Hello everyone! When I started building my board there was a lot stuff that i didn’t understand, like what are battery cells and what wire do i need to get for about 70A of current… Now that I know a lot, I would try my best to explain almost everything and if there’s something that i missed, just ask!
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BATTERIES
TYPES OF BATTERIES:
There are lots of battery types but in this territory we usually use lithium ion or lithium polimer batteries (Li-ion, Li-po for short)
When you need more voltage, connect your batteries in series and when you need more capacity, connect them in parallel
Batteries have voltage, capacity and C rating which tells you how much current can you drain from one cell in moment of time
–VOLTAGE: (Li-ion, Li-po)
One cell:
Li-ion: Nominal= 3.6 Max=4.2 Min=2.5
Lipo: Nominal=3.7 Max=4.2
If you get them under min or over max you can damage them
–CAPACITY:
Amper is for current and Amp•hour is for capacity. 1Ah is 1000mAh If the battery is 1Ah and your consumer takes 1A than you can run it for about an hour. There is also that C rating C rating tells you how much Amps you can “pull” from the battery. My batteries are 5000mah and 20C so 5Ah*20C = 100A That means that i can pull up to 100A from them
–CHARGING: (Li-ion, LI-po)
If battery is 3s 1p (2300mah) for example 3s * 4.2V = 12.6V, so that is the voltage that your gonna be charging your battery at You also need to limit the currant because if you charge the battery too fast it can also explode You need to look for charging C rating, multiply that with capacity and that is your maximum charging currant!
If there is more questions, feel free to ask!
Only true for Lipos. Not 18650.
Amp/hour is not the correct unit for capacity. Amp•hour is.
False. Depends on the battery. Some are capable of 0.5C, some are capable of 5C. Refer to the spec sheet.
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Okay, thank you for correcting me but Li-po and Li-ion voltages are same
No they’re not. Li-ion: Nominal= 3.6 Max=4.2 Min=2.5
Lipo: Nominal=3.7 Max=4.2 Min= There is alot of different numbers here but abselout min is 3.0 before the battery takes alot of damage, but 3.6 If you want your batteries to last and not loose capacity
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Would also add typically 1C is safe charge rate but in general slower is better (cells have internal resistance and build up heat like any other component more current equals more energy dissipated as heat due to resistance, C rating is a round about way of communicating internal resistance). The C rating is a maximum and ideally you want much higher than you will ever draw, higher current draw on a cell with high resistance will cause more voltage dip while under load as well.
Also would add take C rating with a grain of salt look to third party discharge tests when possible.
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IMO,
“Quick and simple explanation of electronics” -> “Quick and simple explanation of batteries”
No talk about any electronics… yet at least.
should i worry about frying the ESC or motor because the original battery is 33v, while my 12s1p will have 50.4v?
yes
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Capacity (wh) is the same. Amp hours (and therefore maximum current) is increased in parallel. a 1s12p board will not have 12x the range of a 12s1p board (even in an ideal world where 1s is as efficient as 12s)
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Capacity is measured in amp•hours not watt•hours. So @DjamboBuksne is correct here.
Energy is measured in watt•hours, range is more closely related to energy than capacity, so you are kind of correct in that aspect but had the terminology messed up
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oh whoops. Thanks for the correction.
Watt hours is energy and you calculate if like this; Voltage*capacity
If you need to calculate something else, there is one simple formula, R=U/I R-> resistance U-> voltage I-> current
And also power -> P=U*I
Maybe read a bit more or look a bit more there is already a thread like this appreciate the effort though
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Thank you 