12 volt hack for Gen 1- Gen 3

My comments are not to minimize the work you did in writing this up. I just want to make sure everyone is aware of the safety hazards and potential economic drawbacks.

 

In RE Battery-backed solar power, a 500 milliamp shunt is often added in a circuit to provide a known quantity of resistance to get an accurate current-draw estimation. One could do the same with Prius batteries in order to get a very precise current draw at low and high capacity.

 

12V Battery YUASA 48Ah YBX5053 P+ 5000 series
Price in Europe around $70-80.
No modification required.
Properly serviced, i.e. charged with an ordinary transmormator charger, e.g. every 6-12 months to 16.2V (not any microchip automatic "superchargers"), will live peacefully 3-5 years or longer ... Certainly long enough for LiFePo4 technology has reached the level of today's ordinary battery

Vented AGM technology is a fake in my opinion.
VLA valves are ordinary rubber bands, while all modern hermetic 12V batteries have safety valves.
At the same time, anything that escapes during overload will be sucked out through the vent in the trunk wall (Vapors are generated during charging, but this applies primarily to charging at home with open plugs and is about gassing the electrolyte to obtain density - normally we do not drive in the car with the plugs unscrewed and the battery is practically 100% tight).
And if you want to have 99.9% protection, connect the hose to the core in the battery and lead it to the ventilation duct of the hv battery or through one of the holes in the floor, e.g. the one from the seal "draining" (there are two next to and under a 12V battery).

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That's a nice looking battery for a great price and I agree with what you wrote up about the safety valves... Not sure if the battery you're pointing out is available in North America though? Here's one that's similar though that my friends and I have been using: 12 Volt (12V) 55 Amp (55Ah) VRLA AGM Sealed Lead Acid Battery 55 AMPS HIGH CAP | eBay

 

YUASA should be available worldwide, possibly under some "daughter brand".

The price of this battery is amazing for this capacity.
If they really have 55Ah then there is nothing to think about but mount
We have AGM of this type more than twice as expensive, hence the option with the traditional YUASA Ca-Ca.

Have you measured somehow, do they have about 55Ah?
In Europe, distributors of many low-cost sub-brands apply tricks with lining like a sponge, thus deceiving customers...
In the Battery you provided, however, its weight 16,8kg is a plus ... As long as they provided the real

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Myself and my local hybrid car nerds have bought three of these thus far and no issues with them... I even managed to fit one of them in a Gen1 Prius, which was a bit awkward. As for actual measurement of AmpHours, please buy one and do that, we'd love to know what you find out.

 

What connectors and posts are you using?

 

At first I used a stack of washers and a slightly longer bolt of same thread type to simulate the normal post the Car's terminals used. But most recently I've found it's easier to just use the slightly longer bolt with a big huge metal washer on the top and bottom of the terminal, which seems to require less material and is a much tighter fit.

 

You forgot this double fatality:

Cayenne Poss. Hydrogen Sulfide from wrong 12v Battery | PriusChat

You mean 2016, when they moved the 12V battery out of the passenger compartment. My 2012 most certainly does have a vented 12V battery.

... starting in Model Year 2016, when the 12V battery was moved to the engine compartment.

 

No I did not... It's not an incident directly attributed to battery in a way that can be proven... It's a lone incident that lead investigators to believe that it was the only logical explanation even though they couldn't directly prove that it happened.

Furthermore the mobility/wheelchair batteries we use are approved for use in both homes, hospitals and for people with health issues to sit directly on top of... None of these approved designs see any need whatsoever for "venting."

 

That rationalization is understandable after just the first media reports, but much less so after the coroner's report.

While this case might be uniquely identified among passenger cars (the vast vast majority of which don't have the battery inside the passenger compartment), proof of concept is very well established by industrial fatalities.

I am not at all peaked on wheelchairs. But I must wonder how many power wheelchair users use them in an enclosed room of similar volume to a passenger car (much smaller than any ordinary dwelling room), while simultaneously and continuously charging with a charger capacity similar to an automobile alternator.

