Is adding a second battery possible?

I think that some people mentally scale up their phone to an entire car.

The phone has to be both thin and cheap to make. Our cars have more room and cost more, so the manufacturer can build a more elaborate charger. Almost any charger would be better than a wall wart, but the Prius has a very advanced charging system.

It is NOT going to wear out the battery in 5 years, in the US all batteries are warrantied for 8 years, some for 10 years. If even 5% of the batteries went bad during the warranty period, Toyota would go bankrupt.

Assuming lopezjm2001 is not just here to spread misinformation, he may just not have paid any attention to the structure of the Prius.

 

I wanted to do same. Now Im thinking more along lines of adding an Aquatune kit. It uses available hydrogen to improve fuel consumption, power and reduce emmissions. On the Aquatune website there is a Gen 2 Prius that gets over 30% more fuel efficiency. Company promisses at least 25% or money back. For just over $800 it wont save a mountain of money, but better power and reduced emmissions would make that money well spent, for me. Kit also seems to clean out engine gunk as side bonus, people say they run more smoothly with hydrogen. Does anyone have experience with these kits? Adice? Considerations?

 

Check out this exposè on Aquatune and other alleged hoaxes
MPG Gas Gadgets Debunked - The Truth about MPG-Boosting Fuel Mileage Gadgets

 

I'd be very skeptical of Aquatune. First, the technology doesn't make sense. It uses "water injection, air injection and ultrasonic water injection that also uses a hydrogen generator"... Um... Ok.

Water injection does allow you to use a lower octane fuel (good for a Prius in a third world country with terrible gasoline I guess.) The main benefit would be it could allow you to use a higher compression ratio. You could also run leaner at high loads. It also lets you advance the timing. But there are two things running against it. One, water and steam have a lower specific heat ratio than air. In other words, it expands less and creates less pressure with the same amount of heat energy. It also slows the burn rate, which creates more pressure before top dead center and less after top dead center which of course is not good for efficiency. Water injection only helps if you're building an extreme engine, for an example with a very high compression ratio or with turbo or super charging.

Air injection... So does that mean it runs leaner? Don't get me wrong, leaner can be more fuel efficient. It also creates more NOx emissions (think diesel scandal). It also will set off the "Check Engine Light" since your O2 sensors will be seeing more O2 than they should.

Ultrasonic water injection sounds like a good way to emulsify water... But it's still water injection.

And then there's the good ol' hydrogen generator. These things have been exposed as a fraud for decades.

If you want a clean running engine, use Top Tier fuel, change your spark plugs often and change your oil every 5,000 miles or 6 months or sooner, maybe even go for every 3,000 miles or every 3 months on those oil changes. And use quality oil and filters. You can't go wrong with OEM but others, like Mobile One, are also good.

 

aqualung would work better...

 

just get a prius aqua, it comes preinstalled...

 

Wow, some real negative posts on this thread :lol: I am actually looking at do just what the OP has suggested, just in a different configuration.
I'm looking at building a total of 4 NiMh cell batteries, each 4P7S (28 modules) to make 4 x 56v batteries ..... the tricky bit is the 7S and 8S packs form one module pr seen by the Prius computer, as does 23S and 24S, not unachievable or all that complicated.
This would give a 24Ah NiMh battery pack that could be charged from the mains or solar but also increase the capacity for regen braking.
For those that did short commutes within city speed limits it would give quite a decent improvement in fuel mileage. For me, it would improve the regen capability for the long down hill run into Adelaide that see the original battery fully charged in the first part of the decent, then I have to ride the brakes for the rest of the trip down to avoid getting a speeding fine from the multitude of speed cameras they have recently installed .... they are making a killing from the one speed camera so they figured if they added 4 or 5 more they would really clean up ...... such is the way the govt minds work .... but that's a whole different topic .....

I also want to combine this idea with the Re-hydrating the battery modules. | PriusChat idea but actually looping the modules together with electrolyte being pumped in at the top and back out from extended tubes that reached the bottom of each module so it would also flush out any rubbish from each cell.
This would provide cooling for each module and ensure each module was fully hydrated at all times. The hydrogen and oxygen could be vented off, even fed into the ICE intake to be burnt as fuel, but that would be more of a byproduct than a design feature.
The whole electrolyte system would need to be under around 60 psi to limit the amount of electrolytic action from each cell within each module (the greater the pressure the less electrolytic action taking place)

The over all advantage should be a higher current supplied at a better voltage than the single NiMh battery can supply along with a smaller load per module when under load and regen so the cells charge and discharge slower so they should achieve a higher state of charge each cycle.

Need to figure out just where the other 3 batteries will mount ...... as well as getting another 3 batteries :lol:

What are the thoughts of the brain trust?

T1 Terry

 

Let us know how it turns out.

 

You can find MUCH better ways to spend your time and money.
The "rehydrating" part might be downright dangerous.

