openinverter forum

Hi Folks,

My project is slowly progressing. It has a GS450H motor and inverter with a Zombieverter to give it the magic.
I am working on the battery configuration at the moment.

I see on the wiki that I can run this from around 300v to 650v but I am curious to know what people are doing.

If you have a similar set up to mine, what voltage are you running and what current are you seeing in the real world?



Thanks,

Andy.

I'll be keeping an eye on this one, so thank you for starting it. My original plan was to use the 400v platform battery from one of my MG4s, 385vdc nom. (416vdc @ 4v per cell fully charged) for the NMC 64kwh battery and 332vdc nom. (360v @ 3.45vdc per cell fully charged) for the smaller 51kwh LFP battery. Gregski shows 345vdc on the battery in his '71 GMC frankenmonster truck, but no idea at what SOC the battery was then ..... another post further down shows it slamming a massive 3.5 amps into the battery and still showing 345vdc, so I'm guessing that's not fully charged voltage.

I know the voltage relates to motor RPM, but I can't remember where I saw a graph representing output shaft speed to battery voltage ....

T1 Terry

There's no real point going above the usual 96-108s standard. In the GS450H setup on zombie Amp draw reduces with increase voltage so you won't find any extra power. But it does make sourcing other HV components harder.

There's people on here who have used them as low as 78s... But basically 72-92s holds true for most stuff gs450h or most inverters we use (108s in more trouble than it's worth as you have to be selective with chargers)

The MG4 battery pack is 104 cells, to add another 4 NMC cells to make a 108 cell pack only increases it to 432v fully charged, hardly worth the effort, but 2 x 92 cell LFP battery packs in series produces 625v fully charged at 3.4v .... it does involve 2 isolated 320v chargers if you were looking to do it from 240vac mains, but is it worth the effort and cost ..... it would be easier on the cells because the peak current draw would be less, I'm assuming that if the L110 transmission can handle the 650vdc then it can also regen that voltage ......
So, I guess the question is, has anyone actually tried it to see if it can handle that sort of voltage?

T1 Terry

T1Terry wrote: ↑Sat Aug 16, 2025 12:39 pm So, I guess the question is, has anyone actually tried it to see if it can handle that sort of voltage?

You seen the Silent Classics datsun? thats over 600v.

Rest of your post adds zero to this thread also is very inaccurate and very disjointed. Please keep it on target.

Thank you everyone.

That's all very helpful


Cheers,

Andy.

The beauty of this unit is that it will run very well on a very wide range of voltages, but your best bet is to aim for the standard 96S (approx 360V nominal). This provides the best balance of safety (you're more likely to blow up the inverter and yourself at higher voltages), and torque (400V is enough to give you full torque at highway speeds). I've seen people running it at 360V and at 600V and both were monstrously powerful at a wide rane of speeds. Above 500V you are at a considerably higher risk of failure, and you will reach the mechanical limits of the gearbox long before needing more than that. On the lower side, I don't know much about it, but I would avoid going too much below 300V.

tom91 wrote: ↑Sat Aug 16, 2025 1:13 pm You seen the Silent Classics datsun? thats over 600v.

Rest of your post adds zero to this thread also is very inaccurate and very disjointed. Please keep it on target.

OK, I'm always ready to be corrected where is the information inaccurate .....

The disjointed part is because it would seem like talking down to anyone reading the thread after reading my previous post explaining the different MG4 chemistry cell voltages, both batteries are 104 cells and both battery packs have individual cell voltage sensing and cell balancing, even if it is the very slow resistor discharge method, and the charger works with this BMS (Battery monitoring/management system).
2 x 92 cell LFP MG4 batteries, series, connected complete with the 2 x MG4 BMS and chargers, would give a 625v battery and answer the post @rstevens81 put forward about chargers and BMS systems ......

T1 Terry

LRBen wrote: ↑Sat Aug 16, 2025 8:06 am There's no real point going above the usual 96-108s standard. In the GS450H setup on zombie Amp draw reduces with increase voltage so you won't find any extra power. But it does make sourcing other HV components harder.

Just to update this post with new information. This post I made is incorrect. The GS450H will pull all the amps whatever the voltage. As for how that affects the life span of the inverter I couldn't say. But I will say it's not the original inverter we installed into the 650v project, or the 2nd.