[DRIVING] 1979 MG Midget with GS450h and custom battery pack

Tell us about the project you do with the open inverter
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

TheSilverBuick wrote: Tue Apr 26, 2022 6:11 pm Inspirational!

I feel like these projects are simpler to take on for IT/electrically mined folks than us mechanically minded folks, but seeing two concurrent projects going forward with the GS450H is very motivational to figure it out!
Please reach out with questions. I'd be open to chatting with you, too. Happy to help!
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by TheSilverBuick »

I very well might! Today I finally plugged in the Arduino I bought like a year ago. I'm going to start dipping my toes into it's programming language.
Need to learn. Starting from the basics.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

A quick update. Dash is back in with new gauges and all lights working. Turn signals, headlights, hazards, parking, license plate, etc. all good to go. Next steps is center console and some relays to force driver to put system in Park and depress brake to place in Drive. Reverse will be called up by pushing the windshield washer function on the right stalk. Pics attached. Gauges from left to right: Thunderstruck/Dilithium BMS display screen, 500v meter, 15v meter, AutoMeter electronic speedo coming right off the pulse pin of the 450h trans.

Video tour to come after console is built.
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1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

Videos of quick drive and startup sequence


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Re: 1979 MG Midget with GS450h and custom battery pack

Post by montyjohn »

Can I ask, does the regen work with your inverter and VCU board. If so, how does the GS inverter know what voltage to use to charge your battery?
Do you have the program the VCU with your specific battery data or does the inverter just magically know?
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

montyjohn wrote: Mon Jan 02, 2023 8:26 pm Can I ask, does the regen work with your inverter and VCU board. If so, how does the GS inverter know what voltage to use to charge your battery?
Do you have the program the VCU with your specific battery data or does the inverter just magically know?
Regen works great. But, I did not change anything in the code on Damien's VCU board. When I let off the throttle, the torque absorbed by MG2 just routes power back through the inveter to the batteries. And the voltmeter doesn't show a spike. I may be doing it wrong, but I can push 50+ amps to the batteries when coasting from 40mph.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

NEW PICS --

Rust-o-leum paint job complete. Officially 2 full years since I started work on the car.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by robertwa »

Love it. Looking sharp!
Building: 1964 International Scout 80. LS600H transmission with zombieinverter, B250e battery pack
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by PatrcioEV-ATX »

omg, LOVE the paint! If you're ever in Austin and want to talk about the GS450h set up, give me a shout.
1998 Ford ZX2 - DC EV conversion(sold) http://evalbum.com/2093
2012 Nissan Leaf (sold)
2016 Mercedes B250e (sold)
2023 Volvo C40

Current: 1964 Rambler Classic 660 w/ GS450h set up. 36kwh Tesla batteries from B250e.
https://www.instagram.com/rambler_660e/
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by chrskly »

Love this paint job. Looks amazing!
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

Any updates on how well this is working with your code to maintain oil pressure? By locking the input, does that also mean mg1 cannot provide oil pressure? I'm a little confused by this how does mg1 add torque in the locked input shaft situation? Thanks
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

It's working very well. The input is not locked in my application. If it were, I would not be able to make oil pressure without the external pump. Since the input is not locked, I spin up MG1 to make oil pressure, and then once MG2 is above a set RPM, then I shut down mg1. Underway, oil pressure is maintained by the spinning of MG2. There's no need to run MG1 at all or the oil pump for that matter underway in this application to generate oil pressure.

Happy to answer other questions.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

Rereading your post - no, locked MG1 cannot provide oil pressure at a full stop because it's locked to the rotation of MG2. When input is not locked, it can freewheel, able to provide oil pressure at stop when applying torque to it.

When input is locked, MG1 and 2 work together to power output shaft. You will not need mg1 for that MG.... Extra power sure would be nice, but I have all the power I need with MG2 only.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

Thanks, and one other question. Whats the max rpm can you spin mg2 and at what voltage?
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

MG2 I believe has a max of 10K RPM for safety reasons. And you can get there with very few volts as long as it's not hooked up to anything.

I can spin MG2 over 2000 rpm at 30v/10a (300w). It's not the voltage that drives power/rotation under load, it's the watts. Unloaded, you can push MG2 to it's max as long as the supplied wattage can overcome internal friction. Once you put it in a car, though, more torque is required, hence more wattage. The inverter will make whatever volts it needs.

