12V battery cumulative drain higher then overall charging.

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Just for grins, made a few current measurements by inserting a small precision resistor in series with the ground terminal and measuring the voltage across it...

Power OFF, car unlocked = 17.2ma
Power OFF, door locked using key fob = pulsing between 17ma and 20.6ma, faster than my DVM could track

Basically confirms Al123's measurement.

Realistically, I would not leave the car sit for more than a week without either running it (to recharge the 12v battery) or putting a float charger on it. Lead acid batteries do not like to be cycled. If outside, use a small solar panel + regulator. I have a fused Anderson PowerPole connector on every 12v battery in every one of my cars, which makes this quick and easy.

Had an 'interesting' experience: after I unlocked the iMiEV door with the key fob I then tossed the key fob onto the driver's seat through the open window... about 30 seconds later, the doors all locked themselves!
Greetings from across the pond. I am new to your forum, but found this thread on Google as the 12V battery in my Peugeot Ion (badged iMiev) went flat recently.

I could not understand how this could happen as I thought it was powered continuously from the main bank, but your posts indicate this is not the case which is a relief as I thought I had a major problem. I was also interested to see your measurements of the parasitic load, or residual current as we call it in the electric boat business.

As you have calculated, a 20mA residual will draw approx 0.5Ah per day, 4A per week, 40Ah in 10 weeks.

However if the battery is old it will not have its original 40Ah capacity. This is due to sulphation and general degradation of the plates. Some of you are saying you still have the original battery, so 12 years old, in which case I would strongly advise buying your car a birthday present. By this age you could be down to 10% capacity, so 1 week to go flat.

Also disconnecting the battery long-term is not a good idea, as it will self-discharge due to internal currents, and this will increase as it gets older. A low output trickle-charger is the best solution, but buy a good quality one, otherwise as people have said you could damage the battery.

Out of interest I am still getting 65 mile range in summer, 53 in winter 10C from what I think is the 13kWh pack, 32k miles.

Thanks again

@georgetheboat, welcome to the forum. Just like electric cars, IMO electric boats are the future. Your range is still excellent - I take it that your iOn is newer than 2012 as that indicates LEV50N cells?

Our i-MiEV stock 12v battery is ideally 33Ah, and I just slap a float charger on any of my cars that will sit for more than about four days as I hate to see lead-acid cycle. Your advice to replace it is well-taken, as that is the simplest way of avoiding various issues with the i-MiEV triplets.

As you had noted, the i-MiEV's 12v battery is not continuously monitored and the car does not wake up to recharge it from the main pack - unlike a Tesla (and some other BEVs?). For myself, living in a mild climate, all my future 12v batteries will be LiFePO4.