3ricj
Posts: 6
Joined: Fri Mar 16, 2012 7:45 pm
Delivery Date: 16 Mar 2012

How fast does the 12 volt battery charger charge?

Fri Mar 16, 2012 8:09 pm

I'm sure some of ya'll are trying to max your miles and usage - - but I'm headed in the other direction.

I'd like to hook up some power hungry 12 volt devices to my 2012 leaf. Specifically, around a 1kw sound system.

I'm sure the 12 volt battery can deliver the watts I need. From what I can tell, the leaf will topup the charge on the 12 volt battery using the solar cell (I assume this is at best 50 watts).. but in addition also uses some onboard charger to maintain charge using the main batteries.

My question is: At what rate does the onboard charge system charge the 12 volt battery?

Cheers,
-3ric

User avatar
TomT
Posts: 10570
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: Foothills of Granada Hills, CA
Contact: Website

Re: How fast does the 12 volt battery charger charge?

Fri Mar 16, 2012 8:14 pm

By measurement, about 4 to 5 watts...

3ricj wrote:From what I can tell, the leaf will topup the charge on the 12 volt battery using the solar cell (I assume this is at best 50 watts).
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2016 Volt Premier. Model 3 configured.

User avatar
Ingineer
Posts: 2736
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: How fast does the 12 volt battery charger charge?

Thu Jun 21, 2012 12:43 pm

It should be able to power your 1kW stereo rig with no problems, and no voltage sag.

The Leaf's DC-DC converter can supply up to about 1.7kW or 135a. This unit takes ~400v power from the traction battery and makes approximately 13 volts. (varies according to charge requirements of the 12v aux battery) It should be able to power up to 1.5kW of external load with no problems, provided most of the accessories are left off.

One interesting thing is, unlike the 12v system on a ICE car, there is almost no voltage sag. The DC-DC converter is a high-frequency switch mode converter, so it can respond very fast to high current surges, whereas a normal ICE car alternator cannot, and it's also RPM dependant for maximum output.

WARNING: NEVER connect anything directly to the negative post of the Leaf's 12v aux battery! This is a current sensor and doing so will disrupt the charging system! (Connect all accessories to the body ground, or, if high-current, the black wire screwed to the top of the DC-DC JB. (Behind the inverter)

Note: I have not tested it at full load for an extended period of time, so there may be some thermal limiting that could cause output to drop after long runs of high-current use.

Here's my test:
Image

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/ - - - - Like us on Facebook: EVSE Upgrade

taztaz
Posts: 68
Joined: Mon Nov 22, 2010 9:17 am
Location: King's Hill, Sweden

Re: How fast does the 12 volt battery charger charge?

Wed Jul 11, 2012 10:06 am

That is perfect to know! thank you! Will the 12v battery be charged when the car is "turned off"? .. For example if i connect some appliances to the 12v that will use power when car is off? .. By the way, is there outlets in the car that can give 12v while car is off?

SierraQ
Posts: 185
Joined: Mon Oct 18, 2010 8:44 am
Delivery Date: 02 Sep 2011
Location: Dallas, TX

Re: How fast does the 12 volt battery charger charge?

Wed Jul 11, 2012 10:15 am

Ingineer wrote:WARNING: NEVER connect anything directly to the negative post of the Leaf's 12v aux battery! This is a current sensor and doing so will disrupt the charging system! (Connect all accessories to the body ground, or, if high-current, the black wire screwed to the top of the DC-DC JB. (Behind the inverter)


Thank you for that one! I just know one of these days I'll be connecting my inverter directly to the battery to run something big and I probably would have done this!

PS: LeafScan looks pretty. Where is mine? :D :D :D
"Please tell me this doesn't run on gas! Gas explodes, you know?" --Susan in I-Robot

defiancecp
Posts: 367
Joined: Mon Aug 16, 2010 4:02 pm
Delivery Date: 25 Aug 2011
Location: Little Rock

Re: How fast does the 12 volt battery charger charge?

Wed Jul 11, 2012 10:57 am

For reference, my own system has been running about 6 months - total of about 60A max draw, most channels driven at minimum acceptable impedance, and the impact to range has been below measurable levels. No visible impact to 12v accessory systems either (no lights dimming, etc). It's been so surprisingly low impact that I'm planning to ~double it :)

the one thing I've been extremely dissatisfied with is the head - I thought due to its interaction with the rest of the vehicle I'd figure out some way to make line output converters work, but it just hasn't been an acceptable solution. The output from the head unit itself is simply too low quality.

