How does jump start works on hybrid engine?

You could be right, and maybe with the increasing electronics more right these days, but I've been getting away with it since the early eighties. FWIW, the Owner's Manual agrees with you: saying to charge a battery only when it's removed.

Downsides to removing the battery for charging: it makes for more wear-and-tear on clamps/posts, increases the odds of a screw up, and reduces the convenience of a regular top-up charge session.

 

I use a 750 mA Battery Tender on my more sedentary vehicles. I consider it to be a very very small risk to my vehicles and wouldn't hesitate to use it on my Prius if circumstances called for it.

 

Jeff after doing some testing on the gen2 charging system I found that it does not charge a partly discharged battery slowly as I mistakenly thought. I discharged a new battery by 10% then measured the charge voltage and current. The charge voltage was 14.6 volts and the current was 43 amps! I intend taking further measurements when time permits, but have no doubt with a greater level of discharge the current will be higher.

John (Britprius)

 

As the 12v bus can supply 100 amps, you are correct. Our little 12v batteries need a smart charging system or when given a deep discharge, the charging system will damage them with excessive current.

My OE 12v battery was still good when I replaced it after 8 years of service. It now serves as the starting battery for my ancient AC generator. I attribute its survival to averaging long trips (keeping it fully charged) and never subjecting it to a deep discharged.

JeffD

 

I changed my battery for a mobility battery after only near 4 years, using the OEM battery for my ride on mower. The OEM battery states on it max 4 amp charge no wonder they fitted it with a vent.

The problem with only charging at a low rate on a lot of the Prius cars with little use would mean the batteries would be in an almost permanent state of discharge.

The battery I have fitted gives initial charge rate as unlimited and having a 60 AH capacity should last a long time in my car being used almost every day for long runs.

John (Britprius)

 

Charging via ac doesn't cause much fluctuation in the DC current. The DC output average about 13.5V and it may hit 15V if you AC voltage rises from 110V to 120V. Remember that a car engine is very harsh environment, back EMF from relay can range form 35 V to -35V and ignition coil runs with voltage 5000V, the car manufacturer has incorporated many suppression and protection circuit into the ECU.
Only word of caution, do not start your working car with jumper cable attached as the voltage surge will kill the electronic of the dead car.

 

Oops forgot to tell, you should not off your engine when jumping the other car also else your car electronics will be fried. And lastly please don't charge during thunderstorm.

 

I'm not sure how the Gen II is set up but I attach the negative jumper cable to a mounting on the inverter. Just wondering if the engine mounting was insulated from the body preventing a circuit.