Site Moderator
Posts: 3459
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Investigation - fast 12v depletion while stored

Tue Apr 10, 2018 11:14 am

jray3 wrote:...I confirmed that the ACC position does not bring in the dc-dc, as my house battery (a yachting term) is resting at a measly 12.1V even after an overnight charge plus an hour of driving. :o With temperature correction for 50 degrees F, that's only 25% state of charge, and turning on the headlights and radio pulls it down to 11.5 V within a minute.
:shock: jray3, where exactly are you measuring that 12v?
jray3 wrote:Teslas are notorious for a short service life on their 12V batteries due to the standby loads and continuous wireless connectivity.
Yup, the inordinate cycling contributing to its demise, which is why I keep my Tesla's 12v battery on a float charger. Left to its own devices, the Tesla wakes up and recharges that 12v battery from the main pack a few times daily, depleting the main pack at about 1%/day.

Back to the i-MiEV: if I know one of the i-MiEVs won't be driven for even a couple of days, I slap a float charger onto it. Have a fused Anderson PowePole connector directly across each i-MiEVs 12v battery.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Posts: 1470
Joined: Tue Dec 06, 2011 1:05 am
Location: Tacoma area, WA
Contact: Website

Re: Investigation - fast 12v depletion while stored

Tue Apr 17, 2018 2:23 pm

Joe, I'm reading that 12V at the cigarette lighter, err. 'accessory outlet'. Need to go straight to the battery posts, it's just harder to do solo. I haven't gone further than this because the car shows no other signs of being dissatisfied with the 12V system, the weather is warming up, and I have a lithium jump starter in the emergency kit.
2012 i-SE "MR BEAN" 87,000 miles
2012 i-ES traded at 21,648 miles
1983 Grumman Kurbwatt,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh
1965 Karmann Ghia Cabriolet

Site Moderator
Posts: 2908
Joined: Fri Apr 27, 2012 4:22 pm
Location: Pittsburgh, PA
Contact: Website

Re: Investigation - fast 12v depletion while stored

Sat Apr 21, 2018 3:27 pm

Been a while. I went to get my flash drive with music out of the I-MiEV. The car's been sitting since April 3. I went out to the car, it unlocked and started just like normal. I started it up and let the battery charge up a bit.

Tonight, I plan to go out, unlock the car, open the door, close the door, and lock it back up, and let it sit for a few days to see what happens.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

2017 Bolt EV LT in Orange with QC - 7/31/2017

Driving electric since 2-21-2013.

Return to “Batteries and Battery Management”