openinverter forum

Scratch that, reactance is an ac issue, I still feel the inductor is the limiting component and boosting to an even higher voltage will only result in lower current, short of building a 500v battery or a a standalone high powered booster (I have 2spare gen2 boost modules and inductors if you want to try)

I initially had it running at 320V with the booster removed completely and the issue was the same (actually worse, boosting the voltage has increased the performance slightly). I’ve never been able to put any more than 15-20kw through the MGR with or without the booster.

Which mgr model do you have? Q210 or q211 they look pretty much the same but q210 is only 18kw

The RX450H and RX400H always have the Q211, right?

When dealing with used parts I’ve learned not to trust or assume anything, With a little parts catalog digging if it’s out of an rx450h it should have part number G1050-48010

It was supposedly from a 2012-2015 RX450h so should be a Q211 but I can try to double check.

There’s also the fact that Bexander has found exactly the same performance characteristics in his Renault Clio with the MGR. This makes me think that it is not just a problem with my setup. As far as I’m aware we are the only two who actually have an MGR running in a car.

Hmm looks like 2015 on part number is G1050-4820

Confusingly though the early estima hybrid which is supposed to be the Q210 has part numbers G1050-4810, G1050-4820 and G1050-4821 all listed for it

I can’t find an easy way to distinguish Q210 from Q211

Have you considered gearing here? If the mgr in a Lexus on Lexus sized wheels is hitting peak torque at 4000rpm doing 84kph (52.5mph) then It stands to reason that the mgr in a cappuccino with wheels 33% smaller (tyre sizes rx450 235/65/18 and cappuccino 175/55/15) you’ll be hitting peak torque at about 35mph, the reason your not seeing more than 20kw would be down to being so low geared in such a light car, it just doesn’t take the extra current to accelerate, how much current can you pull if you try pulling away with the handbrake on? Unfortunately short of cramming some bigger wheels under there I don’t think anything will help

I did think about that being the issue, I guess it could be the cause if the torque drops off a lot after the peak toque is reached. Just seems a bit counter intuitive to put bigger wheels on for better performance! I think it would be difficult to fit tyres that were much bigger too.

To tell if it is gearing do some low speed full throttle pulls with handbrake applied as much as you dare you should be able to load it right up and pull plenty more than 20kw, be interesting to see the runs with and without boosted voltage then,

At standstill the inverter can send plenty of current to the motor, but hardly any power - because motor voltage is very low at standstill. Power = torque x speed

Yes extra load needs to be applied at a speed approaching peak torque ideally, but as long as you are moving under power you should be able to test the theory.

Posted a testing update in the MGR thread: viewtopic.php?f=14&t=190&p=27588#p27588

Cappuccino update!

It’s been off the road since last summer after the Brusa charger broke. I’ve replaced it with a Volt charger (thanks to Arber) and finally got it MOTed and back on the road.

Hopefully I’ll be able to get some use out of it now. The MGR is working well enough but I’d like to investigate improving the performance of this once I’m happy everything else is behaving.

I’ve been commuting in the Cappuccino for the last couple of weeks and all has been going well so far. The MGR performance below 30mph is actually very good. It’ll spin wheels and get the back end sliding in the wet if I floor it. Above 30mph it’s not fast but it will keep up with traffic. Top speed is around 60mph on the flat.

Thought I’d just summarise the hardware setup that I’m currently running:

- 20kWh battery pack (Boston Power Swing 4400 cells)
- Prius gen 2 inverter controlled via OpenInverter board. I’m using the boost converter to permanently increase voltage to just over 500V. Water cooled using EMP WP29 pump and standard radiator.
- Prius gen 2 DC-DC converter
- Lexus RX450H MGR mounted in place of the original rear diff. Shortened standard driveshafts. No additional cooling.
- Volt gen 2 charger (water cooled using Bosch 12v auxiliary pump from a Mercedes). PWM controlled with a 555 circuit and HV cutoff using JLD404.
- Thomas 12V vacuum pump from Smiths Edison van for brake servo

It’s pretty barebones, no CAN or anything fancy but it works for me. There’s a few minor issues and improvements I’d like to make but super happy overall. Thanks for all your help and input into this project!