jump starting another vehicle

Good Point DAVID on the temperature differences & amperage requirement.

Either way I now have a external jump starter that's light enough to keep in the car full time & provides more STARTING current than my current 12V can provide.

 

Good move. Here's my son in action, about a week after I gave him my old, freshly refurb'd JNC660. Just ran into someone in a parking lot, needing a jump. Note the custom, hood support, lol.

 

Note that battery was for a Prius C. I just replaced the 12V battery in Pearl S for less than $200. Dealer wanted $200 (jobber cost - friends in a body shop) - 1 year warranty, Sask Battery wanted $240 delivered for either an Optima Yellow top with JIS terms. or Exide AGM - 1 year warranty. Canadian Tire wanted $170 for their AGM battery (looks like an Exide), JIS terms. and vent - 5 year warranty, AND I got a $20 gift certificate! So Pearl S carries a Canadian Tire battery.

Do note the Prius 12V battery is not a starting battery, as in "red top Optima", it's a "float battery", as in "yellow top Optima". "Not recommended for starting applications". It just powers up the electronics. The traction battery is used to actually start the engine.

While yes, there are many fanatical opinions on Prius Chat , this is not one of them. You should never use the Prius battery to jump start another vehicle (unless it's a Prius ). The Prius battery is not designed/built to be a "starter battery". Yup, once again, you -can- use it to start another vehicle, and once again, you should not. The battery manufacturer states clearly that damage could result, and shorter life will be the gift to the generous user. Not that we might notice. Three years is a ridiculously short lifetime for a lead acid battery! grrr! But I digress!

 

I'm warming up to Canadian Tire. Recently picked up a replacement battery for our son's (pic above) Civic Hybrid, it was badged "MotoMaster" but was a perfect match for the Honda battery, likely coming from the same manufacture plant.

 

I like that humanity keeps alive the "Good Samaratin" and "Good Neighbor" philosophy of helping people out.

BUT....

When it comes to jump starting other vehicles? I'm just NOT using my Prius. I've got too much invested and it's just too risky.
In this day and age, where portable jump start stations are readily available and relatively cheap? Well I bought one at Costco that is a jump start, and a portable air compressor. Two birds with one stone.

If I have the need to help someone else out? Or help myself? That's what I'm using.

 

Can you "jump" a Prius with one of those USB charge packs plugged into the 12v port? I know they can be used to maintain system power when disconnecting the main 12v battery (to maintain settings), but in some vehicles, they will "jump" a weak or dead battery because the circuit to the 12v is active. Others won't.

 

Last time I looked, the Prius 12V was rated at 28 Amperes. With later models it may be a bit higher. To try to jumpstart a larger draw vehicle 200-400 Amps, is financial suicide? Not to mention Warrantee problems with Toyota. Answer is NO

 

My reason for discouraging jumping other cars with a Prius? Same as my reason for discouraging jump starting the Prius itself. Risk to the inverter if you get polarity wrong.

For years i have heard that if you reverse polarity, even for a moment, you will do $4000USD damage to the inverter. Recently I heard once you can now replace just one board in the inverter and the cost is closer to $500USD, but I have not heard any confirmation of that.

 

I don't know a lot about battery rating systems, but I think you're mixing units. Maybe "amp hours" and "cold cranking amps"? I recently got this Optima as replacement. It's CCA is somewhat higher than stock, at 450, and amp hours is 38.

OPTIMA 8171-767 YELLOW TOP POST GR#51JIS $239.99 FREE SHIPPING SASKBATTERY.COM

 

Not that I advocate dishonesty but how would a dealer know that you used your Prius to jump start another vehicle with enough conclusive evidence to deny some type of warrantee work?

 

If you are referring to the power outlet (cig lighter), I think the fuse on it is rated for 15 amps, so I think trying to jump start with it would pop that fuse. If you were charging a weak battery, I think it might work if you left it for 10-15 minutes. Just hope the dead vehicle doesn't draw more than 15ADC inrush...

I think you could probably do several thousand dollars worth of damage to ANY car if you reverse the polarity, even for a moment. That could blow main fuses, body control modules, and engine ECUs on any vehicle, so that danger is not really Prius specific.
By the way, a gen 2 inverter is $700 with a $600 core on Rockauto:
More Information for DORMAN 587901
$4000? Maybe at the stealership....

 

The "accessory power outlet" (no longer called cig. lighter socket) is off when the car is off. Won't be able to charge the battery through that. Best place is the "boost terminal" as the hood can be opened even if the battery is dead. Best place -electrically- is across the 12V battery, but you have to remove the hatch floor and cargo tray as well as two small panels to get to it. You also have to open the hatch, which can be troublesome if the 12V battery is dead.

 

Although in the manual for my 2012 Prius c, the fuse name is still "CIG", described as "Power outlet".
Old terminology dies hard.

 

There, see how it happens? You sit down at the keyboard, determined you're not going to write one of those fanatical PriusChat opinions, and by the time you're done, just because of a simple detail like getting the comparison between the two battery types backward, you end up having written one anyway.

A low-CCA, non-starting-duty battery is more robust and less easily damaged than the high-CCA starting monsters, not the other way around.

Here, let's look at the one in my Gen 1.

