12 v prime battery

Unlike Gen 4, Gen 5 Prius Prime will recharge the 12-V battery during PHEV charging; so, it should last even longer. Gen 4 Prius Prime drained the 12-V battery during PHEV charging.

 

That's wrong. The Gen 4 Prime does charge the 12 v battery when the traction battery charges.


iPhone ? Pro

 

It does? My impression was that it was one of the major complaints with Prius Prime that it did not charge the 12-V battery during PHEV AC charging.

Gen 5 is a completely different beast. You can use the PHEV battery with the inverter as a power-storage system or the ICE engine with the MGs as a generator to power your house or picnic gathering.

 

Yup. It changes the 12V battery but only while the traction battery is receiving a charge. In my case, since I only use level II charging equipment, the charge delivery to the 12V battery is just too short lived to be sufficient. It would be far better if the car maintained the 12V system when plugged in at all times.

If I recall correctly the Gen 1 Prime in the Japanese domestic market also offered the ability to provide inverted AC power. I believe that feature along with the solar roof and Chademo charging, was never offered in the North American market. Let's hope the same does not happen for the 2023+ prime models.

In any case, since there's no confirmation the new 2023 prime will remedy this small problem, I'll likely continue to use an aftermarket 12V battery maintainer when I finally get mine.

 

someone here graphed the 12v charge while prime is charging. it was almost nonexistent.

pip provides a robust charge to the 12v and i've never had issues. idk why toyota changed it.

 

Wouldn't the 12v in a regular Prius be charged even less?

 

I would think so. The problem is, we’ve had a rash of complaints regarding dead prime batteries because the quiescent drain is much higher

 

It's probably because of leaving it connected to the EVSE and not using the car for a long time. That's what I think killed my battery after I went on vacation, left the car plugged in, and came back to a dead battery.

 

A dead 12 volt right? Hook up a 12 volt smart charger. Our low ‘10 hatchback lives on one.

 

That’s true, and Toyota advises not to leave it plugged in.
but if you read the battery threads, the high quiescent drain has been charted and graphed, as well as the 12v charging while the hybrid battery is being charged.
@Salamander_King iirc

 

Not driving often enough is also a problem

 

Here is the thread I showed the graph.
Hopefully, ultimate 12v battery charging system discussion on PP

To summarize, the Gen4 PP has three distinct modes for charging the 12v auxiliary battery while the high-voltage traction battery is being charged. I have not been able to decipher what condition triggers which mode to be used by the car. The majority of the time I have observed on my PP was #2 Maintaining mode in which the charge voltage never exceeds 13v. Also, note that on rare occasions I witnessed the #1 Charging mode, the charging voltage is much lower at ~13.5v, not the usual above 14v level I saw while the car is in READY mode. So, in practice, the charging traction battery is not usually adequate for keeping up the 12v auxiliary battery SOC at near 100% (12.6v or above) if the car is not driven often and long enough.

1. EVSE Charging: While the PP is plugged in with EVSE, it seems to have two levels for charging. The first is ~13.5v charging which occurs only during the time the traction battery is actively being charged.
2. EVSE Maintaining: The second is ~12.7v maintainer mode charging that just keeps the 12v battery at near a full level without actively bringing the SoC any higher. This too only happens during the time the traction battery is actively being charged. I explained this observation in this thread.
3. EVSE Checking: There is one more mode that seems to check the voltage of the 12v battery and charging at 13.5v starts, but immediately stops and switches back to the maintainer mode at ~12.7v.

 

Is it charging the 12V or providing energy for the 12V accessories needed for charging?

I remember quotes from the manual warning about 12V drain while plugged in and not charging.

The gen4 inverter was widget that plugged into the charge port. The gen5's is built in, and photos hint at it being available everywhere.

 

Well, the bottom line is that in Gen 4 Prius Prime, you can't rely on AC charging not to drain the 12-V battery let alone recharge it.

Apparently, Gen 5 Prius Prime actually fully recharges the 12-V battery during AC charging and lets you operate the vehicle accessories without the 12-V battery being drained. In Gen 5 Prius Prime, AC charging may even allow the A/C to be operated (no pun intended), but I am not sure.