[folivier]

I want to disable the alternator output on the generator.
Which wire would I disconnect to do this, without harming the alternator?
I don't want to remove the belt.
I will put a switch so I could enable it if needed. When driving and running the generator that alternator senses the house (LiFePO4) batteries as full so it cuts the amps output and the volts go to 14. This causes the engine alternator to shut down. Which is how I have the Balmar regulator programmed. But the engine batteries aren't getting any charge so they slowly start discharging.

[Retro]

Forest, you should be able to disconnect the main batt, red 8-10 guage wire on the alternator. If you want to switch it run it through a relay.

[folivier]

Thanks Retro. I'll look at it later today, heading out with Tom to do some shelf shopping.

[bestgenman]

[attachment=2058][attachment=2059]When disabling and alternator we remove the excitation wire which plugs into the rear of the alternator. If using a switch the rating can be 15A ~. Some controllers use an extra wire from the plug for a speed signal to control crank disconnect, see the diagram for the pins.

[Retro]

Gordon, correct me if I am wrong here but doesn't the exiter terminal turn from neg when the alternator is stopped to a positive when it is charging? So if you switch this terminal after the alternator is working it would still charge off of the single main battery post wouldnt it? Unless we are talking about a different style alternator? I am thinking delco

[folivier]

The alternator is a Hitachi LR140-714B. So would it be the Ignition wire on the back of the alternator that I disconnect? Is that the wire that tells the alternator to output current?

[Ozarkguy]

Forrest this book is about marine but has some good info that you can gleen from it to help you make a good choice on the How!

Alternator Manual.pdf Size: 1 MB  Downloads: 2

[folivier]

This shows the 3 wires that are connected, output to battery, Ignition, and 3rd terminal (not marked).
I'm assuming that if I disconnect the Ignition wire that the regulator will be turned off and not output. Does that sound right?

[bestgenman]

I cannot say whether the terminal changes polarity or not, it is not a function used in new construction. The alternator needs a positive voltage to turn on the regulator for excitation. The alternator used in most Newells is either a Denso or Hitachi as most sets are powered with a Kubota or Yanmar. Older sets may use the Delco.

I'm also not sure about switching while running as it is not a function commonly used, most sets have the excitation terminal tied to the ignition (or run) source so it is on with the engine running. I know of no manufacturer that switches the alternator excitation during operation. Onan does provide the option to have alternator output or not on their quiet diesel sets. Many times the alternator output conflicts with the inverter/charger output.

The genset alternator charges the same battery used for starting and if that is house battery and you want engine battery charging then you have two options. first, change the genset battery feed to the engine batteries or (second), run a seperate conductor from the alternator output (large enough to handle the current output) to the desired battery set.

Kinda wordy, difficult to explain, so I hope this answers your question!

[Ozarkguy]

That should do it .