quick alternator question

Discussion in 'GM Electrical Tech' started by reggiecab2000, Sep 9, 2012.

  1. reggiecab2000

    reggiecab2000 Epic Member 5+ Years 1000 Posts

    hey guys,
    i need to invest in a bigger alternator for sure thats no question, but as i was talking to my dad on the phone earlier(he disapproves of anything aftermarket on a vehicle, claims it came stock for a reason, no need to change it) one of those guys...
    he told me to watch out, that if i put an aftermarket alternator on my truck and it puts out TOO MUCH power that i will fry my battery possibly.
    is this true? or is he full of it? lol
    is there such thing as an alternator overcharging the battery? i guess if im not using as much power as it is putting out all the time
  2. Enkeiavalanche

    Enkeiavalanche Loving the Outdoors Staff Member 5+ Years ROTM Winner 5000 Posts

    Most Alt's have Regulators that will not allow the Alt to over charge a Battery. So you should not have a problem. As for Good Aftermarket Alt's there is only 1 I would go with and it's Ohio Gen.. Not the lowest price But one of the Best built and Proven...
  3. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Regulator adjusts voltage and has nothing to do with amperage. No, a high amp alternator will do no damage. In fact, it will probably extend the life of the battery. The battery is only supposed to be used to start the vehicle. After it starts, the alternator is supposed to provide the energy to recharge the battery and run all electrical systems. The battery will only draw as much current (amps) as it needs from the alternator. Your alternator needs to be able to supply all of the current the vehicle and it's systems draw. If your alternator cannot keep up with the consumption, the battery will go dead, even while the vehicle is running. Think about a cold, rainy night. You are running the defrosters, headlights and wipers. When you pull up to a traffic light, the lights dim, the wipers slow down, as does the blower motor for the defroster. This is because you have depleted the maximum current output of the alternator and are now pulling from the battery to keep everything going. You need to understand how electricity works...

    Voltage is pushed while amperage is drawn. Amperage is the amount of electromotive current that is available for use. Electrical devices will only pull as much current as it needs to operate. You can take 12 volts with a million amps and hook a tiny led to it and it won't hurt it because it only draws a fraction of an amp from the power source.

    Police vehicles come with high amp alternators from the factory. I would suggest sticking with a high amp AC Delco unit for the best performance.
  4. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Ohio Generator, Mechman, and DC Power Engineering all have decent names in the business and have been doing what they do for years. Ohio's website is about useless, though, and I've read some other forum reports where the quality of their product has been slipping (a la low output at idle) compared to what it once was. Mechman and DC Power Engineering's sites are full-featured and easy to use/order from. DC Power seems to have the most options to choose from.

    I chose DC Power Engineering from among those three and had a good experience. The alternator's been installed for almost a year, now, with no hiccups.
  5. reggiecab2000

    reggiecab2000 Epic Member 5+ Years 1000 Posts

    well nice info moogvo, thanks for that, i figured it must be voltage regulated, but thanks for all the info! lots of help

    Yeah ive been looking at the OEM series 220 AMP alternator for my truck but its still out of stock.... :/
    i definitely notice now especially with my ls1 fans installed the amperage draw on the electrical system is pretty strong...
  6. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Yup, an alternator upgrade is usually recommended in conjunction with an efan upgrade.

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