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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

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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.


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
 

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This is a very super long post
I don't mind the length, it's easier than having to pester you back and forth for sufficient details...

But you seem to have skipped the basic introduction of what you're trying to do and just jumped into the middle of the technical problems. I'm not sure I follow what you're even trying to do.

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.
I can't tell whether you're trying to upgrade the NiMH and add a lithium traction pack, or whether you're talking about replacing the starter battery with a lithium one.

You say you're wanting MPG gains, but then you're also talking about a stereo that can't run on 16v?

You're a bit all over the map here.

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.
Well, does the Prius even have an alternator?

I somewhat presume it doesn't.

Instead it has, built into the inverter block (I believe on the underside), a DC-DC converter that puts out maybe 13.8-14.4v, something like that, and has about a 100-120 amp max. Some guys have used them to power small 12v cabin heaters in conversions.

So, ballpark, something around 1000 watts is the capacity of the DC-DC converter.

You're building a really loud 10k ... (kW?)... audio system, when your ability to replenish your starter battery is 1000 watts.

First up, there is no liar more liary than the liars who lie about the power of car stereo systems. I used to sell car stereos, it's the name of the game. And that was before everything was made in China, so now you have Chinese Watts to lie on top of the usual marketing lies. For all you know, 10,000 watts is actually like, 2,000w but everyone's so busy circlejerking no one wants the show to end. Basically anything that anything says for spec is a big ??? block you'd have to actually measure for it to be useful.

Second, how do these people power their stereos in a normal car, that'll have like, a 2000w alternator max (and more like, 1000-1500w)? You'll have the same problems they will. And similar solutions (including... none... if the specs are straight up lies).

Third, you're mostly positive that the stereo is discharging the HV traction pack to feed the stereo? I'd say that's unlikely. MG1 alone can put out roughly a hundred times as much power as the DC-DC converter can take. Maybe a couple hundred times as much. MG2 can do 1.5x what MG1 can. Even in Toyota spec use, it's gotta be 10x. So, while the DC-DC converter is powered by the HV bus, the limitation certainly isn't how fast power can be shoved back into the HV. It's certainly limited by how much power can be converted by the DC-DC converter. If MG1 can't juice the HV pack fast enough to keep up with a measley 1000 watts, it must mean you're pretty much flatlining the engine (or idling it? maybe it can't pull enough power without cranking up? I'm not sure about the normal operation of a Prius), or needing the power for something else.

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?
3000W RMS is ~4 horsepower. Travelling highway speed uses ~20hp. So, sure, expect to see 20% drop in your MPG. The energy has to come from somewhere, it comes from the engine.

I believe the 12v DC-DC converter will operate as low as ~120vdc input. On a ~215v pack, you're unlikely to see that unless you've strangled the HV pack entirely.

That said, the capacity of the entire HV pack is barely more than the capacity of your starter battery. It's like, 1200 watt-hours.

So if you're pulling 3000 watts, on a DC-DC designed for 1000w... it's going to murder your starter battery by 2000w constant discharge (dead in, oh, 15 minutes when accounting for Peukert limits?). Even if magically you could pull from the HV pack (which you can't), it would buy you perhaps another 15 minutes before you car shut down (DC-DC gracefully chokes, and the car can't run without it).

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.
You're missing words in there somewhere.

You're gonna add a lithium HV pack?

Your concern is to actually increase MPG, or, the Prius' battery capacity display % that is telling you its MPG?

The method the Prius uses to determine MPG, I don't know. But I suspect it's smart enough to actually know how much fuel is being used. So, it wouldn't matter if you gave it a gigantic 100kw pack, the MPG should be accurate to actual gas being used.

The method the Prius uses to determine how full the HV battery pack is, I also don't know. But I suspect it's very simple, based on its voltage. I doubt it's counting amphours in, amphours out. So, I suspect that if you add a giant HV pack, it will just make the voltage drop slower, and thus, the % will be roughly correct. Except that it'll follow NiMH chemistry discharge profiles, so, it might be quite rough.

If you ignore that, and just care about actual gas mileage... adding a battery pack is not going to improve your MPG significantly. The energy still has to come from the engine burning gas. So, you might save a little bit more by running at an even gentler and more efficient RPM, or, from regen (typically 3% in city use, which you might get a tiny bit more to), maybe if you have longer downhills than the Prius pack can absorb. Maybe a tiny bit more from chemical efficiency by now pushing the cells as hard. But, we're talking low single-digit % improvement, if even like... 1%.

If you're turning it into a plug in hybrid, and you want to charge it directly, and you have a big pack, then okay, yeah, you're gonna see some big MPG gains. I don't know how efficiently the Prius functionally idles at, but, that's probably pretty close to what you'd be doing.

From everything I’ve read online it’s because it can discharge / recharge to a higher amount over the stock nimh.
What is "it", and what does "recharge" to a "higher amount" mean? Too many wishywashy terms without asking what you're asking. Can't usefully answer.

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.
I... really don't know if all this super sleek upgrading you're planning on doing is going to have more than like... 0.001% improvement in anything. Sounds like a waste of time, unless you're doing it for fun.

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.
So, typically in EV conversion use... no one is adding up Resonix Butyl Rope and, jeez you're making a lot of non-upgrades you think are going to help.


The inverters have been tested to handle 600v, and 250A out of MG1, 350A out of MG2.

But, that's a different story than when you still have your engine hooked up. The boost module (which is only occasionally engaged), juices you up to 500V. So, that's fairly normal. But I don't think the transaxle will generate that.

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.
Waste of time. The inverters are liquid cooled. Adding air cooling and screwing with the case is a fart in the wind. You're putting all your efforts into the wrong place.

Add a bigger pump or a better rad.

Are you drag racing with this, or econodriving? You're all over the map. You don't need to do anything if you're just driving normal.

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.
Anything in a car should be able to handle 16v. The battery is regularly up around 15v, they'll have more headroom than that, I hope.

... also, how and where is a 16v starter battery happening? Why?

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
So it's just about the stereo again? Why were you talking about MPG?

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.
Nope, your super awesome stereo is bottlenecked by the DC-DC converter. Any bigger starter battery you add to it is still going to be bled dry and unable to keep up. You want 10,000 watts out of 1,000 watt supply. The battery is like a reservoir, it's not a water supply, it just helps you get through a few dry minutes.
 

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You should scrap that 12V/16V POS kiddy audio system and run the power amp directly off the HV battery, where 10kW is mice nuts (EE technical term, much like the RCH is for ME's)

Your kiddy audio amp HAS TO boost convert the 12V/16V to 283V to put out 10kW into 8 ohms.

So, like the dimwits you all are, all your neighborhood-disrupting Prius clowncars are architected to be charging the main HV battery at several hundred volts, dc-dc converting that down to 12V, then upconverting it in the amp to 283V. At 90% CE per stage, half the engine power is being converted to heat.

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