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12V battery and heated seat cover

Posted: Mon Dec 02, 2019 12:59 pm
by mbnvcxz
Hi everyone,

I wonder if you can share your collective experience and tell me whether using a heated seat cover connected to the 12V/cigarette lighter outlet will strain the 12V battery too much?

If I've understood things correctly, whilst driving (or in 'Ready' mode) the 12V battery is being continuously topped up by the DC-DC converter... does that mean you can draw as much power as you like e.g. with seat heater and not worry? Am I right in thinking the same is true when charging the car (via Type 1 cable and also via CHAdeMO)?

My instinct tells me it might be unwise to use a heated seat cover while parked and not in ready mode (or charging?) as I assume that would be draining the 12V battery.

I have a 2012 Peugeot iOn (bought used earlier this year) and I can't find any evidence that the 12V has ever been replaced, though I'm not certain. So I guess I'm a little wary of working it too hard just in case. Is it true that if the 12V gets too low then you can't charge the main battery (or drive)?

I have done a few checks on the 12V battery with a multimeter and here's what I got.

On a coldish day (maybe 5 deg C) when the car had been driven earlier the same day:
12.81V just parked
14.66V in Ready mode

On slightly colder, frosty morning (maybe 0 deg C) when the car had not been driven or charged for around 36 hours:
12.60V just parked
14.74V in Ready mode

Any opinions on the 12V battery's health based on that?

Thanks

Re: 12V battery and heated seat cover

Posted: Mon Dec 02, 2019 3:42 pm
by Don
You're correct on all counts . . . . except you can't "draw as much power as you like" from the cigarette type outlet because . . . . it's fused at 15 or 20 amps. But, it's safe to use something like your seat heater, so long as the car is in 'Ready' mode. I wouldn't use it any other time, as the cars 12 volt battery is small and easily depleted. The DC to DC converter is good for something like 80 amps, so no problem overdrawing anything when you're driving

A healthy, full 12 volt battery will show 12.6 volts at rest, but it may take an hour or two for it to fall to 12.6 when you remove the charge voltage. The DC to DC puts out on the order of 14.5, so what you have looks healthy and normal

But . . . . if you can determine for sure that it's still the original battery, I would replace it NOW, as most original 2012 12 volt batteries which haven't been changed out yet will very shortly become a problem - The car doesn't like a weak 12 volt battery at all. Measure your voltage after it's been sitting for a day or two and see what you get

Don

Re: 12V battery and heated seat cover

Posted: Tue Dec 03, 2019 5:42 am
by DBMandrake
mbnvcxz wrote:Hi everyone,

I wonder if you can share your collective experience and tell me whether using a heated seat cover connected to the 12V/cigarette lighter outlet will strain the 12V battery too much?

I have not one but two heated seat covers connected via a two way adaptor that also gives me a USB socket to charge my phone...
If I've understood things correctly, whilst driving (or in 'Ready' mode) the 12V battery is being continuously topped up by the DC-DC converter... does that mean you can draw as much power as you like e.g. with seat heater and not worry? Am I right in thinking the same is true when charging the car (via Type 1 cable and also via CHAdeMO)?

My instinct tells me it might be unwise to use a heated seat cover while parked and not in ready mode (or charging?) as I assume that would be draining the 12V battery.

As Don points out the cigarette socket itself has a maximum current limit - I generally would not try to draw more than 10 amps from a cigarette socket on any car, and even that much can cause quite a bit of heating of the socket if the plug isn't making a good connection, so a good quality plug with spring loaded centre pin is important for high current applications.

While the car is in READY mode, or Chademo or AC charging the DC/DC converter is topping up the 12v battery constantly to about 14.4 volts, under these conditions you cannot run the 12v battery down and effectively it is being powered by the charger or the traction battery.

However when the car is not charging and only in accessory mode (or key on but not READY) the 12v battery is not being charged and the seat cover is running from the 12v battery. If you were to leave this running many hours it would eventually discharge the 12v battery.

A heated seat cover is typically about 3 amps so would discharge a 30Ah battery in about 10 hours. I run my seat cover for up to about 30 minutes with the car not in READY and haven't had any problems, but that's on a recently replaced 12v battery which is nice and healthy. The original 12v battery couldn't manage that and in fact that's what made me first realise the old battery was stuffed!
I have a 2012 Peugeot iOn (bought used earlier this year) and I can't find any evidence that the 12V has ever been replaced, though I'm not certain. So I guess I'm a little wary of working it too hard just in case. Is it true that if the 12V gets too low then you can't charge the main battery (or drive)?

If a 2012 car has the original 12v battery replace it now! Before it lets you down... easy job to replace, here's the one I fitted which is a perfect fit and a higher Ah capacity than the original:

https://www.tayna.co.uk/car-batteries/yuasa/ybx5054/

Yes, if the 12v battery discharges too low you will not be be able to "start" the car, nor will you be able to put it onto charge without a "jump start" of the 12v battery to get it started.
I have done a few checks on the 12V battery with a multimeter and here's what I got.

On a coldish day (maybe 5 deg C) when the car had been driven earlier the same day:
12.81V just parked
14.66V in Ready mode

On slightly colder, frosty morning (maybe 0 deg C) when the car had not been driven or charged for around 36 hours:
12.60V just parked
14.74V in Ready mode

Any opinions on the 12V battery's health based on that?

Nope. All that 12.6 volts tells you after the car has been parked for many hours is that the State of Charge of the battery is near 100%. However that could be 100% of a very tiny usable capacity.

Mine also passed that test and was a healthy 12.6 volts the following day however when I tested the capacity after replacing it it was down to about 1Ah from an original 30Ah.......!

