# Thread: Battery based tank circuit (tested)

1. I'm going to use a LM317 after the diodes to bring back up the voltage to what the ITPS likes.

2. Originally Posted by LESLIEx317537
I'm going to use a LM317 after the diodes to bring back up the voltage to what the ITPS likes.
The LM317 is a linear regulator, it will only lower voltage, not raise it.

3. OOps, then how about a 7815 to bring voltage up to 15 volts? Then mess with that?

4. Originally Posted by LESLIEx317537
OOps, then how about a 7815 to bring voltage up to 15 volts? Then mess with that?
Same deal. Needs something like 17.5 volts in to put out 15 volts.

5. Originally Posted by LESLIEx317537
Did you mean you don't need to limit the voltage?
Well, you do, but your car's alternator should have a ~13-14V regulator built in. 15V for a Hawker 12V battery is the max. Hawkers dont need any current limiting either, most sealed lead acids do. This can be done with a properly sized resistor.

To understand ni-cd charging - do some searches and read http://www.vencon.com/articles/nicd2.html

If you want to charge at a rate of 4C, then you need a very good "peak detection" charger - one that detects the battery is charged and shuts off.

Once a battery is fully charged, if you continue to charge, the battery produces gas creating a high internal pressure, and a sudden rise in temperature. High temperature kills batteries.

Typically NiCd are charged at a constant current, say 3C for good cells that we use in Battlebots. I have a 2.4amp-hr pack that I charge at 7.2 amps. To charge at a constant current, the charger needs to vary the voltage. It also monitors the voltage for its peak, and then needs to shut off or go into trickle charge 10% of C or in my case 0.24 amps.

I would never hook up a nicd battery to an automotive system. I use Astroflight 112 chargers

http://www.astroflight.com/e/env/000...roducts:af-112

6. This is the best method and you don't need tank circuit of any kind.
When park, park up or down hill.
When ready to go, release e-brake, push clutch, engage gear. When the car roll fast enough, release/pop clutch, car start. ZERO voltage drop solution. hahahaha.
You never need to use the car starter
BTW going thru this thread, it look very messy and a big install. Why not go with Opus or Sproggy? Those don't cost that much more and they survice cranking. And most important is you don't have to worry about a having a bomb in the cabin (slave battery).
AS for Sproggy 3.0 design, the 12V @2A out is regulated by boost method from 5V rail. 3.5 using the same method but output on 12V line is 5A. If you have some or little electrical knowledge, Sproggy PSU is a very good learning tool and it works.
I am not sure about the issue between Sproggy and Via M mobo but it work well with standard ATX mobo.

7. Yes, I'm going with a SLA battery. I know about charging slightly since I fly RC PLanes, Astroflight are good chargers, I use a Great Planes Triton for my Ni-Cd's, Ni-MH, and Lithium Polymers (ETECS, Kokams).

Just thinking of a good way to hook everything up. Seeing everything, I definetly need the diodes and resistors if I use a SLA other than the Hawker. What's the price of the Hawker 12 volt and where is the best place to buy online?

8. Originally Posted by MatrixPC
BTW going thru this thread, it look very messy and a big install. Why not go with Opus or Sproggy?
Agreed 100%.

9. Cause my Keypower puts out 250watts and rocks.

I am gonna buy a Opus soon too. I'll have two nice PC PS for the car.

But for 25 buks or so, I wanna make my carpc not reboot when I get gas in my car since my 300HP AWD car eats so much gas, I have to always stop at the gas station and then kill my engine, no hills on my gas station so I can't pop the clutch.

So the Opus is guaranteed to survive a crank? Will it run a P4 board? I plan on changing my 1Ghz P3 to a P4 soon in summer.

Not only to have the most powerful 4 banger in North America, but also the fastest P4 in the car in North America. Besides, making your own stuff is fun. Sometimes I don't feel like buying premaid stuff. I'ma do it myself kind of person. I change my own oil, why not go to Jiffy lube, You goto Jiffy lube or your dealer, I'll do it myself. It's part of the fun part, building and learning and posting questions on this forum

10. Originally Posted by LESLIEx317537
Besides, making your own stuff is fun. Sometimes I don't feel like buying premaid stuff. I'ma do it myself kind of person. I change my own oil, why not go to Jiffy lube, You goto Jiffy lube or your dealer, I'll do it myself. It's part of the fun part, building and learning and posting questions on this forum
Sproggy! (Mastero mk3.5.)

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