SDU loss of power

[Audia2electric]

Hi!

Just completed my conversion and have been driving my converted Audi A2 for 2weeks. Im in heaven! Thanks to open inverter community that makes it possible to use a Tesla motor!
Im running R sine 5.20 and almost unchanged values from dellivery of my v6 board from Johannes. The car felt almost perfect so I have only tried different settings with regen and lowering boost from 3800 to 3000.

Last week only 50 met after starting driving home from work, car on charge during the day (375v ish 15 deg celcius) during acceleration it suddenly loses power, It felt like it got into ICE ’limp home’ mode annother 100met before there is practically zero power. Come to a standstill and test cycle off on and try forward or rewerse a couple of times but car have almost zero power and jitters/ jumps. Turning car off for a minute and cycle on again and then car feels ok again. Trying to drive home again car works approx 1km before same thing happens again. This time stopped in a bad place on road I got little worried and just keeep throttle 100% after cycle on off dont give any power at all the car suddenly gives 100% power in 1-2 sek bursts and this gives me oppertunity to reach a parking at side of road.

Checking parameters, I can test that inverter changes from neutral to forward and throttle values on 0% and 100%. At that time I give up and got help towed back home 10km.. Well back home I can start car and drive it back into my garage.
Now i’ll trying to undrstand what went wrong and shout out if anyone have experienced same behaivor and if there is something that can be done if the same thing happens again???
Right now I dont know were to start troubleshoot and I might been lucky not destroying everything towing a shout down electric car with a tesla motor producing power without have anyplace for it to escape.

Best Regards

Mattias, Sweden

[johu]

Fun conversion, very light and powerful

I think it must be the temp derating. Check your cooling works ok and raise tmphsmax to 110°C.

[Audia2electric]

Thanks Johannes!
I will change and raise value, but car and coolant was low temp since charging only was active until lunchtime so it only indicated 20 ish degrees celcius (I have installed an watercoolant guage) The highiest indicated temp have been 42 deg celsius after a longer drive for approx 30km the day before…

Towing car… I totally lost my mind forgetting that Tesla themselves dont recomending towing car so can I have destroyed anything? Motor still runs and good but with wheels off ground.
Testing car after work today

[Bigpie]

Off topic, but please do a build thread, like these cars

[Audia2electric]

Build was started many years ago with a Kostov DC motor. Then I found this community by a friend so no buildthread. Everything and more is found on my Instagram Audia2electric. If ok by moderator otherwise remove.

The Tesla motor makes this car fly! I just love it

[arber333]

Could be your thermistor circuit went sideways. It happened to me on highway. It wasnt malfunction but heavy foot

[Audia2electric]

Johannes was spot on!
Waterpump not flowing enough or have given up and tempsensor far away from inverter fooled me. Indicated 24 deg celcius on guage is much more deg in inverter. Long but gentle driving and first full pull day after then charger heating water and inspired drive from start lead not to limp home but overcurrent and inverter shut down. Testdrive tonight lead to annother overcurrent when I did a 50% throttle pull so inverter have got beaten up for sure But first a better coolantpump is needed. Look at inverter temp…omg

Any ideas what pump to search for? Craig davies?

[johu]

Very good. Nissan Leaf pump perhaps?
Also just noticed tmphs can't reach 110°C so more like 95°C should be the maximum

[Audia2electric]

I’ll check leaf pump Got an diy alternative found in vw hybrid and electric cars with 19 mm tubes otherwise 2 models that could work from davies craig called boosteroump. First one dellivers 25lit/min and a more powerful version with 27lit/min with a pump outlet pressure of 0.85 Bar for just under200 Euros.