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Old Jun 09, 2009, 12:32 PM
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Rhondas's Avatar
usa
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older jetti esc with a lipo

i have an older jetti 60 amp esc and want to switch to lipos, i have a can motor speed 400 a sma;ll prop 5x3 and a S3 lipo 2100mah, can I use this set up
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Old Jun 10, 2009, 07:36 AM
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Ware, herts. U.K.
Joined Sep 2008
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Hi,
Seems to me that, since I assume we don't know if the Jeti has LiPo support (the right low voltage cut-off), you have two choices.
Yes, it will probably work fine BUT... you need to make sure you don't drag the LiPos below 3V per cell so time your flight and land early to check cell voltage so you'll know for the future how long you can safely fly for. That would not be so critical for a 2S pack as most ESCs shut power to the motors at about 6V which is right for 2S.
Another point of concern is that a Speed 400 doesn't like more than about 9A and I reckon on 3S it'll pull way too much on the prop you suggest. Again 2S would be better.

The other possibility is that (since the Jeti was - by today's standards - phenominally expensive at about 70 if my memory serves (I bought one years ago! OUCH!)) why not buy a complete setup and go the 'whole hog'?
Brushless motors ar about twice as efficient as the old brushed sort so you'll double your flight time for a start.
There is no reason to think that you could not get an entire setup for less than the cost of the Jeti - have a look at
http://www.giantcod.co.uk/
They do a range of motors (Thumrun) that will out-perform a Speed 400 for less than 10, (in fact they'd out-perform a Speed 600!) their ESCs are very cheap, and their Loong Max LiPos are excellent - and cheap too!
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Old Jun 10, 2009, 10:45 AM
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usa
Joined Dec 2004
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LIPO WITH A JETTI ESC works OR NOT

Quote:
Originally Posted by eye4wings
Hi,
Seems to me that, since I assume we don't know if the Jeti has LiPo support (the right low voltage cut-off), you have two choices.
Yes, it will probably work fine BUT... you need to make sure you don't drag the LiPos below 3V per cell so time your flight and land early to check cell voltage so you'll know for the future how long you can safely fly for. That would not be so critical for a 2S pack as most ESCs shut power to the motors at about 6V which is right for 2S.
Another point of concern is that a Speed 400 doesn't like more than about 9A and I reckon on 3S it'll pull way too much on the prop you suggest. Again 2S would be better.

The other possibility is that (since the Jetti was - by today's standards - phenomenally expensive at about 70 if my memory serves (I bought one years ago! OUCH!)) why not buy a complete setup and go the 'whole hog'?
Brush less motors are about twice as efficient as the old brushed sort so you'll double your flight time for a start.
There is no reason to think that you could not get an entire setup for less than the cost of the Jeti - have a look at
http://www.giantcod.co.uk/
They do a range of motors (Thumrun) that will out-perform a Speed 400 for less than 10, (in fact they'd out-perform a Speed 600!) their ESCs are very cheap, and their Loong Max LiPos are excellent - and cheap too!
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
I think you are right, I just got into lipos , and I have so many 7, 8, 9, cell packs even new ones that I cant really use the lipos on the older can motor setups so I'm sort of a bit stuck in between the change over I have 3 ESC's left over and one is the jetti 60 amp an ther other is a car ESC 70 amp, and last is a new 20 and gws all intent for brushed motor s and nicad batteries,so I thought if I could just plug in the fling wing with the speed 400 and the 60 amp jetti I should fly it keeping in mind my throttle low for the first 4 minutes and then lading in approximately 10 minutes not to exceed the lipo drop out voltage less than 3.2 volts per cell on a S3 pack.?
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Old Jun 10, 2009, 01:53 PM
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Letchworth, Great Britain (UK)
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The older Jeti ESCs lvc kicks in at about 68% of the starting voltage, irrespective of what kind of battery it is. So, with a fully charged LiPo at, let's say, 4.18v the lvc would kick in at 2.84v -- much too low for a LiPo.

You certainly can use a LiPo with it if you time your flights to avoid going below 3.2v per cell, or whatever. Or you can get a LiPo Shield http://www.all-battery.com/browsepro...po-Shield.HTML which will take over the lvc function from your ESC, and shut down the motor in good time.
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Old Jun 11, 2009, 04:41 AM
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Ware, herts. U.K.
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Thanks abenn - I just learned something!
I hadn't come across that gizmo before. It should certainly do the job for Rhondas too. Another expense yes, but if it saves writing off a pack of LiPos, well worth it.
That's what the forum is good for!
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Old Jun 11, 2009, 06:15 AM
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Out of interest I've just found that Perkins do what looks like a similar thing http://www.jperkinsdistribution.co.u...s%20and%20accs . Presumably it'll be easier to get hold of in UK.
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Old Jun 13, 2009, 08:53 AM
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Ware, herts. U.K.
Joined Sep 2008
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Yes, I'm still interested - and certainly will be if and when I get around to doing a large single-engined job that will call my Jeti back into service.

Checking back, although at first glance the units might have seemed the same (price similar with exchange rate) and do a similar function, the JP job is more capable as it checks each individual cell and will cut if any is low. Thus it will be safe if a pack is out of balance - which the first did not seem to do.
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Last edited by eye4wings; Jun 13, 2009 at 08:59 AM.
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