RCCrawler Forums

JohnRobHolmes · 07-29-2005, 04:49 PM

only 1.2 volts. lets say that you draw 1 amp at 6 volts. thats about normal for a weaker servo. amp x ohm = volt. so your ohm rating is 6 ohms. at 7.2 volts with 6 ohms your amp draw is 1.2 amps, a 20% increase. most 6 cell packs charge up to 8 volts at least, some are closer to 9. a fresh pack at 8.5 volts would force the servo to bite 1.41 amps, a 41% increase over normal voltage. since volts x amps = watts, 6v is 6 watts, 7.2 volts is 8.64 watts, and 8.5 volts will make the servo dissapate 9.71 watts. thats a 62% increase in load from 6v to 8.5v, and a 44% increase of load from 6v to 7.2 volts. even though its only 1.2 volts, its a big step for a servo to cover. even going 25% past a manufacturing spec is pushing it, going 62% past takes luck or careful planning.

these numbers were pulled outta my ***, and servos' resistance changes according to load. but, most servos do draw about one amp at 6v under load.

nd4spdbh · 07-29-2005, 05:38 PM

THANK YOU johnrobholmes.... i couldnt figure out an explaination for the people who over volt their servos... thanks a bunch!

JohnRobHolmes · 07-29-2005, 07:31 PM

No problem man. Nobody had brought up wattage and amp draw concerns. Ive been watching the thread for a while. I made a couple of those voltage regulators a year back with the exact same parts. i used higher ohm resistors though so that the variation between resistors wasn't so high. 1 ohm off on a 100 ohm resistor is a lot more than one ohm off on a 800 ohm resistor. Say that ten times fast!

Although i haven't overvolted my servos, I'm sure there are applications where it could be useful. I might run it one day, but only with full knowledge of what's going on in my electrics. Not condemning, not condoning.

As stated before, you don't know if it works for you unless you try it. I bet a powerful anolog servo used to turn tlt tires would work like a charm on 7.2 volts as long as the heat was watched. I wouldn't dare overvolt it with full size moabs, 10 pounds of truck, hot weather, and freshly charged and matched GP's.

nd4spdbh · 07-29-2005, 10:08 PM

Quote:

Originally Posted by johnrobholmes

I wouldn't dare overvolt it with full size moabs, 10 pounds of truck, hot weather, and freshly charged and matched GP's

He he... its sounds like some people would but people like u and me realize what happens when you do stuff like overvolting.

I just made a second one of these regulators for rear steering YEAH... damn freakin USPS nowadays is crazy fast... i orderd my tq3 tuesday, it was shipped on wednesday, and i got it today (friday) at 10 in the morning

.....

INDEPENDENT REAR STEER KIX A$$

MKX10 · 07-31-2005, 01:10 AM

Quote:

Originally Posted by nd4spdbh

He he... its sounds like some people would but people like u and me realize what happens when you do stuff like overvolting.

Ya, you miss out on the ultimate potential of your servos.

The thing is playing it safe has its place. Pushing the envelope also has its place. When to do either is determined by the owner of the equipment. I think we've shown that overvolting can be done successfully, if deemed necessary. I deem it necessary. You don't. Instead of flaming people who have a different idea than you, just state your case and leave it up to the person who asked to question to decide.

For the record that same 9351 also did time in a 13lb E-maxx, with Panther Pythons in 100 deg Texas heat on 8.4V. The motor ended up frying, but the servo didn't

SPEED_RACER · 07-31-2005, 02:39 AM

over volting will shorten the life of the servo.no way around it.your lucky yours didn't burn out yet.yes,i'm saying this out of experiance.didn't exacting burn them out but the ones i've done it to are now wimpy servos instaed of high torque servos like they once was.give it time,they'll die

nd4spdbh · 07-31-2005, 06:03 PM

so very ture!!

JamisonWorkshop · 08-02-2005, 09:14 AM

Wanted to update on the Novak servo regulator that I picked up. Very nice product for the $$$. Smaller than I thought.

Has a nice switch and LED so you know it is on. And the LED is neon purple. Sets off the Red Rooster Led nicely.

