Is my controller 'bad'? Severe loss of power at low SoC?

[dominik]

I have installed an extra noisy 60x60mm 18W fan, from a Server rack, kicking in at 50C on the big mounting plate I have installed the controller onto.
That reminds me even under the helmet to go slower.

[bob2.0]

Thanks.

Well, I have found the controller. I then put it down somewhere 'safe' and forgot where I put it again! I later found it for the second time!

I am now thinking about how it can be installed, given heat is already a proven issue.

It has the thicker finned heat sink.

The standard controller I can get my hands under the controller to swap cables, but this might be more of a problem, I was hoping not to have to take battery pack out.

Anyway, that is normal engineering. What I am less sure of is how to mount it.

Should I space these fins away from the underside of this box (for better air movement), or hold it close (for heat transfer)?

Another thing would be whether to update the installation by drilling holes in the mounting panel below the 'glove box'? If I did, then a fan could be conveniently fitted on top of it to suck air out, through the fins. If I took the battery out then I might as well do that straight away, within and up from the battery cavity?

[jeff-jordan]

I installed two 80x80x15 mm fans above the controller (below the "fuel tank" compartment). To ensure the Fardriver is sufficiently cooled, I cut a suitably sized rectangle out of the metal sheet on which it is mounted.
The fans are quite quiet, so I can easily power them with the on board 12V as soon as the E-Odin awakes.

[bob2.0]

Thank you for sharing.

I have removed my battery and now I get a good look at it, this is a design joke. The painted steel sheet the heat sink is bolted to is actually BLOCKING heat coming off it! Heat can only come off the edges!

No wonder it was overheating!

I think trying just drilled holes first is OK, and I will space the heat sink with a couple of m8 nuts. If it has worked so far, I think this might be enough? But I like your large fans, the larger the quieter.

I will probably go with one relatively slow 120x120 if it needs more cooling, I have a couple somewhere, they were going to go on a different project I have not finished, but didn't find them anywhere. For now I will drill some holes and get it back together, see that the controller is functional.

I am thinking the normal laws of cooling should do the work. A hot source underneath with vent holes in the middle should suck air inwards from the edges. First thing I can try is to get the thermal gradients to do the work rather than a fan (like yours, a better solution that guarantee the flow).

I appreciate the input from you guys.

The battery is quite a lump. I'll weigh it tomorrow! I wanted to get it out to check for corrosion. I will clean it off and spray the inside with lanolin.

[bob2.0]

It only took an hour or so to physically install the 72530, yesterday.

It's taken 3 or more hours yesterday and today to try to get it set up, though! It is still not perfect, but it's great getting 'cruise control' as a feature now!

I'm still getting an odd start-up beep, there is something the software thinks is not right but won't report it. No errors, but no 'system OK' either?

Anyway, this thread is on my original controller, and the answer is now, very clearly, that it was overheating. The surface area from which heat could escape was just the very edge of the solid heat sink, which was hopelessly inadequate for my long fast rides, which was when I was experiencing this.

I have spaced the 72530, with its heat sink fins, suspending it with a cm gap or so. This has meant that after I rode at full speed for over half an hour up some steep hills. There did seem to be some slight derating, but the time I got home (another 10 mins) the controller was at 54C. After another 5 minutes, it was at 50C. So, maybe it had got hot but nothing that had a big impact on performance, unlike the old one.

So, this thread is basically 'resolved'; controller was overheating, nothing to do with SoC, lowvoltprotect, or the battery. I'll reserve any more observations about fitting a 72530 controller to the thread focused on that.