That charger seem OK similar to the bmax 6 ac that others use. As for bms it’s not necessary if you are going to use one of these charger you just have to be carful with the voltage and not running them to low so my esc has a cutoff of 3.4v per cell so x6=20.4v and I now run a volt meter on my board. And as long as you balance charge them with that charger the levels should stay good.
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Ok I see. Can you link me to the volt metre you’re using? Also, how do you decide on the cutoff voltage? Thanks
Will get a link just on eBay https://www.ebay.co.uk/itm/331724469467
The cutoff is what’s been researched by a lot of people from Rc community, when the voltage drop to low they can get damaged and possibly catch fire which is why you need to take lots of care with lipo when discharging and charging.
I think you have some good suggestions and options already, but wanted to clarify the C rating of the batteries. I wouldn’t go below a 100a ability of the batteries (my minimum) as most are marketing from the company and totally unreliable and likely incorrect. So an example is the 3s 5000mAh 20c (20c * 5Ah = 100a). The better they can provide, or the more in parallel to lessen the load - the less voltage sag - and if you don’t heavily draw (=heat) the batteries they will also last longer.
I also recommend DIY w/ two 3s for 6s. I usually get the thinnest (C dimensions on HK) batteries i can find - and with only 3s you can get some super thin ones around 20-25mm. Nice and stealthy!
Cutoff voltage - i set mine to 3.6v because with a little bit of sag you can pull them lower and i don’t want to damage my cells. Also get a lipo alarm to yell when you hit that voltage - vs just relying on the ESC to let you know, or by feel.
GL!
Thanks for the additional info. I’m guessing to be safe getting two 3s 5000mAh 25C would be best?
If you could get 30c is the ideal and what I run and have no issues but I am looking to upgrade and get that pre build 10000mah or find some decently prices 3s 10000mah to get more mileage as get 6 miles at the moment but would love more.
I read through the post quickly so I might have missed it but did anyone mention that you’ll need some sort of anti spark solution? And I would recommend that you get the highest C rating you can. It really makes a difference in performance and range using 60c packs over 20c It might seem like over kill but really it’s not. Even with a 300a battery, there will be some voltage drop under load.
I thought the C rating just determines highest discharge rate of the battery and it depends on the motor to pull the necessary current from the battery? I might be wrong since I’m new at this.
You are correct. The motor draws the current. If your using a standard RC Esc, the throttle controls the amount of voltage supplied to the motor and the amount of current will be determined by the amount of load placed on the motor. If your using a Vesc in current control mode, full voltage is supplied constantly while the Vesc limits the amount of current the motor can draw. More throttle=more current. Now, you are also correct concerning the C rating of the battery. The C rating X mah = max constant discharge rate. There is however one other important factor. That is Voltage sag. The more current you draw from the battery and the closer you get to the max discharge rate, the more the voltage drops. Reducing power and range. The reduction of range is a factor that I have just recently discovered testing various batteries on flat and hilly conditions. And the science to back it up is this. Voltage X Capacity /G = Range The value of G was 22 with my 145kv hub motors The value of G was 18 with my 230kv belt drive with 16/36 gears So as your voltage drops, your range is decreased. This is why you want your max discharge rate to be as high as you can get it. There are two ways to achieve this. Some have used multi rotor packs with very high capacity and low C rating. I chose lower capacity with very high C rating. 5000mah X 60c for 300a discharge rate. Higher C rated Lipos tend to have lower internal resistance which makes them more efficient and less prone to heat.
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Great post @Namasaki! @r0ymanesco - listen to what he’s saying here. If you look at some of the battery tests (mooch is amazing for these) you can see the voltage sag he mentions.
The big impact to range on sag is both heat and reduced battery capacity (you get less than the claimed xxxxmAh’s).
here’s a good example:
It’s a LOT of squiggly lines… but the things to look at are the big “sag” on the far left as you try to pull more and more amps from this 18650 - and the corresponding poor capacity ( 1000mAh capacity @ 20a discharge of a 3100mAh cell!) when you pull too much amps from a cell. This is an extreme example, but really illustrates performance at different discharge rates. The heavier you draw a cell the more heat it generates - losing energy to heat is likely a huge reason for the poor capacity.
HTH!
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I see, thanks @Namasaki and @sl33py Great info, I will try to get the highest C rating I can afford.
How did you get that meter to read voltage instead of percentage?
I use these 2s packs in series. Its a simple setup and keeps the battery low profile. For 6s you would only need 3 and you could charge them all at once with a 6s balance charger or put more in series and use an onboard BMS as I did and charge with a laptop charger. http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=52279
Great, given that this is tried and tested, I will be getting three of these then. Cheers 
So far I am really stoked with the performance of these batteries and the hard case is a huge plus. Check out my build thread here:
When buying on Hobbyking.com, create or log in to your account first. They tend to give better prices when your logged in. You should get these batteries for $25.79 ea. If there showing a higher price, sit on the page until they pop up a discount offer. Service has been great buying for Hobby king west warehouse lately. Their delivery time is really fast!
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Button on the back changes it
okay this much science made me smile 
you really sound like you know this stuff man i wish i could be thesame. i just forgot half the stuff i read 
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Is it possible to use a single lipo battery with 35c 6s 4200mah
Is it possible to use a single lipo battery with 6s 20c and 4200mah battery for electric skaye board
If you want to run 6s it is recommended to not use a Vesc because of high current. This is what I’ve heard, I haven’t personally tried a Vesc with less than 10s. As for the battery, get something that will handle high current and yield long range like this:
http://www.smc-racing.net/index.php?route=product/product&path=67_119&product_id=467