3rd gen Prius inverter question hybrid battery power draw and LIFEPO4 & LTO

So you're going to build a new HV battery, using these 12, 14 or 16 volts high amperage modules that cost $1000 each? You're looking at $14,000 to buy 14 modules? Each module is more than 3x wider than 1 block (2 modules) in the original battery?

 

i'm wondering if you'd get more audiophiles in the audio forrum. i realize there is a lot of electrical technology going on here, but a lot of those folks deal with it every day, albeit, perhaps not to this extent.

 

I am pretty damn positive it will draw power from the hybrid battery throttled by the vehicle dc to dc converter built in to the inverter as soon as you go to Ready. It won't wait until the 12v is drained.

See comment above.

1. Your custom hv lithium battery won't work. You have a passing knowledge of the reason why; you need a custom battery ecu to emulate the standard battery charging algorithms while converting that strategy to one that works with your lithium chemistry.

2. If your main goal is supplying adequate12 vdc amps to charge supplemental 12v batteries for the 10k rms audio system, you will be limited to the extent the Toyota inverter can supply it. Typically that limit is around 100 amps once you factor in the vehicle loads. The solid state dc to dc in the inverter is not as expandable as discrete alternators can be.

3. Otherwise you might need to add a hv voltage dc to dc converter directly to the hv battery. Given money is not a big consideration, you could go with the projectlithium hv battery upgrade to add a little capacity. The downside of a supplemental dc to dc is the size and extra protection devices, cabling and connectors.

 

Retail is "insane" but 7k is "measly"..ok, you're the one that posted the prices, not me. I apologize if you got offended if you took my questions as if I were saying you couldn't afford it. Idk or care what you can afford or can't afford. nbd, we all have different hobbies...

Having built a few of these hybrid batteries and having tried some of my own battery experiments, I suppose I was just curious if you've actually really looked at the size difference. Apparently you have a significant amount of equipment in the car already. The prius has a limited amount of room available. Trying to fit the equivalent volume of 3 or 4 HV batteries, associated housings, additional cabling and ventilation ducting, etc seems like it shouldn't be left to chance. Have at it my brother. I think you're right, the 12v models should work great.

 

Wow, this post of yours is total chaos... If you want us to help you gotta edit and simplify. You could literally make 5 different posts about the amount of things you're asking in this. Let's see what I can help with:

--When you push the power button the 12v turns the car's computers and also some relays that turn on hybrid battery. The Hybrid battery is a high voltage system ~220v DC and it sends a 14v signal to charge the 12v battery. This charge going to the 12v is weak sauce and you'd have to go on a 10 hour drive to get it fully charged. That's where your problem is. There's a trick or two to boost this charge going to the 12v, but not by much, mostly just tricking the system into thinking the battery needs more charge than normal.

--Your Project Lithium pack is designed to match the parameters that the Prius battery ECU accepts as normal. If the pack was designed for maximum amps or greater capacity you'd get a red triangle and it'd go into limp mode. The magic in Project Lithium is it gives you all the benefits of a far more advanced battery chemistry in a tiny package that makes the Prius think it has a normal NiMh with slightly more amps and faster recharge rates.

--Same thing with boosting the electric motor to handle more power. Unlike Honda, Subaru or BMW there is no piggy back chip, no hacked source code. It's all locked down with no access to change settings. And almost all upgrades will turn into a red triangle and limp mode. Toyota Racing Design was successful at massively boosting power in their Prius mods because they had access to the source code / settings and us DIY Toyota folks don't have access to that and we aren't a large enough community to reverse engineer the firmware to control settings. You have to switch to Honda, Subaru or BMW to do that.

--Your comments keep confusing the 12v DC system the car runs everything versus the hybrid battery's 220v DC system that the inverter and motor-generator run on. There is a way to tap into your 220v DC and power your house or your sound system and these folks offer the best, but most expensive solutions: HOME | PlugOut Power, Generator for hybrid vehicles | United States Or you can just use an inverter off the 12v.

--As someone who grew up working car stereo installation jobs and also owns a recording studio with pro-audio rack mounted gear I can assure you that no matter how expensive your car audio gear is, it has an awful signal-to-noise ratio and is overpriced junk. What's more putting a huge amount of speakers and amps into a tiny metal box on wheels that drives on bumpy roads with the usual license plate rattle is the exact opposite of a high quality sound system and the annoyed look on everyone's faces when you drive by with your music too loud reflects that. In other words the entire car stereo industry that gets people spending tens of thousands of dollars is a massive scam that sells low quality equipment and depends on folklore, not science to sell "quality" products.

--Getting back to how to power your sound system without wasting money or draining down your cars existing 12v I'd recommend buying a second 12v AGM like this one for $117: https://ebay.us/5n8222 and also buy a 12v battery charger that can push 8 to 10amps to keep both 12volts in the car charged up while not driving. You could connect them or add some switches to have different connection options or keep them seperate. But keep it simple.

--Any type of expensive 12v Lithium battery alternative is going to require a battery management system (BMS) to prevent over charging or too much discharge. Some of these 12volts are so expensive they probably have a BMS built in to them but I don't know the market well enough to suggest one. If you don't want your Prius exploding and catching on fire, you have to have a (BMS) or just use traditional Lead acid based battery.

 

Not to mentioned, lithium titanate is the least efficient of the lithium family. Your FE will go south, it would be wiser to get a non hybrid / EV for that application

 

Keep in mind, his plan is to build an HV battery using 14 of these high capacity batteries in series, and also have separate individual cables connected to the (-) and (+) of each module, each set supplying power to a 12v amplifier. So there would be 14(?) sets of additional cables connected to the battery pack. This is where DIYers with no real wire biter experience run into significant problems.
A couple significant problems to overcome, but I'm sure it'll get figured out since cubic buttloads of dollars are available. May want to start with overcoming a P0AA6 and potentially cross connecting the HV system with the 12v system.

