battery and controller question

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lucajo16
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battery and controller question

Post by lucajo16 » Dec 28, 2017 8:19 am

So I'm nearly complete with finishing my first kit and I have a problem I wanted to ask before going further. my controller is rated at 27 amps at 1000watts but I wanted to use a lower AH battery. the battery in question is https://www.aliexpress.com/store/produc ... fc27WHQHAt . I think it will fit as a first time battery. I did plan to buy a bigger AH battery later on but I just wanted something that would take me back and fourth to work. If I have to charge it when I get there its not a major issue. I did the homework on vendors from aliexpress and these guy's were a trusted vendor from here. a question that may answer my problem is does the BMS matter when being connected to the controller? if the battery itself is rated at higher amps would it be ok to fit my controller?
anyways would love to have this cleared up for me.

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dogman dan
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Re: battery and controller question

Post by dogman dan » Dec 28, 2017 9:24 am

27 amps controller will quickly kill that size battery.

But not if you use self control, and run slow. Then you only pull 15 amps, which that battery can handle better.

Keep it below 20 mph, with less than full throttle on starts, and you can use that battery. Really, to ride fast with that kit, you should have 30 ah. 20 would do, but it would not perform real good. With a 20 ah pack, voltage will sag a lot under load, and cause lower capacity on the ride, and lower top speed. But a 20 ah will at least last a few years.

If you are stuck financially, get the 10 ah now, and if your kit allows speed limiting use it. Then get a 20 later, and by running the two in parallel, you will then have a great 30 ah battery, that you can ride long, or ride hard, as you want.

The bms should not be a big problem, but if it is, its because you gave it full throttle on the take off, which will kill the battery.

lucajo16
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Re: battery and controller question

Post by lucajo16 » Dec 29, 2017 7:58 am

Well my program connection (( the one to the controller from the motor )) is the same as the BBS02's. I could buy the program cable and adjust the amp draw from it. I think I got myself to deep buying a 48v but I work and live in a vally where I have a lot of hills. but Ive been told that if I don't wanna struggle to hard on hills that id need a high voltage and high wattage motor. I just don't want to buy something like a big battery and it not fit my bag on my bike. I just want to keep everything in one compartment so I don't have trouble with it. :?
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amberwolf
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Re: battery and controller question

Post by amberwolf » Jan 01, 2018 5:27 am

lucajo16 wrote:
Dec 29, 2017 7:58 am
I just want to keep everything in one compartment so I don't have trouble with it. :?
Don't stick the controller in the bag, heat will kill it.

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dogman dan
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Re: battery and controller question

Post by dogman dan » Jan 01, 2018 8:59 am

That will make a nice two fer..

If you run high discharge rates, you either need a battery made for that, or one big enough.

RC lipo will handle your amps in a 10 ah size. About 8 pounds for 48v 10 ah pack, and it can do 30 amps easy.

Using lipo generally means building a battery with bms, or you perform the functions of the bms on discharge yourself.

If you already bought the cheap ali express battery, you will simply have to tone it down till you get at least 20 ah of it. Or parallel it with just a small bit of lipo, like 5 ah.

Aim for 15 amps, and pedal a bit more on the hills. Bear in mind, you can easily climb a 10 mile long grade of 8% on 700w, with some medium hard pedaling. This supposes you only weigh about 200 pounds of less. The full 1300w will be nice when you get it, but you will just kill your battery fast if you hammer it with 27 amps now. Meanwhile, you won't fail to get up a pretty steep hill with only 15 amps, and 700w.

If you need to climb a wall, then you might have to get off and walk up, but the motor will at least push the bike. if its so steep you drop below 10 mph, get off before you melt the motor.

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