Just replace it and then be happy knowing that your heated seat covers won't cause you a problem and that you won't have the 12v battery letting you down any time in the next several years.

Re: 12V battery and heated seat cover

Posted: Wed Dec 04, 2019 7:33 am
by mbnvcxz
Thank you both for your advice. So basically heated seat cover is fine unless you're just parked without either charging or being in 'ready' mode. Which is great cos Chademo in December is getting to be a chilly experience thus far!

Except it's probably not fine if your 12V battery is 7 years old and if so it might let me down even without a heated seat cover. So I very much would like to find out if it was ever replaced by a previous owner...

Does anyone happen to know what the original 12 battery in a 2012 (62 plate) UK Peugeot iOn looks like? I've taken a couple of photos of what's in there: (mostly dust but I did try and rub it off where the writing is!)

Image

Image

Thanks again.

Re: 12V battery and heated seat cover

Posted: Wed Dec 04, 2019 9:23 am
by JoeS
The 2012 North American stock i-MiEV battery is Yuasa 34B19L(S).

I cringed when I saw the photo of your battery, as contamination of the top of the battery provides a minute leakage path. In your shoes I'd carefully clean the top of that battery and its terminals and, while you're in there, get a small mirror and flashlight and check the battery fluid level and top up with distilled water. Having that battery on my benchtop I also realized that the case is translucent and that shining a light through the battery will show the battery fluid level within it.

Re: 12V battery and heated seat cover

Posted: Wed Dec 04, 2019 9:31 am
by DBMandrake
mbnvcxz wrote:Thank you both for your advice. So basically heated seat cover is fine unless you're just parked without either charging or being in 'ready' mode. Which is great cos Chademo in December is getting to be a chilly experience thus far!

Yes if the car is in READY or you're actively charging (not just plugged in but not charging) then you can't run the 12v battery flat so use the seat cover to your hearts content while charging or in READY. Otherwise I'd limit heated seat cover use to about 30 minutes, and then it will top up the 12v battery when you start or charge the car again.

There are significant overheads (of at least 300 watts) in having the car sitting in READY going nowhere, even with fan/heater/lights etc turned off...so if you have a 20-30 minute wait to pick someone up (as I often do) and want the seat heaters on during that time, it's more efficient to just have the car in ACC and run the seat heaters off the 12v battery for that time and then allow it to be recharged when you go into READY to drive off than leave the car in READY while you wait the 30 minutes.

3 amps for 30 minutes is a 1.5Ah discharge from a 40Ah battery which is nothing for a healthy battery but will probably make your old 12v battery choke.

I also use the heated seat covers during Chademo charging in winter - boy does it make a difference! :)
Does anyone happen to know what the original 12 battery in a 2012 (62 plate) UK Peugeot iOn looks like? I've taken a couple of photos of what's in there: (mostly dust but I did try and rub it off where the writing is!)

Yours is the original factory fit battery, which is not available as a spare part in the UK anywhere other than dealers as far as I know (as it's technically a Japanese domestic market battery) so it's 99% sure that its the original battery, so I wouldn't even bother cleaning it or checking the water levels, just replace it...

You can see the original type here vs some of the replacements:

https://www.gogreenautos.co.uk/how-tos/ ... ry-battery

Re: 12V battery and heated seat cover

Posted: Wed Dec 04, 2019 10:21 am
by Don
DBMandrake wrote:. . . . so it's 99% sure that its the original battery, so I wouldn't even bother cleaning it or checking the water levels, just replace it...

Man, I agree! That battery has been in there a loooong time - Just look at the hold down nut

One good option is to use a Mazda Miata battery, if you can get that one over there. They use an AGM battery, so they can be shipped or mailed. The battery is a bit shorter than the iMiEV battery, but if you sit it on a block of wood 1 1/2" thick, it fits correctly using the stock hold down hardware and since it's sealed, you won't have all that junk accumulating on the top of your battery. I have them in both my cars and one of them has been in there 3 or 4 years now

Don

Re: 12V battery and heated seat cover

Posted: Thu Dec 05, 2019 3:05 am
by DBMandrake
While I've heard of a few people using AGM batteries in their i-miev's an AGM battery has slightly different charging regime requirements and maximum charge voltage than a normal flooded cell type, so using an AGM in these cars will actually slightly overcharge it all the time.

Personally I would just stick to a regular battery that is going to be a perfect fit and direct swap, then change it again in another 5 years...

Re: 12V battery and heated seat cover

Posted: Thu Dec 05, 2019 9:12 am
by WReed82
Hi Simon,

I put two AGM batteries in my 1982 Toyota diesel pickup truck more than ten years ago and they are still working very well.
The batteries are a bit smaller and lighter than the original equipment batteries.

Our Mitsu, named Maeve, got an AGM in May.
It's a little smaller and lighter than the factory battery, with higher specs.

Thanks and good health, Weogo

Re: 12V battery and heated seat cover

Posted: Thu Dec 05, 2019 10:13 am
by Don
DBMandrake wrote:While I've heard of a few people using AGM batteries in their i-miev's an AGM battery has slightly different charging regime requirements and maximum charge voltage than a normal flooded cell type, so using an AGM in these cars will actually slightly overcharge it all the time.

Gel batteries don't like charge voltages much above 14 volts, but AGM's do fine in any system which does not overcharge a flooded battery, causing it to gas and lose water. I'll be very surprised if an AGM in an iMiEV doesn't outlast a flooded battery. I've put AGM's in all my vehicles for many years with very good success - They usually last about twice as long as the flooded types they replaced

Don