Has anyone added a second traction battery?

Has anyone purchased a second traction battery and installed it in parallel with the existing battery? Perhaps one from a wrecked Prius.

I'm thinking that would double the Ev range, which would be very handy in my current commute due to long term construction on one of the highways I use. I am in sub-5 mph stop and go so long each day that I wear down my battery and the ice ends up running while stopped, thus killing my hypermiler goals.

Thanks in advance for experience or thoughts.

 

I'm thinking that charging the second battery while cruising wouldn't cost much energy from the ICE.
The weight would be a little penalty.

But doubling the range on battery would help my drive.

 

I did do a search...but had no luck by the way.

 

I like my Prius a lot, amazed by the technology.

I come from the Corvette world where modification is very common, so was just wondering if anyone tried what seems as pretty simple to me, just buying a second battery and running in parallel.

Probably not that easy but I'm sure I'm not the first to think if it...there must be some tinkerers out there.

 

I have a specific reason for asking. I have 3 miles of stop and go, 5 mph or less traffic every day due to long term construction. I run the battery from full to 2 bars every day, and then sit with the engine running while stopped while it recharges.

If I had twice the capacity I could do this stretch on battery and recharge both while cruising.

Obviously it's not cost effective to do this...but I'm the tinkering type.

 

I have a basic understanding of physics, thanks.

In my specific case I have 3 miles if stop and and go and I wear out my battery half way through. I had double the battery it would carry me through this without the engine running while stopped to charge the battery. I could charge the battery while cruising, using energy that is being produced in a more efficient manner (the engine is running anyway to cruise).

So it's a simple question, I wish someone had tried it and say it either works or doesn't work with experience.

 

Thanks for posting this cwerdna, those were very informative posts. I wouldn't plan to make a plug in, so they weren't exactly on point but surely evidence of the complexity built into our cars and what can happen when things go wrong. Even Boeing has trouble charging the batteries properly so there is serious science there!

My idea is due to specific circumstances, to double the range on EV and charge both batteries when cruising when the engine is running in its most efficient range, rather than sitting not moving and charging the batteries which is when the engine is in its most inefficient range.

Frankly at $2k for a spare battery the economics don't make sense, but, I was hoping it might generate some good conversation on this board and since I'm new I'm excited to learn more about the car from experts. After a lifetime of wrenching on cars and specifically Corvettes for the last dozen years, I have a lot of knowledge about effective mods on those, but the Prius world is new to me and I'm exciting about learning more about the technology in the car.

 

The computers don't scare me, I've been using HP Tuners to tweak my GM cars for years. I used to set timing and fueling looking at spark plugs and listening to the engine but now my knock sensors and wide band do a much more detailed job than I could ever do. I embrace the technology and like that I don't get gas all over my hands anymore swapping jets in a Holley!

But your point is excellent, apparently there is no "HP Tuners" or "EFI Live" for the Prius that allows tweaking the factory set parameters so that might kill the idea.

I have to get a scanner for the Prius so I can see what's going on. I'm on the iPhone platform and I understand the bluetooth OBDii adapters don't work with iPhone which is too bad at the Torque app looks great. But that's a subject of a different thread and I haven't researched it yet so will do so before I post.

 

That is a great idea. I'm well experience with scanning and tuning so perhaps I can help him too.