xjzaped

I'm not gonna say that it won't...but I'm not gonna say that it will. There are factors I don't know, such as the power output of the drill, and power input of the alternator required do provide 12.1V (assuming the battery can provide enough amperage to crank the engine at 12.1V).

It's all a balanced equation. In theory, yes. In terms of actual practice, numbers I don't have access to need to be ran. Depends on what the power input of the alternator needs to be in order to make the minimum charge level to start the engine as well as the power output of the drill.

PocketsEmpty

This makes me want to break out an alternator I have laying around, and a belt, and hook it to my drill to see the output. Sounds like a fun experiment. I may do this after work today and post results!

I think you would need some sort of larger pulley to attach to the drill. The larger it is, the faster it'll spin the alternator, methinks

SHELBYGT NSM

Thank you guys for sharing your input in this theory, i am just thinking outside the box of what you could do in the event if your battery was to die in the middle of nowhere . Is there anything that could work or is it safe to think i should start walking home now, any ideas would be helpful, lol i thought i was going to get made fun of when i asked this question,

F1Addict

My friend once had a dead battery. To resolve this, he attached an inverter (12v DC to 120v AC 60hz) using the accessory socket in the cab. To the inverter he attached a 120v battery charger which he then correctly attached to the positive and negative battery terminals.

He'd done everything correctly but for the life of him, could not figure out why the battery wasn't charging .

In your scenario, the most efficient way of getting your Jeep started would be to bypass the alternator entirely and jump start it using the drill battery. Converting the drill battery energy into mechanical energy (and heat) to spin the alternator then back to electricity introduces enough loss that it becomes pointless. It will not work, but I look forward to the results of your experiment.

PocketsEmpty

That's interesting, but how would that play well with an 18v or 20v drill battery? Mine is a 20v. Does sound like a better idea though. I think the real challenge with the drill idea is the pulley setup, and having enough tension on the belt for it to work...You'd almost need to fab up a pulley, have some sort of small-ish belt, some tools on hand to do it.

salad

Doesn't the VRM (internal or external) need to be fire up to even let the alt produce any voltage? I would be very skeptical of this working at all without the PCM being alive on a Chrysler XJ.

Your cordless drill battery is not going to be able to jump start anything bigger than an RC car lol

SHELBYGT NSM

I do know that a 18 volt portable drill battery can jump start a 2009 F-150 V8 i seen that with my two eyes, plus i lost 5 dollars saying it can't be done. But the truck battery was not all the way dead, just enough where it wouldnt start. I thought the pcm on the jeep stayed on all the time even when the key is off as long as the battery was connected, but with a absoultey dead battery then the pcm wouldn't be able to stay on. If the battery wasn't all the way dead then i believe that the pcm would remain on

F1Addict

If you broke down near a stream or hose you could use that axe you have mounted next to your high-lift and your electric drill to fashion a waterwheel that would drive the alternator pulley and charge your battery. There's still the issue of field coil voltage but I've got this idea about removing the electric fan and converting it to a wind generator with some capacitor and resistor doo-dads. No wind, you say? No problem! Just attach the fan blades to your waterwheel!

I know it's genius, you don't have to tell me.

PocketsEmpty

I imagine that this could apply to certain vehicle alternators that have the VRM built into the regulator. As for our Jeeps, the PCM regulates it, so the alternator is simply a mechanical generator without it. That being said, I think it *could* work to some degree.

salad

A drill battery boosted a truck? lol Obviously the battery wasn't THAT flat...

PCM is only energized when the key is turned to ON. It needs a certain voltage to even be alive, so dead-dead won't work very well.

Brilliant!

SHELBYGT NSM

The battery on the truck would not start the truck. But with the 18 volt battery from the drill acted as a booster.

salad

VRM = Voltage Regulator Module. Yo dawg i herd u liek a regulator in ur regyulater?

On at least OBD-II models it's actually a 3-phase generator that is rectified to DC. The PCM's VR operates by grounding the field coil for the second rotor. Note the whole thing is connected in series from the ASD relay, through the PCM, through the coil, to ground. The FSM isn't entirely clear on this but I think that without the PCM firing that coil the output is either none or very minimal as the generator uses electromagnets versus fixed rare-earth units like most alternators. The FSM also isn't entirely clear if the VR circuitry is integrated electronically or if it's simply part of the PCB.

At the very least the ASD relay should be operable to get it going.

PocketsEmpty

LOL Whoops, I meant to say alternator there on the end. How does the battery temp sensor play into that hot mess?

salad

Used by the PCM to determine the output voltage. Colder = slower charge (lower voltage)

SHELBYGT NSM

So do you even think with a actual setup of the drill and pulleys it wouldn't actually work.