# Opinion of DC Power Engineering Alternators?



## KillerBox (Jan 7, 2011)

I wanted to see what everyone's opinions might be of DC Power Engineering Alternators? https://www.dcpowerinc.com/fit/Lexus~LX470~2001~4.7L-V8-2UZ-FE/13859-270-xp.html

Short story: I purchased a 13859-270-XP alternator from DC Power about 3 months ago. At the same time, we did a Big 3 wiring upgrade, new OEM battery in factory location and two new batteries in the rear.

Since the upgrade, my battery voltage gauge has read a steady 14v with only a small about of light blinking at very high volume. I am running three amps with a fuse rating of 60a, 60a and 90a, so 210 amps total fuse rating. My factory alternator was a 100a.

Needless to say, I only used this alternator for about 500 miles in the three months. I had my vehicle idling one day with the stereo system completely turned off and it started putting a full 17.2 volts all the time. So I assume the voltage regulator has went out. When the DC Power Alternator was removed it looked brand new the stickers were not even dirty. 

DC Power has agreed to warranty the alternator but, it is a pain to keep installing and removing, so I wanted to see what everyone's opinions or suggestions might be?


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## DC/Hertz (Nov 27, 2011)

They sent me the wrong one about 6 years ago. Argued for weeks saying it was right even after I sent pictures. Two months later finally agreed to send it back.


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## UncleHungry (Jul 18, 2017)

I have a 270 that I haven’t installed yet. They took too long to ship, and what they sent me wasn’t billet and has the factory pulley, contrary to the description on their website. So far, I’m not impressed. However, like I said I didn’t use it yet.


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## avhound (Sep 15, 2017)

i want to know more.
been reading up on the three or four so called HO Alts. i just don't want to change the size of my belt, i emailed each and every one of these MFG's (manufactures, seams these are all cores). not one could get back to me on the belt size i would need for their smaller pulley. XP was the only one i believe don't have to change belt size.


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## 18inch (Jul 19, 2017)

not familiar with HO alternator, but i did ask Singer alternator for a quote a while ago and he replied with details and all, seems like a nice person, he has his own thing goin on so everything is done directly with him... no company customer service crap and all.. of course it has its + and - but he do have lot of positive review
anyways i dindt end up pulling the trigger cuz it was too expensive for me and thought it was the least "mandatory" thing for me... so keeping the HO alt upgrade as a last resort, i dont really need it , battery doin pretty fine for now !


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## SilentWrath (May 23, 2017)

The higher the amps you try to get out of the same size casing alternator, the lower the lifespan will be. Ask any shop that rebuilds them. 

I would recommend finding a local shop to work with. I went from 105 amp to 155 amp on my OEM tsx alternator. That was the highest the shop I worked with was comfortable going while guaranteeing OEM reliability.

Find a highly recommend shop near you to discuss details. 

If you need higher than they will go on the OEM casing you will need to find a larger casing that will fit in the stock location or look into custom fabing a way to make a larger case fit in the engine bay.


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## avhound (Sep 15, 2017)

i was told by a mechanic your consuming current through your batteries, the alt. just keeps them charged unless you are sitting in accessory (engine off) then that's where you would need something HO to replenish your batts a little quicker and stay topped off. 
kinda what you two were saying.
i'm not ready for a $500+ alt. my stock is 136Amp.
and from what i have read it seems they're hit and miss and they do not last that long.
some swear with what they have and some wish they chose an alternative.
have plenty of time to continue study and learn more about these HO ALTS.
What's nice is they are pretty quick to change out.


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## SilentWrath (May 23, 2017)

Not exactly.

The alternator is what is providing the current to run everything when your car is running. Everything from the ecu to the headlights to the stereo. 

The battery acts as a reservoir/buffer in the electrical system. If you demand more than your alternator can provide while the car is running, you will draw reserve power from the battery.

When the car is not running the battery is supplying all power, from running accessories to cranking the motor. 

The power that is drawn from reserve in the battery is replaced by the alternator once the car is running again. 