If giving up some functionality is acceptable, you can definitely run an aftermarket unit, but you lose quite a bit:
-Control over charging timers
-Display of climate control functions
-Remote control (climate/charging) functionality
-All carwings functions
-Setting of car functions like auto headlights and auto door locks
-most power consumption/usage displays

Now none of those are functionally critical, but some are relatively important - probably most notably being the charging timer controls.

I started development of a USB device and PC software to interface via CAN and replicate a lot of those functions (so you could use an in-dash PC to replace the stock head unit), but got distracted on other projects. I did get basic CAN-to-device and device-to-PC functionality, but that's about as far as I got. Need to get back to work on that darnit...

Most of the development is just needed work, no hurdles other than time... The only real hurdles I had were hardware... I really don't want to cut wires, but I need to interface with about 2/3 of the ridiculous number of wires connected to the thing :) Wish I could find wired connectors to connect to all the plugs, but I'm pretty sure that's not happening. Thought about dissecting my stock unit and just using the plugs from it, but when I found out the factory prices them in the $1200 range, I thought maybe I should keep it intact :)

User avatar
Nubo
Posts: 4511
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: How fast does the 12 volt battery charger charge?

Wed Jul 11, 2012 11:34 am

Ingineer wrote:It should be able to power your 1kW stereo rig with no problems, and no voltage sag.

The Leaf's DC-DC converter can supply up to about 1.7kW or 135a. This unit takes ~400v power from the traction battery and makes approximately 13 volts. (varies according to charge requirements of the 12v aux battery) It should be able to power up to 1.5kW of external load with no problems, provided most of the accessories are left off....

-Phil


Phil, isn't this somewhat below a typical alternator setup? Although some blame the reflectors, I think this is maybe why the high-beams are underwhelming despite having what are normally high-output bulbs. Lumen output of a incandescent bulb is highly dependent on voltage.
I noticed you're still working with polymers.

defiancecp
Posts: 367
Joined: Mon Aug 16, 2010 4:02 pm
Delivery Date: 25 Aug 2011
Location: Little Rock

Re: How fast does the 12 volt battery charger charge?

Wed Jul 11, 2012 12:14 pm

I know into the early 2000's many alternators were in the just-over-100A range (ie, most 90's-to-2000's GM Alternators were 105A). Also keep in mind those ratings are not idle amperages, I think they generally need to be spinning @~2000rpm to reach rated output.

Just checked on a couple examples - a 2010 Escalade Platinum uses a 160A alternator, so they're definitely increasing, but amperages in the 135A range still should NOT be a problem, especially considering the constant nature of the dc/dc in comparison to an alternator at idle/low cruise...

Oh wait, you're saying voltage, aren't you? That's a fair point then - If the leaf is in the 13v range, that does compare a little bit unfavorably to expected alternator system voltage of ~14.4v

User avatar
Ingineer
Posts: 2736
Joined: Fri Oct 15, 2010 1:09 pm
Delivery Date: 13 Jul 2011
Leaf Number: 6969
Location: Berkeley, California
Contact: Website

Re: How fast does the 12 volt battery charger charge?

Thu Jul 19, 2012 11:30 am

It's maybe slightly lower, but that doesn't explain the high-beams. Reflectors is one, and the other is that the LED low beams work so well that in comparison the halogen high's just don't look all that bright.

One thing you can do is adjust the LED low beams a little higher, then use the wheel on the dash to raise them high when on dark roads.

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/ - - - - Like us on Facebook: EVSE Upgrade

electrifeyed
Posts: 18
Joined: Tue Apr 16, 2013 10:19 am
Delivery Date: 13 Apr 2013
Leaf Number: 401128
Location: Alabama
Contact: Website

Re: How fast does the 12 volt battery charger charge?

Thu May 09, 2013 5:56 am

Here's a question: could you replace the original 12-v battery in Leaf with a larger deep-cycle one (assuming you could make it fit in the space)? (Or would this do more harm than good, since car recharges this from the traction battery?
2013 Leaf S /2006 Toyota Highlander Hybrid / 1991 Mercedes 300D Diesel / 2006 Mercedes SLK 280
Affiliated with The University of Alabama / Engineering Dept.

Return to “Batteries & Charging”