DC Power Engineering h.o. alternator issues

What voltage are you getting from yours? My Scangauge reads anywhere between 14.5 warm at idle, and 14.8-15.0 on the highway. I typically get 15.0 volts at startup, and even on the highway in cold weather. I ask because I had BOTH of my Sylvania SilverStar bulbs burn out at the same time while up in the snow this past weekend. Had them for about 1.5 years and 8,000 miles. Not sure if they both burned out simultaneously since I had been using them during the day. I always carry a spare bulb, but it really irked me! Do you find you're going through headlights quickly, or if you are running HID, have there been any problems? DC Power Engineering says that those voltage readings are considered normal.....

I wonder if anyone else here is running these alternators and how they like them. At 2 years and 10K miles, no issues with mine other than the bulbs...

 

Um, yeah as of late, I'm having a voltage issue. It doesn't do it unless I have my amp/sub cranked up, as well as all my led light bars. It starts a "pulsing" effect on ALL my lights, where they dim and go bright rapidly. And once it starts it doesn't stop even if the radio is turned down. Only stops once I turn the ignition off then back on. Normally I see about 14.1 volts when I first start. Then it goes down to about 13.8 Or so. With all my lights on and stereo it doesn't really drop, but my lights will flicker to the bass. Then if I really strain it for an extended period that's when it start the pulsing effect. I thought this alt would be able to handle it all. Apparently not. I have been meaning to call them and have it sent in for inspection. My only guess is a voltage regulator issue.

Edit. I've also got the big 3 upgrade as well.

 

13.8 is a normal output, does the flickering go away if the radio is completely turned off?

 

Nope. Everything pulses. Headlights. Dash lights. Even the engine pulses a lil. All to the same beat. But not to the beat of stereo. Its a steady unchanging rapid pulse. It changes a lil at idle, and pulses more rapidly and dims/brightens more when I start to give it a tiny bit of gas. It seems to change with changes in rpm. But the effect stays the same until the truck is turned off then back on and it disappears.

 

I would say it's the diodes. Seems like you've had a batch of lemons with these alternators. Did you try charging a drained battery with it after running the stereo and lights with the engine off? Trying to charge a low/dead battery with an alternator (even a heavy-duty, high output one) will cook the internals- especially if done on multiple occasions.

 

Yeah maybe a couple times. Idk. I was just guessing with the regulator. That's what I was told anyways, that it might be the culprit. Not sure about diodes. Not very knowledgeable with alts.. I was also told to get a capacitor for my amp. Haven't done that yet. I'm just gonna send it in one of these days. And eventually look into another option for a h/o alt, probably when I get around to redoing all my light wiring with distribution block and relay box. Along with a dual battery setup. I've tried researching into my pulsing issue, but only keep running into issues with people that don't have big 3, or a h/o alt. Seems unprecedented in my case.

 

Inside the alternator all the electrical parts are held together by screws or small bolts. These also join them electrically. If one of these is loose it can cause the pulsing, and the flickering of lights. This happened to me once on an old Honda. I had replaced the brushes and didn't tighten one of the screws holding it and the regulator on. I took it back apart, tightened it better and all was good. I'm just throwing this out as a possibility. I don't know if it would explain why it doesn't happen after a restart.

Bad diodes can also cause the voltage to fluctuate. The alternator will only put out current during part of the rotation.

Some people like digging into the parts to find out what's wrong, some don't.

 

Well, looks like I'm having the same issue with the alternator bracket as well. Was doing an oil change the other day so decided to take a look at the bracket and sure enough, there was a hairline crack in the exact same place as yours. I will say that the bracket did not align perfectly with its mounting point on the alternator due to that spacer they put on the back of it. I bought a new bracket and thought about bending it to fit, but considered the other issues you've had with the upper mount cracking and have decided to look for another high output unit. Considering a Mean Green 140 or 220A. What did you end up doing? Did you go with a different manufacturer? Very curious what happened with this.

 

Ha.. Guesssss what.. Its currently being shipped back to them yet again for another new billet case. The top cracked again.. Plus they are gonna check out the regulator. This is the last time though.

I wrote them a lengthy email about it too. Basically telling them in detail the issues and that I thought the mounting system was kinda flawed. It was my opinion that the way it's mounted, only having the front of the alternator supported by the front billet case, was not enough to hold the alternator in the back, which would cause stress on the whole system. And that it really needed an extra support for the back of the alt too that attached to the top pivot mounting point. And not just that big spacer which didn't seem to do the job. Other alts including oem, have a much beefier case and seems to support the alternator much better by distributing the weight and supporting it by the top mount alone. With the tensioning bracket not being used for support at all, but for adjustment only. Which I think is what's going on. The top isn't being supported enough, and that extra weight and stress is being transferred to the bottom tensioning bracket, causing it to loosen or break. Then the top breaks due to that from it being skewed..

They blamed it on the design of Toyota's brackets. Saying that in their opinion the lower tensioning bracket on early Toyota's was a flawed design, that would loosen over time and cause the stress. And tension and bolt torque needed to be checked more often. And that they didn't have any other solution besides using loctite on that lower bolt to keep it from backing out.... Which is not really the sole issue here. Its the top mount, and not enough support.

