Jump starting from portable jump start units

[patsparks]

The techos on here may be able to tell me if this is viable.

Get a 12 volt battery from an emergency exit sign from a battery bar such as battery world, get a good size diode from an auto electrician or radio shack that will cope with charging the small battery but will prevent it discharging to the in car 12 volt battery if it goes flat, and an on off switch from radio shack to bypass the diode on demand.

Connect the emergency exit sign battery to the 12 volt car battery with the diode to allow charging but prevent discharge and switch in parallel with diode. You should be able to find a spot to wedge in the battery somewhere near the main 12 volt battery. Leave the switch off normally.
If you try to start your car and it wont start just switch on the switch and start it, the emergency battery should provide the voltage needed to start the inverter.

Another method is to be careful not to flatten the main 12 volt battery and if it "just goes flat" replace it.

Do people think this would work? Can people follow this?

[jayman]

Originally Posted by patsparks

Do people think this would work? Can people follow this?

Yes, I follow you and that should work. However, it's a lot of bother to go through. For less cost, I can purchase a booster box from Canadian Tire and just hook it up to the underhood jump point if needed.

I purchased another booster box for my FJ Cruiser, just in case that thing should ever die on me. I have already used my booster box to jump start dead cars at work, as we have been down to -26 C a few times already

[Jon the Chief]

Four weeks till I get my Prius, could the tech veterans answer two questions which are related to this post.

My present car is fitted with a tracker system to give a radio signal to locate the car if it is stolen. Is that what they call Lo-jack in USA?

If the car is left unused as when on holiday the tracker will drain the battery.

Now when I’m parked in my home garage I plug in a battery charger, this is with a keyed plug and socket that will only fit one way, the plug part is fitted direct to the battery. (with a fuse in the live side)

The charger is electronic and will switch from charging to maintaining when the battery is fully charged.

Sorry for the long intro, but my questions are.

1 Does the small battery on the Prius have a problem being drained by Tracker/Lo-jack?

2 Is there any reason I can not have same set up on a Prius?

If the same system is fitted it would be a place to parallel up another battery for jump starting.

Jon the Chief

[David Beale]

The Prius takes a 1/2 second 45 Amp pulse from the 12V battery when you press the brake pedal and one more when you press start. Then it charges with a float voltage of 13.8 V.

-You- don't need a 300 Amp booster unit, but if you want to help others with ancient technology cars then it would be a good idea to have one. It will work just fine on the Prius.

You would need to connect the charger on the Prius. Its' small battery would be drained sooner than whatever other car you currently have by the security/tracking system. You can connect the cable to the fuse box where the boost point is. You could also use it to boost the car. Use #10 wire to the connector, and keep it 10-20 cm long max.

[qbee42]

Originally Posted by Jon the Chief

Four weeks till I get my Prius, could the tech veterans answer two questions which are related to this post.

My present car is fitted with a tracker system to give a radio signal to locate the car if it is stolen. Is that what they call Lo-jack in USA?

If the car is left unused as when on holiday the tracker will drain the battery.

Now when I’m parked in my home garage I plug in a battery charger, this is with a keyed plug and socket that will only fit one way, the plug part is fitted direct to the battery. (with a fuse in the live side)

The charger is electronic and will switch from charging to maintaining when the battery is fully charged.

Sorry for the long intro, but my questions are.

1 Does the small battery on the Prius have a problem being drained by Tracker/Lo-jack?

2 Is there any reason I can not have same set up on a Prius?

If the same system is fitted it would be a place to parallel up another battery for jump starting.

Jon the Chief

1.Yes, the small 12V battery is easily drained.

2. The same setup can be used with the Prius, just make sure to wire the charger so that it connects to the battery even when the car is off. The standard 12V power outlets disconnect when the car is shot off. You can connect to the 12V jump point under the hood.

Tom

[Boo]

Is the charger that Jon the Chief describes also called a "trickle" charger (in the US anyway)?

[fruzzetti]

Originally Posted by Charles Suitt

Howdy Justifyd

Previous responses are right on. The likely reason that Toyota made the 12v accessory outlet {"Cigarette Lighter"} off when the Prius is in "Ready" mode, is the potential of depleting the 12v auxiliary battery - it's about the size of a motorcycle battery and a plugged-in accessory could run it down.

If you're curious, you might want to open the hatch and take a look for yourself at the 12v battery, it might surprise you how small it is. It's a little tricky to check it - you can find a diagram in your Owner's Manual - Section 8-2 'DO-IT-YOURSELF MAINTENANCE - Checking 12 volt battery exterior' {Pages 414-415 in the 2007 Manual}. Getting the small cover off you need to slide it forward and pull up.

