# 12vdc equals what 110 ac?



## Bser (Jun 3, 2008)

large trucks and semi's have a commonly used 65a 12vdc alternator. they are cheap and have a good reputation for durability. My question is what this would equal in 110 ac? Could it be altered to put out 110 ac? What hp does this unit need for full load operation? Am I wasting my time thing on this?


----------



## artificer (Feb 26, 2007)

Not really sure what you're asking. 65 amp alternator is a normal car size, even for small cars. A large truck (diesel pickup) is going to be at least 125amp.

12vdc and 65 amps is about 7 amps of 110v ac or 780 watts. While this is close to 1hp, it would take at least 2 hp, and probably a 3hp engine to provide it. If you want to run the engine slower than 3600 for a B&S, it will have to be even larger. (3-4hp)

Sounds like you want to make an alternator battery charger to use with an inverter.

Michael


----------



## 12vman (Feb 17, 2004)

Here's a calculator to play with. There's a pop up that bugs ya when ya go there but I don't think it's a vicious one.. Just so ya know..

http://www.angelfire.com/pa/baconbacon/page2.html


----------



## radiofish (Mar 30, 2007)

artificer said:


> Not really sure what you're asking. 65 amp alternator is a normal car size, even for small cars. A large truck (diesel pickup) is going to be at least 125amp.
> 
> 12vdc and 65 amps is about 7 amps of 110v ac or 780 watts. While this is close to 1hp, it would take at least 2 hp, and probably a 3hp engine to provide it. If you want to run the engine slower than 3600 for a B&S, it will have to be even larger. (3-4hp)
> 
> ...


Bser - I will try not to confuse you, with too much electronics theory.. I'm not BSing you with this.

Michael pretty good answer for the math. Off of the top of my head, I believe 1 HP is equal to 750 watts... Ah it is 746, I was close before I giggled up the answer..

Here is a link for comparing HP to watts...

http://www.onlineconversion.com/forum/forum_1028626736.htm

*According to Ohm's Law {P = I * E} *

Power = Current X Voltage (DC)

Power (P) = I (current [65 amps]) times E (voltage [12 VDC/ or more like 13.8 VDC] from alternator/ generator output in real life) = 

65 Amps X 13.8 VDC = 897 watts produced per hour

This could go to a storage device/ battery bank. Or it could be used for an inverter, which changes DC Voltage to AC Voltage. Depending if you get the modifed sine wave or the true/ pure sine wave DC input to AC output inverter will effect the price of the inverter, and the quality of the AC Waveform of the output.

For AC inverter capacity in output Amperage is (P) 897 watts/ (E) 110 VAC = (I)

Or 897 divided 110 = 8.15 Amps of current available at 110 Volts AC - theoretically.

In one of my pickup trucks, I run a dual battery system with an isolater from an 110 Amps per hour alternator. One large deep cycle 100 amp hour battery is dedicated for all of my amateur "ham" radios in my truck.

If you are thinking of cobbling up a charging system from a used alternator from a vehicle, get a used GM alternator. They have the Voltage Regulator built into the unit. Ford's and Dodge use an external Voltage Regulator.

Check out this page, which may answer any questions you may have on using an old alternator to produce power..

http://www.theepicenter.com/tow082099.html

Hope that the above helps.. Plus I got to use some of my electronics education, for something besides ham radio..


----------

