Tesla Roadster 2010 Power Limit

[Noob_2This]

Hi all, posting for the first time.

I have a 2010 Roadster, still on its original battery pack, i use it regular and can still get 200km out of a full charge.

Recently power limit in orange has been coming up on the battery consumption dial. I looked it up and it points towards a component overheating.

Any information would be greatly appreciated.

 

[X.l.r.8]

does you AC work? What’s the ambient temperature. 200km is not all that great. The bottom backwards arrow on the screen will give you a rough temperature for PEM, Motor and battery. Put it in that screen to check if it’s the PEM. In the trunk/boot is the coolant circulating, is it at the right level? The battery is cooled by AC and the PEM/motor by air using fans at the rear. Do you have 2 fans with separate motors or one motor controlling both fans. You should hear the fans. If not try popping the rear cover under the car and turning them by hand, or blowing compressed air through them. If your PEM is overheating it may simply need taking out to clean or a new fan. If it’s your battery you need to look to coolant and AC issues.
OVMS gives you a better idea being more detailed thsn the screen as it shows actual temperatures. Highly recommend to problem solve

 

[X.l.r.8]

 

[Noob_2This]

Hi , thanks for the reply.

The AC is working fine
I am based in Cyprus so the outside ambient temperature is about 33 deg.
It is a double fan running from one motor, i can hear the fan running and had a new one fitted about 6 months ago.

Interesting about the coolant.. After i got the overheating message i checked the coolant, it was on minimum.. So i topped it up with some distilled water, but it only required a tiny amount to top it up. 70ml.
But in doing so i noticed the coolant was only luke warm, no pressure , i expected some pressure when removing the cap due to thermal expansion, i also noted that the coolant at this time did not appear to be circulating.
But then again, i don't know what is meant to be normal..i never checked it before so i have no comparison.

 

[X.l.r.8]

The reservoir is just that, an expansion tank rather than a closed loop system, so definitely not under pressure. Was the fluid circulating? Usually when you do anything like open a door the pump should come on and you can see the fluid and hear it running in the back. If it’s not then you may need a new pump. Not the end of the world thankfully

 

[X.l.r.8]

@ML Auto may have more advice as I believe he has changed his

 

[Noob_2This]

That's great advice, i will check again Tomorrow to see if the coolant is circulating. Thank you for your help.

The reservoir is just that, an expansion tank rather than a closed loop system, so definitely not under pressure. Was the fluid circulating? Usually when you do anything like open a door the pump should come on and you can see the fluid and hear it running in the back. If it’s not then you may need a new pump. Not the end of the world thankfully

 

[gregd]

If you replaced the under-car blower assembly, and it's really blowing, the temps should not in the "red" zone (in-car VDS screen) and there should be no reason the power would be limited.

Curious, why was the blower assembly replaced? Had it actually failed? I ask because I thought mine had failed, and it was actually fine. Instead, I found that both the connector under the PEM that drives it, as well as the connectors at the motor itself had failed contacts. If the blower motor isn't getting enough power through the connectors, that could easily cause a power limited situation. See: Think I need a new PEM Fan... Anything else to check? (long saga... skip to the last 2 pages for the final resolution.)

 

[Noob_2This]

Thanks again for the information.

Today i checked the pump..i can see water is circulating back into the expansion tank.

I will do diagnostic on temps from LED panel see what area is overheating.

Fans, they sound like they are working..but i will get this checked out again... Its difficult to get a good engineer in Cyprus so i think i am best checking it myself.. How do i get access to the fans for a visual ?

After i got the power limit problem the first time, i took it to electrical engineer to check all connections.. He said everything was good
But when i got the car back , which was only two days ago, i got the same warning message and also an additional problem.
Now the car won't take a full charge, before i took it to the electrical engineer it would charge full to 250km... Now it will only charge 3/4 of that(190km).. Why would this have happened? Could it be he let the battery go flat? He had the car for 3 weeks.

 

[X.l.r.8]

Probably the PEM fan is not cooling during charging. When the alert is on the screen take a picture of the screen, it will give a code and point you in a better direction. I suspect if you try and charge at the lowest Amperage possible 15 amps or so, it will charge fully. If you have a 1146 code then it will be possible that the plug from the fan to the PEM has seen the end of its life cycle and needs replacing. But I would watch the temp screen to see exactly what is limiting power and take pictures of the warning screens. The car is pretty got at telling you what hurts.

