Battery Tender / NOCO and Phantom Drain, ? by preventing the MS to go into Sleep Mode

[iCharge]

So I have had my MS hooked to a battery tender type device / NOCO G7200
My reasons to do so are detailed here
Any reason not to hook up a battery tender to the 12 volt battery ?

How ever I always had this lingering feeling that NOCO was just cycling through the charging current itself as the charging light would never stay steady red or orange or green [ representing various charging states] but was cycling through red, amber and green at a frequency more than what
- it does with my ICE 12V LAB
- the TB would charge the 12V. [ from the famous graph referenced in the thread of the post above ]
So I listened to the NOCO hooked up to 12V and noted that every time the NOCO cycled through its lights, the car would make whirring sounds esp in the front, the HV connector click, and so I decided to measure range loss as car seemed never to be silent as it was without the noco.

In true [non] scientific way, I chose days that had similar ambient temperatures. I checked range at same time with NOCO off and NOCO on. Garage was opened exactly same # of times letting some outside cold air in.I wish I had the ammeter to compare the current running against time while the NOCO was hooked.
Experiment started on Saturday at 10 PM. I did not hook the NOCO

Saturday 2200hrs @188 miles. NOCO off
Monday 0828 hrs @181 miles. NOCO on
Tuesday 0842 hrs @ 176 miles. NOCO off
Wednesday 0842 hrs @ 175 miles. NOCO off
Thursday 1000 hrs @ 168 miles. [ this night was particularly colder ]

I know the numbers are non conclusive, but when the NOCO is on, the car is never silent for more than 3mins. As the NOCO cycles through its lights, the car starts to whirr with sounds in the front and I can hear the high voltage connector click.

This would be a good experiment to run if some one has NOCO or any other battery tender device and Tesla Fi service [ I do not have TeslaFi]

Thoughts ? Criticisms ? Ideas ?

 

[iCharge]

bump !

 

[iCharge]

bump

 

[SSedan]

Do you happen to have a kill-a-watt type device you could measure the consumption of the Noco with?

 

[iCharge]

Do you happen to have a kill-a-watt type device you could measure the consumption of the Noco with?

THanks for the reply and suggestion, I Dont but I was thinking about this too. I ll borrow or buy one and report back

 

[iCharge]

Do you happen to have a kill-a-watt type device you could measure the consumption of the Noco with?

some one has already done that, Any reason not to hook up a battery tender to the 12 volt battery ?
May be that post can help you frame a reason ??

 

[murphyS90D]

Use a smart battery charger instead of a battery tender. My Schumacher 100 amp charger keeps the 12 volt battery charged and the high voltage battery never comes on line while the car is parked. This totally stops vampire drain from the HVB.

 

[rrolsbe]

The NOCO G7200 is a Smart Charger or at least is supposed to be. I know this is a Model S thread but follows is my previous experience with the Model 3. I never got the NOCO to work to keep the AGM 12V topped off and provide the power required while the car was asleep which should have keep the car for waking up. No matter what I did the car would wake up for up to 4 to 6 hours a day and run the DC-to-DC converter pumps etc. When I first tried to get the Smart Charger to work, I assumed if the frunk was open the car would not enter sleep model. That turned out to not be true until several months later after many firmware updates now if the frunk is open the car will not enter sleep mode. I basically gave up on the experiment maybe things have changed and I should try again? I now put the car is storage mode when parked in my garage and will not be driving the car for an extended period of time. Unless things have changed, the Model 3 will never actively warm or cool the traction battery while parked and NOT plugged into shore power so storage mode should do no harm. Not sure if the temps are colder that -22F or above 140F and not plugged in whether the BMS will warm or cool the traction battery using its own stored power? and if it does, what happens when the SOC is 20% or lower.

 

[linux-works]

I have not read thru all the long threads; but I would be hesitant to connect what I would call an 'external charger' to a battery that already has an internal charger (the car and all its cpu/circuits) wired to it.

that's 2 power supplies attached to a 'load' (the battery).

in general, that's not a good idea. now, make at least one of those 'smart' (the tesla) and instead of that charger circuit seeing a normal natural lead battery, it sees a different impedance, discharge curve, maybe even noise level. its no longer the 'thing' that it knows very well.

I don't recommend having a smart system be attached to something that is not exactly what its going to expect. if the car expects to see the lead 12v battery deep cycle down and back up again during normal daily 'use', it should see that and not a constant 12v on the battery, as if its some 'ideal battery'. there may be internal fault codes thrown when some very exact condition is not met due to the external charger being connected and powering the battery at the 'wrong time' (when some task runs on the car and 'cares' about things like this).

on dumb cars, sure, no problem. I used to keep a tender/minder (I forget which was the 'real' one that was well designed; one was crap and one was good, and they differ by names that sound alike, lol) on my ice car. I would not do this on my m3, now. I'm going to let the car deal with itself. its way too complex for me to second guess things. if I had source code access and I could know what is going one, that would be one thing, but none of us here have that (I assume) and so we're all guessing as to what would happen if you put two PSUs against each other, like this, at the wrong time.

if my battery wears out during warranty, I hope they replace it. if it becomes a problem that happens too often and the company does not address it, then its time to get rid of the car. to me, this is more of a hands-off product, even though I'm very technical and a hacker by nature. I'm not going to guess what their charger will do if it sees my charger there at the same time and the battery has not gone down as it expected. the least amount of exceptions (DTCs) that are thrown, the better.

 

[rrolsbe]

@linux-works All of the points you raise are VERY valid points and I was concerned about them during my previous testing. The NOCO smart charger did back off when when the car woke up. The NOCO did appear to keep the AGM battery topped off and supply the power needed to power the on-board electronics while the car was in sleep mode; however, this did not keep the car from waking up for many hours to perform tasks that included topping off the 12V AGM battery (which did not need topping off). From everything I have read cycling of both the AGM battery and the traction battery slightly reduces their useful service lives. My thought process was why cycle them if a safe method could be used and proved safe with instrumentation. For most owners who drive their cars almost daily this would definitely would not be necessary. At the time of my testing, my phantom drain was up to 10 miles per day, which used more power than was used to propel the car down the road . IE.. I do not drive many miles in a month.

 

[linux-works]

if tesla is wearing out their own battery, they need to fix it.

but as a firmware guy, myself, I would not want users to 'go around my code' and try to charge the battery out-of-band, from my own control loop.

say I'm the car: I start to put some non-used systems to lower power modes (sleep states) and I take note of the battery voltage every so often. I expect the voltage to be X when I poll it (every minute or 5 minutes or whatever). I know what my drain should be and I know what the battery should be at each poll interval, more or less. over time, systems will wake up, do things, go back to sleep. more systems will sleep. its very dynamic. the car may be noting the power drain as each 'quantum' step happens.

by going around all this, the code now has an exception. a 'magical battery' is now present that charges itself and perhaps the voltage even *increased* since the last poll interval, all 'on its own' (ie, by you doing the charging).

I just don't like that. from a user POV, I see it, completely. but this car and all like it that will follow, have their own very controlling minds. you can't just go around them in all cases and get away with it.

in fact, as cars start to get more security focused, anything out of the ordinary can be taken as a hack attempt and the car may start to log other events or even shut down ('immo', aka, immobilize).

I support such strictness, in fact. the car really does need to have pretty much full control over what goes on, so that it can know what a true 'exception' is.

this is not the car that we all grew up with. the new cars are computers on wheels and the rules are not what they used to be (for mostly valid reasons, some less valid, but mostly for good).