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Running brushless at less than rated volts?

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Old 08-31-2012, 07:39 PM
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Zeldinio
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Default Running brushless at less than rated volts?

Ok, so I have a 1.2 size brushless outrunner motor, that is recommended to use 9-10s lipo. Unfortunately, the largest lipos I have are 6 and 7 cell. So my question is, what will happen if I run this motor on the smaller batteries? I realize this may be a completely idiotic question, as I am not an electrical genius. Thanks in advance for any help.
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Old 08-31-2012, 09:18 PM
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Default RE: Running brushless at less than rated volts?

G'day Mate,
I think it will just run slower, because you are using less voltage, It won't swing as large a prop, for the same reason.
As long as the ESC will handle the current, that's the main thing.

Cheers
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Old 09-01-2012, 12:52 PM
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Default RE: Running brushless at less than rated volts?

Lower voltage will make lesser demands on the existing ESC so you are safe there.

You'll get less power if you don't change the prop.

If you DO change the prop, you may get close to the same amount of power, but you'll have to choose carefully.

The decrease in power with your existing prop will be rather dramatic however, so you will not be satisfied.

You COULD run your 7S pack with a 3S pack ( of the same capacity ) in series to make up the difference and end up with an effective 10S.

Likewise you COULD run your 6S pack with a 4S pack ( of the same capacity ) in series to make up the difference and end up with an effective 10S.

In your shoes I would do either of the latter.

However you'll need to charge and balance the batteries separately.

Remember that the add-on packs must be of the same capacity as the ones you have now.

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Old 09-01-2012, 12:57 PM
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Default RE: Running brushless at less than rated volts?

Thanks alot for the info. I knew the power would decrease with the lower voltage, but I wasn't sure if I would somehow damage my engine or battery.

Thanks a ton for the batteries in series idea. I don't know why, but I had never thought of that. I will most likely go that route. Thanks again.
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Old 09-01-2012, 09:12 PM
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Default RE: Running brushless at less than rated volts?

You can wire up your own series connectors or use commercial ones.

The latter is a good idea and will prevent you from having to modify anything you already have.

Plus you'll get more bang for the buck too. Your add-on packs can be used on or for other planes too.

The ideal situation is to get a set of batteries of the same brand that you have now so both chemistry and resistance, etc. are identical.

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