maintaining settings while changing the 12v battery

And because some people might be not sure about the Prius charging system, that was why I covered that question exactly in post #6 of this thread.

-Chap

 

Have you tried this in a Gen III Prius? Let's say it works on a Gen 3 Prius. Let's say some guy took your advice. He started to work on his car following your advice because you said it's OK. He accidentally let the positive terminal touch metal and created a short. That in turn fried his DC-DC converter. He's out 4G cause he was dumb enough to follow your advice.
He's gonna tell his mechanic "some guy on a forum said it's OK to do it this way" How would that look?

 

Have you missed both places in the thread where I pointed out that the positive cable connectors, when you unplug them, are female terminals encased in plastic and are not going to create a short? That's why on a Prius there is an easier, while still safe, way to isolate the battery than the 'loosen ground cable first' approach that has always been the standard advice with conventional cars. Others on PriusChat have noted the same fact in other threads. Observe that doesn't stop 'loosen ground first' from being the best standard advice for conventional cars. It only means we can be smart enough to adjust procedures to match changed facts. Those other cars don't have insulated connectors to unplug at the battery. Prius does. People are capable of telling the difference.

If another model of Prius ever comes out where the construction is not as I describe, people are capable of seeing that what I've said doesn't apply to that model. That's why I don't just give advice without explaining what it's based on.

There is a lot of advice gets posted on PriusChat that a reader would be wise to think twice about. I would say it's always a good idea for readers to (a) try to get a sense of the overall reliability of various PC members who post advice, and (b) read all advice carefully, including the explanations and support, and judge how well it applies to their situation.

I'm actually fine with how that looks.

-Chap

 

I just replaced my battery about a month ago so I know exactly how the positive terminal looks. And yes, there's a plastic removable insulator that the owner has to reattach after removing the terminal, but accidents do happen. What happens while he tries to slip the plastic insulator into the terminal and the terminal slips away from his hand and shorts out? The terminal has a 140 amp fusible link. The Prius DC-DC converter is rated at 120A. Guess which one's gonna go first in case of short? I put a glove over my terminal as soon as I remove it from the battery post for protection but not everyone's gonna do that.

The only way I would agree with your advice is if there's documents from Toyota that shows the charging system's output is no more than 14.4V without battery attached AND that the battery cables are connected to the battery with an Anderson plug which it's not.

You can get a cheap trickle charger from harbor freight for less than $10. If any accidents happen, only the charger is fried. The factory battery cable is more than capable of handling 1 or 2 amps of current. You're out a cheap trickle charger that you're very likely able to return. If you really want to be on the safe side, put a 1 amp fuse on the trickle charger. Besides, probably nothing will happen to the charger because most modern chargers have short circuit protection.

 

Aha! I now see how we ended up at cross purposes, and some of it was my fault. From your photo, it appears that Gen 3 no longer uses the unpluggable cable connectors at the positive terminal, as found in Gen 1 and Gen 2. (That's too bad, 'cause it's really convenient. The oil filter access and turning radius were already two reasons I wasn't hurrying to upgrade from my Gen 1, and now this ... darn.)

I see that this thread is in a Gen 3-specific forum, so it was natural for you to assume my comments were specific to G3, and it would have been better for me to notice that at first and write a big "if it's the same as G1 and G2..." at the top. As it happens, I saw the thread in the site-wide Recent Posts list and I wasn't careful to check what specific forum it was. That, combined with my not knowing that Gen 3 had dropped the feature I was talking about, led me to make a comment that didn't quite fit the forum it was in.

Fortunately, anybody thinking to follow my suggestion on a Gen 3 would have immediately reached the point "hmm, Chap talks about an insulated plugin connector I can simply unplug back here, and I'm looking and there isn't one, something doesn't fit." That's an important backstop, one of the reasons I do put that level of detail into my posts: so if something I'm saying doesn't fit your situation, you can tell it doesn't.

A quick "hey, Chap, you're talking about an insulated unpluggable connector at the positive battery terminal, have you heard that's not there any more in Gen 3?" would have brought us both to this point in one or two easy posts instead of four or five testy ones, and for my part in that, and not seeing earlier that's what was going on, I apologize.

Anyway ... that's interesting. Can you describe what type of fuse they are now using for the battery end of the cable, and exactly where it's now located? Have they changed from the Yazaki B1-type (PAL male bolt-in) from Gen 1 days, to some other fuse type?

Regards,
-Chap