 

Just in case anyone here still harbors the myth of Gen3 Prii not venting the 12V battery, our own PC member and YouTube channel host NutzAboutBoltz clearly displays and calls out this vent in his video "2010-2015 Toyota Prius 12V battery replacement". While this video isn't linked on the PC page listing many of his Gen3 maintenance videos:

Nutz About Bolts Prius Maintenance Videos | PriusChat

it is found directly on YouTube (vent visible from 0:40 on, verbally called out at 1:40):

 

Wheelchairs are approved for use in hospitals where there are very small rooms as well as highly explosive sources of pure oxygen and large amounts on industrial equipment that can create all kinds of trouble if safety rules aren't followed.

What's more, most 12v car battery vent tubes area sealed and never used unless internal battery pressures break through the seal and by the time you get to that point, do you really think your 12v battery is going to keep its failure a secret from the sensors & computers long enough for the vent seal to brake and kill everyone in the car...

And while it makes sense that from a liability perspective that automakers these days are going to put a vent system in a car that has the 12v battery inside the vehicle, it makes no sense from the lack of records of accident caused by lack of venting... I mean remember the VW bug and van? They all had batteries under the rear seat with no venting and are there any documented incidences of poison gas in the cabin in those vehicles? You'd think there would be at least some with the amount of those clunkers that have been on the road in the past 75 years?

 

Funny stuff sometimes......
We often talk about buying more expensive LRR tires, instead of just basic tires...
We talk about changing rims or adding aero effects....
We talk about adding cat shields...
We talk about using high end oils and lubricants..
We talk about adding aftermarket stereos.....
and so on and so on....

Yet, we can't stand to buy the factory correct size 12v battery....no fabrication or extra effort rigging required.
One thing I always ask myself when modifying a vehicle from OEM. What if I'm not the one driving it? Am I risking someone else's safety? A wife, a son, a daughter, or any of their friends?

I didn't think twice over the weekend about spending several hundred to buy a kayak and safety gear, yet I'd flinch like crazy over a $200 battery. Guess we all do it. Life is strange sometimes...

You guys know the factory Camry Hybrid battery terminal clamps are identical to the Prius except they are normal size instead of the JIS? I have a couple sets on the shelf, just in case I ever feel like trying a standard Group 51 size battery or something. The ground cable is a couple inches longer. The positive clamp is identical and just attaches to the + terminal fuse block assembly the same way the original attaches, one fastener. Cost me only a few bucks a set from a salvage yard and it keeps the OEM look.

 

If someone was selling higher quality kayak safety gear for 1/2 the price but the online kayak forums said don't do it because it required a minor kayak modification and they hadn't tried it / didn't know the option existed, would you spend more to get less to gain the acceptance of the people on the Kayak forum? Or would you realize a stick in the mud when you see it and save money and get higher quality?

 

No, I don't personally remember VWs. But carbon monoxide poisonings in cars were common in that era, I remember numerous fatalities in the news in my area through the 1980s. Online VW Bug history suggest they were quite susceptible to cabin CO problems. H2S incidents could be hidden among them, e.g. the recent Porsche incident was initially suspected as CO.

PS. What ampacity did OEM Bug alternator / generators have? (I.e. how much current could it dump into a battery during a charging system failure?) How does that compare to modern cars?

 

I've never seen a hospital room with a volume as small as a typical passenger car.

But considering the serious level of medical equipment safety regulations, it would seem plausible that the electrical requirements that prevent dangerous levels of explosive hydrogen gas formation, may also prevent the even greater level of battery overcharging abuse needed to produce the much less common hydrogen sulfide emissions.

