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P70 - Battery Warning???

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Old 07-08-2009, 11:42 PM
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JohnW
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Default P70 - Battery Warning???

P70, bought new last June, I put a new fuel pump in this evening to replace one going bad. With the new pump, the engine starts normally, spools smoothly from idle to full (123K rpm), max pump volt is 2.0, temp around 690C, in other words, it seems to run perfectly. But at full throttle after a few seconds, say 10-20 or so, the turbine would smoothly spool down to idle. I could regain control by moving the stick to idle, spool it back up, but then in 10-20 seconds it would go back to idle, etc.

My first thought was low ECU battery, but I have low battery warning disabled. In addition, while my battery was lower than I normally fly, which reinforced the low battery idea, it was still in the low 7's or so (using 2 cell lipo that came with the engine.) I just finished charging the ECU battery now, put 1250mah into it, and it is a 2500mah pack, so maybe considered low, but not dead. I've already tried the patience of my neighbors tonight enough, too late to retest with fully charged pack. Will try again after work on Thursday.

What is the voltage threshold for the low voltage warning when using 2 cell LiPos? Would the ECU send the throttle to idle as a warning even if the low battery warning is disabled? Looking for advice on what to look for before I retry running the engine Thursday evening. Thanks.
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Old 07-09-2009, 05:50 PM
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Default RE: P70 - Battery Warning???

Update - I cannot reproduce the issue with a freshly charged ECU pack, so I think all's good. However, I'd still like confirmation on if this is a battery failsafe feature, why it is functional when I have battery failsafe disabled, at what voltage is being used for the warning threshold with a 2 cell lipo. Thanks.
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Old 07-09-2009, 11:10 PM
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Default RE: P70 - Battery Warning???

I have got to check on this. Is there any way this is a RX battery failsafe? Those usually behave exactly the same as the ECU failsafe function.

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Old 07-10-2009, 06:06 PM
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Default RE: P70 - Battery Warning???

RX Battery failsafe - good point, now that you mention it, I can't rule that out either, and i bet that was it. I think I have a low RX battery fail safe enabled enabled on the radio, I'll double check later. I also charged the RX batteries when I charged the ECU battery so I have no way to know if the original issue was due to ECU or RX battery.
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