I did email technical support and outlined a few concerns that were being voiced on this site. Hopefully Alpha can also have some input for us. I agree with Dai that we should have little to worry about after spending nearly 600.00. The boat is very nice, but realiability is also important.
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Rascal76,
LCV is low cell voltage. Another term is LVC or low voltage cutoff. Most ESC's will monitor a battery back (Lipo, Li-Ion, Nihm etc) at a certain threshold the ESC stops the motor. But will allow other functions to continue to work. It will allow short bursts of motor but nothing long. This is done to protect the battery.Comment
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RSRN,
Good luck on getting an email from tech support and keep us posted.Comment
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Rascal76, Low Voltage Cutoff... it shuts down the motors to protect the lipo battery from getting below a preset voltage, and damageing the battery.
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Ok. I did a little math. If the NiMH setting is used the ESC is looking for 4.8 to 10.8 volts. If the LiPo setting is used it is looking for 7.4 to 11.1 volts. Doesn't sound like that should be enough of a difference to burn out an ESC.
If the LVC is just to protect the battery then maybe it was just low grade electronics.
Has anyone out there not had this problem? If so we're the jumpers in the correct positions?
I just want to run the boat.Comment
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Rascal76
I believe they installed low grade electronics. The other option is poor designed to have a marine ESC and not keep it cool with water. I haven't put my boat into the water yet. I am planning to next weekend at the campground. However, I am concerned that if I get it on the lake I might not get it back without renting a canoe to go fetch. Hoping someone can chime in on their successful run. Also, hoping RSRN receives some news from his email.Comment
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Low grade electronics is the default pattern seen in RTF/RTR packages from China. For 600 USD , totally unacceptable. I could banned from making comments like this on MRC sponsored site but as consumers who spent hundreds of dollars and up, we deserve better ! DaiOriginally posted by pdansalvish View PostComment
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dia phan,
Wondering if our problems are three motors running off one ESC. The Fletcher captains have not reported any problems with their ESC's. According to them they are only running two motors.Comment
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Three motors off one ESC is fine as long at the total current draw is under the rating of the ESC. I have both the Fletcher and the PT. The ESC is different in the boats.
i am going to run a load test on the PT to see what the full load draw is. I report the result.Comment
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On my Yamato, there is one ESC that runs 4 motors. Yesterday while testing in the tub, after 2 minutes the ESC stopped working and EXTREMELY hot after running at constant 25% speed. At the lake it worked fine but I never kept the same power more than 30 seconds straight. If that problem happens in the air, I would have lost the plane ! DaiOriginally posted by pdansalvish View PostComment
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If indeed the ships came with unappropriate ESC, I think MRC should recall the old ones and provide us with the proper set up. All purchases have 30 day warranty. DaiComment
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As I stated on the previous page, no plumbing to cool the esc, a little reengineering is needed for water pickups for the esc.Comment
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Do you think this should have thought out at the factory? DaiOriginally posted by southernmd_man View PostComment
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Or maybe a little testing would have exposed the weakness.Comment
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I believe any mods done by the buyers are to enhance the experience, NOT to correct designing flaws or poor electronics. DaiOriginally posted by Rascal76 View PostComment
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This is what I recieved from Andrew the tech rep today. I going to take the boat out tomorrow am, will report back.
Michael
Michael,
Do your ESC/motors currently work? Did anything get hot? I am a long time boater and work directly with Alpha. It's a 120amp ESC powering 3 brushed motors so it should be plenty.
Regards,
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Yes it's a 120 amp speed control. Unfortunately it doesn't seem like it was good one.
I just finished setting up all the drive of my boat. From the motors to the props. Adding thrust washers were they should be, checking for binding etc.
I hooked the motor set up to my large DC power supply. At 7.4 volts DC the motors are only drawing 6.5 amps. This is no load spinning in the air.
If I drove the voltage quickly up from 0 the load went up to almost 10 amps and then settled down to the 6.5 amps. (startup load, to be expected)
I took it out to my pond had it in the water restrained. Unfortunately I couldn't get a reading as it exceed the 10 amps my supply can provide.
I can say the the motors did not get hot. They seem to run well.
As I said in post 40 after the system failed (about 4 minutes of running time) and retrieval the motors were not hot, not even really warm. There was a burnt electronics smell.
I agree that a 120 amp ESC should handle these three motors easily.
I believe it was just a case of the failure of a cheap electrical component.
Rascal76
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Wonder if RSRN heard for Motion today.Comment
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Hey Pdansalvish,
I did, see post aboveComment
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On a happier note the crew arrived today. It's going to be a lot of work fitting and painting. I think they'll look great!
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