Example, my Midget pulls 250a @ 320v under full acceleration (which I rarely do 'cause it's kinda scary and because my fuses are only good for 300a). That's 80,000 watts. That's a crazy amount of electrical power, but only 107HP doing the straight conversion. You *could* feed the inverter 12v@6000amps to get the same *power* but lord help you trying to wire that up.

So, in this application, you want to maximize volts so that your wiring is practical. (The Toyota inverter can handle up to 600v input I'm told). Lots of tradeoffs. For me, I built a pack by hand out of individual 6ah cells (3.2v LiFePo4). These cells can run comfortably discharging up to 18a and in a burst are good for 60a. I wired 1152 of them in a 12p96s configuration. That gives me 12*18 = 216 safe amps continuous coming out of the battery pack at 307v nominal (I charge the car up to 320 typically and consider 300v "dead"). So, the pack can safely generate all the torque I need at all RPMs I need. Which for me, gets me to 60mph before I lose courage.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

ggeter wrote: Wed May 31, 2023 3:17 pm MG2 I believe has a max of 10K RPM for safety reasons. And you can get there with very few volts as long as it's not hooked up to anything.

I can spin MG2 over 2000 rpm at 30v/10a (300w). It's not the voltage that drives power/rotation under load, it's the watts. Unloaded, you can push MG2 to it's max as long as the supplied wattage can overcome internal friction. Once you put it in a car, though, more torque is required, hence more wattage. The inverter will make whatever volts it needs.

Example, my Midget pulls 250a @ 320v under full acceleration (which I rarely do 'cause it's kinda scary and because my fuses are only good for 300a). That's 80,000 watts. That's a crazy amount of electrical power, but only 107HP doing the straight conversion. You *could* feed the inverter 12v@6000amps to get the same *power* but lord help you trying to wire that up.

So, in this application, you want to maximize volts so that your wiring is practical. (The Toyota inverter can handle up to 600v input I'm told). Lots of tradeoffs. For me, I built a pack by hand out of individual 6ah cells (3.2v LiFePo4). These cells can run comfortably discharging up to 18a and in a burst are good for 60a. I wired 1152 of them in a 12p96s configuration. That gives me 12*18 = 216 safe amps continuous coming out of the battery pack at 307v nominal (I charge the car up to 320 typically and consider 300v "dead"). So, the pack can safely generate all the torque I need at all RPMs I need. Which for me, gets me to 60mph before I lose courage.
Thanks and very interesting. My applications are a large van with a less than excellent aerodynamic profile so the load will be high and ideally I'd like to maintain my current top speed (85mph) which makes the lexus gearboxes a little concerning with regards to achievable top speeds. I'll be looking to drop a 90kwh battery into it to get around 100 miles range so hopefully should have enough juice available to spin at top speeds....

Somewhat confusingly though, you are the first to suggest it's power rather than voltage that's the main driver of rpm, often the claim is volts provides revs and current provides torque but would you disagree with this?
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Pete9008 »

As normal it's never quite that simple, both answers are right!

There are a number of voltage terms that add to give the terminal voltage on a permanent magnet motor, one is the back emf which is proportional to speed but there are others that are due to cross coupling between the D and Q fields and these are proportional to current and speed. This means that the more current you use the less volts you have left to drive the back emf.

There is a trick that is normally done with the voltage due to D current. It turns out that this is in anti phase with the bemf, so if you drive the right amount of D current into a motor it can completely cancel out the bemf making more volts available to drive Q current which allows torque to be maintained at higher speed (this is field weakening). In theory, with no load and an ideal motor, this would allow infinite speed! Unfortunately it can't do anything about the voltage due to the Q current so the moment you add load/friction you end up back in the position where you can either have torque or speed.

If you want to understand this better have a read of the simulator thread. If you can find the motor characteristics it should be possible to use that to get a rough idea what might be possible.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

Large van? Well.... I have a 24kwh battery, of which 15-18 is usable (I don't drain it and I don't charge it completely). I can get an honest 80 miles with those 15kwh in a car that weighs maybe 1700 pounds, and that's only in-town driving with mild regen. At a constant 60mph, my car pulls 60-80 amps and would barely get 60 miles range.

