Add an additional 8Kw battery to double the range

absolutely. but they all gave it up as a bad job.

 

some people are never satisfied, first it was the PIP 4 KW wanted to expand to 8 KW now it's the Prime

 

GREAT IDEA! I mean what could go wrong?

Ni-MH Battery Explosion | Flickr

 

Well... apparently the containment system did is job-... wait a minute, the pictures do not show the bottom of the Prius!

 

No it probably is NOT.

Do some searching on here. I'm pretty sure that there are a couple of threads from folks who have actually tried it......or very similar.

The problem IS mostly with the computer systems onboard that are mostly impossible to modify so that they properly recognize the extra battery capacity. If you DON'T do that, it is likely that the computers would "see" the extra battery as a fault........and the result might be exactly the opposite of what you wanted.

 

There was once several companies offering plug in kits for the Prius that did work, but it took more than wiring in more batteries.

 

For the curious, the PC forum is here.
Prius PHEV Plug-In Modifications | PriusChat

 

There's an economic ROI question that limits my excitement here.

For a prime that travels 20K miles a year on electric only, assuming even as low as $0.12/KWh, you are using $500 in energy.
For a prime that travels the same 20K miles a year averaging about 1800 miles between fill-ups, you are using about $667 in energy.
For a commuter who is exactly 50:50 with gas/electric and could move to all electric with a 2x battery, you are currently using about $750 in energy.

So, doubling the battery would save the 20K mile 50:50 commuter up to $250/year...Over a 10 year span, up to $2500 (assuming gas stays around $3/gal). A 2x battery is kinda a tough ROI sell in my book...

Now compare the prime to my Highlander, and the ROI of a prime is clear...At $2000/year less to operate, I can almost pay for a prime over 10 years...That said, I like my truck.

 

yes, please give it a try, and let us know how it works out. also, if you could document with a write up and pics, that would be ever so helpful for those less knowledgeable if they want to attempt it.
all the best!

 

On top of the of cash cost, doubling the battery is going to use up all of the cargo space.

If electric range is your main priority, a Volt or BEV is a better buy.

 

And, even when not using the extra range, you are hauling around the extra battery weight.

 

IMHO upgrading the traction battery may have sense for a non-plugin hybrid only. For instance, in an italian forum of hybrid cars I'm a member of there is a guy that firstly installed on his Lexus RX400h a 9,9 kW LiIon additional battery pack, then after a while sold the RX400h (w/o the plug in), and bought an used Lexus RX450h on which has installed the same battery pack.

As far as I know, he's still using with satisfaction the pluginized RX , although considering the costs he supposedly beared (at least 4-5000 Euro for the battery pack and the BMS, plus installation costs) I believe that such operation was motivated more from passion and taste of the challenge than for saving money, even considering the cost of the fuel here in Europe.

 

OK this is a nutty, hair-brained idea but stay with me on this.

Turn Prime on. Put car in D, proceed to nearest dealer offering double or more EV miles and trade in car. Not only will this mod be quick and easy to do, you'll get a nice, long warranty with the larger pack.

Yeah, I know, crazy. Never mind.

 

But Tesla does not have dealers...

 

And medical marijuana dispensaries only deal with legit patients.

 

Why did you choose the Prime over the Volt?

If it was for Toyota reliability, the Volt is one of Chevy's most reliable, and enlarging the battery pack could cause issues in the Prime. It will void the hybrid and battery warranty.
If for better cargo space, the extra battery will negate that. Same in regards to cost.
The Prime will likely still have better efficiency after this modification, but the 2.5 gallons of gas saved a week might not be worth the potential issues such a modification could entail.

 

Making TSS-P standard is a game changer. The honorable competition requires:
Plug In Hybrid For Sale: 2018 Volt Pricing | Chevrolet

• Requires "Premier" trim, +$4,000
• Driver confidence packages, +$1,000
  • required for 'adaptive cruise control', the Chevy term

Chevy has repeated the same mistake Toyota used to make by upscaling the trim and over charging for the predecessors of TSS-P.

If someone is commuting 100 miles each way, every work day, TSS-P pays for itself very quickly and getting 54 MPG isn't bad either. Given New York electrical rates are averaging $0.21/kWh, it makes sense to optimize the gas performance over worry about the electrical range performance.

Bob Wilson