Adding 2nd Lithium pack in Parallel

??? You mean a 0.1375 ohm pack assuming parallel and zero interconnect resistance ?
Noting that one pack will require a much longer series of cables and interconnections that raise its resistance but not the onboard OEM pack?

And at the end of the day the current monitor and coulomb counter will have to throttle more for inverter and power limits.
Generally interpack current loops are considered irrelevant in your scenario, All OEMS tolerate reduced resistance and adjust but higher has a limit.

Just buy a pack, wire it in and have a Toyota OBDII tool and OBDII monitor

Test it, if it’s for fun you can see what Toyo does when the battery has unexpected capacity, my guess is (considering Toyos track record) it likely will use slightly more capacity as it learns and have slightly more power at the extremes of voltage.

It is possible you might throw a cel but some older cars wouldn’t.

Do you want to be patient zero? Test it out, start a new thread and report your results, it’s only money

Are you feeling lucky punk?


Now something I have not noticed “tested” is the grid charger scenario on lithium Gen iv

With a proper charger and bms you could likely fully charge a normal onboard lithium package then start your day with a couple potential EV miles.

Now would the car spin the engine even when ignition off in response to charge?
Would it brick?
Would it cel?

Never saw this scenario played out and given the small SOC window Toyo allows you could get as much or more gain doing this than twinning packs at the cost of wearing out the battery more rapidly in hot weather and can’t charge in very cold weather (unless you like a failed pack)

 

First any serious design meeting starts out with a well written proposal and a conceptual block diagram in an attempt to get everyone on the same page. Reaching a common understanding of your proposed path forward has not happened yet based on observed feedback.

Sure anything is possible; modifying the vehicle's control logic is the most likely path forward. I like the demonstrated concept of replacing the primary battery assembly with a bigger version that emulates the original interface.

Comparing this proposal to a group of paralleled solar microinverters or to a group of series parallel solar panels seems completely different. Recognize this is an opinion based on minimal information. If the Toyota vehicle network was designed for multiple battery ecus the challenge would be largely eliminated, safety would be vastly improved and long term reliability might be possible.

Safely charging a group of series connected battery cells with multiple temperature and voltage inputs is quite different than safely charging a macro level series parallel system that seems to be proposed here. Paralleling at the module rather than the whole battery assembly might be more successful. At least some indication of over temperature and or short circuits might be possible.

The idea of running an unmonitored second battery assembly with no safeties is concerning, assuming that is your strategy. One might wonder how the second battery ecu would even allow power to be connected. It might require a hard wire bypass inside the second assembly.

Most likely the worst scenario is it would not work at all especially if no internal modifications were made to either pack. It is likely a bypassed secondary assembly would cause a high voltage leak shutdown of the first assembly.

 

When no one has publicly done what is being proposed on a Gen IV it’s unlikely you can meet the requirements for an intelligent review.

Modifying control logic is extremely difficult (unlikely), spoofing or hacking around it more likely .

Only in the last year has the original Honda Insight logic been mapped and modded effectively enough to in essence control and bypass OEM systems for lithium and other tech installation by a layperson

 

Lol,

Can’t scope something in the way described unless you are willing to destructively reverse engineer everything non-public.

Next your proposal doesn’t make sense, what do you expect togain from 2 pathetically small 1kwhr flashlight batteries instead of 1? Your proposal would make more sense if you were swapping in a pip or prime battery which is actually large enough to be useable for something

As you can imagine that isn’t going to happen soon, only now is Brian Batista reverse engineering some of the firmware to improve 2011_2015 volts.
Without someone dedicated and willing to destructively test components, it won’t happen.

If you are an EE and serious (not looking for someone to give you a turn key answer/solution)
I recommend joining the Openinverter forums and see if the EV systems designers will give direction. Gen II/III have had the software and controls broken down enough to externally drive OEM systems. Funny part is Toyota recycles some of the components and control laws generation to generation.

Also
I didn’t miss anything if you read my post I say the resistance between large parallel packs is irrelevant, contrary to everyone else in the thread said, I know this due to experience, I’ve owned and modded antique EVs most of my driving career.
Toyota systems are generally treated like they are overengineered black boxes tracking all power metrics, and being immensely complex
those I’ve seen are far from this and can sometimes be simplistically spoofed. Unless you are willing to just do it potentially causing damage as others have done with Gen2/3 & Volt there isn’t a rapid way of progressing.

Next The part you are missing is absolutely no one has publicly done any of the things you describe on Gen iv, period.

There is no public facing data on the control system software.

So you are the first, if this subject is important to you, you would have to test it, no one here will be of much help besides providing tool sources like Dr Prius, OBDII software and grid chargers.
Might even get a tech manual.

Asking these questions on a newer car is very similar to throwing a hotdog into a dark hallway .

 

Connecting things in parallel doesn't work that way.
There is no "average" when it comes to resistances.
With each additional post it becomes more obvious that you don't know what you are talking about.
You have to EARN respect......and you aren't doing a very good job.

Just stop please.

 

Criticism occurs to warn someone
so they don’t waste time or effort,
no one is stopping you from doing what you wish.

If you want to talk to a been there done that I recommend locating this guy

Converting Prius G3 to all Electric removing ICE | PriusChat

as the problems and solutions end up being very similar.


As stated you are in the wrong forum to modify power electronics on a newer car

The people that do what you propose are here

https://openinverter.org/docs/index.html%3Fen_home,3.html

Years ago when the Prius was simpler there were aftermarket solutions similar to what you describe, my previous 2000 Honda Insight had dual packs from a previous owner without any modification except for mima, this solution provided very limited benefits above just using the mima
and was removed as the packs aged out. I still have the grid charger.

I wish you luck but I’ve seen your particular request hundreds of times and been there myself,
yet my answers remain similar.

Someone always has to go first.
Maybe it’s you?

 

Not arguing, honest question. Do you expect to recover costs through fuel savings? If not, how much expense do you feel that the pleasure of the (possible) improved performance is worth?

LKQ is the largest national salvage dealer in used parts. I've gotten parts from them and had good experience. On LKQonline.com they have a 2016 Prius Li battery from a wrecked vehicle that had 37K miles on it for $1425. You might get lucky and find one locally for less but probably not a lot less.

 

Another thing to consider - insurance.

 

Every 2016 Prius Prime will be faster and have better mpg. Why not just sell yours and buy one? The path you are heading down may end up burning your 2016. Seriously.

 

I always have at least 3rd Party insurance - in case I accidently write off a million dollar car (or a building by clipping a pillar).

 

Not sure how good of a discussion this has been. But very similar ideas are discussed from time to time here with some giving very little consideration for the qualifications or experience of those dispensing free advice. There are several dealer mechanics here as well as electrical and software engineers. At least one EE professor. But most won't weigh in on something presented badly. Sometimes I wonder if the forum should charge an admission.

Tennessee does require minimum insurance if you drive as do banks or credit unions when you finance a car through them.


Minimum Liability Coverage: 25/50/15
$25,000 bodily injury per person
$50,000 bodily injury per accident
$15,000 property damage per accident

 

Someone added two extra packs to a Gen 3 (or was it a 2?). There is a long and interesting thread about it on that forum, detailing design, sourcing of components and getting it all in place. It behaved well while driving (apart from the weight). Unfortunately no temperature sensors were installed on the new packs, the last post was a video of the car in flames. Total loss.

 

lmao

 

So you're of the opinion that he wouldn't get longer acceleration boosts with a second battery?