Simple Precharge Circuit

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T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

Great find Alex, can you tell us where on the Prius this part is located? I can see a trip to the wreckers on the horizon :lol:

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Re: Simple Precharge Circuit

Post by francisco.shi »

You should also have a time out so that you don't blow up the resistor if something is wrong. You can also monitor the voltage from the inverter and do not close the contactor unless the voltage in the inverter is above a certain voltage and the rate of change in voltage is below a certain value.
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Re: Simple Precharge Circuit

Post by Bukes »

Thanks Francisco, I’ll code something up and share it on here. Might even set up an AEVA git repo at some stage, if there isn’t one already?
Terry they’re on the end of the battery. I found 2 of the older 144V 6.5Ah packs for $300 each at a country wreckers. They’d taken it out and didn’t really seem to know what to do with it. The inverters were still in the car so I took one of those too (also $300). Cheaper than I can find them on eBay, paid in cash and took them out myself (saved them the labour). Took the whole HV harness with them, and the water pump too… Was a fun morning!

Precharge module on the end of the battery stack - you need to remove the battery case to get to it:
BBFC7805-4FCD-4C1D-AD2D-11AB38EA6F10.jpeg
BBFC7805-4FCD-4C1D-AD2D-11AB38EA6F10.jpeg (2.25 MiB) Viewed 1148 times
T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

Bukes wrote: Tue, 12 Apr 2022, 22:03 Thanks Francisco, I’ll code something up and share it on here. Might even set up an AEVA git repo at some stage, if there isn’t one already?
Terry they’re on the end of the battery. I found 2 of the older 144V 6.5Ah packs for $300 each at a country wreckers. They’d taken it out and didn’t really seem to know what to do with it. The inverters were still in the car so I took one of those too (also $300). Cheaper than I can find them on eBay, paid in cash and took them out myself (saved them the labour). Took the whole HV harness with them, and the water pump too… Was a fun morning!

Precharge module on the end of the battery stack - you need to remove the battery case to get to it:
BBFC7805-4FCD-4C1D-AD2D-11AB38EA6F10.jpeg
What model, they are not mounted there on a Gen 2 .....

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Re: Simple Precharge Circuit

Post by Bukes »

Hmmm, is yours the 28 module one? These are only the 20 module (144v not 200v)
In the 200v that I have, the precharge components are wired together rather than combined inside an assembly.
This is a pic of the base of the 200v / 28 module traction pack with the battery removed - the precharge components are on the right side:
D2E903C9-8AC3-44BF-93C8-8FA467679F13.jpeg
D2E903C9-8AC3-44BF-93C8-8FA467679F13.jpeg (3.4 MiB) Viewed 1117 times
It’s the same components (although possibly beefier, I haven’t confirmed yet), just mounted individually and wired together, instead of placed in an assembly with bus bars.
T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

Ahhh, yes, the wife still needs to find where she "put them away" from the last battery pack I stripped out. The ones from the battery that went up in flames aren't real healthy looking ...... warning, have a charging cut off that stops at around 8.5v and a load cut at between 5v and 6v ...... it only takes one weak cell in the module to go over voltage and produce loads of hydrogen and oxygen ..... till it runs out of electrolyte, then the plates buckle and short creating that much needed spark to ignite the whole gas cloud .... dramatic to say the least :shock: :o :twisted: :oops:

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Bukes
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Re: Simple Precharge Circuit

Post by Bukes »

Holy crap, a lot more “bangy” than a lithium fire, I’m guessing!
T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

Not that bad, nothing like the "RIP Miss daisy" Tesla battery fire. More like a blow torch burn out of each affected module and buckling of all the modules, both vertically and horizontally, enough pressure to buckle the steel outer case and bust the retaining rods/bolts out of the end covers. Even though the modules are bolted down to the bottom of the steel casing, they ripped the threaded bits out of the modules in the rush to buckle up into the top of the case.
Fortunately, the terminals are on the ends of the modules, otherwise there would have been a big arcing fire as well when it tried to melt the steel cover sheet .....
The volunteer fire people made the most mess, emptied a 9kg dry powder extinguisher in there, even though I'd already put the fire out using one of those small car sized extinguishers .....
Exposed exploded traction battery.jpg
Exposed exploded traction battery.jpg (125.19 KiB) Viewed 1080 times
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antiscab
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Re: Simple Precharge Circuit

Post by antiscab »

that fire extinguisher powder is pretty corrosive too I've found
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T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

The fire melted holes in the computer mounted at the end of the battery so I'm guessing the dry powder finished that off. All the other bits have cleaned up on a wire wheel and I'll nickle plate the links between the modules before I use them. The powder did attack the coating on steel cover plates though and I've still gotta get it out of the car and the seats etc. Lucky the insurance company called it a write off and paid me out, less $2,000 they wanted for the wreck as a buy back.

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Re: Simple Precharge Circuit

Post by Bukes »

Have you still got the transaxle? Apparently a bit of welding on the planetary gears and they make a pretty decent electric motor. I’m about to get into the prius inverter as well - supposed to be good for 300 kw
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Re: Simple Precharge Circuit

Post by T1 Terry »

I'm resurrecting the Prius using a 2P28S battery built from recycled modules to improve the regen capacity.
You wouldn't happen to have a spare battery computer you could sell me? Seems the wife can't remember where she tidied away the bits from the last battery pack I removed from the silver Prius not long after I bought it. These were the modules I brought back to life, they'd had 14 yrs service life and around 285,000 kms. I managed to buy a full replacement battery from an Adelaide wrecker for $400, not a hope of finding another bargain like that these days.