 

It always scares people when talking about mods to cars that haven't been "proven" effective, already.
The failures are what draws the most attention from the uninitiated and there are typically a lot more of those than there are of successes. It's also easy to take any mention of batteries out of context, just look at all the arguments concerning this or that type of battery for this or that type of application. Endless.

 

Basic battery technology hasn't really changed much in about 80 years or so.
A really LOT of things have been proven INeffective though.
That information is usually pretty easy to find these days........if you are serious about finding it.

 

The "proven" one is always a laugh, everyone is scared to actually try anything so nothing actually gets proven because it doesn't even move from the thought part.
Not sure why the rehydration idea would be dangerous, it's only a weak solution of caustic soda, not like it was sulphuric acid or something. A tank to act as the reservoir to allow the gas bubbles to separate and maybe a grid of pipe work circulating a coolant, or simply pump the KOH through a radiator to cool it before circulating it back through the modules.
Liquid cooling moves 3 times the heat energy of force air cooling, actually cooling the cells from the inside would be muck more efficient than blowing air across the outside of the modules.

T1 Terry

 

@bwilson4web I've read, did some rehydration experiments on Gen 1 cells a long time ago, with not very promising results. So that may explain some of the hesitation in regards to that issue. That is only hear say from me as I've not read the thread that I can remember, other than possibly clicking a link to, and maybe skimming the thread.
I only have 3 Prius modules I was given as a gift many years ago to experiment with. I haven't had much time to, or application to, connect with anything other than hooking them up to charge and watching them bulge as they approached full charge.

A funny thing about electrolyte, I'm still in the process of trying to understand old school hydrometer readings as relates to flooded lead acid
https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery#/media/File:Hydrometer_(PSF).png
currently available battery acid premix, etc. with 5 different sized flooded and AGM units in service.
I just last year replaced a 12 volt flooded lead acid from the 02 civic which to the best of my knowledge was original, So I'm no stranger to outliner amazing unbelievable incidents as well as how many failures along the way I've also witnessed.

a feast for the inquisitive https://www.t1lithium.com.au/batteries/why-t1-lithium.html
inquisitive Kwisatz Haderach from an old favorite

 

why not go with lithium ?

 

My experiments were driven by a Toyota patent that made a hole, added water to a target weight, and sealing the hole with plastic welding. But the fundamental problem were the "O" ring seals on the terminals.

Normal operation electrolyzes part of the water into H{2} and O{2} that in a sealed battery will recombine. The seals are weakened by excessive heat and leaking some of the gas. I could not find a credible way to close the terminal seals so the gas won't leak out.

Bob Wilson

 

Anyone ever seen a set of Prius DTCs like this before
2009 not going into gear, several codes | PriusChat
, possibly from leaking modules.

Thanks for explaining exactly what the issue was that you found Bob

 

we are in the pip forum, no?

 

No, just harking back to the days of yore (pre-PiP) when adventurous people spent thousands of dollars hacking batteries to make what Toyota wasn't ready to make.

 

That is my wife's site for her business and she has a real big head now that it has been mentioned on a US forum :lol:
I get the pleasure of work there for zero $$ while being flogged like a red headed step child, just so I can have the workshop/man-shed to do my experimenting and stuff.
I've been into getting an understanding of the different chemistries in a practical hands on way for the last 15 yrs. My goal is to find a battery chemistry I can use in my vehicle conversions including a 36ft 10.5 tonne motorhome I built from an ex passenger bus. I want to be able to power the motor home to drive it as well as use the battery for house power and utilise the big DC charging stations dotted throughout the country, handle the huge regen expected when trying to stop 10.5 tonne from running away down a long hill .... and incorporate a gen set and roof mounted solar for when we are away from any grid power.

This makes the Prius an excellent test bed and I can use the results to build the big project.

At the moment I'm looking to see if I can use the NiMh as an interface battery so a controlled current can be fed to the LFP battery, or do I need to build a big LTO battery that can handle the big current both ways ...... that would be a big area/weight/expense.
The NiMh battery is much cheaper than the LTO battery and I have some here to play with, well I have all 3 chemistries here to play with and two Pri to experiment on, so I thought I'd share my ideas and outcomes on here.

T1 Terry

 

Interesting, do you know for certain the recombination will happen under the 80 psi pressure that the relief valve in each module is designed to limit the pressure at? The major issue that causes the seals to leak is the pressure valve get stuck in the closed position .... this is talked about in the re-hydration thread when the modules are pressuring up to 125 psi in some cases before the valve will release, but then returns to the 80 psi they were designed to operate.

The lead acid AGM batteries have a recombiner as part of the cell cap that uses a catalyst to reform the hydrogen and oxygen back into water droplets ..... but this process generates heat so the AGM battery doesn't use an equalising charge simply because the recombiners can not handle that much mixed gas resulting in cell over heat and cell bulging. I was considering including this idea in the reservoir rather than venting the gases into the ICE intake ... still might do that.
I know from my experiments with different electrolysers that pressure raises the voltage required between the plates for the gases to form on the surfaces, but once formed, the pressure will continue to increase until something lets go ...

T1 Terry