This is why you can actually remove the battery once your car is running. NOT RECOMMENDED. Remember the battery also acts as a buffer to prevent voltage spikes from the alternator damaging sensitive electrical equipment on the car like the ecu and other computers.


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## BrainMach1 (Jun 19, 2014)

Yes a second battery will be an extra load on your system when it is not actively supplying current. 

It will supply extra current when the stereo is cranked beyond the capacity of the alternator. It will consume current when the system is not demanding as much current. 

The battery will charge to 12.8V when the alternator is at 14.4V. The voltage drop of 1.6v will be dissipated as heat through the battery. 

A second batteries function is to allow you to play music longer with the engine off and it can supply extra current on demand, but also taxes the system at idle. 

Sent from my SM-G955U using Tapatalk


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## Swaglife81 (Oct 15, 2016)

There are countless brands that use good internals for a higher than factory output. I advise everyone to shop around and buy the alternator they like. I ran no name HO alternator for years and years on my Mustang. DC, overpriced powermaster, tuff stuff, PA, etc etc. In all honesty brand of alternator is like brand of a/c compressor. It's pretty irrelevant given wuality internals. Just my 2 cents. As long as the battery isnt under and overcharging


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## Locomotive Tech (May 23, 2016)

SilentWrath said:


> Not exactly.
> 
> The alternator is what is providing the current to run everything when your car is running. Everything from the ecu to the headlights to the stereo.
> 
> ...


Not sure I agree with this, a car will run with either the battery or the alternator disconnected, the car doesn't care "too much" where the power is coming from. Although running the car with battery disconnected is a bad idea, running with an alt. disconnected or a weak alt is not as bad.

My car has a 105 amp alt. and I have recorded 160 amps +/- 10 amps on full acceleration and all the load I could apply during the acceleration, factory radio high, A/C (which shuts off under hard acceleration) fan on high, aggressive steering. In Fact, when I measured this The alt didn't even turn on for the five seconds of this excersize, it ran soley from the battery.

Furthermore, I have ran my car around town for a maximum of 41 minutes before the alt. started the charging cycle.

The battery is the primary source of supply power in a car. Think of it this way, if your battery is fully charged, (1) there is no bypass circuit that allows the car to run soley on the alternator. (2) Charging demand or requests (if you will), are based on voltage not current, at least in my car.

The battery and alternator work together and if you have a need to increase the output of your alternator then you should also increase the capacity of the battery. An alternator cannot deliver current on demand like a battery can. A battery has it, an alternator has to make it. If you have an HO alt. and a stock, tiny battery, you will be increasing the duty cycle of the battery charging cycle. When a batteries capacity has deteriorated it is difficult to tell, usually you will begin to notice weak starts, if this goes on even for a few weeks you have significantly decreased the service life of the alternator....heat......and continous operation that is compensating for a weak battery kills alternators. Increased and heavy/long charging cycles kills batteries. The two go hand in hand.


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## SilentWrath (May 23, 2017)

A car will run without an alternator until the battery is depleted to a point where sufficient spark can no longer be generated. 

A car will run with the battery disconnected forever....not forever in reality, but certainly much longer than sans alternator. 

Both situations assuming an infinite supply of gas.


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## Locomotive Tech (May 23, 2016)

SilentWrath said:


> A car will run without an alternator until the battery is depleted to a point where sufficient spark can no longer be generated.
> 
> A car will run with the battery disconnected forever....not forever in reality, but certainly much longer than sans alternator.
> 
> Both situations assuming an infinite supply of gas.


True, but if you ran a 100 amp alternator at 80 amps continuously, it won't last more than a few weeks, at best. The heat generated by the Alt under this demand will cause an increase of resistance causing a higher amperage draw , causing more heat. A thermal runaway situation will ensue and end the alternator. They work together


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## SilentWrath (May 23, 2017)

Yes, obviously they are part of a system. That's why cars come with both. 

I was over simplifying to make a point. Like a said in my first post, the alternator supplies the current, the battery acts as a reservoir/buffer.


