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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › what all do i need to run my reciever on lipos?
02-12-2006 07:04 PM  12 years agoPost 1
wakeboarder2342

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USA

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i was wanting to switch my reciever to lipo and was wondering what all i need? i have looked at systems like the duralites but they seem way overpriced, cant i just buy a couple of 2000 mah 2s lipos, wire them parallel and they throw a regulator on it like the one from formeco?

i was thinking the 40 dollar regulator and a 40 dollar true rc 4000 mah 2s lipo?


80 bucks sounds a lot better then over 200!

any problems with doing it this way?


thanks

favorite quote, no honey thats the same helicoptor i have always had

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02-12-2006 07:32 PM  12 years agoPost 2
Raffy

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Chicago, Illinois

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cant i just buy a couple of 2000 mah 2s lipos
You end up spending more or take a risk having problems making your own. It is best you invest on a complete package the first time rather than experiment and not get good results.

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02-12-2006 11:23 PM  12 years agoPost 3
wakeboarder2342

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USA

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um thats my reason for posting here so others can share what results they hvae gotten


anyone running a similar setup?

favorite quote, no honey thats the same helicoptor i have always had

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02-13-2006 01:47 AM  12 years agoPost 4
PietervA

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New Zealand

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2200mA 3S lipos and UBEC switched regulator. Very simple, and allows 10 flights or more on a standard digital setup.

If you do a search, you'll see this has been well addressed in the last year or so.

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02-13-2006 02:45 AM  12 years agoPost 5
cyclic fever

rrApprentice

Seymour Indiana

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I've used MPI's regulators for a number of years now. Both 5.4v and 6v regs with 5-cell and 7.4 li-po setups without fail. They are 10amp cont. and 20amp peak and only cost 20 bucks.

http://www.maxxprod.com/mpi/mpi-21.html

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02-13-2006 10:22 PM  12 years agoPost 6
wakeboarder2342

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USA

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i think i will go with the maxxprod regulator,


tell me what kind of flight times do you think i would expect on a 2s lipo around 2000 mah?


or should i buy a 4000 mah lipo? what kind of current draw should i expect from a regular reciever system? no more then a few amps i wouldnt think?


thanks for the input so far

favorite quote, no honey thats the same helicoptor i have always had

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02-14-2006 12:49 AM  12 years agoPost 7
Yug

rrMaster

UK. Herts

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Current draw depends on your flying style and which servos and gyro you use. Provided you use a switching regulator, power in = power out.
Lets say that at a particular point, your system was sucking 4 amps at 5 volts = 20VA; and your battery was delivering 7.4volts, then the current would be 20/7.4 = 2.7A.

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02-14-2006 06:21 AM  12 years agoPost 8
PietervA

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New Zealand

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Most digital systems need no more than 5A at max. The supplier (eg http://www.koolflightsystems.com/ultimatebec.htm) will give you the regulator's rating, which in the case of UBEC is 3A cont, 5A for 5min. I understand this is output current.

Efficiency for switched regs is 85 to 95% (there are no free lunches), but at least excess voltage is not "dumped" as in a linear reg. This means you can run a high input voltage, such as 3S or 4S packs, and the current drawn off the pack is only an amp or two. As to whether you use a 5, 5.3 or 6V reg is a different matter, and depends most on the voltage the gyro will accept. Futaba 401 (for eg) are rated to 6V, but JR gyros are more restricted. (If you're really obsessive, you could have 2 regs, of course)

Switching rates of 200Hz theoretically cause interference with Rxs, but in practice this appears not to be the case, particularly if you face the reg's base towards the Rx, and separate them by a few cm.

Many have found a satisfactory wiring thus: lipo pack -> switch -> reg -> Rx. This way you can charge via the switch lead, check pack voltage likewise, and overcome the effect of small voltage drop across the switch.

I've used this for the last 6 months or so, have had no problems (besides a lipo pack dented by a crash, and discarded for safety's sake), and have never flown to the pack limit in a day at the field. The average flight appears to draw 100 to 150mA from a 3S pack.

HTH

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02-27-2006 11:46 AM  12 years agoPost 9
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

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I just ordered the 5v Kool UBEC too. Talk about good timing.

PietervA, you state that your set up is:

lipo pack -> switch -> reg -> Rx

and that among other things this permits you to overcome the effect of 'small voltage drop across the switch.' Does this mean that the main battery switch would be happier passing 3 amps at 12v than it would passing 7 amps at 5v?

I'm currently (no pun intended) using a JR 001 heavy duty main switch which I believe has 18ga wiring. Do you consider this to be a heavy enough gauge for the load the Kool UBEC and 5 digital servos will draw? 3 of the servos are Airtronics 94758's, bad boys for sure and known for their thirst. The battery will be a 3-cell TP 2100.

Would any of you 'more-savvy-than-I' LiPo users have any reservations about that setup?

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

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02-27-2006 11:51 AM  12 years agoPost 10
Yug

rrMaster

UK. Herts

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GimbalFan - sounds fine

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02-27-2006 11:55 AM  12 years agoPost 11
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

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Thanks, Guy. Making the 'switch,' hoping it works. I couldn't even put the two cyclic 94758's on the R50 with a 2700 NiMH. One alone on collective sucked so much it was possibly giving me lockouts. Oy.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

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02-27-2006 12:00 PM  12 years agoPost 12
PietervA

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New Zealand

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Hi Gimbalfan

The switch is fine for the currents drawn from the lipo pack (viz: 0.5 to 2.5A). When charging the pack at day's end, I use 2.5A without problems. Assuming the switch resistance remains constant, there's a greater voltage drop at higher current, ie if you place the switch AFTER the regulator.

There's much fuss made of a technique that's been powering mobile phones, laptops, cameras etc for years. Strange.

Good luck and enjoy.

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02-27-2006 12:04 PM  12 years agoPost 13
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

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Thanks to you also, Pie.

Another question: Would you expect that the Kool UBEC would get hot or warm while doing it's job on a heli?

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

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02-27-2006 12:15 PM  12 years agoPost 14
Yug

rrMaster

UK. Herts

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possibly warm. not hot.

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02-27-2006 12:19 PM  12 years agoPost 15
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

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"possibly warm. not hot." -- Kinda like some of the chicks on the Hot Girls Thread, eh Guy?

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

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02-27-2006 12:28 PM  12 years agoPost 16
Vigor3DFX

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Oakthorpe, Midlands, UK.

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Just from another perspective i inititially tried to take the cheap route.
I had a 2500 flight power pack 2s and was looking for a reg, i stumbled accross these and thought they'd be perfect..

Yes, it did kinda work and yes it said suitable for heli use to regulate a lipo setup.

From day 1 i was getting lockouts either in fast backward inverted flight towards me or inverted hovering with the nose pointing right at me.
Didnt occur it may be my power supply but it was,
I had a range of about 10m with the ariel down,

Plugged in a nicad and range was back to normal 50m or so.

Invested in some Duralite 5.1v regs and all has been perfect.

Its my guess the cheap regs were very noisy causing my loss of range, never have checked on scope yet but i do intend to.

So, just beware if your thinking of taking any shortcuts to save a few bucks, it just aint worth it in these applications.

Tony

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02-27-2006 12:38 PM  12 years agoPost 17
Yug

rrMaster

UK. Herts

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Nose in does tend to be the weakest orientation for range, and as you say, noisy electronics on the nose makes it worse. I think this is the reason why my Trex whent down: I was doing a big outside loop away from me and on its way down, nose in, from the top of the loop, it stopped listening so it didn't pull into the bottom the loop.

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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › what all do i need to run my reciever on lipos?
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