS.
Bestech comes default at 2.8v and that is too low for Lipos. Better 3.2-3.4v.
You can have the parameters custom set when you order it.
I’m not sure about battery supports.