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

Discussion in 'Gen 3 Prius Technical Discussion' started by Trunks9us, Jun 27, 2022.

  1. Trunks9us

    Trunks9us New Member

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    This is a very super long post so I apologize in advance explaining everything and really I only have a few questions but I exaplined the whole situation so I don’t have people comment about this and that I just need answers to my species questions so I laid out most of everything.


    So I’m trying to figure some things out specifically about the inverter and battery power draw.


    The Stock is coming with a nimh and with project lithium have upgraded to using lifepo4 which has been proven to make mpg gains most likely due to discharge and recharge and size availability.


    While I already know all of this and that’s good and dandy I am actually wanting to make sure I am correct on a couple of things.


    Let’s use the example here of what I’m doing

    I’m building a really loud 10k rms audio system and I am pretty damn positive that when the draw from the 12v is drained it start pulling juice from the hybrid battery.


    According to what I’ve seen on my volt meters and gas mpg going down when running about 3k Rms it seems to be what it is doing I’d like to confirm this though does anyone happen to know if the 12v will pull power or better yet will the hybrid batter convert the power to the 12v side when it is low if the mg1 can’t keep up?



    Moving on


    Now my understanding about the way inverter works on the project lithium batteries is the inverter still goes by off a percentage number which is why it was able to get more mpg as well because the lithium is bigger Capacity.


    Now I could be wrong and would like someone To verify or at least explain to me about why they would get higher mpg? From everything I’ve read online it’s because it can discharge / recharge to a higher amount over the stock nimh.




    1. So my real question about the hybrid battery modules since project lithium is using lifepo4 and I and gonna be considering to use lithium Titanate.


    What specs is the battery pulling for the vehicle that’s most important here? Is it the Ah,voltage, watts, current draw? What is the hybrid battery most needed for discharge because the batteries I am gonna use are the XS Power

    Lithium Titanate Battery I just don’t know which thing is most important for the hybrid power draw with these specs.


    These have built in bus-bars for direct bare wire so I can use straight 0 gauge ocf wire and no need to use posts and lose conductivity on those aluminum binding post for the stock hybrid battery.


    Now just so we understand these batteries are made specifically to have high power discharge and recharge for wattage on amplifiers if anyone needs to know of if it even matters.


    This is the 12v 14v16v


    [​IMG]

    [​IMG]

    [​IMG]


    They have 12/14/16 batteries which I am still trying to see which one I would need as well I think I could get away with 12v cells as long as I get the end voltage to match or very close to it since there is actual play on the hybrid batteries. I’ll explain below why I want to use the 12v over the 16v


    I was recording my battery voltages between drive stop and flooring and braking on Toyota techstream tonight and I’ve seen the fluctuations from 14-18v maybe even a little lower than 14 per cell. So I know a 16v battery could work as long as I make the setup match the way Toyota is. I just don’t know if a 12could work with the hybrid batteries.



    I’m trying to not get off topic here but I’d like people to know that there isn’t weak links here.

    Understand everything I am doing has a upgrade it will not just be this hybrid battery.


    The wires from the junction block to the batteries. The inverter internals have upgraded wires on the dc converters 4 gauge everything else is 0 gauge and they are all shielded with 3m 1345 embossed tin copper. Even the 3 phases for the HV MG2 MG2 have 0 gauge wires. Everything I am using is Ofc and copper there isn’t any aluminum involved in this with the exception of the junction block and the relays.


    The junction block will be getting replica made in copper and will be a lot thicker than the thin aluminum block they use for current transfer on the HV wires. All my grounds are all connected together sanded down with a wire brush and everything is all polished as well with a fine wire brush.


    Everything is tied into a distro block so it is all connected together to avoid resistance issues or other weird problems As I said everything is sanded down


    Inverter chassis - ecvt - block - both strut tower ends which is technically (chassis location) - valve cover - both sides of the frame under the car - inside dash metal cage that holds the dash in bolted to the firewall.


    All the ground electronics which all the computer grounds have all been sanded and polished on body and connectors as well.


    Now I know there is a modded logic board that evbmw sells and I’ve been paying close attention to everything and doing a ton of research for the last two years slowly getting things together.


