What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Doubeleive]

I am slightly confused... how did you come up with 245 amps needed???

quality power has a calculator on there website, you enter all the things you have on your vehicle some have a box to enter the watt's then it keeps a running tally at the bottom. mine added up to 245 with me entering a moderate rating of 2000 watts on my 5000 watt amp & subs, i'm sure it doesn't peak since I have it turned down

 

[Doubeleive]

How long you plan on idling with everything on?

I know mine idles at like 535 rpm or so. The alternator you have now, what does it put out at different rpms? Like what's it put out at 550, 750, 900 rpm? Maybe it'd be easier just to raise your idle a few hundred rpm to get the charge you need?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

it's California and pretty much 90+ all summer, so A/C is going full blast, seat coolers, stereo, that + heat is keeping my battery's below a charge that I'm comfortable with, when the charge gets below 11.5v my alarm starts sending me voltage warnings, the alternator I bought is supposed to be 300amp but it was pretty cheap, I don't think it is up to the task in this summer heat, it starts out good but a few miles down the road it is hot and volts are sinking.

I don't know what it's actually putting out I don't have a clamp meter, these alternators are internally regulated by the bcm, I don't think it is putting out 300amps like it should especially when it is hot

 

[Rocket Man]

quality power has a calculator on there website, you enter all the things you have on your vehicle some have a box to enter the watt's then it keeps a running tally at the bottom. mine added up to 245 with me entering a moderate rating of 2000 watts on my 5000 watt amp & subs, i'm sure it doesn't peak since I have it turned down

5000 watts? Sweeeet!

 

[Doubeleive]

5000 watts? Sweeeet!

ya if I turned it up though it would blow my JL's so the gain is almost all the way down

 

[swathdiver]

By that wording, the short answer is 'no'.
When idling, you're achieving no mileage per unit of fuel burnt. Can't get any worse than 0 miles per gallon. A higher idle results in more consumption, but not worse mileage. I don't know what the proper terminology for idle consumption would be. Hours per gallon?

Gallons Per Hour, GPH

My average is 2.12 GPH over 23,998 miles.

 

[Tonyrodz]

I sent them a message to see if i can order the 320amp one with a stock sized pulley $499, lol it's only money right?

Why not reuse your old stock pulley to save some $$, unless it won't fit.

 

[Doubeleive]

Why not reuse your old stock pulley to save some $$, unless it won't fit.

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

 

[Tonyrodz]

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

Gotcha.

 

[kbuskill]

sometimes the shaft's are different size, mechman makes there own case so no telling if it would fit or not.

I am curious what they tell you. My guess is with the standard size pulley you will have the same problem of not charging at idle.

 

[Doubeleive]

I am curious what they tell you. My guess is with the standard size pulley you will have the same problem of not charging at idle.

ya the drive pulley on the 6.2l is to big (7 3/4) so putting the stock pulley on the 320amp would make it less amperage than there 250amp unit that comes with the stock pulley, so I went ahead and ordered there 250amp unit just now, 399.00 out the door, 2yr warranty, free shipping, no tax. 2-week build time so I should have it first of next month. I didn't want to have to change drive belts, this alt should put out more at idle than the oem one does maxed out. They recommended upgrading the charging wire so I will probably check into getting a welding wire made