joeblow231 Posted October 11, 2016 at 01:04 PM Report Share Posted October 11, 2016 at 01:04 PM For the second time in about a year I came out to my garage to find the 12V battery dead and the HVB fully charged. I've looked at some of the other 12V battery threads and I don't think I saw anyone posting about this scenario. How is it even possible for the 12V to die after fully charging the HVB? The first time I was almost positive I hadn't but I assumed I must have left a light or something on that ran down the battery. I checked the battery this morning before starting and it was at 12.4V. It was colder today than it was the other day and it made it through last winter's coldest days without it happening. So it seems entirely random to me. The day before it died I only used the car for a few short trips and then plugged it back and I do recall seeing a battery saving message after one of the trips when turning the car off. I thought the charge process for the HVB also charged the 12V back up though. Quote Link to comment Share on other sites More sharing options...
Phatman Posted October 11, 2016 at 01:13 PM Report Share Posted October 11, 2016 at 01:13 PM Hey Joe- what year is your car? There's been several posts about this. The battery drain could be from a faulty Telematics Control Unit (TCU) or faulty wiring in the trunk where the battery is located. If your car is under warranty I would take it in and have the TCU replaced. See my post on TCU that I just posted. Let me know what happens. Good luck Quote Link to comment Share on other sites More sharing options...
murphy Posted October 11, 2016 at 03:27 PM Report Share Posted October 11, 2016 at 03:27 PM The charge process will charge the 12V after the HVB is finished. It does not monitor the 12 volt battery so once charging stops the car computers can run the 12V battery flat if left long enough. If my car sits unused for a week I connect a 12 volt battery charger with float capability to the terminals under the hood to keep it charged. Phatman 1 Quote Link to comment Share on other sites More sharing options...
joeblow231 Posted October 11, 2016 at 03:59 PM Author Report Share Posted October 11, 2016 at 03:59 PM It is a 2013 and is past the 3-year mark. I need to take it in for a recall so I'll ask about it when I do that. Both times this happened the car only sat overnight since that previous time it had been used. So between late afternoon/evening when it completed charging and the following morning the 12V ran down. Phatman 1 Quote Link to comment Share on other sites More sharing options...
larryh Posted October 11, 2016 at 05:06 PM Report Share Posted October 11, 2016 at 05:06 PM (edited) My 12 V battery was completely drained this morning. So I ordered a $66 Powerall portable battery charger from Amazon using Prime Now and jump started the car. It arrived within 2 hours as advertised. I had to use the key to open the door and fold down the back seat and use a weed puller to open the trunk. Looking back at my logs, the SOC of the 12 V battery was fine for the past week, around 85% (which is normal). I note that in the previous two days, there was excessive 12 V battery drain/charging while the car was on and running (more than 10x the normal amount). There was no significant drain while the car was sleeping or off. Also, the car was generating the warning tone when the car was started, but no indicator lights came on. Something was wrong. Yesterday morning the SOC was 77%. This morning when I jump started it, it was 18%. Something had failed to turn off last night. I suspect it was the TCU. The TCU no longer works at various locations. AT&T must have ceased 2G operations in those areas. When I arrive home, where 2G still works, the car uploads all the previous trips that it couldn't upload while I was away from home. Last weekend, it failed to upload the previous days data when I returned home from a trip. I suspect the 2G outages are confusing the TCU. I will have to monitor what the car is doing more carefully in the future to determine what is not turning off. I have the car currently plugged in so that it can charge the 12V battery. It charges the 12 V while charging the HVB and continues to charge the 12 V after the HVB has finished. SOC so far is back up to 72%. Edited October 11, 2016 at 05:15 PM by larryh Quote Link to comment Share on other sites More sharing options...
joeblow231 Posted October 11, 2016 at 06:41 PM Author Report Share Posted October 11, 2016 at 06:41 PM How are you determining the 12V SOC? Quote Link to comment Share on other sites More sharing options...
larryh Posted October 11, 2016 at 07:17 PM Report Share Posted October 11, 2016 at 07:17 PM (edited) You need and OBD II scanner and the ForScan application running on at tablet PC or smart phone to read the SOC from the car. It currently reads 80%. You can also measure the 12 battery voltage with all the doors closed and everything powered down. It reads 13.2 V at the moment. So it is fully charged. Edited October 11, 2016 at 07:17 PM by larryh Quote Link to comment Share on other sites More sharing options...
jdbob Posted October 11, 2016 at 09:04 PM Report Share Posted October 11, 2016 at 09:04 PM The TCU no longer works at various locations. AT&T must have ceased 2G operations in those areas. When I arrive home, where 2G still works, the car uploads all the previous trips that it couldn't upload while I was away from home. Last weekend, it failed to upload the previous days data when I returned home from a trip. I suspect the 2G outages are confusing the TCU. I will have to monitor what the car is doing more carefully in the future to determine what is not turning off. That's what I found. As long as I didn't drive out of town into 2G coverage it was fine. But when I went on vacation and there was 2G and then came back home, the next day the battery would be dead. After about the 3rd time I removed the TCU. Got it replaced under warranty this April so at least Go Times would work. Will be interesting to hear from Ford what the terms of the 3G replacement TCU will be. Quote Link to comment Share on other sites More sharing options...
