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LEAF 12 Volt Battery Logging

Posted: Sat Aug 18, 2012 1:42 pm
by Nekota
I attached a MCC USB 503 http://www.mccdaq.com/usb-data-acquisition/USB-503.aspx to the LEAF battery using a fuse tap to a spare fuse near the driver door and grounded to the LEAF chassis at the same fuse panel. I set the logging rate to 1 per minute and recorded the voltage starting at 9:15 for about 40 hrs.

The data is graphed and commented in the following pdf. The LEAF Telematics was activated by the GreenCharge app every 30 minutes and shows up as spikes every 30 minutes. I use two charging timers, one with no start time but to end by 7AM and one that starts at 1AM and stops by 7AM. This LEAF is a 2011 SL model and has 13K miles and is parked outside. The pdf graph shows these details.

There appears to be a noticeable drop or load on the 12V battery after 80% charging is complete for 15 minutes. I will disable the GreenCharge app and up the sampling rate on the next set of data and see if the solar charging can be detected.

PDF Graph
https://docs.google.com/open?id=0B-80HT ... zBUeFdPWVE" onclick="window.open(this.href);return false;

CSV data
https://docs.google.com/open?id=0B-80HT ... i1TYmVnam8" onclick="window.open(this.href);return false;

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 9:18 am
by garygid
Very nice graph.
Shows 12.4v rising to 12.6v after charging.
Shows about 0.2v discharge during the day.

I intend to add 12v logging to my upcoming Black-Box logger, which will
log at least the EV and CAR CAN buses, and hopefully GPS info, among
with the 12v battery voltage.

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 9:28 am
by DesertDenizen
garygid wrote:Very nice graph.
Shows 12.4v rising to 12.6v after charging.
Shows about 0.2v discharge during the day.

I intend to add 12v logging to my upcoming Black-Box logger, which will
log at least the EV and CAR CAN buses, and hopefully GPS info, among
with the 12v battery voltage.
I wonder what language garygid and Nekota are speaking? :lol: :lol: :lol:

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 9:39 am
by TonyWilliams
I'm surprised how low the voltage is allowed to go.

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 10:33 am
by RegGuheert
Nekota wrote:I attached a MCC USB 503 http://www.mccdaq.com/usb-data-acquisition/USB-503.aspx to the LEAF battery using a fuse tap to a spare fuse near the driver door and grounded to the LEAF chassis at the same fuse panel. I set the logging rate to 1 per minute and recorded the voltage starting at 9:15 for about 40 hrs.
Thanks for doing this! I've been doing some manual 12-V data logging in hopes of seeing hate effect of discharge for many days. Unfortunately, I never know when the car may be driven and when it may be parked.

One annotation which might be interesting would be whether the EVSE is plugged in or not. That seems to have a significant impact on quiescent draw.
TonyWilliams wrote:I'm surprised how low the voltage is allowed to go.
Me, too. I will also note that the use of 13-V charging does not quickly restore the battery to full charge. There is certainly a trade-off between risking overcharging and letting the battery sit too long below 100% SOC. All other vehicles I know of opt for 14.4-V charging (only). Perhaps Nissan felt this was the best choice for the deep-cycle battery in the LEAF.

I do hope Nissan figures out a way to reduce the current draw on the LEAF 12-V battery when it is just sitting.

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 11:24 am
by garygid
Are we speaking too much "nerdish"?

If so, please ask and I will try to explain better.

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 11:49 am
by MikeD
I recommend people who have a "low tech" (and low cost) interest in the 12v battery hook up a small multimeter to that battery via an accessory plug in the 12v accessory port below the center console. Note that the accessory port is not connected to the 12v battery in "Off Mode".

Having done that myself I can also add that when the DC-DC converter initially starts charging the 12v battery it does so at 14.4v. After multiple observations it appears that if the 12v battery is only lightly discharged the charging voltage quickly drops to 13.1v -- otherwise it takes longer before this change.

Re: LEAF 12 Volt Battery Logging

Posted: Sun Aug 19, 2012 11:43 pm
by Nekota
garygid wrote:Very nice graph.
Shows 12.4v rising to 12.6v after charging.
Shows about 0.2v discharge during the day.

I intend to add 12v logging to my upcoming Black-Box logger, which will
log at least the EV and CAR CAN buses, and hopefully GPS info, among
with the 12v battery voltage.
I will send you my analogin code for your "v13" black box soon and am collecting some data to see what sample rates should be.

Re: LEAF 12 Volt Battery Logging

Posted: Mon Aug 20, 2012 1:17 am
by Nekota
RegGuheert wrote:
One annotation which might be interesting would be whether the EVSE is plugged in or not. That seems to have a significant impact on quiescent draw.
The LEAF is connected to L2 when ever it is at home which is right after commute home and until begin commute to work.