[NSRCA-discussion] regulators

[Ed Alt]

It's a linear regulator.  It appears to be working properly too.  Check his 
numbers:  No regulator, load battery voltage is 8.2V.  Drops to 7.84V at 500 
mA load.  A drop of 0.36V.  Add the Jaccio and he gets a drop of .39V.  The 
regulator added a bit more resistive wiring, accounting for the majority of 
the extra 0.03V loss.

At 1A, no regulator it's a drop (change) of 0.69V.  Add the regulator and 
the drop is only 0.48V.  That's BETTER performance as far as the load is 
concerned.

At 1.5A, no regulator it's a drop of 1.0V.  Add the regulator and the drop 
is only 0.57V.  Better than an unregulated arrangement again.

This is the key: the percentage of change at the load is less with the 
regulator added.  With the regulator at 1.5A it was only a 9.3% change. 
Without the regulator it was a 12.2% change.  For all practical purposes, 
the 3% improvement was due to the regulator reducing the effect of the 
battery wiring and internal resistance of the battery.  Also realize that 
this change is nearly 100% due to resistive loss (I.e. voltage developed or 
"dropped") along the wiring AFTER the regulator. The only way to get around 
this is as I mentioned in an earlier post - put a small regulator out at 
each servo.  That's cool, it works, it's not strictly necessary though.

To sum it up, keep in mind that with no regulator, assuming you could use it 
unregulated, the battery is going to wind down all day long and you will see 
that effect in servo response.  By going with a LiPo, the results will be 
consistent all day long.

Ed

----- Original Message -----
From: "Jay Marshall" <lightfoot at sc.rr.com>
To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, December 06, 2006 12:57 PM
Subject: Re: [NSRCA-discussion] regulators

> Regulators typically require a specific higher input voltage than output
> voltage. You would have to look at the spec sheet. I also assume that this
> is a linear regulator, not a switcher?
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Robert 
> Mairs
> Sent: Wednesday, December 06, 2006 7:53 AM
> To: NSRCA Mailing List
> Subject: [NSRCA-discussion] regulators
>
> I've got a Jaico that regulates to 6.11 volts.   Using a 480 mah TP lipo,
> and the Jaico, I got the following.
>
> no load, 6.11v
> 500mah load, 5.72v
> 1A load, 5.63v
> 1.5A load, 5.54v
>
> Just with the battery, no regulator I get
>
> no load, 8.2v
> 500mah, 7.84v
> 1A, 7.51v
> 1.5A, 7.2v
>
> I don't understand.  Why doesn't the regulated voltage stay at 6.11v with 
> a
> load?  I always thought using a regulator was supposed to give you a
> constant voltage so the servos reaction would always be the same, yet it
> acts just like a battery,  just not as great a drop off it seems.
>
>
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