80 Series Electrical Limitations with an inverter.

[97 FZJ80]

It means max 500 amp inverter in a single bat setup with stock alternator . ?

You mean a 500 watt inverter? A larger inverter will work fine, as long as you keep the continuously load under 500 watts.

Here is a quick summary of the power capacity on the 80

90A stock 80-series alternator output
20A usage for engine + control system
70A available current at 13 volts for accessories, assuming other major power-hungry accessories are off (such as wipers, headlights, heater, AC etc)

70 Amps X 13 Volts = 910 Watts
910 Watts x 90% inverter efficiency = 819 watts of available AC power

I have a 1.2k watts inverter that I use to power a microwave with 600 cooking watt. The microwave uses about 800 watts of AC power and I use it to heat up food. Since heating up food only requires the microwave to only run a couple minutes at a time, it doesn't really work the alternator very hard. I have no experience "cooking" with this microwave, as I never had a need to run the microwave continuously for over 5 minutes.

This is assuming that
1. All wirings and groudings are in good condition and are capable of providing the current for the accessories.
2. All the other major electrical accessories on the vehicle are off
3. The RPM is set to high (2k RPM) to keep the alternator near its peak output
4. the stock battery is in good condition and can provide buffer for the power consumption in excess of alternator output for a short duration.

 

[Tapage]

You mean a 500 watt inverter?

Yap .. you are right ( my bad sorry )

I't means in my HDJ-80 I have few more amps available ..

 

[semlin]

good thread. as a data point for those thinking of using the 80 cigarette lighter plug and a small inverter for small appliances, I have a laptop rated at 16 volts and 4.5 amps, or 72 watts. using the 80 ciagarette lighter I could not get enough juice out of a 300 watt inverter to run the laptop, although it would recharge it.

 

[Romer]

good thread. as a data point for those thinking of using the 80 cigarette lighter plug and a small inverter for small appliances, I have a laptop rated at 16 volts and 4.5 amps, or 72 watts. using the 80 ciagarette lighter I could not get enough juice out of a 300 watt inverter to run the laptop, although it would recharge it.

You were probably limited by the wire in the standard harness. Have you wired an extra with lower gauge wire? Interested in what the difference would be. I have 3 "lighter outets currently wired. 1 Stoc, another just to the right of the center console and one in the rear.

 

[lovetoski]

This is a good thread, but the idea of limiting inverter size (and watts drawn through it) based on the alternator output alone is safe, but probably too conservative for most people most of the time.

A properly designed and built system can handle much higher watt loads than nearly any alternator can put out. Proper design must include careful consideration of quite a few variables.

All of this and more is covered in a $20 book titled "Managing 12 Volts." Author is Harold Barre. ISBN 0-9647386-2-7.

This book is simply the one resource you need to mod your 12V system - dual batteries, 3 or more batteries, isolators, inverters, solar panels, troubleshooting components (batteries, alternators, isolaters, etc) how to use a multimeter, wire guage, theory, practice, extensive examples and diagrams, on and on.

I'm not affiliated with the author nor the publisher in anyway - but my dog-eared copy has served me well.

 

[calamaridog]

Also, an alternator rated at 90 amps only puts out a fraction of that at idle. We're going to need to hook up a fast idle switch now too. Set it at 4500rpm!

So you need a Mean Green alternator now