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EREV owner
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Discussion Starter #1
Sorry guys, long post.
Last weekend I had my first problem in over a year of ownership.
I arrived home on Friday just as the range ran out. I parked the car but didn't plug in because I was going out in a few minutes. In the end I didn't and forgot to plug in the car.
Next day I realised but didn't overly care and just ran on petrol.
After driving about 20 miles I had a number of shorter trips.
On one occasion I turned off the car and remained in it while she went into a shop for 5 minutes.
When I pressed the blue button the car did not 'boot' up. I got 4 error messages on the dash, none of which were related so I expected the 12 volt immediately. I tried all the obvious, like getting out and locking the car, waiting, etc. But nothing helped. I eventually called a breakdown service who would take an hour to arrive. We left the car and returned an hour later and I tried to start the car but no change.
When the breakdown arrived I asked him to use the 12 volt booster and the car started normally, with no errors displayed other than the check engine light, which went off two days later. I drove home and told the car to charge immediately and have had no issue since.

Now, I have a new 12 volt battery in the car, bought last March, a Tayna D52 Varta Start-Stop Plus 027 AGM Car Battery 12V 60Ah

Having read up on how the car charges the 12 volt, it is a complicated and well thought out system. My understanding is that when plugged in every 6 hours the car looks at the 12 volt and will charge it if required.
When driving the 12 volt is charged from the high voltage battery determined by what systems are being used, like wipers, lights, etc.

I checked the voltage on the 12 volt the next morning on the terminals of the battery and it was 12.1v. According to the manual this is ok for cold weather. The snow was on the ground and the temp was around 1 deg C when this happened. I turned the car on and checked again and the voltage was 14. something so the car is servicing the 12 volt.

Any suggestions what happened? I know I should have plugged the car in but as I had driven 20 plus miles that day I would have expected the 12 volt to have been charged normally, especially with a new battery.

Has anyone else had an issue with this battery in lowish temperatures?

Thanks for reading this longer post and any help/suggestions offered.
Peter
 

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I suspect your driving profile for that day meant that the 12v got discharged more than normal, I had the start up problem with a hot battery temperature 30 degrees not a cold one but same efect.
The voltage from the 12v sagged under load to the point where the electronics could not start up and I needed a 12v power pack to suessfully re-start the car, all the issues went away when i chaged out the 12v battery.
Just measuring voltage is not really a good test you need to measure the voltge at specific load and look at the rate of voltage drop.
AGM batteries don't tolerate high charge rates in the same way as nornal lead acid does so they take on energy slowley, given that the enenrgy to charge them has to come from the traction battery I'm sure that if you measured it it would only be enough to maintain battery condition and that recharging a flat 12v takes a long time in the car.
12.1v on no load seems a bit marginal to me, fully discharged voltage is 11.5v.
Is your car a 2012 model, they have issues taking care of their batteries compared to later cars.
 

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EREV owner
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Discussion Starter #3
Thanks for this.
My car is a MY 2013. I agree 12.1v seems low but the information on the 12 v charging system states 12.1 as being within spec. when cold.
 

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This "problem" with the 12v battery always amazes me that it is even there. At 60Ah and a 550A cranking current spec it should last donkeys years.
How can the 12v battery fail to pull in a 1-2A contactor coil? Even when discharged there should be a reasonable voltage there.
The ECU should be designed to operate on 9v or less as ICE ECU's have to in cold weather when turning over a cold engine.
Pb batteries are designed to drive hundreds of amps for a short time. Headlights and a couple of amps for a coil is a stupid reason for all these low battery failures and to think we have a page on the in car display for warnings etc but no low battery alarm?
Pathetic!
 

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EREV owner
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Discussion Starter #6
Ok guys, this has happened again.
This time I did charge the car the night before, fully charged, everything fine. I drove it about 30 seconds and parked for about 2 hours, then drove back. 5 minutes later I pressed the blue button and got the same issue as before. I now have a 12v battery booster pack and with it connected the car started fine. I drove 15 miles and stopped for 10 minutes while I went shopping, car started fine. About 90 minutes later the same issue occurred again, started with the booster pack, and again about 90 minutes later.

The air temp was higher this time, around 4 or 5 deg C.

This car has a 10 month old 12v battery fitted, a Tayna D52 Varta Start-Stop Plus 027 AGM Car Battery 12V 60Ah.

Has anyone else had any similar issues using this battery?
I'm so glad I have the booster pack now as this will leave you stranded without warning.
But I still don't want this to become a habit.

Help please

Peter
 

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I'm not crazy, the attack has begun.
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Crap battery?

Tayna delivered me a totally dead Bosch S5 and I am never sure it was really properly working still after being charged back up. I would be reluctant to buy a mail-order battery again, and will pay the extra to buy one from a local stockist due to the convenience of being able to go bend an ear to check it. As it turned out, and had I known, the local official Bosch stockist would have supplied for just a couple of quid more than Tayna did it for.

I have a standing recommendation to move away from cranking batteries for EVs and to use deep discharge batteries. They are lighter smaller and charge more efficiently in terms of the overall energy you can suck out of them down to relatively low voltages before they 'sag' under sudden loads. You will have to figure out all the little details yourself if you want to take that advice, like size, terminal fitments, etc..

But my presumption would be that the battery was delivered in a somewhat defective state.

have you ever charged it with a proper battery charger? It may never have fully achieved float charging and might have started sulphating while in Tayna's stock. Get or borrow a quality charger, if you don't have one already, remove the battery and put it on a desulphation cycle one weekend when you're not using the car.
 

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@ArchivePete you need a voltmeter to check for low volts. You may have one or more cells duff as the power required to power up an EV is very minimal.

I've noticed that under certain conditions, the dashboard socket will power up without the start button pressed. A voltmeter plugged in here will give a representative idea of the battery voltage before the DC-DC power supply is started to charge it and take over power requirements.

When its very cold, mine shows 12.5v before powering up and from 13.5v up to 15v when in operation.

@donald is correct, EV's are ideally suited to use deep discharge marine/standby batteries as that basically is what they do.
 

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I'd be interested to know the process to get the dashboard cubby-hole-box 12V socket to energise, before pressing the Start button. Maybe there's a way of energising the entertainment system when in "standy-by" mode or something, like the one-click on older key ignition systems? Maybe it's in the manual somewhere...

I have a 12V meter on permament connection - and a 3D printed bracket I made to hold it. Let me know if you want a similar bracket making up for you. Details here of the meter I use. (Being a cheapo Chinese item, it doesn't always boot-up cleanly, sometime shows me garbage voltage like 4V! So I just have to reach into the cubby-hole & break-and-make the connection. Will be inserting a small push-button into the charger itself soon, to make the reset trivial...)
MUST have upgrades Ampera? Lights, etc
 

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I follow lots here and somewhere it was recommended to get a voltmeter and plug into the cigar lighter to assist with judging the condition of the 12v battery. So I got a cheap one from fleabay. For the first half mile ot so mine is in the 14 - 14.5v range then it drops to anything between 12.1 and 12.6 volts. It varies all the time, which I wasn't expecting.

What should it be? Car is a MY13, 2015 reg.
 

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14 - 14.5 is the charger in the car re-charging the 12v, anything above 12v is normally fine, 11.5v is regarded as flat so as long as you don't see less than 12v all the time no need to worry. The charger will have a cut in voltage between 11.5v and 12v
 
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