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Voltage regulator question

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Old 05-31-2011, 10:46 AM
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jblloyd
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Default Voltage regulator question

I have an application that requires 7.4v (designed for lipo)but I would like to use an A123 battery instead. The problem is that the A123 cells are 3.3v so I will have to use a 3 cell pack (9.9v) and regulate it to 7.4v in order to get the required voltage. It seems that all current voltage regulators are designed to reduce 7.4 volts to 5 or 6 volts so lipos may be used as receiver batteries. Does anyone know of an regulator that would work in this situation?
Old 05-31-2011, 11:08 AM
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huck1199
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Default RE: Voltage regulator question

I have not seen a 7.4 regulator. I use 2 cell A123 in large planes ( .60 and up) for receiver packs. The extra weight and bulk make them unsuitable for small planes. If you are powering a motor, it may be OK as is if your motor can handle a 3 cell lipo.
Old 05-31-2011, 11:29 AM
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jblloyd
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Default RE: Voltage regulator question

The application is a turbine ECU and it requires 7.4v to operate properly. A two cell A123 is not enough power and a 3 cell is too much.
Old 05-31-2011, 11:44 AM
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RCKen
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Default RE: Voltage regulator question

You might want to ask this question over in the RC Jet's forum. More than likely somebody over there has already tackled this issue and will have an answer for you.

Ken
Old 05-31-2011, 02:13 PM
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moe7404
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Default RE: Voltage regulator question

you need a lm338 google it. is like the radio shack lm317, but the package at R.S, for the lm317 has the wring diagram wrong. use the diagrams from the Internet.
Old 05-31-2011, 02:56 PM
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jblloyd
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Default RE: Voltage regulator question

Thanks for the info but I don't think I want to try and build a regulator. My soldering skills arelimited to Dean's connectors I was hoping to find a manufactured one.
Old 06-01-2011, 02:57 AM
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jetmech05
 
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Default RE: Voltage regulator question

I thought smart fly had a board that would allow 7.4V for high voltage servos but keep the receivers at 6V
Old 06-01-2011, 04:09 AM
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Default RE: Voltage regulator question

What I need is one that will do: 9.9v input >7.4v output.

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