# Thread: 12v at 33amp survicing crank?

1. ## 12v at 33amp survicing crank?

Hey everyone, I have a quick question. How does one make a regulator that can survive cranking? :-P Basic, right?

Basically, I'm trying to think of a way for people with inverters to survive crank, minus a new battery. If there's a way to make a quick and dirty circuit that can survive crank and supply 12v, let me know. I don't need 33 amps, but that's what my 400 watt inverter wants.

I imagine some type of regulator? A bunch of them in parallel I imagine making a PCB that has room to add more of these circuits, so you can increase the power ratings.

BTW: It doesn't need to be a filtered12v, just 12v.

2. itll never work with just regulators, I suggest you look intostep up circuits

put it this way: if thre was a way to make a wuick and dirty circuit to do what you propose, itd be done by now

3. why would people with inverters need a regulator?

4. Sorry, I didn't know of the type of circuit to "step-up". Just because it isn't done yet, doesn't mean it can't be done. I mean - it's a custom circuit, so it would have to be made by yourself. Anyone with that kind of knowledge would be making a sproggy, or other.

That or no-one though of messing with the voltage going into a inverter.

5. Originally Posted by KyleYankan
I don't need 33 amps, but that's what my 400 watt inverter wants.
I don't get this. 12 volts X 33 amps = 396 watts but that doesn't mean that your inverter "wants" 33 amps. It depends on the circuit load. If your computer only draws 200 watts, then you inverter will only "want" 16 amps. No load, no amperage required.

6. pudge: not a regulator: just something to keep the 12v during crank.

BTW: http://www.xs4all.nl/~odu/dcdc.html

6v to 12v, at 1a sustained.

My Inverter needs to output 1.5a at 120v, for my PC to work.
Assuming my inverter is 90% efficiency:
1.5 * 120 = 180 watts

180 watts at 90 effiencecy: 200 watts

200 watts needs to hop into my inverter.

200/12v = 16.6 amps.
Seems doable. I mean, I can order up to 5 samles of the step-up chip at a time. That means in a week or two, I can have 15/20 of the chips. Then the rest of the components seem trivial in price/sample. Make a bunch of these circuits and run them in parallel. It means you can run your computer even on a 6v battery.

7. Originally Posted by Bugbyte
I don't get this. 12 volts X 33 amps = 396 watts but that doesn't mean that your inverter "wants" 33 amps. It depends on the circuit load. If your computer only draws 200 watts, then you inverter will only "want" 16 amps. No load, no amperage required.
I know,my computer is only 180 watts actually, but I wanted to be able to fully use my inverter. At least, plan to use it. I'll probably end up with an extra battery for crank. My system survives crank right now, but Ithink that's because I have a battery that's like 2 months old. Has anyone played aorund with the bank of batteries in the back of a hybird? *heads to junkyard*

8. why not just a small SLA with a diode?

9. Diode? Would that work? I thought you had to use a battery isolator? Like a relay?
I imagine a diode that would let the main battery charge the SLA, and the PC hooked up to the SLA?

Additionally: What's a good high-wattage didoe good for this? anyone know?

10. 4you cant run step ups in parallel

Originally Posted by KyleYankan
pudge: not a regulator: just something to keep the 12v during crank.

BTW: http://www.xs4all.nl/~odu/dcdc.html

6v to 12v, at 1a sustained.

My Inverter needs to output 1.5a at 120v, for my PC to work.
Assuming my inverter is 90% efficiency:
1.5 * 120 = 180 watts

180 watts at 90 effiencecy: 200 watts

200 watts needs to hop into my inverter.

200/12v = 16.6 amps.
Seems doable. I mean, I can order up to 5 samles of the step-up chip at a time. That means in a week or two, I can have 15/20 of the chips. Then the rest of the components seem trivial in price/sample. Make a bunch of these circuits and run them in parallel. It means you can run your computer even on a 6v battery.

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