I will say that the lower tensioning bracket isn't the beefiest and surprised it cracked like it did. Which this time it didnt, only the top, as I caught it in time I think. And that I probly should be checking it more often. But never had this issue with any vehicle before. The freaking belt should loosen and squeal as your first sign, and at most the belt should break before Any of the compnents. So there's certainly something wrong here. And I want to say I nailed it, but idk, what do I know.. Ha. At least they are still willing to work with me on it, especially since its only a 2year warranty and I'm pretty sure it's long past that. So I'll give Them props for that.

So anyways, I'll give it another go. Hopefully they'll have fixed the regulator too. And I'll just keep checking the tension periodically and see how long it lasts. But if it fails again, I'm moving on. I should just try to sell it now with a new case on it. But I'd feel bad for bestowing that burden on a fellow Tacoma owner. Or maybe for like a hundred bucks, with a disclaimer. Ha. Idk.

 

Case design is no good. There's to much weight hanging out back beyond the mounting points. Is there any threaded holes in the back of the case another bracket could be added to stabilize it?

 

Nope. That's what I asked them about too when I emailed them. If anyone else has had this issue and had come up with a solution. Because all their alts seem to be designed the same way so figured I couldn't be the only one.


"Due to the mounting style of the Denso alternators we use, there is no room to add a rear bracket nor is there a mounting point we could use to fabricate one to. Basically it’s more of a maintenance precaution to check it than a design change we can make."

 

So how many lower brackets and replacement alternators has it been up this point? Did you purchase all of your brackets from Toyota? The DC Power unit mount looks like a design flaw indeed..... I'm going to mull over the Mean Green option- I did speak with them last week, and they claim the case is exactly like the Denso unit with the single-piece molded upper mount. I do wonder if the extra horsepower needed to make that higher output puts extra stress on that lower mounting bracket, regardless of who makes the alternator? The replacement bracket I picked up from the dealer looks a little more substantial than the original one, and measuring it with calipers, it came in approximately 1/16-1/32" thicker...

 

I think I'm currently on #2tensioner bracket, maybe 3, idk, ha.. And #2 billet case on alt. The tensioner bolt broke once. Still have a spare bolt and tensioner bracket just in case.

Still haven't heard anything from dc. They were supposed to get it on the 12th. I think I'm gonna sell this one and get a different one. Tired of going in circles. I really wanted to make it work because their alts seem to have the best specs as far as output goes, especially idle output. But this is getting old. I was hoping @BamaToy1997 would respond as I tried reaching out to him for a new alt, but seems he's in a bad spot atm for some unknown reason.. Not sure what route to go. The singers look nice too. But you gotta fill out a request form to get a quote. Which is nice as well because they can build it to your specs with that. But I'm not even sure what I'll end up needing exactly because my system will be changing eventually, as far as additional lights, dual battery setup, maybe a winch. Not quite ready to invest in all that just yet.

 

I have been off and on TW as much as possible, but sometimes I do miss PMs and emails. It's no easy task running this company. Anyone who says runningtheir own business is easy is full of it! hahaha.

What information are you looking for?

 

I was looking at your first post and what I see wrong is the spacer allowing the alternator to apply too much stress to a bracket that is already not the strongest part. Those Toyota brackets are not well known for strength. That plus a spacer will allow excess stress at the bracket that could (and evidently has) resulted in a cracked bracket.

 

This pivot point is the weak link. Its not the full length like the Original Alt.

 

Which is why I like my alternators. They use the factory original Toyota case, so no spacers or special modifications needed.

 

Ha yeah I figured as much actually and completely understand. Figured it was something along those lines. And I have purchased the Stage One upgrade from you in the past and was quite pleased with it, and planned on going to you first for my future upgrades! But yeah, I just wanted to make sure and check on the status of how things were going and if you're still offering all the options.

I'm certainly interested in getting a 250a alt from ya asap. These are putting out about 100 idle amps you say? Also interested in the stage 4 with the SSCS system in the not too distant future, that sounds like a sweet kit. I will eventually have quite a few demanding accessories to power and am already on the verge of needing a dual battery setup as it is. But I gotta tend to some other things first, among them being reworking all my wiring in preparation for additional accessories.

But for now, do you have any 250a alts readily available by chance? I'm ready to purchase

 

I can usually get just an alternator shipped out within a day or two from order. Info PMed.

 

Replied! I'm done with this dc alt tho. Hopefully they don't charge me to put in a new regulator. They said last time it would be $50, but didn't mention it this time. plus the $25 it costed for me to ship it, that's $75 down the drain. Oh well. I'll live with it. Maybe I can sell it for $75 (with that disclaimer) and at least get that back. ha. Probably won't sell tho. I wouldn't buy it. lol. I'd hate not to mention it to the buyer and have karma bite me in the ass. It really is a nice alt, well, nice looking. And performs great! It just has the fitment issue. And a glitchy regulator at times. If they had a beefier mount to support the case better. There'd be no issues. Hard to believe they promote these being used on "off-roading, hotrod and performance vehicles". When it can't even hold up to a daily driver/occasional trail runner.