Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

PEM second failure

This site may earn commission on affiliate links.
Regarding the cells, hope it's not the original cells as in NOS.
Freshly fabricated OEM cells of original construction/chemistry would be great, but not NOS.

We all have different needs, but it would be great to have a pack:
1. longer life than 3.0
2. lower price than 3.0
3. capacity similar to or slightly higher than original 1.5, 2.x, but lower than 3.0 is perfectly fine
4. higher power and more stable impedance with life than the original would be a nice plus
5. lighter weight would be a plus also
6. longer warranty than the 3.0

Frankly, I would be happy purchasing the original pack again if it was composed of new cells and lower price than 3.0.
 
  • Like
Reactions: AtAge19
Higher power will never happen, the PEM runs hot as it is. The additional amps would cook it if it wasn’t already regulated, the fact the PEM houses everything means you have to keep things pretty stock as you can’t just add a model S dual charger, you are stuck with what you have.
I doubt you can even buy 18650 with that low capacity anymore. 12 year old tech would be cost prohibitive to remake, no ones making vhs or laser discs for a good reason. In my opinion they should offer the tooling to remake packs to a 3rd party then make their money reprogramming the PEM / charging with the parameters for cell spec.
 
Higher power will never happen, the PEM runs hot as it is. The additional amps would cook it if it wasn’t already regulated, the fact the PEM houses everything means you have to keep things pretty stock as you can’t just add a model S dual charger, you are stuck with what you have.
The new pack if it has greater capacity will deliver more maximum power due to higher voltage. It is already experienced by 3.0 owners that current is not changing but the voltage drop due to drawing max power is less, hence power output is higher.
Especially they report about quicker 50 to 80 miles accelerating time.
 
Sustaining max allowable amps is not really the same as increasing the max power. This could be done with better cells with a higher C discharge rate. Does not need to be bigger capacity, the 18650 is as packed as it’s ever going to be, some cells have higher available capacity in a trade off for discharge rate, while those with amazing discharge rates do not allow as much capacity. Even buying cells your looking at $20,000 before you even build a pack with anything modern in 18650 terms. If the 3.0 pack is not performing then I wonder why, is it because that supposed feel in power is just to high discharge rate for the cells. The ability to overcome voltage sag may have left the cells with different characteristics to not sustain that higher C rating. Im still surprised they have not used cells from model S packs to try. But I think now the time has passed, if you are waiting for a new revised battery pack, I think you are in for a long wait. Salvaging sheets is the only solution until we can put together a pack that we can replace the original with, I don’t care if I’m only able to access 75% of the packs potential if it means I get another 10 years out of it. I still wonder what would happen if someone got a pack, replaced the cells with model S cells and put it in. What would the car make of it. I don’t think it cares if it is able to operate within its parameters.
 
Indeed, when I noted desire for higher power/lower impedance, it relates to voltage retention under load. It will lead to improve kW retention and also cooler batteries under load without affecting PEM negatively. Actually, it may lead to less current going to PEM per kW as a higher V is maintained under load thereby allowing the PEM to run cooler also.

Agreed that no one will remake LiCoO2 18650 as per redesign now. So if we receive a new pack of original chemistry design, it is likely NOS. Which I would question using.
 
  • Like
Reactions: AtAge19 and Mark77a
Indeed, when I noted desire for higher power/lower impedance, it relates to voltage retention under load. It will lead to improve kW retention and also cooler batteries under load without affecting PEM negatively. Actually, it may lead to less current going to PEM per kW as a higher V is maintained under load thereby allowing the PEM to run cooler also.

Agreed that no one will remake LiCoO2 18650 as per redesign now. So if we receive a new pack of original chemistry design, it is likely NOS. Which I would question using.
That is a nice bonus with the 3.0 battery. The lower sag directly relates to higher punch at higher speeds. The 3.0 shaved 2 tenths of a second off my 1/4 from a fresh original battery and 4 tenths from an 8 year old pack.
 
