User avatar
IssacZachary
Forum Supporter
Posts: 833
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Apr 19, 2018 3:45 pm

jkenny23 wrote:Are you not considering hybrids for the larger initial cost? Priuses are dead on reliable from what I've read (and my personal experience with a 2011 as my second car), and with electricity prices as crazy as they are for me in California, it's cheaper per mile to drive the Prius, though I get free charging at work so all my commuting is with the Leaf. Sadly longer range EVs are still very much in a higher tier price bracket, and look like they're going to stay that way for at least a decade.

Since I've been keeping track in 2015, my total cost per mile including maintenence for my Prius is $0.066, and since I've bought it, is $0.044 for the Leaf (thankfully greatly offset by free charging, otherwise at $0.279/kWH would be $0.074/mi at 4.2mi/kWH).


Here in Colorado my electric rate is much cheaper than California's (around 10 cents per kWh). And I also can charge for free at work and some other places. (Of course good things don't last forever.)

I've seriously considered buying a hybrid. In fact with both the Colorado and Federal tax cuts I could get $9500 off of a new Prius Prime. And after driving a 1985 VW Golf for several years that consistently gets over 55mpg, a hybrid would likely be the only kind of car that would make me feel good about the fuel mileage. But the numbers don't crunch because, like you said, the high initial cost. Even a used Prius would be more expensive to own and operate than a cheap used ICEV, at least according to Edmunds TCO. And this may just be coincidence, but I keep finding lots of hybrids around here with dead traction batteries. I don't know if it's the cold or the steep terrain around here or just coincidence. I also understand that the cold offsets the fuel mileage quite a bit (well I guess it does in an all-electric too). The coldest I've seen it is -52°F. The second coldest record in Colorado was set not too far from here at -60°F. Most winters it gets down below -30°F for a few days.

Just yesterday I drove over 150 miles in the Leaf and went up more than 10,000 ft and down more than 10,000ft, starting at 7°F in the morning and getting back at 25°F at night with a peak ambient temperature of around 58°F. Battery temp bars ranged from 3 to 5. Charging off of level 2 with about 65 miles between charging stations, I got all my work done with time to spare. The total cost of electricity was $0 for the entire trip. Not bad for a 24kWh, 11-bar Leaf! :mrgreen:

It just feels like the Leaf just barely makes it though. I pulled up to my house with only 9% left on the battery.
2013 SL SOLD :cry:
1972 VW Beetle SOLD :cry:
1984 VW Golf diesel CURRENT :x
2013 Toyota Avalon Hybrid CONTEMPLATING :shock:

User avatar
IssacZachary
Forum Supporter
Posts: 833
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Mon Apr 23, 2018 5:23 pm

Any recommendations on what contactors to use?
2013 SL SOLD :cry:
1972 VW Beetle SOLD :cry:
1984 VW Golf diesel CURRENT :x
2013 Toyota Avalon Hybrid CONTEMPLATING :shock:

mux
Posts: 150
Joined: Sat Jan 13, 2018 3:52 am
Delivery Date: 13 Oct 2011
Leaf Number: 6177

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Mon Apr 23, 2018 10:32 pm

IssacZachary wrote:Any recommendations on what contactors to use?


Not that easy of a question to answer, because I've run into a couple issues.

Ideal choice: buy a Leaf contactor assembly and use those (e.g. https://www.ebay.com/itm/CONTACTOR-MAIN-RELAY-DC-450V-250A-500A-DISCONNECT-NISSAN-LEAF-GEN-2013-2015-2016/262994278965?hash=item3d3bae3a35:g:rscAAOSwfRdZH4oE).

Second good choice: get a salvage set of contactors from a recycler, ebay, etc. Any contactor from any plug-in hybrid or fully electric car will do, and I've seen them come by pretty cheap (like $40 for a set).

Nonideal, but what I did initially: get a couple of cheap contactors from China. I purchased https://www.ebay.com/itm/200A-12V-24V-48V-DC-High-Current-Relay-Contactor-On-Off-Car-Auto-Power-Switch-HQ/332602202242?hash=item4d70a2d882:m:mmbBymiKdBTKti955Pjmeiw.

The contactors will usually run fairly warm at 12V (12V x 0.4A ea = 10W for a set). I made a little circuit that engages the relays at 12V and drops down to ~5V after a second. Secondly, you HAVE to use two relays, don't skimp and only implement one. You'll get HV isolation warnings and your car won't start once in a while. Lastly, it's good practice to use a separate relay driver and not drive the relays directly from the RLY P/N lines on the VCM. Some people have had trouble with the relay drivers not managing the extra current and/or throwing errors. So treat the RLY P/N lines as 'digital' inputs to a separate relay driver circuit.

User avatar
IssacZachary
Forum Supporter
Posts: 833
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Mon Apr 23, 2018 10:52 pm

mux wrote:Not that easy of a question to answer, because I've run into a couple issues.

