Milwaukee Battery to Run IP / Wiring ?

[Kizer]

I found a 12v stepdown for 18v Milwaukee batteries (Link).

The plan is to mount the stepdown in the cab, as backup power supply, to run the IP.

I'm not sure how to wire it. My thought is that I'll need a diode (maybe 2?) and some kind of protection for the Milwaukee battery.
Am I on the right track here?

Also, I 've read that the FSS draws about 2 amps. Does that sound right?

 

[The_Josh_Bear]

What's the point? Like incase your batteries get stolen you can still push-start the beast and get home? Understanding the use-case would help with wiring ideas. That said... you make a good point about isolating the system and I'm not sure you can with the IP being case-grounded.

I'd think it would make more sense to have a dedicated 12v battery(lead acid or I think a NiCad pack would handle it) that could handle the charge of the alt and just leave it in the system, but again I'm not sure of your use-case.

 

[Kizer]

What's the point?

Thank you for the reply, I hadn't thought about the IP being case grounded ... I'm sure that there's a "work around".

The point is to be able to a run the IP, with no alternator power or truck batteries, instead, to power it with one of the many Milwaukee batteries that I, nearly always, have on the truck.

 

[IDIBRONCO]

The point is to be able to a run the IP, with no alternator power or truck batteries, instead, to power it with one of the many Milwaukee batteries that I, nearly always, have on the truck.

That should work for a while as long as you don't have to start the engine. I'm afraid that the Milwaukee battery won't hold up to that kind of abuse.

 

[Kizer]

I'm afraid that the Milwaukee battery won't hold up to that kind of abuse.

I wondered the same, hence the question about FSS draw.
At 2 amps, I think that it has enough amp hours to keep me rollin'.?.

 

[IDIBRONCO]

I wondered the same, hence the question about FSS draw.
At 2 amps, I think that it has enough amp hours to keep me rollin'.?.

That should last for quite a while. I meant that the battery won't hold up to the starter for very long.

 

[Kizer]

That should last for quite a while. I meant that the battery won't hold up to the starter for very long.

Understood.
All of my (running) trucks are "bolt action"... gravity, push or pull start works pretty good.

 

[IDIBOBS]

Yes this would be accomplished very easy. Many company’s make adaptors from 18 or 20,24 volt power tool batterys to 12volt. Check flee bay and Amazon. Or make your own. And all you would have to do is chassis ground your battery neg and go hot to the ip. Then just push start away.

 

[BeastMaster]

18 volt Milwaukee cells? Several of them? If so, in series ( charge imbalance issues likely ).?

If you have ample 18 volt power, do you need to simply drop 6 volts at 2 amperes by using a 3 ohm "ballast resistor" ( E=IR: R=E/I=6/2=3), P=IE=2*6=12, Go ahead and use a 100 watt one. ( They are sealed , rugged, cheap, reliable, and easy to mount - besides a known ballast resistor gives you a handy test point to measure IP solenoid current by measuring the voltage drop across the resistor.. a six volt drop across 3 ohms confirms a 2 ampere current flow. )

Yes, way oversize the power ratings for resistors. They run hot, and practical heat sinking conditions are rarely, if ever, ideal . I'd want to specify the use of heat transfer paste, but I would probably settle for a dab of silicone sealant. Anything gooey that doesn't evaporate readily or conduct electricity has worked well for me in the past.

I am leery of anything electronic, as inductive kickbacks and alternator load dumps have caused me much woe.

Amazon.com : 100w 3 ohm resistor

Seems I remember another BOOB here had problems about losing IP solenoids and stagnant fuel flow leading to thermal issues...so I consider that a heads-up keeping an IP solenoid engages without the engine running, as the fuel is likely also serving as a coolant for the IP solenoid.

If you have no alternator running, that constant 2 amperes load adds up over time.

Theoretically, a 12 volt 10 ampere-hour gel cell should power your 2 amp solenoid for five hours. Theoretically.

( BOOB : Brotherhood Of Oil Burners ), should anyone think I am disrespecting an honorable resident here.

 

[ihc1470]

How often do you for see actually having to do this? If just a back up for someday just in case I think I would just run a couple of wires out to the pump and if the need came up just connect them up at the time. If the ends are all ready on everything it would take less then a minute to pop the hood, disconnect the factory wire and connect yours. An old extension cord would all ready have the wires bundled and most are at least 16 gauge.

 

[Kizer]

do you need to simply drop 6 volts at 2 amperes by using a 3 ohm "ballast resistor"

No f'n clue man ... that's why I'm asking y'all.

18 volt Milwaukee cells? Several of them? If so, in series ( charge imbalance issues likely ).?

I was thinking just one.?.

How often do you for see actually having to do this? If just a back up for someday just in case I think I would just run a couple of wires out to the pump and if the need came up just connect them up at the time. If the ends are all ready on everything it would take less then a minute to pop the hood, disconnect the factory wire and connect yours. An old extension cord would all ready have the wires bundled and most are at least 16 gauge.

I like the way that you think.

 

[franklin2]

You need to search out the manual shut-off threads in here. I do not know what they came up with, but apparently these pumps did come with a mechanical shut-off instead of the electrical one. No battery needed.

 

[Kizer]

You need to search out the manual shut-off threads in here

Thank you, will do.

 

[Kizer]

You need to search out the manual shut-off threads in here.

I appreciate the advice.

I'd prefer not to modify the IP in order to achieve my goal.

I believe that I'll move forward with the M18 stepdown, as soon as I understand which diode(s) to use and where to wire them in.

Additionally, I'd like to understand how to protect my M18 battery.

If any of you have insight, I'd certainly enjoy hearing it.

 

[IDIBRONCO]

Additionally, I'd like to understand how to protect my M18 battery.

If any of you have insight, I'd certainly enjoy hearing it.

Are you planning to mount it under the hood? I'd mount it inside the cab. That will protect it and let you disconnect it in order to shut off the engine. I mean disconnect it manually or with a toggle switch inline with a wire.