12V battery
05-25-2019, 07:16 AM
#31
AudiWorld Member
If the HV battery charges the 12v battery when the vehicle is "on", I think that's good enough to deal with the problems I've had with both BMW and Porsche. When I was doing a lot of in-town driving, the charging profile of those two cars would not run the alternator hard enough to replenish the 12v battery's use for the starter and after a couple of weeks of short stop driving the 12v battery would be "flat". I had to keep the cars on an auxillary charger. The HV battery surely has enough capacity to replenish the 12v battery quickly, plus there is no "starter" load. So, It appears that there is little chance of the 12v battery not being regularly recharged to full capacity. In my 2015 BMW, the 12v batteries were being replace as a matter of course at the 2-year point because the charging profile had the alternator feeding it only on coast down and over run (an attempt to maximize fuel efficiency). BMW found out that the 12v battery was never getting fully charged with short trip driving using this regime.
05-25-2019, 07:37 AM
#32
AudiWorld Member
Thread Starter
I issue I face is when I leave the car garaged for a few months when I go away to my seasonal home. With my ICE and my 2017 Leaf, I would put the 12v on a battery tender. Worked great and no issues when I returned. Audi strongly states NOT to charge the 12v. Bummer.
If you want to be safe, you can install a battery disconnect. That would make it safe to run the battery tender during that time.
05-25-2019, 08:11 PM
#33
AudiWorld Member
I was curious and I plugged in a cigar lighter volt meter. and am seeing 14.75 V as soon as I turn on the e-tron. That voltage reading means the e-tron is charging the battery, as normal "idling" voltage of a 12 V lead acid is < 12.8 V
08-31-2019, 03:34 AM
#34
AudiWorld Junior Member
DC-DC Converter capacity
Anyone know what the DC-DC converter capacity is? Anyone tried running an inverter from the 12V battery with the car on? This has been done on a Bolt with a 2KW inverter.
09-01-2019, 07:33 PM
#35
SWFla-eTron
perhaps somebody can post a VIN number or one that is one digit off from one and we can then look at a manual. The previous posting of VIN numbers was from pre-production cars (I think they had XXX in the number) and thus a non-valid number to get the manual.
Audi Online Owner's Manual
Audi Online Owner's Manual
09-02-2019, 04:36 AM
#36
AudiWorld Member
Several forum members have been told by Audi USA, myself included, that you can use a battery maintainer such as a Battery Tender (tm) with the e tron especially when it will be idle for a long period of time. As we travel a bit, we have use our BT’s on all of our cars when away. All are hardwired to the connector including our e tron. One car that we rarely use can be on a BT for months at a time. When we finally remember to exercise this IC vehicle, it fires right up. If you wd like a description on how easily I hardwired the e tron, let me know.
09-03-2019, 04:35 PM
#37
SWFla-eTron
Pos terminal 1/2” SS hose clamp
Pos terminal inside this junction box
Negative terminal with 3/4” clamp as it is slightly larger
Used a quick ‘n dirty connection instead of mounting the ring connectors under the positive and negative terminals. I was concerned that I would inadvertently disconnect the battery and erase some items programmed in the MMI, e.g., garage openers, Amazon Music.
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John (aka Daddio) (09-04-2019)
09-03-2019, 06:02 PM
#38
Does anyone know if you can use a battery maintainer that uses a lighter plug. I have one that I have used for a number of years with a car that was regularly not driven 5 months at a time.
09-03-2019, 06:19 PM
#39
SWFla-eTron
I would check with Audi USA even if your lighter plug remains hot when the car is off. I wrote to them about use of a Battery Tender and they got right back to me.
09-04-2019, 05:36 AM
#40
I don’t think that is the case. My radar detector shows the voltage and I have found that the voltage can increase substantially as the car is parked overnight. It often shows higher voltage when I drive off vs when I arrive back home.