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Thread: How To: Installing an MPI voltage regulator

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Old 05-26-2007, 11:17 AM   #81
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Ok thanks...All that Droop reading and thinking Crap fried me.
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Old 07-26-2007, 07:09 AM   #82
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I finally made time to hook up my MPI regulator on my new super and I have a few observations.

1) Holy crap. I've never seen those 5955s or 5995s properly powered. They throw around the steering like nothing. In fact it makes me realize how crappy those mounting systems are because they have so much play in them. I can see that regulator being worth every penny for getting proper steering out of the truck.

2) I'm running on 11.1 3S lipo and at 5.75ish the regulator got HOT after less than 5 minutes. I turned it up to 6.5 but I didn't run it very much. I should have grabbed my temp gun and measured exactly how hot. Why would this be? Am I throwing too much voltage at the front of it? I'm sure I remember others running this with 3S battery packs.
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Old 07-26-2007, 10:43 AM   #83
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Quote:
Originally Posted by Cloak View Post
I finally made time to hook up my MPI regulator on my new super and I have a few observations.

1) Holy crap. I've never seen those 5955s or 5995s properly powered. They throw around the steering like nothing. In fact it makes me realize how crappy those mounting systems are because they have so much play in them. I can see that regulator being worth every penny for getting proper steering out of the truck.

2) I'm running on 11.1 3S lipo and at 5.75ish the regulator got HOT after less than 5 minutes. I turned it up to 6.5 but I didn't run it very much. I should have grabbed my temp gun and measured exactly how hot. Why would this be? Am I throwing too much voltage at the front of it? I'm sure I remember others running this with 3S battery packs.
Cloak,
Glad to hear you like it. I love mine.

The reason it is getting hot is because of wattage, not voltage. But that is directly related to how much voltage and current you are using. The idea is that the larger the voltage drop across it, the less amperage you can pull through it.

The max wattage this unit is designed for is 20 watts. So we can calculate how many amps are available for your servos to pull.
current = watts/voltage
I = P/V
I = 20/(11.1-5.75) = 3.74 amps
You can safely pull 3.74 amps with the 5.75v setting you had initially. Your servos pull way more than that and so the reg got really hot.

with your second setting
I = 20/(11.1-6.50) = 4.35 amps
You can safely pull 4.35 amps with the 6.50v setting, still not enough I bet but better.

If you turn up the output to 7.0 volts
I = 20/(11.1-7) = 4.87 amps
This MIGHT be enough but I bet the reg will still get hot under hard use.

There are a few other things you can to reduce the heat of the regulator.
1) Make sure that a large surface of the regulator's aluminum heatsink is touching the chassis. (zip tie it or even better, bolt it in place) This will dissipate heat into the chassis and keep the regulator cooler. Combine this with a 7.0V output and you will prolly be fine.

2) Run 2 voltage regulators. This is what Kris does on his super.

3) Run one high powered servo and one weaker servo. This is what I do on my super to run both servos through the Super Rooster's BEC. I run a HS998TG in front and a 645MG in the rear.

4) You can drop down to 7.4 volts on your main battery. This will allow you to pull 14.3 amps with a servo voltage of 6V.

Hope this helps.

Last edited by Grizzly4x4; 07-26-2007 at 11:00 AM.
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Old 07-26-2007, 11:09 AM   #84
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Thanks for the info. I might volt up to 7 on those servos and see what that does for now. Long term the best bet will probably be to have 2 regulators. I might see about putting a little fan over that unit as well for the hell of it. I've got so many wires running already, what's another couple.

How are you mounting your steering to actually handle all this power? I can't believe how sloppy both methods I'm using right now are. One is the side mount in the rear which seems to work better than the front, which is the ttr bta setup. That one just wobbles all over the place. I'm going to play with a brace for that one tonight.

Edit: Looking at it here at work, I think I'm going to run the front links right there in the front. It seems to turn smooth and still get full throw out of the cvds.

Last edited by Cloak; 07-26-2007 at 11:23 AM.
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Old 07-26-2007, 11:33 AM   #85
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A fan would help too, anything to help dissapate heat.

Here is the servo brace I run. My steering mount is rock solid.

SuperDuke brace

Last edited by Grizzly4x4; 07-26-2007 at 11:48 AM.
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Old 07-26-2007, 11:40 AM   #86
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Great info on the regulators output, and also the servo brace, i knew i hadn't done something to my clods steering and this was it, cool idea Grizz.
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Old 07-26-2007, 11:46 AM   #87
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Originally Posted by cartronicshn View Post
Great info on the regulators output, and also the servo brace, i knew i hadn't done something to my clods steering and this was it, cool idea Grizz.
Thanks cart, it's a simple mod that works great.

