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Tuning the Lithium cars for more IMA power.

10257 Views 101 Replies 10 Participants Last post by  PeterPerkins
Tuning the Lithium cars for more IMA power.

You will have seen my long thread on tuning the Nimh system for more IMA power.


In that I hacked the current and the voltage to double the motor Kw output. It was very lively. :p

It involved swapping in a Lithium car inverter and dc-dc converter and using the cars original Nimh BCM/MCM module along with an up-rated 200A fuse.

So what can we do with the Lithium cars?

Well we can hack the current in exactly the same was as we did for the Nimh setup.
This will likely get us another 5-7kw or so. Taking us to ~20kw+...

The voltage is more tricky in the Lithium cars especially if we want to keep the Lithium control modules.

The Lithium MCM/BCM gets it's voltage data from three places.

1) The four BMS CAN boards on the pack.
2) A HV input into the BCM. (We can fake this as per Nimh with a very low current HV supply)
3) Serial data from the IPU IGBT module. (We can fake this as per Nimh)

So to tackle 1)

Can we make an interceptor type device that will send out perfect 75% SOC equivalent cell voltages on the CAN bus?
I'm saying 75% as at that voltage equivalent about 3.8V per cell the car will allow full assist and regen.

Yes I think we probably can fool the voltages, but this only gets us to around 190V which is where the OEM Lithium DC-DC and IGBT module max out.

To go higher we might need to use the HCH2 DC-DC which goes to 220V and possibly the HCH2 IGBT module which probably goes to a similar voltage.

That should get us firmly in the 30kw+ camp with a suitable battery pack.

Now to go even higher we need more voltage.. :eek:

So what IMA cars have higher voltage packs?
Do these dc-dc converters and inverters use the same data stream for control as the CR-Z etc? I bet they are similar.

So would a CRV 2019 or Jazz dc-dc and inverter work in a CR-Z????? Only one way to find out..

But before I start buying expensive parts.........

I'm going to need access to the Honda workshop manuals for these later models to check specs and wiring for compatibility.
Does anyone have current Honda subscription access to this data? Can you message me please.
If people want to support this research in some other way then feel free to message me.

Have a good Christmas and Thanksgiving etc. Peter UK
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A hunch... :unsure:

I'm following a bit of extrapolation and suspicion here but I suspect the HPD IMA tuned 30+kw CR-Z was basically using a hacked HCH2 IMA setup.

I've been studying the workshop manuals of the CR-Z and the HCH2 IMA side and the basic signals all seem to be present in the right places.
The CAN data on IMACAN & FCAN looks very similar so I am suspecting an HCH2 battery/control assembly might actually work in a CR-Z.

The HCH2 was a higher voltage setup and I know from testing the DC-DC can take 220V
(Almost double the Nimh CR-Z 100V and +50% over the Lithium 144V version)

So plenty of potential for pure voltage increase power there.

Also looking at the HCH2 phase and current sensors they might be easily fooled with some resistors to allow higher currents as well. Double whammy.

So I'm going to buy a complete HCH2 IMA assembly and plug it into my Lithium car and see what happens!
If it works I'll then increase the voltage and current.

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Just looked at the HCH2 Inverter on the bench and the U,V,W phase sensors and it does look like they can be fooled with resistors to allow higher currents.
Basically they are a 3 x 5v powered 2.5V = 0A bidirectional sensors.

The output can be manipulated by inserting a 220R resistor in series with the output and then 2 x 1k resistor pull up and down to +5V and GND on the output end.
This basically forces the signal to remain at 2.5V more strongly and reduces the voltage swing by about 30%. So for 10A flowing the inverter sees 7A.

So the inverter effectively only sees about 70% of the flowing current.

Basically it says I want 100A but only sees 70A, so has to open the gates wider to let more power through until it sees the 100A
In order for it to command a detected 100A it has adjust the phase control to allow ~140A (+40%)

If we assume a 200V system then 200V x 140A = 28kw = ~37hp

That's a nice increase and the same % as we currently run in the G1 Insight systems.
Of course we can/will likely start with lower % increases and crank it up in +5% or 10% increments until it falls over or blows up!!

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HCH2 = Honda Civic Hybrid gen 2?

What is the IC on the sensor board? If it's got a part number maybe i can find a datasheet for it's pinout.
If the IC on the sensor board is a current sensor using a magnetic 'u', then there should already be an external resistor we can change to scale the output.
It will be in parallel across the current output and feedback pins.

I'd suggest we use a digital variable resistor in it's place so we can change the % current reading for all three at once.
I agree but the ic is not identifiable on my board. :(
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Can you share an up close picture of the sensor circuit board?

It might follow the same pinout as other current sensors.
On the ones i've used it's been pins 3 and 4.
I was trying to get a look at the MCM and get the part numbers for the uCs off that if you know what they are already that would be a big help to make the MCMs rewritable since i can see some of them have factory updates from Honda in HDS.
I'll post close up pics shortly.

