Step-up to 16v or Step-down to 12v

[Robert.Stever]

Hi y'all, I'm an EE that also runs a 16v daily driver. One of the things that has really ticked my off was the lack of a high current 12v-16v dc-dc regulator on the market. I was not content on paying a crap ton of money for a new alternator and investing even more time safeguarding the rest of my vehicle's electrical to just run a 16v battery bank for my two amplifiers. So I instead decided to build my own dc-dc SEPIC boost regulator. Currently it's still in the design phase, however Tina-TI looks promising and so does the test model on my bench.

My question to the community; if I build an adjustable (16-21v output with a 9-15v input) 2kw power supply would anyone be interested in buying it? Essentially you could run a stock alternator and 12v electrical. You would just have my box in between your 14-16v bank and your 12v battery at the front. I know of no power converter that can sink this much current, I've seen dinky 10 and 15 amp units (mine will do 100 amp at 20 volts, by month's end) for around $500 with no more than 50 bucks in components on the inside.

This came to me as I have seen one of two options done with a 16v setup in comps. 1. You use a wall charger. 2. You pay a crap load of money on a new alternator and spend even more time rewiring your car.

Just think for moment, 1. You don't have to buy an expensive alternator. 2. You don't have to touch anything under the hood (except for the single run of 0 gauge cable going to your battery bank) 3. The rest of your car will still run at 12v preventing electrical damage 4. Ease of use, it's a drop in solution.

Keep in mind I am an electrical design engineer and marketing speak does not go well with me. Also not a one-post-wonder here. I've been lurking on your forum for the past six years and decided to create an account just for the above. I have been an electronic design engineer for over a decade in power conversion and analogue logic. I wouldn't be using my real name if I didn't stand by it.

[SnowDrifter]

I'd be more interested in a good 18v to 12v step down. A high current one that could run mids/high amps and car electronics. Not much in the way of 150-200a buck converters out there. Most stepdowns are just diode packs. They work.. But they're ineffecient and get hot hot hot.

[Robert.Stever]

Interesting idea, I'll take that into consideration. My project is aimed at those who don't already have a 16v alternator and would like a second route to try.

[SnowDrifter]

Reason I say step down vs step up is most of the amps capable of running 18v are in the 3.5k plus range. And most people who run 18v will have way more than that as far as total power. 2kw is a lot but not enough to keep up with an amp that will to 5k at 12v and in the 7k range at 18. It's a LOT of current haha

[Robert.Stever]

Reason I say step down vs step up is most of the amps capable of running 18v are in the 3.5k plus range. And most people who run 18v will have way more than that as far as total power. 2kw is a lot but not enough to keep up with an amp that will to 5k at 12v and in the 7k range at 18. It's a LOT of current haha

True, however you are not running that much power for the entire time the car is on, most of the time you are not drawing anywhere near the rms output of your amplifier.

For example, you draw 10kw of power for 5 seconds (tone burst, not real music), my 2kw step-up will take 25 seconds to recharge the amount of energy consumed from the battery. Every comp I've been to you are not allowed to have your engine on either, it's battery only.

[Kyblack76]

Ive never been to a comp where you CANT rev to 2k ?

I run 30s and 3min full tilt runs....

Pulling around 600amp, the entire time.

(just off the alts)

then demos, doing the same thing.....

[Robert.Stever]

Ive never been to a comp where you CANT rev to 2k ?

Ive never been to a comp where you CANT rev to 2k ?

I run 30s and 3min full tilt runs....

Pulling around 1000amp, the entire time.

then demos, doing the same thing.....

Then it would take 28.5 minutes to charge that battery bank with my step-up. I see. So a step down is wanted then eh? Would 2kw be sufficient for y'all?

I'm still going through with my step-up for myself as I want a 16v battery bank for my ap30001d's. However I don't drive around running a 60hz sinewave into my Fi's for the entirety of my drive. I listen to music which has peak transients, my little 2kw charger will be enough.

[Bump4life]

i love the enthusiasm and ingenuity, but a step up for it to be useful must be able to be used on 5k plus amps where people actually use higher voltage. and yes it wont be 5k continous. but even so after efficiency you are talking about needing to supply 200-300 amps for a 5k amp. thats gunna be expensive to manufacturer a reliable step up module. even then if people had the money they would just have adjustable alternators. it cost about 150 to make an alternator any voltage you want. and buy a step down for your car which consumes much less than an amplifier.

i wouldnt waste your time trying to market that, that market isnt big enough to create a large enough demand for the idea to be profitable.

[Robert.Stever]

i love the enthusiasm and ingenuity, but a step up for it to be useful must be able to be used on 5k plus amps where people actually use higher voltage. and yes it wont be 5k continous. but even so after efficiency you are talking about needing to supply 200-300 amps for a 5k amp. thats gunna be expensive to manufacturer a reliable step up module. even then if people had the money they would just have adjustable alternators. it cost about 150 to make an alternator any voltage you want. and buy a step down for your car which consumes much less than an amplifier.

i wouldnt waste your time trying to market that, that market isnt big enough to create a large enough demand for the idea to be profitable.

That's why I'm using SEPIC topology. I'm getting into the 95% range with 12v in and 18.5v out under a 50 amp load, the greater the input/output differential the higher the efficiency. The same supply can be used in Buck mode, just swap the diode and the inductor around.

Also, If I wanted to make a 500 amp step up, it's totality doable. The 50 amp model on my bench would have to have an extra 9 npn igfets (each FET costs close to $12 btw). It would handles 500 amp continuous, and 5000 amps for a minute before thermal runway takes effect.

So would a step down that is 90-95% efficient be something that members here would buy?

[Bump4life]

i love the enthusiasm and ingenuity, but a step up for it to be useful must be able to be used on 5k plus amps where people actually use higher voltage. and yes it wont be 5k continous. but even so after efficiency you are talking about needing to supply 200-300 amps for a 5k amp. thats gunna be expensive to manufacturer a reliable step up module. even then if people had the money they would just have adjustable alternators. it cost about 150 to make an alternator any voltage you want. and buy a step down for your car which consumes much less than an amplifier.

i wouldnt waste your time trying to market that, that market isnt big enough to create a large enough demand for the idea to be profitable.

That's why I'm using SEPIC topology. I'm getting into the 95% range with 12v in and 18.5v out under a 50 amp load, the greater the input/output differential the higher the efficiency. The same supply can be used in Buck mode, just swap the diode and the inductor around.

So would a step down that is 90-95% efficient be something that members here would buy?

efficiency is great, but the components still need to handle a 500 amp continous load at a minimum IMO for it to be reliable in the HOT summer