    There is also another site that use modded ecu files as well you can purchase and still revert back to stock for the hybrid inverter.


    [URL unfurl="true"]https://ffffff.ru/toyota_cuw_lexus.php[/url]


    I do also know that the HV / MG1 can be modded to output more than 250v. I’ve read where they been I able to output 400v with some changes on the programming side.


    Truthfully idk what the max the inverter can actually push out voltage wise but I already have the cooling issues solved as well so that’s Also not a concern. The inverter isn’t 100% sealed really.


    I’ll end up using Resonix butyl rope around the hoses ends and the inverter connector points because it isn’t technically 100% sealed on the Hv mg1 mg2 areas. So hot air is still getting thru some which is why I am also gonna be using high speed fans in a Push pull setup with a variable rotary knob I can control flow 100% the time which will make it where it won’t over heat stay a lot cooler.



    Anyways….


    So My amplifiers are running off 12v and I am not gonna get them modded to run 16v it’s A last option for me to do which I’d rather not.


    My real end game goal here is to have the amplifiers hooked Up to the 12v hybrid battery cells one amp per titan8 and leaving the starting battery completely alone. I know these batteries will be more than enough to handle the amps more like overkill at this point. What I don’t know if the safety sensors will be a issue or not


    Doing it this Way will give the amps easy access to power quickly even those they Are all tied in together it still takes time to move power from one battery to another which is why I really don’t want to put All the amps on the one 12v accessories battery unless I 100% know it will pull power from the hybrid when it needs it after it drainsand the mg1 can’t keep up. But even then I really would rather go the route of individual batteries.


    Going this route would also give me the ability to have basically a hybrid that never goes low on battery power this should give me the most maximum mpg it can ever achieve.


    So after typing all this up if someone has answers to my questions I would really appreciate it. Thanks
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    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?
     
  3. Trunks9us

    Trunks9us New Member

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    Seriously man you couldn’t just help yourself to not say anything that answers my questions.

    No why would anyone pay retail price on these especially for what I am doing that’s insane I’m paying that much I know plenty of people to get it formulae the price. And yes $7000!isn’t that much I have over $20k in my system now and it’s not ever done yet so why dominate about a measly $7k when I need the battery power no matter what for my system
     
  4. bisco

    bisco cookie crumbler

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    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.
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    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.
     
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    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...:rolleyes:

    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.
     
  7. PriusCamper

    PriusCamper Senior Member

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    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.
     
    #7 PriusCamper, Jun 27, 2022
    Last edited: Jun 27, 2022
  8. Grit

    Grit Senior Member

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    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
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    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.
     
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  10. PriusCamper

    PriusCamper Senior Member

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    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...
     
  11. SFO

    SFO Senior Member

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    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 :cool:
     
  12. PriusCamper

    PriusCamper Senior Member

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    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
     
    #12 PriusCamper, Jun 28, 2022
    Last edited: Jun 28, 2022
  13. rjparker

    rjparker Tu Humilde Sirviente

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    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.
     
    #13 rjparker, Jun 28, 2022
    Last edited: Jun 28, 2022
  14. T1 Terry

    T1 Terry Active Member

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    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
     
  15. T1 Terry

    T1 Terry Active Member

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    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
     
  16. Trunks9us

    Trunks9us New Member

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    I agree with what you and pretty much everyone else is saying. I am still researching a lot of things I have been for about a year now and have come across a lot of things to do. What I meant by mg1 tho was it powers both the Hv and the 12v is all but i know it’s ac power. I will have to reply to everyone else at a later date when I have more time available. E8867D10-5B34-4AF3-A8A8-8143A32288E3.png F686871E-6A4C-432F-8D05-561CA621C445.png D47D7EF6-9AB3-4D9D-987B-3CBF80EDE168.png AF4B454D-856A-4EF8-BE2C-7C44B3360A59.png DAA251E3-69F3-4517-B85C-1212FE5F5830.png 3C7CFF5C-0373-4E3B-A167-81962F4DB19F.png
     
  17. rjparker

    rjparker Tu Humilde Sirviente

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    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.
     
    #16 rjparker, Jul 4, 2022
    Last edited: Jul 4, 2022
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