Hi all, silly non-mechanical-person question, didn't get far with the Nissan service department. What is the Amp rating of the 2013 D22 ST-R alternator? I am led to believe a sticker on the thing tells me that, however it is obscured by the incoming leads. I'm looking to buy an isolator and want to ensure its suited to the alternator rating. While I'm at it can anyone recommend a suitable and budget consious isolator set-up? I'm thinking to attach this to my toolbox in the back of the tub and attaching a deep cycle battery to it (running to the main battery in the engine bay). That way I can keep the double battery set-up as is in the engine bay and create a power source in the tub to run all other crap off. Cheers.
Alternator rating D22
- Thread starter PeteV
- Start date
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I'd imagine that it's a 90A alternator, but that's not what should guide your choice in isolator.
Your alternator is only going to put out that 90A at high rpm - your engine will be screaming to deliver that power. It'll happily deliver around 60A at cruise. It won't be delivering all of that to your aux battery either - some has to go to the main battery, which is busy powering the ECU, injectors, BCM, instruments, fans and if it's night, obviously lights. You would be lucky to send 30A down to the aux battery at night and might manage 40-45A during the day.
However, what's supplying the aux battery with power is the main battery. That's where the isolator goes - between the main battery and the aux. The main battery is capable of dumping up to its CCA rating - for our diesels, that's 600A or better (770A in the D40, and I replaced mine with a 910CCA battery).
What you're doing with the isolator is limiting the amount of power you can dump down that long, long cable to the rear. In low voltage situations, anything over 2-3m is considered long. Allowing it to have 100A isn't a bad thing - as long as your cable can handle it. Don't skimp on the cable to the tub, and I really strongly recommend that you send both positive and negative down there - I've done it twice now (yes, I have 4 cables that are 21mm2 or 8Ga running from near the battery to the back of the car).
Your alternator is only going to put out that 90A at high rpm - your engine will be screaming to deliver that power. It'll happily deliver around 60A at cruise. It won't be delivering all of that to your aux battery either - some has to go to the main battery, which is busy powering the ECU, injectors, BCM, instruments, fans and if it's night, obviously lights. You would be lucky to send 30A down to the aux battery at night and might manage 40-45A during the day.
However, what's supplying the aux battery with power is the main battery. That's where the isolator goes - between the main battery and the aux. The main battery is capable of dumping up to its CCA rating - for our diesels, that's 600A or better (770A in the D40, and I replaced mine with a 910CCA battery).
What you're doing with the isolator is limiting the amount of power you can dump down that long, long cable to the rear. In low voltage situations, anything over 2-3m is considered long. Allowing it to have 100A isn't a bad thing - as long as your cable can handle it. Don't skimp on the cable to the tub, and I really strongly recommend that you send both positive and negative down there - I've done it twice now (yes, I have 4 cables that are 21mm2 or 8Ga running from near the battery to the back of the car).
