Not enough voltage

I got a new group 31 x2 battery and put a voltage booster in but I’m only getting 14.28 instead of the recommended 14.4-14.6

Without booster it’s 13.8
I disconnected all positive accessories, no lights on and just the truck idling at start when I tested 13.8

Is my alt going bad?

 

Those alternator numbers are fine/normal.

Guessing you fall into this camp;
https://www.tacomaworld.com/threads/the-northstar-agm-battery-voltage-booster-upgrade.604478/

 

Is there way people test whether alt is going bad? If it’s not the alt then curious on how to get to 14.4-14.6 range.

 

I think it's an option in the tunes folks install.

What I'm seeing is your alternator is just fine for the battery it was designed for

 

A tune will not help.
The 2nd Gen trucks are NOT voltage regulated by the ECM like the 3rd Gen trucks.
A diode in place of the Alt-S fuse is the only way to up the voltage.
The best way is the booster style linked in post #2.

OP, how are you booting the voltage?

 

Thanks for the clarification / correction!

 

It's all good.

FWIW, I don't think there is anything wrong with OP's alt.
I think he needs to run it at 2,000 RPM and report back.

 

I’m using a voltage booster off eBay that placed a diode in the alt-s used to bring up by .5 which isn’t enough to get 14.4-14.6 since I started with 13.8

Do you mean keep my foot on the gas at 2000 rpm while parked?

 

Yes. See what it charges to then.

But 13.8v is a pretty good for these trucks stock.
If all you got was a .5v increase with the booter. (13.8+.5 = 14.3v)
Than you need the adjustable .2v-1.0v in the link above.

Again, bump up the RPM to about 2000, and see what it is outputting.
Most of the time, the truck isn't going to be idling. It will be at 1,700 - 2,000 rpm while cursing.

 

Did rpm up to 2000 and got to 14.35 cold start.

 

I run my truck at about 2,000 RPM all the time.
I use 4th if I'm driving under 55 mph.
I hate the constant locking/unlock of the torque convertor.
The Automatic trucks need a lower differential gear ratio in my opinion.

 

So I got a voltage pro that can adjust from low +.5 to high setting +1.0

I would be getting 14.4-14.8 the entire time driving the truck. Is that okay to keep the battery at?

 

You should be fine with the voltage you are getting, the 14.28. The difference without and with the voltage booster was drastic for my at rest voltage on my Optima Deep Cycles (I was running 3 group 27s in my truck, yes a triple battery setup). I'm about the same as you now and have been running the 27F X2 now for a few years. Working great, and much more usable capacity than before the booster.

 

What was the resting voltage? Mine starts 14.28 and goes down to 13.5ish while driving more. Those numbers are with the voltage booster.

 

Resting is after shutting off the truck for a couple hours.

My house batteries would be at like 12.6 or 12.7volts. with booster it was 13.2, which was right at Optima's recommended voltage for 100% capacity. Looks like X2's recommended resting voltage is only 12.9 to 13.0. So you should hit that easy enough.