Last edited by Grizzly4x4; 07-26-2007 at 11:48 AM.
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Old 07-28-2007, 04:07 PM   #88
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wow my brain is throbbing after reading all this great info. i am getting ready to hook up my system
dx6 radio
2-hyperions
2-mamba maxes
2-5955 servos
1-regulator
1-3s lipo 11.1v 2100mah
just wondering now if i should just do 2-regulators and if so do you still just wire them together through a y-harness to the reciever and then adjust each to the 7volts
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Old 07-30-2007, 10:53 AM   #89
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Originally Posted by rcjunky3 View Post
wow my brain is throbbing after reading all this great info. i am getting ready to hook up my system
dx6 radio
2-hyperions
2-mamba maxes
2-5955 servos
1-regulator
1-3s lipo 11.1v 2100mah
just wondering now if i should just do 2-regulators .....
Your setup is pretty much identical to Cloak's. All the same advise would apply. The best thing for the voltage regulator's life would be to run 2 reg's. If you don't want to spend the extra money and are willing to experiment you can try the other tricks.

Quote:
Originally Posted by rcjunky3 View Post
......and if so do you still just wire them together through a y-harness to the reciever and then adjust each to the 7volts
You would need to Y-harness from the main power to the two regulators. I would then run power directly to each servo, rather than tie both outputs together and run them to the receiver.
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Old 07-30-2007, 10:57 AM   #90
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The Cool BECs I have now can actually run inline with the servos. They have a male and female end, so one end goes to the RX and one to the servo. If you want to cut power from the RX side you can just pull the power wires and leave the signal wire, no extra Y harness needed. It is like a servo extension with built in regulator.
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Old 07-30-2007, 10:59 AM   #91
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John, that's exactly what I was thinking of doing. I don't really have need for the resolution the MPI offers, I just want "power/more power" settings.

Hell, I should order a couple more for my 2.2s before you pack up that box.
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Old 07-30-2007, 11:01 AM   #92
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already packed up, but I could repack it if you want a few more
looks like I have one more in stock.
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Old 07-30-2007, 11:03 AM   #93
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I'll take it.

Now that I think about it, putting that BEC between the servo and the receiver wouldn't the limiting factor be the BEC of the esc?
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Old 07-30-2007, 11:21 AM   #94
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I dont quite get your question.
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Old 07-30-2007, 11:56 AM   #95
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I know it's kinda covering old ground, but could you chaps take a look at my proposed wiring scheme and let me know:

1. whether it'll work?
2. if it's the most effective way of delivering power to the servos/rx without burning things out

I plan to use 4mm bullet connectors at the battery/reg connection and std servo connectors elsewhere.

Thanks ds
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Last edited by mrbenn; 07-30-2007 at 11:58 AM.
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Old 07-30-2007, 12:11 PM   #96
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Quote:
Originally Posted by mrbenn View Post
I know it's kinda covering old ground, but could you chaps take a look at my proposed wiring scheme and let me know:

1. whether it'll work?
2. if it's the most effective way of delivering power to the servos/rx without burning things out

I plan to use 4mm bullet connectors at the battery/reg connection and std servo connectors elsewhere.

Thanks ds
It looks like it should work good.

If this is for a rig with 4ws and a couple high powered servos then that's prolly the best setup.

On my 2.2 rig the second servo is just a 50 in-oz servo. I have had no problems runnnin the VR output to the receiver. This would save you a little bit of wiring.
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Old 07-30-2007, 12:14 PM   #97
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This would work the same for nimh 7.2, 8.4, 9.6 volts etc, right?
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Old 07-30-2007, 12:16 PM   #98
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Originally Posted by cartronicshn View Post
This would work the same for nimh 7.2, 8.4, 9.6 volts etc, right?
Correct, it doesn't matter what type of battery you are using, the same wiring harness will work.
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Old 07-30-2007, 10:34 PM   #99
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With the about diagram could you run power to the rx from the ecs. And not have to power the rx from the voltage regulator. Any pro or cons to either way?
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Old 08-01-2007, 10:36 AM   #100
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One more question, do i run my dig and/or winch wires of the same voltage reg? just add a y harness and will it be enough to power all 3 or 4 servos?
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