Works perfectly and no complaints. for any not up bulding one or needing more than 1 amp out of your regulators. This is a nice little product to go with.

nd4spdbh · 08-02-2005, 09:37 AM

i bet it is.... lol i didnt even kno they made purple led's

N e ways i think i found a regulator that could work....it would give you 15 continous amps

for right around the same size as my 1 amp one

SPEED_RACER · 08-03-2005, 08:47 AM

Quote:

N e ways i think i found a regulator that could work....it would give you 15 continous amps for right around the same size as my 1 amp one

please post some info.thanks.i like the info hear.when i get a few hobby bucks for my trucks i'll be looking to do this.it'll be nice to get away from the need for rx packs

nd4spdbh · 08-03-2005, 09:42 AM

ok well im still lookin around... i let you kno when i find a good high current regulator BUT i just use 2 of the little ones i described above for my 2 hs645's

JohnRobHolmes · 08-06-2005, 12:57 AM

i havent been able to find any good regulators more than 1.5 amps capacity. i built three of those homebuilt regulators last year, and it worked well. one of them seemed to heat up more than the others though. they were wired in parallel for 4.5 amps handling in theory.

if you find a better reg, let us know!

nd4spdbh · 08-06-2005, 09:27 AM

ok but i would actually recommend wiring them up seperate... i have found that it spreads the load alot better. so pretty much u have one for each servo. But yes i will let you kno if i can find better ones...

Big Ahso · 12-01-2005, 11:06 PM

Is there any way to build a regulator to output 7.2 volts while running an eight cell pack? I was looking at the 7808 from parts express * Vout: +8 V * Vin: +10.5 V min, +35 V max * Iout: 1 A * Case style: TO-220 I have a servo rated at 7.2 volts and would like to get close to max input voltage. Is this possible with this regulator?

nd4spdbh · 12-02-2005, 07:29 AM

HOLLY OLD THREAD!!!

LOL ya you can make a 7.2 volt voltage regulator but you have to use a voltage reg with a Vout less than what you actually want so in my and yours case we would use the 5 volt one... after school i will do the calculations on the resistors to get you as close to 7.2 as possible

RCHunter · 12-02-2005, 12:24 PM

I burnt up 2 ultimate bec's... I run a 12 cell battery on my brushless maxx. How would you go about making the input voltage 17-20 volts, output voltage 6v 3 amp?

darkfly · 04-20-2007, 12:14 PM

can we update the pics on this?

nd4spdbh · 04-20-2007, 02:36 PM

wow old thread!... what pics you want updated... all of em work fine.

WheelChair · 04-22-2007, 08:41 PM

I had this same Idea, only using Radioshack parts rated @ 1.5A...

I think I will try it with 2 per servo.

OLD EVX heatsinks will be perfect!

I built an adjustable MAP sensor for my XJ and it works sweet!

darkfly · 04-23-2007, 07:41 AM

none of the photo's work all i get is an "X"

07-29-2005, 07:31 PM	#43
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	No problem man. Nobody had brought up wattage and amp draw concerns. Ive been watching the thread for a while. I made a couple of those voltage regulators a year back with the exact same parts. i used higher ohm resistors though so that the variation between resistors wasn't so high. 1 ohm off on a 100 ohm resistor is a lot more than one ohm off on a 800 ohm resistor. Say that ten times fast! Although i haven't overvolted my servos, I'm sure there are applications where it could be useful. I might run it one day, but only with full knowledge of what's going on in my electrics. Not condemning, not condoning. As stated before, you don't know if it works for you unless you try it. I bet a powerful anolog servo used to turn tlt tires would work like a charm on 7.2 volts as long as the heat was watched. I wouldn't dare overvolt it with full size moabs, 10 pounds of truck, hot weather, and freshly charged and matched GP's. Last edited by JohnRobHolmes; 07-29-2005 at 07:35 PM.

07-29-2005, 04:49 PM	#41
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	only 1.2 volts. lets say that you draw 1 amp at 6 volts. thats about normal for a weaker servo. amp x ohm = volt. so your ohm rating is 6 ohms. at 7.2 volts with 6 ohms your amp draw is 1.2 amps, a 20% increase. most 6 cell packs charge up to 8 volts at least, some are closer to 9. a fresh pack at 8.5 volts would force the servo to bite 1.41 amps, a 41% increase over normal voltage. since volts x amps = watts, 6v is 6 watts, 7.2 volts is 8.64 watts, and 8.5 volts will make the servo dissapate 9.71 watts. thats a 62% increase in load from 6v to 8.5v, and a 44% increase of load from 6v to 7.2 volts. even though its only 1.2 volts, its a big step for a servo to cover. even going 25% past a manufacturing spec is pushing it, going 62% past takes luck or careful planning. these numbers were pulled outta my ***, and servos' resistance changes according to load. but, most servos do draw about one amp at 6v under load.