But denying that overcharging abuse in non-medical environments can cause hazardous levels of hydrogen sulfide emission, is a head-in-the-sand viewpoint. The possibility is very well documented. Here is a smattering of the first items I ran across:

IEEE: Hydrogen sulfide and sulfur dioxide evolution from a valve-regulated lead-acid battery
"Abstract:
Two incidents concerning copper contamination associated with uninterruptible power systems (UPS) were observed. Valve regulated lead-acid (VRLA) batteries used in the UPSs for back-up powering were diagnosed as the possible source of the contamination. One of the VRLA batteries from the damaged UPS unit was subjected to overcharge in the laboratory, to simulate the incident. Overcharge currents greater than 10 amperes, coupled with battery temperatures over 60/spl deg/C, can cause a VRLA battery to release significant amounts of hydrogen sulfide and sulfur dioxide. Under extreme conditions, hazardous levels of hydrogen sulfide could be generated. ..." [emphasis added]

https://download.schneider-electric.com/files?p_File_Name=SADE-5TNQZQ_R3_EN.pdf&p_Doc_Ref=SPD_SADE-5TNQZQ_EN
"Toxic gas emissions are miniscule, but can include arsine and hydrogen sulfide. These gasses appear only during severe failure events such as thermal runaway, and are not always present during such events."

https://ehs.umass.edu/sites/default/files/Battery%20SOP.pdf
"In addition, overcharging a lead acid battery can produce hydrogen sulfide gas. This gas is colorless, poisonous, flammable, and has an odor similar to rotten eggs or natural gas. The gas is heavier than air and will accumulate at the bottom of poorly ventilated spaces. Refer to the guidance on battery charging (below) for information about safely charging lead acid batteries. "

Health Concerns with Batteries - Battery University
"Over-charging a lead acid battery can produce hydrogen sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs. ... Being heavier than air, the gas accumulates at the bottom of poorly ventilated spaces. Although noticeable at first, the sense of smell deadens the sensation with time and potential victims may be unaware of its presence."

https://www.concordia.ca/content/dam/concordia/services/safety/docs/EHS-DOC-146_LeadAcidBatteries.pdf
"2.2.4 Bad Odors
Over-charging a vented lead acid battery can produce hydrogen sulfide (H2S). The gas is colorless, very poisonous, flammable and has the odor of rotten eggs. Being heavier than air, the gas accumulates at the bottom of poorly ventilated spaces. Although noticeable at first (olfactory detection between 0.001-0.13 ppm), the sense of smell deadens the sensation with time and potential victims may be unaware of its presence. When the odor is detected, one must turn off the charger, vent the facility and stay outside until the odor disappears. Refer to Section 2.4.2for proper charging safety tips."

What hazardous gases are associated with lead acid battery charging stations? | GfG Instrumentation
"Lead acid batteries are used to power forklifts, carts and many other types of machinery in many industrial settings. Many facilities have charging areas where multiple heavy duty lead acid batteries are recharged at the same time. In some cases facilities maintain large banks of lead acid batteries that are used to provide backup power to critical systems during an emergency. Fire engines, HAZMAT and emergency response vehicles frequently include banks of lead acid batteries for the same purpose. Gases produced or released by the batteries while they are being charged can be a significant safety concern, especially when the batteries are located or charged in an enclosed or poorly ventilated area, or on the truck.

Sulfuric acid contains sulfur, and hydrogen sulfide (H2S) is a possible by-product of over-charging and battery decomposition. ...

Overcharging, especially if the battery is old, heavily corroded or damaged can produce H2S. Deteriorated, old or damaged lead acid batteries should be removed from service, as damaged batteries are much more likely to be associated with production of H2S."

Hydrogen sulfide in VRLA cells
"... First, VRLA cells produce significant amounts of H2S even at normal float voltages. Second, the lead dioxide in the positive plates absorbs much of this H2S. Third, this "H2S cycle" in VRLA cells results in an equilibrium concentration level of no more than 1 ppm of H2S in the gas space of a typical cell. ..."
(The kicker here is non-typical events.)

 

I'd like to, but shipping is more expensive than the Battery itself

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