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Storage mode: what percentage?

FANGO

Active Member
Jun 6, 2013
1,287
412
California
I've never left my car in storage mode before, but am testing something out right now. I've got it plugged in, and every night at 10 I get an 1173 warning ("To gain the advantages of storage mode, car must be plugged in"). OVMS shows it plugged int, shows some voltage/amperage being delivered for a second, then it stops and goes back to 0V/0A.

I've successfully forced the car to start charging, at which point I got error 934 ("DMC FW: Line OverCurrent Peak fault"), but the car did start charging. I've had trouble with my 120v cable before, but have only ever tried it on one outlet (it's now on a different one), and it seemed to heat up and then stop charging after a while.

I first plugged the car in at 44%, but it gave me that warning and wouldn't actually charge. Now it's down to 30%, and still gives me the 1173 warning every night. What I'm wondering is: what percentage does the car actually maintain itself at? I thought it maintained at 50%-ish, but is it 30, or 20 or something instead? If the problem is the cable, then I'm probably just going to buy a new one, but don't want to buy a new one if the cable isn't the issue. Given that I can manually start charging, it feels like the cable isn't the issue, but I don't know.
 

eHorses

Member
Jun 23, 2019
146
118
St, Pete, FL
I believe the storage mode takes it down to ~20% SOC or around 40 ideal miles for most ‘good’ original ESS. At higher SOC it comes on than turns off but the ESS will recharge and maintain if lower than 20.

As a caution, you may want to sort out the charging issue in case it’s something else. Having ESS at 20% SOC does not give you a lot of round for help before bricking.
Good luck!
 

Roadster

JdeMO Powered
Dec 10, 2016
1,571
1,266
SoCal
Line input fuse issue perhaps?

 

FANGO

Active Member
Jun 6, 2013
1,287
412
California
Line input fuse issue perhaps?

Thing is, it gives that error but then it will charge anyway
 

gregd

Active Member
Dec 31, 2014
2,597
1,815
CM98
I've not read of anyone who really liked Storage Mode, given the risks. Nice idea, but in practice I don't think it worked out all that well. Notice it's not something they carried forward to the newer cars.

Is there a reason you don't want to just use the standard charging mode? There are alternatives to Storage Mode for long duration inactivity.
 

FANGO

Active Member
Jun 6, 2013
1,287
412
California
Looking for a way to remotely manage the car's charge, rather than having to plug and unplug it myself. If I happen to be on a different continent for a time, for example.
 

FANGO

Active Member
Jun 6, 2013
1,287
412
California

IMHO wouldn't want to own a Roadster without an OVMS! Very reasonable, not difficult to install or setup and incredible support.
Yes, I have OVMS, that's how I'm checking charge remotely. What I'm saying is that I can't leave it plugged in without storage mode unless I want it to charge to 100%, which I don't. So that's why I'm asking what percentage it will remain at in storage mode. Because right now it just keeps going down and doesn't seem to be charging and I'm not sure what the issue is. At 26% now, which is a larger daily drop in capacity than I usually see, so I feel like charging it back up to 40 or so and I guess just remotely managing the charge manually... 🤷‍♂️
 
Last edited:

slcasner

Active Member
Supporting Member
Feb 20, 2011
1,392
939
Sunnyvale, CA
Perhaps an acceptable solution would be to remove the scheduled charge time and control the charging manually if you are willing to keep on top of it with OVMS. Let the car charge to full (standard mode) which will let it balance, then just leave it until the charge wears off to 50% and manually charge again. You could monitor during the charge and manually stop the charge at the level you desire, but the pack would tend to become unbalanced over time.

If you have JS software skills you could create a script that runs in OVMS to implement the above strategy.
 

Retiredeh

Member
Jun 28, 2019
48
31
BC
Glad to hear you have an OVMS. Based on what I have read I have come to the conclusion it's best to treat my new roadster like I charge my M3. I just leave my M3 plugged in at a setpoint of 80% so I always leave home with a "full tank" I have a destination charger and of course it's easy to give the M3 a setpoint.

With the roadster I leave it plugged in to 240v set at the lowest charge rate in Standard mode. I believe this equates to an 80% ESS charge by comparison to M3 jargon. Standard mode charging equates to 80% when you switch to Range mode. Keep in mind when Tesla wrote the instruction manual for the roadster in those days they came up with all these modes to try and encourage people not to charge much more than 80%. My research says you want to run Li Ion between 20-80% to get best life. I don't think the Storage mode makes too much sense especially as the battery ages. If a cell goes bad you will have a lot more time to deal with it from an 80% charge and I doubt leaving the battery at 20% prolongs the life much. In fact it sounds like more people have bricked their batteries leaving them in Storage mode.

Are you having any problem charging your car at 240V? Relying on 120 volt charging in Storage mode seems very risky to me.
 

gregd

Active Member
Dec 31, 2014
2,597
1,815
CM98
Yes, I have OVMS, that's how I'm checking charge remotely. What I'm saying is that I can't leave it plugged in without storage mode unless I want it to charge to 100%, which I don't.
So, the Roadster's charge indication is different than (most) other cars. "100% full" is context dependent. In Standard Mode, that's actually about 83% SOC on the battery itself, not 100%. In Range Mode, it's about 94%. "Empty" also depends on the mode, with Standard mode hiding the bottom 10% or so.

If you're going to not use the car for weeks to a month or so, just leave it plugged in on Standard mode. If it's going to be many months to years, you can disable the APS and pull the HV disconnect, and the car can then just sit there.

