dual altenator install

[w1ldb1ll]

Do you need to update the computer if you install a second altenator on a 2002 HD?

[mdrag]

w1ldb1ll,

Welcome to the TDP forums. I installed dual alts on my '01 and did not require any updates. The procedure for the dual alt install is the same for the '02 trucks, and I don't remember anyone posting that a computer update was required for'02. The serp belt and idler pulley part #'s are different for '01 and '02. Good luck.

[dmaxalliTech]

Like Mittie said, no updated needed.

[w1ldb1ll]

Thanks guys. Now I need to find out where I need to plug in the wires to the computer. I think it is in the Helms book.

[mdrag]

Add a terminal to the ECU @ C1-32 using the same procedure as for the high idle - see Kennedy's site for the TECH TIPS (http://www.kennedydiesel.com/dmaxtechtips.html). Run this wire from the ECU to the 4 position alt connector that plugs into the alt.

GM refers to RIGHT and LEFT generators, RIGHT is the driver

[BlueOx03]

I wouldn't include the battery as an option for connecting a second alt. The only right way to do it is to hook it to the junction block with the other one wit a fuseable link as stated above. Hooking the alt directly to the battery will probably over charge the battery and destroy it. You should upgrade your engine ground strap as well, the strap with the factory duals is much bigger.

take care,
Ox

[Michigana_Joe]

Wiring from the alternator (voltage regulator if external) directly to a battery is never a problem. From what I understand the optimal way to wire dual alternators is the following:

1. Positive on each alternator to positive on one of the batteries (each alternator gets it own battery).

2. Negative on each alternator to frame.

3. Positive on one battery to positive on the other battery.

4. Negative on one battery to negative on the other battery.

5. Negative on each battery to the frame.

6. Replace engine ground strap with wire.

At least that is my current plan -- using 1/0 for wire.

[BlueOx03]

What alternators and external voltage regulator are you planning on using? Were did you find alternators with negative terminals? What is the purpose of connecting the negative posts of the batteries to each other?

[Michigana_Joe]

"What alternators and external voltage regulator are you planning on using?"

GM alternators have an internal voltage regulator, other manufacturers do not -- I was trying to cover all basis. Even with GM alternators, some people opt to use an external, adjustable regulator (which typically adjust from 14 - 20 volts). I had thought about running a separate 16v electrical system for my stereo (dedicated alternator, batteries, and wiring), but one of my amps will only handle 15 volts (and my stereo is already bordering on massive overkill). The alternators I went with are from Iraggi Alternator. They are supposed to provide over 150 amps each at 700 RPM and 220+ amps each when driving -- we'll see.

"Were did you find alternators with negative terminals?"

The alternator's mounting bolt functions as its negative terminal. For stock amperage alternators the mounting bracket provides a satisfactory ground (to the engine at least). To be safe it is best to ground the bolt/bracket to the frame.

"What is the purpose of connecting the negative posts of the batteries to each other?"

To ensure a common ground. As long as each battery (and amplifier(s) if applicable) is properly grounded to the frame this isn't necessary, but why chance it? Ideally, you'd connect all battery positives and all battery negatives (and connect the amplifiers inline to these same two wires) and then ground the common ground wire to the frame. The only problem with this approach is that it uses alot of heavy, expensive wire (especially if you have additional batteries in back). Using the frame as a large ground wire is more economical.

[ 04-30-2004, 06:11 AM: Message edited by: Michigana_Joe ]

[BlueOx03]

Thanks for the enlightenment
Dude you're past overkill, you're nuke'n it! :eek: :eek:
I'll stick with the stockers until I start browning. I'll have to check out the alts you mentioned.

Take er easy,
Ox

[mdrag]

Michigana_Joe and BlueOx03,

Thanks for all the alternator info. I need to upgrade my ground strap, and will check Waytek the next time I place an order.

[BlueOx03]

Thanks Mdrag. I think I'm gonna 1 up everyone here and install a small reactor :eek: That'll eliminate the need for an inverter, I'll have to lead my firewall though. Hmmmmm....

Ox

[mdrag]

Cold fusion is the ticket ;) :D

And when I said upgrade my ground strap, I'll give Michigana_Joe's idea of using 1/0 wire a try.

mdrag

[Michigana_Joe]

mdrag: Thank *you* for all of the info you have posted on this subject.

I wish I knew what the ECU does as far as controlling the alternators -- any idea?

[mdrag]

Michigana_Joe,

My 2001 Helm's manual has this information on the connector for the primary and secondary alts:

Primary
BRN circuit 25 Charge Indicator Control
GRY circuit 23 Generator Field Duty Cycle Signal

Secondary
BRN circuit 2524 Charge Indicator Control

ECM terminal position C1-32 has this description:

C1-32 BRN circuit 2524 Generator 2 Turn On Signal

Slightly different descriptions at the connector vs the ECM, so I'm not really sure what C1-32 does...

mdrag