RC-Captain

Just need to know what amps to load test my RX batteries. I am currently using four , but need to know current draw of 1 std servo to get accuerate load testing of battery.

seanreit

My Feedback: (60)

These are two links that I was associated with on this issue, if you don't get your answer here, let me know.

http://www.rcuniverse.com/forum/m_88.../tm.htm#888695

http://www.rcuniverse.com/forum/m_18...tm.htm#1899770

RC-Captain

Thanks seanreit, but this is the route I am going to take, [link=http://www.vexacontrol.com/servoxciteref.html]servo current meter[/link]


I found this link this mourning and for 70 bucks I think it is well worth the money.
I wish I had an oscilliscope perform my own test, it would be much more accurate.

P.S. in your post you said you where pulling 1/2 an amp, well from my expertise I do know the more wire the higher the resistance therefore the higher the current.

seanreit

My Feedback: (60)

Dude, for half the money you can get one from Hanger 9 that does the same thing, but it's your money You're asking about standard servos, please don't think that they compare to high end digital performance that I was testing. My tests were mostly related to servos operating at or near full static loads. I have built and flown jets that were not capable (with digital servos of the time) of pulling hard g's at maximum air speed.

RC-Captain

I understand what you are talking about , but you are leaving the voltage out of the equation. Standard servo IMO will pull create more current draw than mini or micro. So if this is true I may start using mini to preserve voltage when trying obtain longer flights with one pack or many flights. Right now I'm getting 2 long flights on a 4.6 1100mAh battery. This cant be good at all.[&o]

Plus different makes have different results also . At 1/2 an amp even with 10 servos your pack has to be a monster. What are the specs on the packs you use to fly your jets? Thanks

seanreit

My Feedback: (60)

4000 Mah, around 8.3 volt lithium through a regulator set to 5.2 volts. I never leave volts out the equation But with the capacity I have, I don't worry about current drain much. I'm more concerned with binding which is why I carry the hanger 9 device through my entire setup and I record in my mind how much capactiy I'm losing over 5 flights by what I put back in the pack. I use some pretty sophistacated charging systems sometimes.

RC-Captain

No we are getting down to the nitty gritty . The regulator you use how much voltage will it accept , for example if I but a 12 volt pack on it and have it regulate for 5.5 will it accept the current being held back?
If it does I have just stuck gold . This would mean I can buy higher mAh and higher voltage batteries which in turn will give me a hell of alot more flights [X(]

seanreit

My Feedback: (60)

Your last post is severly flawed. And doing a search for your posts shows that you are flying very uncomplicated airframes. When you get into more complicated airframes that have real issues and more interesting wiring designs come back on here and let us know. Good luck with your tests. I'm removing my subscription to this thread now, good night.

Sean

RC-Captain

I knew I would shake you uo a little , I am highly trained in electronics , I was just picking your brain to actually see if the equipement we are discussing can actually handle different types of set ups. Although I excel in the electronics area I dont manufacture servos , regulators , RX ,TX , etc. ,so test are the only way I can truly get the answers to what I am attempting to accomplish.

As far as bigger airframes , even if I where to hit the lottery I wouldn't ever spend $2000 + dollars for a toy plane, thas what they are no matter how big or small.

pettit

My Feedback: (23)

To answer the first question, I would recommend placing a load on your battery equal to the milliamp-hour rating of that battery.

Using a 2000 milliamp-hour battery, put a 2000 milliamp load (2 amp) on it.

Do this with a constant current load, not a resistor, since the current will drop as the battery voltage drops.

I'd also recommend placing the load as close electrically to the battery to reduce any wire length induced Resistance, which may invalidate your results.

BTW, if wire length increases, total resistance of that wire increases proportionally.

But, if resistance increases, cuicuit current decreases, under a constant voltage.

Basic Ohm's Law.

RC-Captain

I made a mistake, you are right the more resistance the the less current flow there is , but also the voltage will drop, and I know this to be true because of my profession. 12volts through 22awg wire at 1000 feet will not deliver more power than 12volts through 14awg wire at 1000 feet.

therefore servos use 22awg stranded wire, making them longer only lessons your power to the servos.

Gringo Flyer

My Feedback: (18)

RC Fiend, are you still having problems with flight times?

RC-Captain

lol YEP ! Dude on my best battery 4.5 1100mAh , load tested at 2A=5.20 volts, I can get 2 good flights in meaning I empty the bottle. I just thing I am going to have to get a computer program to do some extensive testing.[&o] , or just buy three new RX batts at a higher mAh.

Whats new gringo.............

Gringo Flyer

My Feedback: (18)

RCFiend. I just think something else is up. With an 1100mah pack you should be able to fly all day. I doubt it has to do with the draw of the servos unless there is a short or one is binding.

I have an 1100 mah pack in a plane with 6 servos (4 are digital) and I fly 3D with it. So I am constantly on the sticks. With that pack I can fly an entire afternoon without even getting close to discharging the pack. My 600mah in my trainer is good for at least 3 looong flights.