Russael Posted October 11, 2016 at 10:15 PM Report Share Posted October 11, 2016 at 10:15 PM I have yet to experience this phenomenon. There have been occasions where I have kept the car parked for a couple days and went out to the garage for this or that, and noticed the car had engaged the EVSE (no, I did not do any updates with Myford Mobile). I know the HVB isn't running down, so it seems the car DOES monitor the 12v and will top it off when it starts running low, so long as it is plugged in. This behavior was probably introduced in later computer calibrations to prevent the 12v from going dead. I had the dealership update all of the modules in the car back in 2015 (paid a pretty penny for it too). They found 10 modules in the car and every one of them had a new calibration for it. I let them go ahead and do the updates which took around 4 - 6 hours. But I haven't had any strange behavior since then, except where post updates the go times wouldn't work... they applied a patch and fixed that, and that was it. Other early bugs such as the AC light not illuminating when the AC compressor was engaged was fixed, and there were likely tons of other bugs that I just didn't know were there that was also resolved. You keep your PC updated with monthly patches and fixes (security or otherwise)... Tesla does that for you remotely. No other car company does this. Sadly, it's a manual, painfully slow process, and isn't something they want to do unless it is deemed broken. I asked for an exception. Quote Link to comment Share on other sites More sharing options...
joeblow231 Posted October 12, 2016 at 01:03 PM Author Report Share Posted October 12, 2016 at 01:03 PM My 12 V battery was completely drained this morning. So I ordered a $66 Powerall portable battery charger from Amazon using Prime Now and jump started the car. It arrived within 2 hours as advertised. I had to use the key to open the door and fold down the back seat and use a weed puller to open the trunk. Which model did you get? I have something similar that I got from Costco but it wouldn't work, It just beeped at me to disconnect every time I tried. So I had to daisy chain some jumper cables to be able to get from another car to the terminals under the hood since it was stuck in the garage. Quote Link to comment Share on other sites More sharing options...
larryh Posted October 12, 2016 at 07:54 PM Report Share Posted October 12, 2016 at 07:54 PM The Deluxe: http://thepowerall.com/index.php?route=product/product&path=304_305&product_id=93 It was $66 through Amazon Prime with free 2-hour delivery. Otherwise, it is $77 with 2-day shipping. Strange. Quote Link to comment Share on other sites More sharing options...
Timewellspent Posted October 12, 2016 at 08:50 PM Report Share Posted October 12, 2016 at 08:50 PM My 12 V battery was completely drained this morning. So I ordered a $66 Powerall portable battery charger from Amazon using Prime Now and jump started the car. It arrived within 2 hours as advertised. I had to use the key to open the door and fold down the back seat and use a weed puller to open the trunk. Will the Powerall work by using the positive jump post under the hood or does it need to be connected directly to the battery in the trunk? Quote Link to comment Share on other sites More sharing options...
larryh Posted October 12, 2016 at 10:35 PM Report Share Posted October 12, 2016 at 10:35 PM I don't know why it would make a difference where it is connected. I connected it to the battery terminals in the trunk. I had disconnected the battery hoping the battery would recover enough to start the car. So I was in the trunk. There was a large drain on the battery everytime I attempted to connect the terminals. The car needed to be jump started. When fully charged, I measure 12.25 V across the terminals of the Powerall. Quote Link to comment Share on other sites More sharing options...
murphy Posted October 12, 2016 at 11:59 PM Report Share Posted October 12, 2016 at 11:59 PM It should be connected to the terminals under the hood for two reasons.1. There may be hydrogen in the vicinity of the battery in a closed space. spark = boom2. The computer needs to monitor current flow both into and out of the 12 V battery. Connecting to the battery terminals prevents the monitoring. Timewellspent 1 Quote Link to comment Share on other sites More sharing options...
larryh Posted October 13, 2016 at 07:46 AM Report Share Posted October 13, 2016 at 07:46 AM (edited) I noted sparks every time I connected/disconnected the 12 V battery. The lights and other things were attempting to drawing significant current from the battery, but the battery couldn't provide enough power to illuminate the lights or start the car. There must have been some other significant power drain. If hydrogen could be present, then there would be a problem connecting/disconnecting the battery and one needs to be careful doing so. The car will eventually recalibrate the SOC calculation of the 12 V battery after the car has been turned off for a while. At the moment, it computes the SOC of the 12 V battery to be 100%. Edited October 13, 2016 at 08:20 AM by larryh Quote Link to comment Share on other sites More sharing options...
rbort Posted October 13, 2016 at 02:14 PM Report Share Posted October 13, 2016 at 02:14 PM Those small jumper batteries apparently don't work in a pinch, other people have bought and tried them and they were not good enough to bring the voltage up enough for the car to start. When the car is in distress (low 12v battery), all kinds of things start coming on, I had my lights flash (parking lights and internal lights) when I was recharging the 12v battery back in winter 2013/2014 with an external charger to get it going again after I forgot the parking lights on. Once the power came up past 10.5v, then the crazy blinking stuff stopped, the car's 12v system became more stable, and I got a text message that the car's 12v battery was low. Only then was I able to plug in the car's stock 110v charger and have it work, once it took over charging the car, I disconnected my external 12v battery charger. -=>Raja. Quote Link to comment Share on other sites More sharing options...
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