Worry about Batteries for no reason?

Are the 12v batteries in the Prius that sensitive that there is need for a battery tender for only 2 months of inactivity?

I've used diehards is most of my vehicles, and I've let them sit for 6 months before without issues. Just puzzled, as 2 months doesn't seem that long to leave a car parked.

 

Yup. Hybrid 12v batteries don't need to "crank" start the engine like non-hybrid cars so it's much smaller than the batteries in those too. The 12v brings the car online and opens the relay to bring the 300v traction battery online.

 

Interesting. So, if I understand; Because they're smaller, they're more sensitive to being left idle.

Thanks.

 

it's more a matter of battery health. if you know that you're car came in and the battery was never run down to empty before you purchased it, and you've never run it down by leaving a light on or a door partly open, then your fine for two months. but the design of these batteries does not allow for deep discharge without damage. so, one incident, and you may be on a tender for any longer term idleness. i have never had an issue for up to 6 weeks in the middle of winter and batteries no older than 4 years.

on the other hand, my 9 year old dodge dakota with oem battery sits idle for months at a time, and cranks like a champ. uh-oh, i shouldn't have said that.

 

Good info. At a shopping center the other day, a guy walked in my direction holding up jumper cables. I avoided him, since my trunk was full and thought that the tiny Prius battery probably doesn't have much cranking power. My 2010's V's battery is like 5 years old. When should it be replaced for good preventive maintenance?

 

anytime now would be a good conservative time. and you were smart not to offer a jump.

 

I just scanned the Prius Owners Manual, and didn't see any specific caution against using the Prius to jump-start another vehicle. That, said, our previous Honda Civic Hybrid Owner's Manual did have such a caution. I'd say the Prius is in the same league, has a very small 12 volt battery, best not used for jump-starts.

All that aside, that guy should just talk to mall staff, they likely have a jump start station, one of those high capacity contraptions, on wheels.

If you're letting the car sit for a couple of months I'd go further than a few extra pounds in the tires. For sure bring them up to max pressure indicated on the sidewall. Or better, if you can: jack up the whole car slightly and put in jackstands. So that the tires are still touching, but with little pressure.

Also, just to clarify: you're charging the 12 volt, and it's the hybrid battery indicator that went from half to nearly full, right?

 

maybe the 12 volt charged the hv battery.

 

You don't need to worry about avoiding them. If asked, you have an extremely solid excuse to decline, because your Prius MUST NOT TRY TO JUMPSTART ANY TRADITIONAL VEHICLE. In addition to the battery being too small and not intended for crank starting, it also puts you at high risk of a high-four-figure repair bill for blown out electronics.

Given no other choice, it will be far cheaper for you to pay for their service call, out of your own pocket, than to allow your Prius provide a jumpstart.

A Prius should be able to safely jumpstart another Prius, but make absolutely sure you know what you are doing first. Done wrong, the combined repair bill could reach into five figures.

Did those vehicles have 'phantom' electrical loads that still pull current even when the vehicle is off? Examples include SKS proximity sensors, engine immobilizer (or at least the flashing light for it), car alarms, etc.

These always-on loads can significantly shorten the time a car can sit unused without battery failure, compared to old fashioned rigs that were truly 'off' when the key was removed.

 

There was a caution in the Owners Manual, to not use the under hood connection, hook up directly to the battery, when jump starting the Prius.

 

You're absolutely correct regarding the hook-up, lol. Hey, I was only 180 degrees away...

I suppose you could use the posts, but no need. Actually, 8 oclock day one with our car I was watching the service dept do just that. They finally caved and gave us a new 12 volt.

And yeah, it only says don't use the underhood for jump starting another vehicle, kinda leaves you hanging, regarding the question of whether it's permissible. I'd be inclined to not.

 

Ours was manufactured Aug '09, looked pretty dust/neglected when we spotted in behind a bunch of other cars, November '10. The 12 volt was completely toast. The hybrid battery has been champion to date.

 

In regards to the 12v battery, I'd assume it has at least a 12 month warranty (if not covered by the full bumper-to-bumper warranty)... at least most do. The HV battery shouldn't be of concern due to the 8 year warranty.

 

Yes, no, maybe.

It depends in large part on how fully it is charged when parked and how healthy it is overall.
One that is inadvertently down to 70% or less might not survive.
Likewise, one that is about at the end of it's useful life might fail too even if fully charged.

IF everything is up to snuff, then NO. But you have virtually no way of actually knowing that with any certainty.

 

Well it depends.......on how LOW it is drained, how often that happens and how long it STAYS discharged.

Many owners here have had trouble at much less than 4 years.