Counter to this, if the garage is subject to extremes in temperature, you really should have it on a 240v outlet so that the car can cool / heat the battery as required. Temperature is a big factor in maintaining battery life.
 

FANGO

Active Member
Jun 6, 2013
1,287
412
California
Counter to this, if the garage is subject to extremes in temperature, you really should have it on a 240v outlet so that the car can cool / heat the battery as required. Temperature is a big factor in maintaining battery life.
Nope, the car's at the beach. Gets warm sometimes but never all that hot. Currently 77º 👍

Probly going to charge it up to 55-ish and then leave it there but on storage mode, see what kind of daily drain I get. Usually get around .5% per day drain when I have it unplugged and charged to that level, wonder if storage mode will change that or what.

If I have scheduled charging turned off completely, does that mean if I stop charging after plugging it in, it will never wake up and charge itself on its own? I'll just have to manually start charging whenever I want via OVMS? Cause I guess that would be a reasonable solution...

Also, noticed that OVMS won't let me set amperage to lower than 12a. Was hoping to do that just to avoid any chance of the old cable overheating or something and interrupting the charge. Is that a limitation of OVMS, or of the car? it shows 10a is possible but whenever I set it to that level, the car still says it's charging at 12a.
 

Retiredeh

Member
Jun 28, 2019
48
31
BC
I have to reiterate what gregd says...you really need to get yourself a 220Volt circuit. Read through may posts on this forum that tell how unreliable 120 Volt charging is. You need a secure 220 volt circuit to protect your investment!!
 

slcasner

Active Member
Supporting Member
Feb 20, 2011
1,392
939
Sunnyvale, CA
Also, noticed that OVMS won't let me set amperage to lower than 12a. Was hoping to do that just to avoid any chance of the old cable overheating or something and interrupting the charge. Is that a limitation of OVMS, or of the car? it shows 10a is possible but whenever I set it to that level, the car still says it's charging at 12a.
US cars only go down to 12. UK cars go to 10 since their base voltage is 230.
 
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LeoNordic

Member
Apr 12, 2015
81
70
Sweden
My Roadster has always been connected to power and in standard-charge (Like 83-85%) something since new. Not so hot in Sweden but the CAC is 155,5 and that is roughly 97% capacity from new. It has only been driven 8070 miles since new (13000km) I get like 191 miles (309km) in range on standard charge. Has never tried charging it to full range. So if you garage has good/normal temperatures I would keep it always connected and in standard-charge.
 

FANGO

Active Member
Jun 6, 2013
1,287
412
California
Well apparently I can't leave it on standard mode because it will continually start charging for no reason. I turned off scheduled charging and yet half the time when I check on the car, it's charging. Sigh.
 

slcasner

Active Member
Supporting Member
Feb 20, 2011
1,392
939
Sunnyvale, CA
Well apparently I can't leave it on standard mode because it will continually start charging for no reason. I turned off scheduled charging and yet half the time when I check on the car, it's charging. Sigh.
Interesting. Can you quantify "continually" a little better? Does it wake up and charge on a daily basis, or more frequently? When scheduled charging is enabled, I believe the car will charge once at the scheduled time each day.
 
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FANGO

Active Member
Jun 6, 2013
1,287
412
California
I can't really, it's in a garage on another property with bad cellphone reception, I just checked in the other day and it happened to be charging and I hadn't started it doing so.

Seems I'm going to have to find another longterm solution here, and that my experiment didn't really work. But at least I know that my 120v cord was broken and the new one is working fine. So, one positive development out of the experiment.
 

gregd

Active Member
Dec 31, 2014
2,597
1,815
CM98
I'm still thinking the best plan is to just plug it in and let it do its thing. Unless otherwise directed, there is a daily "top off" charging session that the car initiates 24hrs after the prior charging session completed. If I do the math, I see that the car consumes some 500 watts (net, including charging overhead) when it's just sitting there, asleep. The top-off charging replaces that on a daily basis. Unless you disable the internal systems and pull the HV Disconnect plug, the car is still going to be consuming that juice, 24x7. It's got to get replaced somehow, and delaying the charging is not going to change that. You fundamentally cannot "put the car up on blocks" and leave it there.

Storage Mode was intended to keep the battery at a lower state of charge, with the intent to extend the battery life a bit, but history has shown that it's generally a higher risk than the benefit it is supposed to provide. At the time the car was being designed, long term use of these batteries in an automotive application was really unknown. Expectations were that a battery in "normal use" would be down some 30% in capacity after 10 years, but the reality has shown that to be far too pessimistic. My own battery is down 14% after 11 years, and it's pretty typical. So, one could argue that the effort put into implementing Storage Mode might have been better applied elsewhere. Note that the newer cars don't have a similar function.

The risk side of Storage Mode is that the battery is kept at such a low state of charge that any issueswith the power will leave you with very little margin. The car does not have an effective anti-bricking system. And at that level, the cells cannot be balanced, so over time the pack will acutally suffer a bit. So most find it's a much better risk / cost / benefit tradeoff to just leave the car in Standard Mode, plug it in (preferably to a 240v service), and let it be. The 240v service is preferred for two reasons - one is that it's enough power to enable the car to provide temperature management (cooling, in particular), and second that a frequent source of interruption on a 120v service is the GFCI circuit that can trip for a myriad of reasons under "relatively normal" use, requiring manual intervention. If someone isn't available for that manual service, and you've got the car in Storage Mode, you have a much higher risk in permanently bricking the battery. With Standard Mode, there is a lot more time to react.
 

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