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T1 Terry
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Re: Simple Precharge Circuit

Post by T1 Terry »

The Gen 3 and Camry trans-axle along with the Lexus seem to be the better choice because they have two planetary sets and a much higher rpm capable MG1 and most of the inverter upgrades are for the gen 3 forward.

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Re: Simple Precharge Circuit

Post by 4Springs »

Bukes wrote: Tue, 12 Apr 2022, 22:03 Might even set up an AEVA git repo at some stage, if there isn’t one already?
I think I understand this sentence in general, would you mind spelling it out? I may be able to help.

If you'd like a place to store files, to give access to anyone, the AEVA website can do that. I can give any AEVA member access to upload files. We could create a web page (or forum post) to index them. A file can be updated without breaking the link (i.e. the link will always point to the latest version of the file).
If you're talking about a Github thingi, as far as I know we don't have one. I don't really understand them, but if you thought it would be useful then great!

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Re: Simple Precharge Circuit

Post by Bukes »

Thanks Chris, yep, meant GitHub. It’s just a file share for software dev, lets multiple people work on the same code at once, with special ways of handling conflicts when merging two peoples changes together.
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Re: Simple Precharge Circuit

Post by Bukes »

T1 Terry wrote: Tue, 19 Apr 2022, 09:19 I'm resurrecting the Prius using a 2P28S battery built from recycled modules to improve the regen capacity.
You wouldn't happen to have a spare battery computer you could sell me? Seems the wife can't remember where she tidied away the bits from the last battery pack I removed from the silver Prius not long after I bought it. These were the modules I brought back to life, they'd had 14 yrs service life and around 285,000 kms. I managed to buy a full replacement battery from an Adelaide wrecker for $400, not a hope of finding another bargain like that these days.

T1 Terry
I think I will. I have three packs I will merge into two. Not sure of final configuration yet.

It sounds like you’re building 28S2P not 2P28S though… the latter could get away with one BMS, because the parallel cells would balance themselves.

I understand why - easier to keep the existing battery compression clamps and cases. I wonder though, if you could somewhat parallelise the two packs by adding jumper leads between “sister modules” in each pack?

Hard to explain in words. Im back home in a week so I will experiment with the two 144v packs to see if that works
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Re: Simple Precharge Circuit

Post by T1 Terry »

Definitely 2P28S, 2 parallel modules x 14 in series for each battery pack. Tried the parallel batteries idea between the existing traction battery and the 40Ah LFP extended range battery ..... not a successful venture as far as sharing capacity when the regen is anywhere up to 150 amps under heavy braking, that takes huge cables with the modules only being a max of 9vdc .....
5 LFP cells across each two module pair brings the voltage up to 18v, but a weak module in any series pair brings the whole plan down, the 5 x 40Ah LFP cells will boil the begeesus out of the weak cell in the weak module

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Re: Simple Precharge Circuit

Post by rhills »

Bukes wrote: Tue, 19 Apr 2022, 20:46 Thanks Chris, yep, meant GitHub. It’s just a file share for software dev, lets multiple people work on the same code at once, with special ways of handling conflicts when merging two peoples changes together.
I'd missed this conversation earlier. There has been an AEVA Github "organisation" established. Not much used yet, only a couple of repositories, but it's here.

Cheers,
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Re: Simple Precharge Circuit

Post by Bukes »

Thanks just had a look but my access is very limited (as you might expect!)
No need to change that right now, I’ll pm you if we do end up doing something that can be contributed to the repo
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Re: Simple Precharge Circuit

Post by Bukes »

Rob, I think we should move forward with github, there are a few ideas making a little bit of progress. I've started a repository for one of them, but it might be better if all of the stuff sits with AEVA.

Essentially the way that AEVA could use Github, is if the projects are created under the AEVA organisation (each project created as a new repository), then people can take copies of the project (fork it), add or update the code, then commit it back to the Aeva repo (if they think it is useful for others). The Aeva org maintains control - can approve or reject these changes - and the code is then kept for perpetuity with Aeva. That way as people like me come and go, the ideas and code aren't lost.

Would you be comfortable providing my github account with access to manage the AEVA repo? I think Francisco would be a good person to add (he doesn't have an account, or know github yet, but he will know it by the time we're finished and he has been around here longer than I have)
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Re: Simple Precharge Circuit

Post by Bukes »

rhills wrote: Wed, 20 Apr 2022, 19:50
Bukes wrote: Tue, 19 Apr 2022, 20:46 Thanks Chris, yep, meant GitHub. It’s just a file share for software dev, lets multiple people work on the same code at once, with special ways of handling conflicts when merging two peoples changes together.
I'd missed this conversation earlier. There has been an AEVA Github "organisation" established. Not much used yet, only a couple of repositories, but it's here.

Cheers,
My github UserID is Empala66 - i should be following the AEVA organisation now, so that might make it easier to find me
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Re: Simple Precharge Circuit

Post by rhills »

Bukes wrote: Thu, 12 May 2022, 11:08 ...
My github UserID is Empala66 - i should be following the AEVA organisation now, so that might make it easier to find me
I've tried, but I don't seem to have the permissions to bring you on board. The "Owner" of the organisation, John Clark isn't actually on this forum (that I'm aware of) so it's probably best if you contact him via his Github handle, referring to this conversation (or the other one).

If you have no luck there, PM me here and I'll email him separately.

Cheers,
Rob Hills
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Total Petrol: 872.3L
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