Thread: odd inverter behavior

Originally posted by jshrieve:
If everyone lives in your cookie cutter world, then yes, DC-DC would always be incredibly convenient and without any downsides.

My "cookie cutter world"? Don't exactly know what that means. I don't want to get into the old "DC-DC Vs. Inverter" wars, but here goes.

Nifty trick, considering I have a tiny non-standard formfactor power supply.

I don't know if you've seen the Arise supply or not (some pictures at http://www.aaroncake.net/projects/mp3player.htm ), but it is not a standard form factor. I don't know how big your supply is, but odds are the Arise supply is about the same size if you run your supply without a case and fan. Oh, and the Arise produces very little heat, so a fan is not necessary. One more part that can't fail.

I didn't say 'complicated'. I said 'more work and little benefit to me'.

I had assumed that by "more work" you meant more complicated. That is the usual response.

Work: either building or disasembling DC-DC power supply, to make it fit within the space I want it to fit.

I haven't seen a picture of your space, but I would hazard a guess that the Arise supply will fit. Especially when you eliminate the large, bulky inverter.

More stable? No. My inverter is 100% stable.

Measure the output with a scope. Not that it matters. DC-DC is more thermally stable, and produces a stable output.

More efficient? Yes, but irrelevant, since I have 85+ amps from my alternator to waste (40+ at city stop and go rates, higher at freeway)

Well, it does waste a small amount of gas, but more important is having the power available for other stuff, and not stressing the alternator with a 5A draw. The DC-DC idles around 1.3A.

Smaller? No. Not without disassembling and rearranging. BIGGER. The inverter about equalizes the space, but the inverter doesn't have to be physically with the computer and can thus be tucked away somewhere more convenient.

Sort of covered this above.

[quote]
Produces less heat? Yes, but irrelevant. I don't live in Texas. [quote]

With less heat, you don't need a fan.

Will run while car is being started: So will the inverter. Both solutions fail if your starter motor causes the voltage to drop too low.

The DC-DC runs down to 8V. The inverter stops at 11 or 10?

No noise? I don't get any with my inverter.

You're lucky. Most people do.

Running with the car off...paraphrased as it was lost in original quote

There are many circumstances when you would want to run the player with the car off. To provide toons while washing it, updating software, copying new MP3s, working on the car, demonstrations, leaving it on while at the mall so you don't have to wait for boot, etc.

Larger.
Requires either building a PS or taking apart one to try and make it fit in the smaller AC-DC PS case.

Not really.

Double or more the cost of the inverter.

But only slightly more then the cost of both the inverter and the standard PS.

Can't plug other devices into it when necessary.

True.

Can't easily unplug the computers without making a special plug or using a screwdriver.

I don't get that one. Just use any number of standard connectors to plug into. Even a cigarrette lighter can be used.

Takes a little longer to replace if anything should happen to it.

True. But odds are that nothing will happen to it. The Arise DC-DC is manufactured to industrial specifications. PC power supplies are made as cheaply as possible.

I don't deny that for many applications a DC-DC supply is better than an inverter, but not all applications are the same, so don't be a bum and try to suggest the same solution as being the best for all problems.

I don't particularily appreciate being called a "bum". I was simply trying to provide assistance. The DC-DC is best for most, but not all. We don't know the specifics of your setup, so providing a solution that will perfectly fit you is impossible.

I think what irritated him (and me sometimes as well) is that whenever someone asks a question about an inverter problem someone always jumps in with 'just buy a DC-DC'..

Thats great, I agree.. DC-DC is much more efficient but maybe they require the inverter for running other devices as well. I use an inverter myself, mostly because I refuse to spend ~$200USD on a ATX DC-DC power supply. Call me cheap or whatever you will, but thats a lot of money. If you can afford it, great. If you can't, use an inverter. Most people who post these questions seem to know about DC-DC but prefer the 'quick and dirty' method of an inverter. You can get perfectly acceptable perfomance and sound with an inverter. It really does depend on the quality of the inverter used and the installation of course.

I think a lot of the regulars (myself included) jump down new users throats when they post something that has been seen a bunch of times before. Oh well, thats just my two cents.

Originally posted by Callahan:
I think what irritated him (and me sometimes as well) is that whenever someone asks a question about an inverter problem someone always jumps in with 'just buy a DC-DC'..

Well, one of the reasons I suggest that is because I am one for really finding the "right" way to do things. For example, why spend $300 on brakes that last for 2 years when you can spend $1200 and have it done right the first time, lasting for 10 years.

To me, converting 12V up to 120 (or 240) then to 120 (or 240) VDC, and then back down to 12V/5V is just plain dumb. Not only inefficient, but also a huge waste of parts and a lot of unnecessary complication.

Thats great, I agree.. DC-DC is much more efficient but maybe they require the inverter for running other devices as well. I use an inverter myself, mostly because I refuse to spend ~$200USD on a ATX DC-DC power supply. Call me cheap or whatever you will, but thats a lot of money.

I can certainly understand the difference in cost between the two, and if you have to operate other devices that's fine. I appreciate that some people don't want to spend a lot of money.