My 1.5 PEM just had a fatal failure. the fuses fried ($800 to replace) but the other issues in the PEM require it be fully replaced $11000 from SC!!! Any one know where I can get a working one?? Did see one on Ebay for $5k, but very leery of anything on ebay.
 
The 2008 Roadster 1.5 PEMs are solid aren't known to fail.

Eric 1.5 PEM failed once before and was under warranty at the time. I believe the Texas heat is very bad for roadsters as it rarely gets below 75 degrees from Jun through Sept. This causes the coolant system to run continually. (this was the first casue for repair, pumps running 5 solid weeks!)
 
  • Like
Reactions: AtAge19
The coolant pump serves the battery pack only, PEM and Motor are air cooled and runs when the pack is above 90% charge standard.
The a/c system kicks in while driving (above 41 C) or charging to cool the cells.
PEM 1.5. has the radiator directly attached or even inside (not sure right now) while 2.X have a fan at the bottom (actually 1 double or like in early days two separate).
Typical overheating of the PEM is caused by debris inside the fins of the three cooling plates or bad fans, power connectors for the fans.
much of it has been discussed here in the forum a lot and in deep ;)
 
Electrolytic capacitors used to be the number one cause of radio/tv failures and this was what kept repair shops alive. 'Computer grade' electrolytics were much improved and most are still working fine since their inception in the 1970s. So to have these fail in the 2008 era PEMs is a bit of a head scratcher. Reminds me of the story about the CEO of Hewlet Packard who chose the supplier of capacitors because she liked the way they looked, and that source had huge premature failure rate for the company to eat.

Likewise the power devices in the PEM, any good repair shop should be able to upgrade these old boards, its not rocket science. And the poor connectors and lack of crucial time-out protection circuits can be solved if a tech has access to enough PEMs to figure out what is going on. So after 8 years may be a good time to get a thorough check up done by an understanding technician.
--
 
As far as I know until now only one case with a blown capacitor is documented by Gruber. I was told that 2 different grades of capacitors were used in the PEM; standard and military grade... but I don't have any further intel about that.
I agree with the remark: every good electronics repair shop / technician should be capable of detecting faulty parts and replace them.
The brain is the software which drives the PEM, not the PEM itself.
 
PEM failure update. Gurber has said the PEM is now fixed (after 5 weeks) and is now looking at the other errors (BSM Failure, etc). Svc Ctr had dropped their $11k cost to $9800 for a reman PEM from California so they did not get the job. Gruber estimate $5-8k to Repair/replace PEM. Battery (I'm assuming) in storage mode has 4 mi left. Max Range was down to 177mi, standard Range down to about 145. Not bad I guess after 11 yrs and 5 years of hot Texas Summers. Interested to see what range will be after full repairs are complete.
 
Just got the car back yesterday. two months in repair and about a month awaiting shipping. Range is exactly the same as when it PEM failed, about 170 Max about 140 standard. Not too bad for an 11 yr old original battery pack. New PEM lifespan estimated at 8 more yrs. Now it's time to look to the new 3.0 battery pack if those are every going to be made available.. Car returned in good condition too. Cost was $5k plus shipping ($1100 round-trip which is much less than I thought it would be).

Only drawback is that the digital clock seems to have locked on 00:00 anyone know how to reset it? Other ongoing issue is the cooling pump. Thermostat must be set for CA temps. TX will not see temps below 75 degrees until late Sept which is when the pump will finally shut off. Last time it ran 24/7 for 4 months straight before it finally died. anyway to adjust that also?
 
@efreedom

Glad your car is back and working... Gurber does an amazing job with the batteries and PEMS. His recent shop pics reminded me of the golden days of only roadsters in the service centers 10 plus years ago...LOL

Im in Houston and my pump doesn't run all the time. It runs from time to time when charging, but normally its off.
Might want to have the SC take a look at what the issue is on your next annual visit.