Although the desire is to use the 12v modules, when I multiply 12v x 14 modules, I come up with 168 volts, but maybe I'm doing something wrong. 14v modules? That's somewhere around 196 volts? 16 volt modules? Somewhere around 224 volts? Maybe the actual voltages are higher when in service. First and second option, the car would probably spend it's entire life trying to charge them up to the normal voltage range expected for NiMH modules. The third option? The car may spend it's life trying to discharge them....idk...going to be tricky. Seems to me the only ones that would have a snowballs chance would be the 16 volt modules, but maybe with the 12 since it matches the amps better and then just use 18 modules to total out the series voltage to 216v or so. Then all that needs to be figured out is how to connect all the voltage sensing tabs to fake out the ecu. Maybe just create a voltage divider circuit that provides equal voltage drops for each tab. This way the tabs wouldn't even have to connect to the battery modules.

 

I agree that this is the most important point. I'm still not convinced OP doesn't has the difference between their 12v system and their High Voltage system sorted out in their own head, let alone in their actual vehicle. But if they got big money to spend on this I'd be eager to assist as much as possible...

 

How long does the 10k rms audio system need to run for?

Will that output be SPL or SQL?

When the end times call for a mobile sound cannon instead of a microwave cannon, nothing is off the table

 

The irony of course is that the actual music being played on the sound system was created with an emphasis on equipment designed for lowest possible signal to noise ratio. Yet the car stereo enthusiasts have so much non-musical noise in their vehicles that they instead rely on how "powerful" the sub woofers are and in competitions they even have to sit on their own windshield to keep it from popping out because their RMS is so massive:

"Root mean square or simply RMS watts refers to continuous power handling of a speaker or a subwoofer or how much continuous power an amplifier can output. RMS values are usually lower than peak watts ratings, but they represent what a unit is truly capable of handling." RMS and Peak Watts: What's the difference? - FAQ techformusic

 

The way I read it, after reviewing these and earlier posts, is he intends to create a bigger hv battery than factory or project lithium for his Lexus hybrid. It would be nice if he shared a block diagram or more detailed design drawing to aid understanding.

The hv battery would be larger physically and have more capacity. He seems to understand the role of the inverter and its dc to dc somewhat but believes increasing wire sizes will make the inverter capable of handling more power. Sort of the audio power paradigm.

Instead of paralleling four or more high capacity 12v batteries to handle the 10,000 rms watt amp's instantaneous power requirements, he wants to tap into the custom hv battery, cell by series cell and drive stock 12v high power amp(s). Typically there would be two 5k amps.

He has ideas that custom code is available and can be configured to make the larger hv battery ecu compliant to the rest of the vehicle. Perhaps he wants to modify the hybrid inverter code as well. New hv battery design, modified factory hv wiring, inverter modifications, all to power 12v inputs of large audio amp(s).

Plus there is the issue of tapping into the new series connected hv battery cells to feed 12v while somehow overcoming their massive common mode voltage differences to ground and to each other.

While still terminating to common amp power terminals.

It would be a significant engineering feat if this is accomplished successfully as described. All to avoid additional 12v batteries at a small fraction of the cost and complexity.

PS... Perhaps we will find out he is a top level automotive ev engineer spooling up for the soon to be hot gen3 ev conversion trend.

 

Where did you get that information from? They are actually the most efficient as far as power in/power out when it comes to high current draw, the weak point is energy density, they weigh more than LFP cells of the same Ah capacity, but actual Wh delivered at a high current draw and the Wh accepted at a high current rate, far exceeds a much higher capacity LFP cell .... so it really depends on what figure you want to do the comparison .... Watt Hours is the actual ability to do work, not Ah

T1 Terry

 

Sorry Trunks9us, I really did try to read all the way through your post, but there are so many wrong assumptions it became impossible to follow.

MG1 generates 3 phase AC power, not DC power to charge the 12v DC battery.

The current the system can recharge the 12vDC battery or any aux battery is limited by the DC to DC converter, push it too hard and it will burn out.

You can not pull power from 2 modules of the traction battery without putting the whole traction battery out of balance

The traction battery modules are only 6Ah, they would power what you want to run for a few minutes at best, then they would be flat.

Peak current draw has little to do with the actual continuous current draw that would be required power your audio equipment for any length of time.

If, and I mean if, you want to power this audio system at 14vdc nom. you will need to build a 6 cell LTO battery with at least 50Ah capacity,
and
fit a power supply filter to deliver the amps you require at a steady 14vdc
and
fit a DC to DC charger that can handle between 200vdc and 250vdc and deliver a constant 14vdc at more than the continuous current draw required to power your audio system.

Remember, the peak to peak audio output requires a lot of power, the bits in between don't, you will be creating a rippled DC at the audio input without very big capacitors, and rippled DC is just square wave AC and will destroy your amplifiers

More time required studying audio power supplies needed, then you will have a better idea of just how big the challenge will be .... it can be done and is being done at the big sound off competitions, but it requires mega $$ and double mega understanding of just what you are doing

T1 Terry

 

The wiki article is significantly accurate although some assumptions are incorrect. Some issues are terminology but I would not use it as an engineering reference for your project. There is a professor at Weber State University that has better material on his youtube channel.

For the best understanding you need to start at the beginning of his playlist but this is a reasonable example:

Finally Toyota is rather secretive around their patents and are certainly locked down with their software which really makes these things work.

PS Hopefully you are a Texas A&M engineering student trying to come up with a Masters thesis or PHD dissertation without alerting the prof your research is Wikipedia and Priuschat.