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## Locomotive Tech (May 23, 2016)

So how does an alternator know when to produce more (or less) current?


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## DeltaB (Jun 17, 2017)

Locomotive Tech said:


> So how does an alternator know when to produce more (or less) current?


Let me try to help clear some of the confusion here. Alternators are controlled by voltage regulators. These are not current regulators. They sense voltage. An alternators output will continue to rise to load until the specified voltage is achieved. As more load is applied, the more voltage drop you will have, hence, the voltage regulator will apply more voltage signal to the commutator, until such point it reaches it's maximum output. When an alternator reaches it's intended set point for voltage, it decreases voltage to the commutator, thus decreasing output. If you have overvoltage issues, then you have either lost voltage sense, or the regulator has failed.

One point of suggestion to all who read this, the body of the vehicle itself, provides the lowest resistance for all grounding. Run your very large gauge cable, as short as it is possible from the negative post to the body itself, and at your amps ground with shortest large gauge cable directly to the body. Also, do the same from a place on the block to the body. Positive feeds must home-run to its intended feed. Just a word to the wise.


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## Locomotive Tech (May 23, 2016)

DeltaB said:


> Let me try to help clear some of the confusion here. Alternators are controlled by voltage regulators. These are not current regulators. They sense voltage. An alternators output will continue to rise to load until the specified voltage is achieved. As more load is applied, the more voltage drop you will have, hence, the voltage regulator will apply more voltage signal to the commutator, until such point it reaches it's maximum output. When an alternator reaches it's intended set point for voltage, it decreases voltage to the commutator, thus decreasing output. If you have overvoltage issues, then you have either lost voltage sense, or the regulator has failed.
> 
> One point of suggestion to all who read this, the body of the vehicle itself, provides the lowest resistance for all grounding. Run your very large gauge cable, as short as it is possible from the negative post to the body itself, and at your amps ground with shortest large gauge cable directly to the body. Also, do the same from a place on the block to the body. Positive feeds must home-run to its intended feed. Just a word to the wise.


Exactly what I was struggling to convey, current will be based on the demand (the capacity of the battery or the load of the car). An alternaor cannot react to instantaneous demands (especially at idle) therefore the battery will supply the load and the Alt. will replenish the battery as needed.

And your advice about large gauge grounds being as short as possible is spot on!

A car does not run soley on one or the other, they work together. I can pull 120 amps with the system turned up and the car demands high, if my car was running soley on the alternator it would stall


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## DeltaB (Jun 17, 2017)

Locomotive Tech said:


> Exactly what I was struggling to convey, current will be based on the demand (the capacity of the battery or the load of the car). An alternaor cannot react to instantaneous demands (especially at idle) therefore the battery will supply the load and the Alt. will replenish the battery as needed.
> 
> And your advice about large gauge grounds being as short as possible is spot on!
> 
> A car does not run soley on one or the other, they work together. I can pull 120 amps with the system turned up and the car demands high, if my car was running soley on the alternator it would stall


Since most batteries can provide hundreds of amps (current) instantaneously, then your understanding that the battery is the actual device providing the current for you amplifier is certainly correct. The role of the alternator is to replenish the current used. If your current demands for a fully loaded system, (i.e. lights, accessories, fans, engine electronics) exceed the current capacity of the alternator, then you would seek a larger alternator output. However, voltage regulators are not instantaneous to load. (this takes seconds or longer) If your lights dim on heavy instantaneous peaks, then you haven't got your grounding setup properly.

In another hobby of mine (amateur radio) I have other operators who come to me all the time with this very same issue, utilizing linear amps that can instantaneously demand hundreds of amps of current during voice peaks, and a simple explanation of the importance of how they implemented their installation, (mostly never providing large gauge connect from the negative terminal to the body, and engine to body) find their lights almost always flashing at night due to the fact all accessories are running through a mostly 10 gauge or less connection from the negative terminal to the body, which cannot support a 500w or 1kW linear and all the accessories. Same holds true for audio amps.


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