 

[X.l.r.8]

Access to the fans requires getting under the rear and removing the 10mm bolts on the aluminium panel, there is about 10 of them. But if you have a new fan its not very likely to be the fault, more the plugs, Go through Gregd's thread above as he did a pretty good deep dive into consumption draws and the effects of poor plug connections.

 

[Noob_2This]

I did some further tests today monitoring temps.
It was fine all day, everything in the blue. That was until, just as i came back home and was going up my steep driveway the PEM temp turned yellow and power limit warning light came up on the main dial.
Any ideas? That's the only time it happened all day.

 

[X.l.r.8]

First thing to check is the hose that goes from fan to PEM, it’s the left fan and has a large hose going to the underside of the PEM.
Read through this to get an idea what you are looking at. The PEM may just need cleaning. Or the fan is not turning fast enough, usually because of low voltage in turn caused by increased resistance. Possibly due to a plug that’s got a burnt or loose pin.

DIY: Roadster 2.5 PEM cleaning - step by step

This is the breakdown with that plastic pin removed.

teslamotorsclub.com

a cool PEM is a happy PEM. A hot PEM will melt the insulation on the power boards and you will no longer be a happy roadster owner. Was the car serviced recently, the hose may have popped off, it’s a simple fix and worth checking. After that I would check the PEM fan plug and the plug further towards the fan. Any corrosion or obvious sign of arcing/melting abs I would change them. It’s a 16A connector pulling 20+ amps so it’s a known trouble spot.

 

[gregd]

As X.l.r.8 said, the car is pretty good about telling you "what hurts". I recommend you pull the logs and see what additional alerts have been posted there. Not everything is sent to the VDS display in the cabin. Instructions and log parser are available here: VMS Log Parser for Tesla Roadster

The alert number decoder is here: Roadster VDS Messages | Tesla Motors Club

 

[LeoNordic]

Regarding different km-reading when charging.

I think it displays it a bit confusingly different in the instrumentcluster and also compared with the VDS-screen depending on which mode you charge it in.

So the mechanics might have changed the charge mode that maybe could explain different km-reading compared to before.

 

[EdMcConnell]

I too have a 2010 (#543) and recently have had a max brick temp too high/power limited message pop up after about 100 miles continuous driving on mid 80's sunny day driving at 50-60mph back roads highway driving. Top was down, so I can't say whether there was an aircon issue or not. I haven't had a chance yet to verify that the aircon is working in the cabin. Fluid levels appear to be ok.

I did not notice any impact to driving at 50-60 mph while the alert existed and was back home in about 30 miles.

The VDS indicated battery temp at the first yellow bar (two more to the right). I believe the battery temperature indication was 33C but not sure I remember the number correctly.

My question: is this a dangerous driving situation? Should I have pulled over to let the temperature drop? Would it have dropped without being plugged in?

 

[gregd]

If the battery is that hot, it's definitely not a good time to go for a drive.

When it happened to me, it was Tesla's fault for over-filling the air conditioning system on the prior (few months earlier) "maintenance" visit. That caused the A/C compressor to overheat and shut down, preventing the battery from being cooled. Try pulling the logs and see if you have a #1463 alert recorded. It doesn't show on the VDS in normal mode. If that's it, the A/C system needs to be properly drained and refilled.

That said, a 33C battery is quite comfortable, if not pleasantly cool. Could the overtemp be for the PEM / Motor? That could be the connector driving the under-car blower going. 1144 or 1146 alerts in the log for that. But if the battery was in the yellow region, that's a lot more than 33C...

 

[EdMcConnell]

Thanks for your feedback. PEM and motor temps were not high per the VDS, so I’m going to first on checking out the A/C and avoid long drives until I confirm A/C to be working, since the PEM and motor are air cooled while the battery takes advantage of the A/C cooling.

It’s time for an annual service visit, but I’ve recently moved and the nearest service center is over an hour away (Richmond, VA), and I don’t know yet if it can service Roadsters. The next closest is in Virginia Beach which is 2 hours away, and after that Tysons/McLean which is 3 hours away and is where I used to live and where I serviced the car last year.

 

[gregd]

Yeah, sounds like an A/C problem of some sort. You can always check the A/C by turning the car "On" with the key (don't need to engage Drive). Run it in the cabin and look for cold air.

 

[EdMcConnell]

Did that and checked the VDS which showed temp at cabin vents a degree warmer than ambient, pre-refrigerant pressure 32bar, and compressor speed 0rpm. So either 32bar is too low for the compressor to kick on, or the compressor has gone bad, I think.