ADDING MORE HYBRID BATTERY MODULES

get a pip.

 

1) without serious safety precautions, you can be killed by the wattage you already have. All the safety gear Toyota installs assume you stay outside of the battery case.

2) it will be up to you to re design the charging circuits if you change the batteries to be charged. 2 or 3 companies do this, but it is non trivial.
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As you will see, most rely on plugging in the additional batteries rather than redesigning Toyota's inverter.

 

The concept sounds simple but I don't think it is. If you put two batteries in parallel, you'll need some sort of safety circuitry to protect the batteries in case on of them goes dead. The dead battery will potentially become a short circuit for the live one. That's my guess.

I would imagine that the battery is not cheap, so you probably would want to add a charging circuit so that you could re-coup your investment sooner. Just a thought.

PS: The extra battery will not increase wattage but will increase kilowatt-hour.

 

Well this is done by some people but unless you are an experienced EE with related field experience (high power inverters/converters, batteries etc) with the right tools and willing to risk your car during development ... this is definitely not a DIY .. I am MS in EE but no experience in these fields so I would surely not try something like this from scratch.

Just my 2c...