HCH2 = Honda Civic Hybrid Gen 2 (2006-2011)
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The core is split with a little 4 pin hall sensor in the gap. It's marked 9 6G

R8 (330k) and C2 are in parallel and connected to the output to the MCM main pcb.

I agree digital pots would be good.

There are no markings on the main 16 pin IC chip even under the scrapped off goo on top of it :(
The reverse of the pcb is just a big ground plane.

I'm assuming the main IC is some sort of OP amp?
Pin 1 appears to be bottom right in the pic.

The circuit appears to have some temperature compensation going on as well with VR1 & 2...
It will get quite toasty in the working inverter and the sensors could see 100C variation between below freezing and nearly boiling.

Passive circuit component Circuit component Hardware programmer Electronic component Electronic engineering

Gas Metal Auto part Machine Screw
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The 5V powered battery current sensor feeds into the BCM module and has two outputs that both sit at 2.5V when no current is flowing.
I'll have a look at one of those on the bench in due course as all the current sensors have to be in sync or the car will detect an imbalance fault.

So if we fool the phase sensors by -30% then we have to do the same with the battery current sensor.
I'll post close up pics shortly.

HCH2 = Honda Civic Hybrid Gen 2 (2006-2011)
You sir are a gentleman and a scholar.
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The main IC in the HCH2 inverter (marked with green line) is marked 64F7047F40V looks like a RENESAS CPU similar to the attached pdf.

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There is a write enable line on the main harness connector so it can probably be reprogrammed via the CANBUS and HDS...

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I can just see on the other phase sensors that it is a STanley? chip and numbers are 0540A1 0622 M56
Probably an OEM specific id. I note ST do do some quad 16pin op amps.
The first thing Ineed to do is get a complete HCH2 IMA assembly and see if it works in the CR-Z then I can start hacking it for more power!
The main IC in the HCH2 inverter (marked with green line) is marked 64F7047F40V looks like a RENESAS CPU similar to the attached pdf. View attachment 69805 There is a write enable line on the main harness connector so it can probably be reprogrammed via the CANBUS and HDS...
OK I'll look into this in the morning. It looks like the part number for the hch is 1b100-rmx right. Should be easy to pull apart the factory update and extract a partial rom from it. Hopefully from there I can get the whole dump from the mcu.
More cross checking and seeing what is possible today while I wait to acquire an HCH2 IMA setup.
I'm also cycling an old HCH2 pack I had in storage for the testing.

It looks like the HCH2 IMA setup will plug straight into the CR-Z wiring harness with perhaps only a minor pin swap on the HCH2 connector. (y)


If this does work then in a Nimh car it would be an immediate +50% IMA boost compared with the stock 100V pack in the early cars. ;)
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More cross checking and seeing what is possible today while I wait to acquire an HCH2 IMA setup.
I'm also cycling an old HCH2 pack I had in storage for the testing.

It looks like the HCH2 IMA setup will plug straight into the CR-Z wiring harness with perhaps only a minor pin swap on the HCH2 connector. (y)


If this does work then in a Nimh car it would be an immediate +50% IMA boost compared with the stock 100V pack in the early cars. ;)
So i found some tables, not all of them, because im missing a lot of context in the disassembly because of the lack of the first 0x10000 bytes, as the factory updates only provide the updatable data and not the rom in its entirety.

i only found about 20ish tables, i feel like there should be well over 100 tables even though its only a 256kb rom. If i had one, i would probably be able to dump the whole rom. Is 0x18dA02f1 the address of the HCH?
So i found some tables, not all of them, because im missing a lot of context in the disassembly because of the lack of the first 0x10000 bytes, as the factory updates only provide the updatable data and not the rom in its entirety.

i only found about 20ish tables, i feel like there should be well over 100 tables even though its only a 256kb rom. If i had one, i would probably be able to dump the whole rom. Is 0x18dA02f1 the address of the HCH?
Also i did find the security handler, and should be able to modify hts to be able to dump/edit these roms.
So if i can get my hands on a willing participant, should be able to dump and rewrite them easily
So if i can get my hands on a willing participant, should be able to dump and rewrite them easily
When I have finished at my end I could send you the inverter pcb and connector so you could probably power it up and connect it to your HTS...
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@da-coder I could send you a phase sensor if you want to play around with it on the bench and see how you can modify (reduce) it's output.
@da-coder I could send you a phase sensor if you want to play around with it on the bench and see how you can modify (reduce) it's output.
With how simple the circuit is, i don't think i need it in person. I think it's a 3 layer pcb. Could you desolder the IC so i can see the traces underneath it?

It's got to be a quad amp but i can't see where the outputs go.

Is it an open loop or closed loop sensor?
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