do this with al larger battery and a larger C rating and it would overpower the motor.
so I thougt. but if itâs only the pottential thats ok
@d-kay You need at least 20C for your build to work well. Especially if you only have 2200 mAh batteries
Hah yeah no worries yeah the relationship between the C rating and Ah does tell you overalll current, but itâs really kind of a matter of the choice by manufacturers to make the C rating based on Ah.
I suppose it makes sense because if they use the same chemistry and techniques, but just increase the capacity for the battery it also probably typically can deliver proportionally more power as well but itâs not strictly true that increasing mAh also increases the total current you can pull/push through it. The reality is the batteries all have their own internal resistance and they get warmer when more current flows like with any resistor, so too much current and the battery gets too hot and basically starts cooking the components that make it up.
Also to add the max Amperage rating (C rating) on a battery is telling you what is the max you can pull from it without it overheating it doesnât tell you how many amps will flow at any given time. The amperage is going to be based on the rest of the circuit the voltage is being applied to, if the rest of the circuit has a low resistance then the amperage at a given voltage will be higher, if the resistance in the circuit is higher then the amperage will be lower (if the circuit opens the amperage will stop flowing). So really your issues when looking at a battery are based on the 3 specs in this way:
Voltage - if too high, the motor or other components in the circuit can get damaged from too high a voltage. This is because the components have a particular resistance based on the materials theyâre made out of. Apply a higher voltage and due to their resistance the current that flows through some components will be too high. Power (W) dissipated by a component is calculated as I^2*R = P where I is amperage, so amperage squared times the resistance tells you power, so more amperages means much more power loss. For an example say you have a 1 Ohm resistor you apply 1V to it then you get 1V/ 1Ohm = 1A of flow if you want to know the power you do 1A squared times resistance, so again 1W, say we change to 2V but still 1 Ohm resistor, now itâs 2V/1Ohm = 2A and the power is 2A squared times resistance, so 4W. So we doubled the voltage it doubled the amperage and it quadrupled the power dissipation needs (that 4W is usually just heat coming off the device, and 4W is actually a lot for a passive component like a regular resistor).
Amperage (typically described with a 10C-20C etc. rating) - There is the momentary flow of electricity rate of electrons through the circuit at any point. With regard to the battery though the C rating helps you determine what is the max Amps rating for the battery that is how much current it can supply before it starts to damage itself (due to power dissipation as described above).
Amp Hours different from amps, this is the amount of time current can flow at 1A at the batteries voltage. So if the battery says 5Ah it means you can draw 1A continuously for 5Hr (or 5A for 1 hr, either way). A more âaccurateâ way of describing the power in a battery is to also take into account the voltage of the battery. If you want an âapples to applesâ comparison between batteries that have different voltages to see which has âmore powerâ you want to compare Watt Hours, simply take the Ah and multiply by the volts, this tells you both âhow much pushâ and âhow fast for that much pushâ can the battery do work.
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Know that was already long but just wanted to add another little nugget of info that helps just grasp the whole thing. As the temperature in a component (battery or resistor or whatever) goes up typically the resistance also goes up so it is a self feedback type situation where the resistance creates heat and the heat creates more resistance, this is why heat sinks are a thing, at some point the heat around the component builds up faster than air can naturally draw it away and you need a heat sink to give the component more surface area to dissipate the heat into the air (or possibly chuck a cooling fan on the heat sink like with desktops or server processors).
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I wil be shoure to use heat sinks on my build so it wonât overheat.
does anyone know where I could buy aluminum heatsink cassings for al my components to fit in.
Ah sorry again didnât mean you really need to use heatsinks (sometimes more information is too much) just saying in general why you see them used in various electronics.
In the case of the e-skateboard the only thing you might want to use heatsinks on in most cases is the MOSFETs on the ESC that deliver the power from the battery to the motor since they can get quite hot with all the amps flowing through them and constantly turning on and off very quickly, but in the VESC tool you can see the MOSFET temperatures (along with a few other temperatures) and see if itâs really necessary or a good idea to throw some heatsinks on there. At least one other forum member made an aluminum case for their VESC that doubles as a heatsink but in most cases itâs not actually necessary.
I was alraedy going to use heatsink so no problem. @wafflejock and I am stil looking for a cassing and the aluminum seemed cool.
how could it be a bad idea to put on heatsink
Yeah true youâre not gonna really hurt anything so long as you keep it all safe from shorting just figured Iâd be explicit about it not usually being an issue really (I tend to over-explain since I donât know peopleâs backgrounds here yet at all). Always funny when Iâm giving advice or discussing with someone then see the board they made puts mine to shame 
Iâm completely new so thatâs not very likely and all help and advise is always welcome. @wafflejock
does anyone know another place to buy good lipoâs for hobbyking is apparently not that good.
hobbyking is good
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hi there. can i know what type of esc that u used ?
guess i should show what it eventually became.
deck: some old deck from a 40 euro board from a toy shop i had lying around
trucks: from a preassebled madrid board i have.
wheels: hawgs 78a 70mm
esc: hobbyking 4.12 vesc
battery: 10s2p Panasonic NCR18650B 3250mAh - 6.7A
mount: hobbyking motor mount
motor: hobbyking sk8 5045 149kv (could no longer find these on the site)
drive: a shitty m3 9mm wide belt drive from banggood i forgot the ratio of. ( kinda got scammed here cuz it didnât mention anywhere that it was m3 or 9mm wide)
remote: the standard hobbyking rc car remote
max speed about 31.5 kph. acceleration is decent ( beats my evolve bamboo gt in eco mode)
the belt has a tendency to slip when braking so always have to go very lightly on those.
range: can comfortably do 15km, 20km on reasonably flat terrain.
on a max range test i got 25 km while constanly giving full throttle. by the end it only went about 20 kph. so in good conditions of a flat road i should be able to squeze out 30 km iff i go lightly on the throtle and stay at 20 kph.
itâs not the prettiest but iâm still proud of this as it is my first build. (itâs a couple years old now and i did the range test yesterday)
donât ask why there are wet crocs. itâs a joke from another chat
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