I think a lot of the regulars (myself included) jump down new users throats when they post something that has been seen a bunch of times before. Oh well, thats just my two cents.

Maybe that's why I keep suggesting people get DC-DC converters....I'm tired of seeing the same old inverter questions...

For what it's worth, I am right in the middle of being kicked in the butt with the not "doing it right the first time" thing. My player's HD is failing. It is a standard desktop drive. If I had originally went with my gut instinct and installed a laptop drive for a little more money, I would have never had this problem...Oh well...

Aaron,

I did not mean to 'turn it into an inverter vs DC-DC war'. I got the feeling that that is what you wanted and were attempting to do, when you responded to a thread that was about inverters, with "stop using that, and switch to my solution" which was in my opinion, completely unproductive. To me, it appeared to just be a troll.

I think Linux is vastly better for almost all of the mp3s players. But I don't jump into every thread that has a question about Windows car mp3s and start arguing about why they should be using Linux.

I was offended by what I perceive as a pointless post.

As for your response, the inverter vs DC-DC argument is pretty much pointless... but I must stand by what I said. The DC-DC is a nicer solution in theory but that doesn't mean in that's it's better for all situations in a real world. I stand by my position that for my situation, an inverter is better. None of the points you most recently made in reply to my message actually change any of those points -- they're still all true.

Next time, please don't jump into threads on one topic with a troll for a different (competing) solution. It's very difficult for someone to read these forums regularly without already knowing the advantages and disadvantages of DC-DC.

And I'll try not to jump down the throats of people who make such posts, as pointless (imo) as they are.

Oh yeah.

Laptop drives are good thing. I got a 20GB IBM laptop drive for about $150 after shipping and it seems to be doing well so far.

Like 1/4th the size of a deck of playing cards (2.5" x 9mm), 4W peak draw, usually around 0.7W-1.3W draw and it can handle shocks of up to 180G/2ms operating and 800G/1ms non-operating. Vibration tolerance is higher too.

I didn't see the point of getting a normal hard drive (unless you already have one sitting on a shelf, but I'm talking purchasing new) since a laptop drive is only a few bucks more.

Oh.. another reason, one of the main reasons I didn't use a DC-DC. All the pre-built ones and all the schematics for building cheap home ones seem to be AT.

I need ATX and don't intend to give up the perfect comp for the situation that I already have.

Originally posted by jshrieve:
I didn't see the point of getting a normal hard drive (unless you already have one sitting on a shelf, but I'm talking purchasing new) since a laptop drive is only a few bucks more.

I got a Quantum HD specifically because of shock protection. When I picked up my HD, I was looking at twice the cost of a regular HD for a laptop HD. Since others have had good luck with regular HDs, I figured that a good Quantum HD would work. I guess this is not the case. Even though Quantum highly touts their shock protection, it doesn't seem to be able to stand up to the RX-7's stiff suspension.

A laptop HD is coming...

I got a Quantum HD specifically because of shock protection. When I picked up my HD, I was looking at twice the
cost of a regular HD for a laptop HD. Since others have had good luck with regular HDs, I figured that a good
Quantum HD would work. I guess this is not the case. Even though Quantum highly touts their shock protection, it
doesn't seem to be able to stand up to the RX-7's stiff suspension.

Yeah, it seems like the cost of laptop hard drives has dropped considerably as of late.

As for Quantum's shock protection, it's mostly just a marketting gimmick. If you read their own whitepapers on it, you'll see that the vast majority of measures they take are to protect it during shipping and installation, not during operation. Furthermore, most of the techniques are things all drive manufacturers usually do, like parking the heads before packaging and shipping it.

Originally posted by jshrieve:
I did not mean to 'turn it into an inverter vs DC-DC war'. I got the feeling that that is what you wanted and were attempting to do, when you responded to a thread that was about inverters, with "stop using that, and switch to my solution" which was in my opinion, completely unproductive. To me, it appeared to just be a troll.

That is certainly not what I intended. I have better things to do with my time then troll the MP3CAR board.

I think Linux is vastly better for almost all of the mp3s players. But I don't jump into every thread that has a question about Windows car mp3s and start arguing about why they should be using Linux.

I don't have anything against this. Linux is better then Windows.

I was offended by what I perceive as a pointless post.

Next time, please don't jump into threads on one topic with a troll for a different (competing) solution. It's very difficult for someone to read these forums regularly without already knowing the advantages and disadvantages of DC-DC.

Please don't tell me how to conduct myself. I post a lot, so my responses are usually short and to the point. I looked at your post count and saw you were a new user. For all I knew, you have never heard of a DC-DC converter before. Therefore, you may say something like "DC-DC will cure all inverter problems? Neat! Where to I get one?". I gave what is a helpful response as you may have not even known there was an alternative to inverters.

And I'll try not to jump down the throats of people who make such posts, as pointless (imo) as they are.

Again, you call my post pointless. Nowhere have I put you down, called your posts pointless, or done anything remotely similar. I guess to avoid this situation again, I will make a mental note not to respond to your posts in the future, lest my answer be deemed "pointless".

For me, this topic is closed.