Noob question thread! šŸ˜€ ask your questions here!

General Discussion
138

You need to wire the batteries in series.

139

Thanks. Now if I wire them in series, what numbers do I end up with. Ive been reading a lot and Iā€™m still confused. That way I can understand the other parts I need like bms, VEsc, antispark

140

oh shit didnt notice thereā€™s a stupid questions thread, here goes;

iā€™m seeing all these premade LiPo cells floating around on hobbyking like zippys, how hard are those to put integrate into a BMS? like say if i got three 10S 30C packs to make a 10s3pā€¦how hard would it be to slap a BMS on them?

and would you have one BMS per pack, or one for the whole thing?

141

In series that would be 12s 3000mah. In parallel it would be 6s 6000mah. I would suggest parallel, would give you a lower top speed and longer ride time, at least until you get used to it.

Thereā€™s a section for builds, browse it and you will see what people have done I. The past that has been successful.

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142

Look at @Namasakis threads, heā€™s the king of Lipos and BMS.

143

oh yeah, like this one

looks like the BMS literally only interracts with the cells through the negative lead, which is interesting, for some reason i thought it would be more complicated and need to be in series with both VSCs or something. and he just straight up solders the leads oh the packs together, no funny buisness. Looks almost easy?

144

Thanks. I was under the impression that I would get 6000mah. 3000 doesnā€™t sound like much. Itā€™s like a portable cellphone battery packā€¦

145

watt hours is a better indicator you get watt hours by multiplying the total pack voltage (6s is 6x3.6= if youā€™re using lipos, 21.6 volts) by the amp hours (6000mah is 6ah) to get watt hours. and 10 watt hours roughly equals 1km of range

so! assuming the cells are all 3000mah individuallyā€¦ 6s4p is 21.6volts x (3Ah x 4parallel) = 21.6x12 = 259 watt hours = ~25km range 6s3p is 19.4km 6s2p is 12.9km 6s1p is 6.4km

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146

So where does the c come into play?

147

Series will add the voltage, parallel will add the amp hours and discharge rate. For the VESC higher voltages are definitely recommended depending on your kV, and hub motors generally have issues with heat dissipation so raising the voltage should lower the amps and heat, however how heat in a motor is generated seems to be debatable.

In series you would have 12S * 3Ah = 133.2Wh with 20C discharge and in parallel you would have 6S * 6Ah = 133.2Wh with a 40C discharge rate. Since lipos are capable of discharging high currents they generally do not need to be wired in parallel, your pack in series should be capable of 60A continuous and 120 in parallel. Li-ion packs need to have cells in parallel since their discharge rates are much lower (eg. 20A continuous for Samsung 25R cells).

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148

Wow thatā€™s confusing but easier than the sites Iā€™ve been looking at. Iā€™m going to read it about 10 more times lol

149

C rating is what they use to show the discharge rate of a lipo pack. You multiply your packs amp hours (Ah) by the c rating to get max discharge rate. eg 20C * 3Ah = 60A

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150

So much math. But thanks so much for your help. Going to try and figure out how much range I would get if I went series

151

use this thing

does a lot of the math for you, even if the interface is a little weird. make sure to hover over all the nodes to see what allā€™s there
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152

I think thatā€™s what you showed me earlier. Iā€™m not on a computer right now though. A bunch of unfortunate events have me 4/4 computers down.

153

That setup is very easy.

154

People usually estimate that 10Wh = 1km of range, your lipo is 133Wh in both series and parallel so your range will be around 13km.

155

So the distance would be the same either way? I thought I understood that I would get about 13km with series but I thought it was about 25km in parallel. What is the difference between the 2? Isnā€™t parallel suppose to give me more distance and less speed and series to give less distance and more speed? I sound so stupid on hereā€¦

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156

speed is based on the number of cells in series you use parallel to add range on that speed its not like adding more in parallel drops your speed

so a 6s4p is slow but lasts a while (24 total cells) a 10s4p (40 total cells) is faster and lasts a while as well

i guess another analogy would be like cylinders. as you add cylinders you get more powah, and parallel is adding more gas tanks

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157

Thanks for the input on my build. Do you have any experience with the ollin vesc/heatsinkā€¦ I want to know if I will need a computer to set it up or if itā€™s good to go out of the box? I currently donā€™t have a computer.