07-29-2005, 05:38 PM	#42
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	THANK YOU johnrobholmes.... i couldnt figure out an explaination for the people who over volt their servos... thanks a bunch!

07-31-2005, 02:39 AM	#46
SPEED_RACER Quarry Creeper Join Date: Nov 2004 Location: MANVILLE Posts: 413	over volting will shorten the life of the servo.no way around it.your lucky yours didn't burn out yet.yes,i'm saying this out of experiance.didn't exacting burn them out but the ones i've done it to are now wimpy servos instaed of high torque servos like they once was.give it time,they'll die

07-31-2005, 06:03 PM	#47
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	so very ture!!

08-02-2005, 09:14 AM	#48
JamisonWorkshop Quarry Creeper Join Date: Jun 2005 Location: Maryland Posts: 319	Wanted to update on the Novak servo regulator that I picked up. Very nice product for the $$$. Smaller than I thought. Has a nice switch and LED so you know it is on. And the LED is neon purple. Sets off the Red Rooster Led nicely. Works perfectly and no complaints. for any not up bulding one or needing more than 1 amp out of your regulators. This is a nice little product to go with.

08-02-2005, 09:37 AM	#49
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	i bet it is.... lol i didnt even kno they made purple led's N e ways i think i found a regulator that could work....it would give you 15 continous amps for right around the same size as my 1 amp one

08-03-2005, 09:42 AM	#51
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	ok well im still lookin around... i let you kno when i find a good high current regulator BUT i just use 2 of the little ones i described above for my 2 hs645's

08-06-2005, 12:57 AM	#52
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	i havent been able to find any good regulators more than 1.5 amps capacity. i built three of those homebuilt regulators last year, and it worked well. one of them seemed to heat up more than the others though. they were wired in parallel for 4.5 amps handling in theory. if you find a better reg, let us know!

08-06-2005, 09:27 AM	#53
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	ok but i would actually recommend wiring them up seperate... i have found that it spreads the load alot better. so pretty much u have one for each servo. But yes i will let you kno if i can find better ones...

12-01-2005, 11:06 PM	#54
Big Ahso Newbie Join Date: Nov 2005 Location: Vancouver Posts: 43	Is there any way to build a regulator to output 7.2 volts while running an eight cell pack? I was looking at the 7808 from parts express * Vout: +8 V * Vin: +10.5 V min, +35 V max * Iout: 1 A * Case style: TO-220 I have a servo rated at 7.2 volts and would like to get close to max input voltage. Is this possible with this regulator?

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12-02-2005, 07:29 AM	#55
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	HOLLY OLD THREAD!!! LOL ya you can make a 7.2 volt voltage regulator but you have to use a voltage reg with a Vout less than what you actually want so in my and yours case we would use the 5 volt one... after school i will do the calculations on the resistors to get you as close to 7.2 as possible

12-02-2005, 12:24 PM	#56
RCHunter Quarry Creeper Join Date: Mar 2005 Location: Florida Posts: 216	I burnt up 2 ultimate bec's... I run a 12 cell battery on my brushless maxx. How would you go about making the input voltage 17-20 volts, output voltage 6v 3 amp?

04-20-2007, 12:14 PM	#57
darkfly Newbie Join Date: Nov 2006 Location: sandy Posts: 45	can we update the pics on this?

04-20-2007, 02:36 PM	#58
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	wow old thread!... what pics you want updated... all of em work fine.

04-22-2007, 08:41 PM	#59
WheelChair Winner of the '07 RCC dumbass award! Join Date: Nov 2006 Location: Up on a Mountain, out in the Woods Posts: 661	I had this same Idea, only using Radioshack parts rated @ 1.5A... I think I will try it with 2 per servo. OLD EVX heatsinks will be perfect! I built an adjustable MAP sensor for my XJ and it works sweet!

04-23-2007, 07:41 AM	#60
darkfly Newbie Join Date: Nov 2006 Location: sandy Posts: 45	none of the photo's work all i get is an "X"

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Thread: HOW to make a 6 volt voltage regulator!