In over 2½ Prius years, I've had no 12v battery problems, even after leaving the Prius parked for over 2 weeks at a time. I do suggest turning the "Smart Key System" off when leaving the Prius parked for extended periods.

I don't know about the statement "a plugged-in accessory could run it down." I have all my outlets modified to constant-hot and I have a cell phone charger for an Ericsson W880i in the center console and an Ionic Breeze car unit in the dash board.

aaaaaaaaaaand i just broke my double-you key. great. time to get creative in considering the phrasing of every sentence i type.

In a combined 115000 miles in Prii, I have never had any battery troubles using continuous-run accessories on a constant-hot outlet. Maybe it's because I never let the car sit for more than six days or so at the most (remember, I can't type "\/\/eek")

[toronado455]

Originally Posted by David Beale

-You- don't need a 300 Amp booster unit, but if you want to help others with ancient technology cars then it would be a good idea to have one. It will work just fine on the Prius.

I want to have the capability of jumping a Prius or a conventional car.

I have a DieHard Portable Power 750 battery booster and DC power source. It's nice because it is rechargeable. It has a 12V 12Ah battery inside. How does that compare to a 300 amp booster?

Does the jump point on the Prius accept regular jumper cable clamps OK? What length of cable does one need to physically get from a portable booster to the Prius under-hood jump point?

The reason I ask is the DieHard booster has very short 18" cables and standard-size clamps. I found out because I had to use it last week to jump a conventional car. And I couldn't connect the negative to the engine or an unpainted metal surface because there simply wasn't enough cable length to allow for that. So I connected both clamps directly to the dead battery and it worked fine. Perhaps it was designed to be used that way anyway.

I'm thinking about getting a set of jumper cables though, so I can have more flexibility. I'm wondering if connecting jumper cables to the booster with clamp-to-clamp connection would be tricky or possibly even unsafe. The 18" cables on the DieHard are 8-gauge, so I would be sure to get 8-gauge jumper cables to use as extension cables. I wonder if there is a product out there designed specifically for use as a jumper cable extension. Say, with clamps on one end and some sort of simple metal pieces on the other end.

If that all proves too complex, then perhaps I should just look for a booster with longer cables!

[fruzzetti]

Originally Posted by toronado455

I want to have the capability of jumping a Prius or a conventional car.

I have a DieHard Portable Power 750 battery booster and DC power source. It's nice because it is rechargeable. It has a 12V 12Ah battery inside. How does that compare to a 300 amp booster?

Does the jump point on the Prius accept regular jumper cable clamps OK? What length of cable does one need to physically get from a portable booster to the Prius under-hood jump point?

The reason I ask is the DieHard booster has very short 18" cables and standard-size clamps. I found out because I had to use it last week to jump a conventional car. And I couldn't connect the negative to the engine or an unpainted metal surface because there simply wasn't enough cable length to allow for that. So I connected both clamps directly to the dead battery and it worked fine. Perhaps it was designed to be used that way anyway.

I'm thinking about getting a set of jumper cables though, so I can have more flexibility. I'm wondering if connecting jumper cables to the booster with clamp-to-clamp connection would be tricky or possibly even unsafe. The 18" cables on the DieHard are 8-gauge, so I would be sure to get 8-gauge jumper cables to use as extension cables. I wonder if there is a product out there designed specifically for use as a jumper cable extension. Say, with clamps on one end and some sort of simple metal pieces on the other end.

If that all proves too complex, then perhaps I should just look for a booster with longer cables!

I would avoid using just a simple jumper cable as an extension. Think about what can happen when you use alligator clip-to-alligator clip connections to extend the wires. When they knock against each other (and they will), the electrical current will knock a chunk of metal clean off, and not to mention if they stay shorted for any length of time it's not so good for your equipment.

A safer choice would be to remove the original wires from the booster and if possible attach the long jumper cables there.

[toronado455]

Originally Posted by fruzzetti

I would avoid using just a simple jumper cable as an extension. Think about what can happen when you use alligator clip-to-alligator clip connections to extend the wires. When they knock against each other (and they will), the electrical current will knock a chunk of metal clean off, and not to mention if they stay shorted for any length of time it's not so good for your equipment.

A safer choice would be to remove the original wires from the booster and if possible attach the long jumper cables there.

Good point. I hadn't thought about the issue of clamp to clamp connections touching negative to positive.

The clamps on the booster pack are very well insulated with plastic and only the surface of the alligator "teeth" are exposed metal. If I connect those to metal points on the "extension" cables in a certain way I can minimized that risk. But, point well taken. It would be better to have something that is designed specifically to be used as an extension.

Also, I'm looking for the kind of jumper cables that have a "plug" in the center that disconnects. So you connect both sets of clamps to both cars first, and then connect the two "halves" together in the center using the "plug". If anyone knows where I can find these that would be a great help.