Gen 1 Prius had two aux battery options; this is the larger one, still pretty modest as car batteries go.
The two numbers that matter (as Mendel pointed out upthread, don't mix them up) are the 51 amp-hour energy storage capacity, and the 355 cold-cranking-amps, measuring its peak ability to deliver power for a few seconds when really cold. (Really cold is the worst case, at comfortable temperatures even this battery will deliver much more than 355 amps, and get your tools or your watchband pretty hot if you're not careful).

So what do you change to turn a battery like this into the kind of 800 or 900 CCA monster you might see under the hood of a truck? Well, you want to roughly double its peak current capacity. To do that, you double the surface area where the chemicals can react, and to do that, you make it with twice as many lead plates, and you make those plates twice as thin. That's what makes high-amp starting batteries such lousy energy-storage batteries.

Well, hold the 'phone ... I seem to recall, what the battery manufacturer stated was

Now, that could mean a couple of things.

1. It could mean "hey, don't try to draw big starting currents from this battery, because it'll self-destruct."
2. It could mean "hey, don't try to draw big starting currents from this battery, because you might not get them."

It happens to mean (2). The battery won't be harmed in the least by the fact that you wanted 800 amps and it only gave you 400. It will look at you calmly and say "what? My label says 355. You wanted maybe a miracle?"

Now, if you don't take the hint, and you keep trying to crank over your Mack truck until the battery's stone flat, and then you hike off into the snowy wastes for help, and you don't get back before the now-depleted electrolyte has frozen in the cells ... yeah, that will have harmed the battery. But just not-giving-you-as-much-current-as-you-wanted will not have.

Don't forget that in warmer weather the capacity is higher, and also engines are easier to crank. I've easily started a big ol' Isuzu SUV a couple times in winter from my Gen 1 battery.

The key is, you just don't want that current to be coming from your DC/DC converter, or through the converter cable, which has only 100 or 120 amp fuses in it. I just unplug that cable from my battery before the other vehicle tries to start, then plug it back in. It's easy in Gen 1 because the cable really does unplug, right at the positive battery post. I think it's the same in Gen 2. I made the mistake some months ago of trying to convince a Gen 3 owner it was that easy, but apparently Gen 3 did away with the plug, which irks me. If I ever buy a Gen 3, I might add a plug.

As you see from the date stamp, my current battery was made in 2013. It replaced the one that was made in 2006, and that one was still starting my car just fine. The ten year old one is living a peaceful retirement in my basement on a maintenance charger, just in case I ever need a spare for something. The other day I unhooked it and used it to fill a 10 gallon air tank to 120 PSI with a 12 volt compressor. Never dropped below 12 volts, and read 75% capacity when I was done and put it back on the charger. I can't say it's given me much to complain about.

-Chap

 

People, believe what Chap says. He's correct. I tried to make substantially the very same points a few months back in another thread. Some folks still have a curiously exaggerated notion of the importance of CCA, which is mostly irrelevant in a Prius. That doesn't mean some manufacturers aren't selling high-CCA (for their size) starter batteries as Prius batteries. All they have to do is adapt a battery used in a non-hybrid car that uses a battery of the same physical size, by substituting the smaller JIS terminals and adding a vent connector. Yes, there are recent conventional cars that use batteries that small, despite what you may read on PriusChat.

 

hey i know this is an old post but i have an ‘06 civic that dies almost everyday the temp goes under 0-10°F. i had AAA test my battery - it was in good condition and doesnt need replaced. i suppose its just too cold for my car to start. could my partners ‘13 prius c jump my civic safely? when i have gotten it jumped by professional external battery chargers or whatever theyre actually called (lol), my car started as soon as the cables were connected, with no hesitation, leading me to believe that i wouldnt need much power from the prius battery. thoughts? i just dont wanna use up all of my aaa roadside assistances in the first month of the year

 

it can be done, but if messed up, can be costly. i would go with a rechargeable jump pack

 

"could my partners ‘13 prius c jump my civic safely?"

If you even touch the cables to the wrong posts for a second, you will do about $2000 damage to the Prius. Plus labor.
2012-2017 Toyota Prius C Inverter Assembly G9200-59035 | Earnhardt Toyota Scion Parts
If you buy used, perhaps $200 on Ebay.
prius c inverter | eBay

By comparison, you can buy a $40 jump Pak for the Civic.
www.amazon.com/SUAOKI-Starter-Lithium-Automotive-Motorcycle/dp/B07D1NS1VJ

 

If a Prius can safely jump start it, then so can a little lithium portable jump pack. And the jump pack will have va$tly le$$ ri$k of expen$ive car electrical damage.

The cost of a single error to the Prius can exceed decades of AAA subscription fees.

 

My little lithium jump pack came with "smart clamps". There's a little electronics box with a green LED that lights if you have them on the right posts, and a red one that lights if you have them backward. It won't close the circuit unless the green LED is on.

The idea goes back further than that. I still have a set of heavy jumper cables from the mid-90s that came apart in the middle. Each connector had an LED. You'd have the middle connectors unplugged, attach the clamps at each end to each vehicle, and not shove the middle connectors together until you saw both green LEDs.



Looks like you can't buy that brand anymore, though you could buy their domain if you wanted.

Anyway, point is, there are fairly simple ways to avoid doing reverse-polarity damage....