the Sierra 3500 HD is code TP2, can any of you tell me if this is just a heavy duty battery upgrade or an additional battery ?? I have seen some older GM's with 2 batteries so the offered option has me wondering. Thanks.

My 2500HD has dual batteries (supposed to anyway...will know for sure when it arrives later this week). It was standard for the Duramax. I think the HD battery is for gassers but not sure.

All Duramax's have 2 batteries.

Hello, as respects your question, on the 2500HD (gas) you can order it with dual batteries, 660cca or a single HD batery 770cca, and/or a HD alternator / 145 amp. Also there is an option of getting one HD battery, and one std battery.The diesels come std with dual batteries, and a single 145 amp alt. std.


Sir-col http://www.dieselplace.com/forum/smileys/Big Smile.gif

all diesel brands have two batt as standard options on gasers its an ption on a camper special

Anyone know what part numbers I would need to get to set up the dual alternator? I heard someone on here had done it and I can't seem to find out who.

Anyone know what part numbers I would need to get to set up the dual alternator? I heard someone on here had done it and I can't seem to find out who.


I think dmaxallitech sells a kit and there is a thread on dual powermasters in the DIY section.

Why would you want or need to add another alternator? Isn't 145Amp. enough for most anything?

The diesels come std with dual batteries, and a single 145 amp alt. std.





Somebody correct me if I am wrong, but the standard alternator that comes with the Duramax is only 105 amps.

My '04 D/A has a 105 amp alt. http://www.dieselplace.com/forum/smileys/Cry.gif My '99 Jeep wrangler came equiped with a 117 amp alt and it only had one battery to worry about...http://www.dieselplace.com/forum/smileys/Disapprove.gif

My 04 has 145 amps w/ plow prep package

The dual battery option was just for the gassers as Sir-Col has said. The Dmax comes with two batteries standard since you need both to crank the diesel, especially when it's cold.


The standard alternator is 105 amps and the alternator that comes with the plow prep package is 145 amps.


I don't know if the 145 is available by itself or only with the package, and I think VooDoo got the dual alts from the factory, but I don't recall what the alternator output was for that option.