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battery charging impossible
12-12-2014, 10:26 PM
Post: #21
RE: battery charging impossible
When actually charging, I have not seen the voltage rise higher than 12.8v never seen it hit 13 which I agree I would expect from an ICE or start suspecting the alternator is on the way out. That said, you're assuming the Fluence battery is 'standard' - and I do not believe it is. It has no requirement to be high-crank/deep-discharge as it is for an ICE.

My RV has a similar battery - and it would be wrecked if installed in an ICE. It also has a 'starting' battery of greater Ah that is both bigger and uglier.
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12-14-2014, 12:31 PM (This post was last modified: 12-14-2014 12:34 PM by beaty68.)
Post: #22
RE: battery charging impossible
(12-12-2014 10:26 PM)Buzby Wrote:  When actually charging, I have not seen the voltage rise higher than 12.8v never seen it hit 13 which I agree I would expect from an ICE or start suspecting the alternator is on the way out. That said, you're assuming the Fluence battery is 'standard' - and I do not believe it is. It has no requirement to be high-crank/deep-discharge as it is for an ICE.

It's always good to be skeptical - so I took my meter and went to the car which I got back yesterday, and here's what I found:
Type of battery (written on the label): 12V/70Ah L3 EN Test 720A, maintenance free, Part Nbr 8200 763 733, "MUTLU" (Mfr?). Looks pretty much standard ICE type to me, probably for the sake of simplicity. Although I agree a deep cycle energy battery would probably make more sense for an EV.

Other interesting values: 12V battery voltage, measured directly at battery posts:
- car off, rested for one day: 12.5V
- car on, parked in P but everything running, ready to drive off: 14.4V
- car off, but charging from mains: 14.4V

That tells me it's probably pretty simple: When running or charging, the DCDC keeps up the 12V aux system on a healthy 14.4V, which keeps the 12V lead acid battery neatly topped off (much like the alternator of an ICE car). If someone's 12V system in a Fluence behaves vastly different, I would first make sure to measure at battery posts, then check the multimeter (seriously!) and if everything proves to be real, I'd let the dealer check the car.
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12-14-2014, 12:56 PM
Post: #23
RE: battery charging impossible
Back to main topic: As I said, my car just came back from the dealer where they changed the drive unit, although the message said "charging battery impossible".
So what had happened?

The Fluence has a current excited synchronous motor, meaning that besides the three AC motor phases in the stator, there is also a small DC winding on the rotor which makes the constant field (it can be regulated slowly of course), that is created by permanent magnets in other motor types. Now this DC excitation current must be fed to the rotor by means of collector ring or similar, and somewhere in that chain the insulation was damaged. Thus the isolation monitor detected an insulation fault (single fault only, yet) which means the car is "half safe", cause if there is a second fault, people can be endangered. These are the facts, no doubt about that.

My interpetation of what happened then: Renault doesn't want to bother the driver (cause there is no direct danger yet) and let him drive home safely, but make him go to the dealer quickly. So they inhibit charging and tell you this, because if you cannot charge any more then you *have* to have a repair quickly, whatever it is in the end.

The electro-mechanic at the garage told me about the defect in detail (seems to be a knowledgeable man btw, thank god ;-) and he confirmed he also noticed the slight vibration and "unclean" motor behaviour before. He said that now this is gone (which I can confirm) and it fits to the defective excitation system of the old motor.

So: I think in this case the riddle of the "impossible charging" is resolved, and I hope the new motor will be good for more than just another 30'000km....
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12-17-2014, 02:31 PM
Post: #24
RE: battery charging impossible
Excellent news. Glad it's sorted!
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12-20-2014, 02:56 PM
Post: #25
RE: battery charging impossible
(12-17-2014 02:31 PM)Buzby Wrote:  Excellent news. Glad it's sorted!
Indeed Smile
Somehow it's a bit worrying that a motor should fail so soon, but on the other hand I'm really glad it's a clear and straight fault, not a "now you see me, now you don't" hassle that's hard to fix. I suspect (but Renault won't ever tell of course) it's a design or production glitch which was not found during system validation. Not so uncommon for relatively low volume projects with limited budget and lots of new development like the Fluence ZE.

Probably solved in the meantime, at least for replacement parts. As long as they handle such things appropriately, I won't hold it against them.
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02-15-2017, 08:13 AM
Post: #26
RE: battery charging impossible
Just going through this exact process with my 2012 Fluence. New motor going in this week - BUT all will be paid by Renault, even though out of warranty! I didn't ask, they offered.

So, great service!

Sam.
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02-22-2017, 04:50 PM
Post: #27
RE: battery charging impossible
(02-15-2017 08:13 AM)Sam Rutherford Wrote:  Just going through this exact process with my 2012 Fluence. New motor going in this week - BUT all will be paid by Renault, even though out of warranty! I didn't ask, they offered.

So, great service!

Sam.

i am having a new motor fitted to the zoe
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