4x the battery and 4x the weight - 100 miles might be attainable, maybe, but not at 85mph. And the input shaft on that Lexus unit would have to be locked to get to 200hp to move that van. So, oil pump for you for sure, and it will need to run all the time.

Also, I'd plan to handle at least 1000 amps in your application.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

ggeter wrote: Thu Jun 01, 2023 3:43 am Large van? Well.... I have a 24kwh battery, of which 15-18 is usable (I don't drain it and I don't charge it completely). I can get an honest 80 miles with those 15kwh in a car that weighs maybe 1700 pounds, and that's only in-town driving with mild regen. At a constant 60mph, my car pulls 60-80 amps and would barely get 60 miles range.

4x the battery and 4x the weight - 100 miles might be attainable, maybe, but not at 85mph. And the input shaft on that Lexus unit would have to be locked to get to 200hp to move that van. So, oil pump for you for sure, and it will need to run all the time.

Also, I'd plan to handle at least 1000 amps in your application.
The current engine is 100hp and 190nm so torque and power shouldn't be a problem just from mg2
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

sounds cool! you'll have plenty of room for that battery pack. what's the vehicle/weight?
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

ggeter wrote: Thu Jun 01, 2023 4:19 pm sounds cool! you'll have plenty of room for that battery pack. what's the vehicle/weight?
It's a mercedes T1 310D (pre sprinter). Currently it weighs about 2.3T, I reckon after conversion I'll be around 2.5T with a few other non EV bits I plan on adding.

Re:battery space, yes and no. The engine bay in these things is pretty small, if I went for a lexus gearbox I'd have plenty of space but the other option is a leaf motor which would take up battery space. Then I'm hoping to get another 2 packs under the van, one on the right hand side replacing the fuel tank and the other on the left, between the chassis rails but it's also a little tight so will need to be a custom built pack. It's a campervan so looking to maintain the internal space as much as possible.

I'd really like to use the lexus is300h gearbox as it's almost perfect but I just don't feel confident enough about reaching 14000 rpm at 400V given the lack of evidence as of yet.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

Nice project!

You're not going to hit 14K because of the 10K limit, if I recall correctly. Why do you need 14K rpm? My rear end is 3.99 and I can get to 60 w/o taxing the RPMs. Just curious. Also, remember the inverter makes all the volts as needed. So, even if you're only running 288v, the inverter will make over 650 if needed to overcome the back emf, etc. Again, just make sure you wire for the amps. I'd think 500-1000 would be a design target for you.

Having made my own pack, I advise you use bolt together modules instead of individual cells and a spot welder... :)
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by Jacobsmess »

ggeter wrote: Thu Jun 01, 2023 8:54 pm Nice project!

You're not going to hit 14K because of the 10K limit, if I recall correctly. Why do you need 14K rpm? My rear end is 3.99 and I can get to 60 w/o taxing the RPMs. Just curious. Also, remember the inverter makes all the volts as needed. So, even if you're only running 288v, the inverter will make over 650 if needed to overcome the back emf, etc. Again, just make sure you wire for the amps. I'd think 500-1000 would be a design target for you.

Having made my own pack, I advise you use bolt together modules instead of individual cells and a spot welder... :)
The gs300H has a 14000rpm limit as I understand.

My rear diff is 4.63 and using the online calcs with a gs300H (gearing of 3.33) I wouldn't achieve 80mph.

Lastly, it was my understanding that to use the inverter it was important to bypass the boost stage, hence no 650V out the inverter and instead running at normal battery voltage, at least when using the zombieverter I guess.
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by crasbe »

Jacobsmess wrote: Fri Jun 02, 2023 3:31 pm The gs300H has a 14000rpm limit as I understand.

My rear diff is 4.63 and using the online calcs with a gs300H (gearing of 3.33) I wouldn't achieve 80mph.

Lastly, it was my understanding that to use the inverter it was important to bypass the boost stage, hence no 650V out the inverter and instead running at normal battery voltage, at least when using the zombieverter I guess.
Don't you think at this point you should start your own project thread instead of littering every thread that mentions the 450h/300h with your questions about RPMs? :?
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Re: 1979 MG Midget with GS450h and custom battery pack

Post by ggeter »

Yes, you wire directly into the inverter with whatever volts you have without using the boost side of the inverter.
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