Not true.
If your pulling more power than the alt supplies at idle-- then you are pulling from the battery.
Viper fan + underdrive crank and ALT pulley drops the voltage down as the factory alt cannot keep up.
" The PCM's in these trucks (and all other vehicles) are what control the charging rate and are designed to keep the charging rate where it's required and can lower/raise it when temperature, load, and electrical requirements"
That IS true... and if you have an alternator (like a powermaster) that puts out MORE amperage at idle than stock, and you have the load that requires it (viper fan, underdrive pulleys, big stereo, the higher amperage alt will help offset that load.
I sell these all the time to people who run big stereos, and have viper fankits that run underdrive pulleys. They work.
Sam
www.socaldakota.com
619-274-1292
---- "Bernd D. Ratsch" <bernd@dodgetrucks.org> wrote:
>
> You are correct in your thinking...more amperage isn't going to help you at
> idle or any other speed UNLESS your engine and electrical accessories
> (battery, stereo, amps, lighting, winch, compressor, welder, etc.) requires
> it. The PCM's in these trucks (and all other vehicles) are what control the
> charging rate and are designed to keep the charging rate where it's required
> and can lower/raise it when temperature, load, and electrical requirements
> change. Yes, the PCM can cut the alternator down to a minimum charge rate
> at idle (daytime, no electrical load) and raise it to maximum when the
> battery is low or dying (dash lights will flicker - common sign).
>
> Best bet: make sure you are using high quality ground wires and good
> connections as well as on the power feed from the battery to the PDC (fuse
> box under the hood) and from the PDC to the alternator. The factory 4-8
> gauge wire is fine but won't handle any decent loads with all of the
> aftermarket accessories. Change them out to a 1-2 gauge wire (preferred
> "0"). I did and my charging rate is very stable at idle with the BM150
> electric fan, HID's, A/C, and onboard PC running - original factory
> alternator (136amp).
>
> - Bernd
>
>
> -----Original Message-----
> From: Mallett, Donald B [mailto:Donald.Mallett@BNSF.com]
> Sent: Saturday, April 28, 2007 12:54 AM
> To: dakota-truck@dakota-truck.net
> Subject: RE: DML: RE: Alternator Upgrades
>
>
> I've been reading this tread and many others about upgrading the alternator
> on this and other forums. The main thought is the what will the "max"
> amperage out put be. Where it seems the main reason for the upgrades come
> from the output of the alternator at idle. The set up in my Dak that is the
> reason why I've been looking to do the upgrade. The Viper fan and underdrive
> crank pulley combined is a killer on my Daks battery at idle. It's the
> amperage at idle I would like to know the rating of on the stock 136amp
> alternator. I've asked two of the after market alternator companies what the
> amperage rating is at idle on there alternators. One told me they would get
> back to me....... Still waiting a year later! The other just blew off the
> question with talking about the bearings. One salesman said they can wind
> one that will produce higher amperage at idle.
>
> Bottom line is where you (I) need the extra amperage, no one has given me a
> answer that I asked for. Feel like I'm just rambling on here!? Anyway you
> get what I mean.
>
>
>
> - --
> *------------------------------Y2KOTA------------------------------*
> Don Mallett
> Y2K QC 4.7L Auto SLT+ 4x2
> http://www.y2kota.us
> *-----I'm not late! It's that the rest of the world is early!!-----*
>
>
>
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