Ideal choice...

Thanks again! (This forum needs a thanks or thumbs up button for each post. Just imagine I put a thumbs up on nearly every one of your posts in this forum.)
2013 SL SOLD :cry:
1972 VW Beetle SOLD :cry:
1984 VW Golf diesel CURRENT :x
2013 Toyota Avalon Hybrid CONTEMPLATING :shock:

Cor
Posts: 161
Joined: Sun Jun 30, 2013 6:53 am
Delivery Date: 07 Jul 2015

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Tue Apr 24, 2018 5:11 pm

IssacZachary wrote:Any recommendations on what contactors to use?

If you want a set of original Leaf contactors (including the pre-charge) then let me know, I have several contactor boxes from the Leaf packs that I disassembled. I am using twin Leaf packs in parallel, each with its own BMS, in my electric truck.
Since it already had its own contactors, I do not need the Leaf contactors that I removed.

mux
Posts: 150
Joined: Sat Jan 13, 2018 3:52 am
Delivery Date: 13 Oct 2011
Leaf Number: 6177

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Tue Apr 24, 2018 11:08 pm

Another video update on my car, posting it here for those who are interested:

https://www.youtube.com/watch?v=0i6VcZXXQyY

In short: Swapped tires out for 51PSI capable ones and immediately saw a decent efficiency increase. Should be able to (just about) hit 250km (155 mi) of range if I'd run it all the way dry. Aeromods so far have not meaningfully contributed, and I'm working further towards making a hardware kit to upgrade the Leaf with an extender.

lorenfb
Posts: 1801
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Apr 25, 2018 2:26 pm

mux wrote:Another video update on my car, posting it here for those who are interested:

In short: Swapped tires out for 51PSI capable ones and immediately saw a decent efficiency increase. Should be able to (just about) hit 250km (155 mi) of range if I'd run it all the way dry. Aeromods so far have not meaningfully contributed, and I'm working further towards making a hardware kit to upgrade the Leaf with an extender.


You mention in the video that you've reduced (~ 50%) the coil currents of the main power relays of the add-on battery.
Are you concerned that the contact resistance of the relay will increase to a point where the relay life may shortened or
that a problematic relay contact voltage drop, e.g. at 100+ amps, may occur?
Leaf SL MY 9/13: 66K miles, 50 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 charges to 100% > 1000, max battery temp < 95F (35C), min discharge point > 20 Ahrs

mux
Posts: 150
Joined: Sat Jan 13, 2018 3:52 am
Delivery Date: 13 Oct 2011
Leaf Number: 6177

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Apr 25, 2018 10:46 pm

lorenfb wrote:
mux wrote:Another video update on my car, posting it here for those who are interested:

In short: Swapped tires out for 51PSI capable ones and immediately saw a decent efficiency increase. Should be able to (just about) hit 250km (155 mi) of range if I'd run it all the way dry. Aeromods so far have not meaningfully contributed, and I'm working further towards making a hardware kit to upgrade the Leaf with an extender.


You mention in the video that you've reduced (~ 50%) the coil currents of the main power relays of the add-on battery.
Are you concerned that the contact resistance of the relay will increase to a point where the relay life may shortened or
that a problematic relay contact voltage drop, e.g. at 100+ amps, may occur?


These particular relays are supposed to be rated to full engagement down to 80mA, and I've tested this before on the bench. So far I've kept an eye on it and it doesn't seem to be an issue, nothing is getting warm even when pounding the car. Obviously a relay fail-open or fail-closed scenario would be pretty devastating, so you have to check these things.

User avatar
IssacZachary
Forum Supporter
Posts: 833
Joined: Fri Jan 13, 2017 9:57 am
Delivery Date: 15 Nov 2016
Leaf Number: 420789
Location: Gunnison, CO, USA

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Apr 25, 2018 11:11 pm

Good work mux!

I also wouldn't think that blocking the grill would do much. According to >>HERE<< those that have done a grill block have seen between a 1% and 6% improvement (which I'm personally skeptical even about those numbers.)

I do want to do a tail like on this car though as well as wheel skirts:

https://aerocivic.com/
Last edited by IssacZachary on Wed Apr 25, 2018 11:24 pm, edited 1 time in total.
2013 SL SOLD :cry:
1972 VW Beetle SOLD :cry:
1984 VW Golf diesel CURRENT :x
2013 Toyota Avalon Hybrid CONTEMPLATING :shock:

lorenfb
Posts: 1801
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Apr 25, 2018 11:14 pm

mux wrote:
lorenfb wrote:
mux wrote:Another video update on my car, posting it here for those who are interested:

In short: Swapped tires out for 51PSI capable ones and immediately saw a decent efficiency increase. Should be able to (just about) hit 250km (155 mi) of range if I'd run it all the way dry. Aeromods so far have not meaningfully contributed, and I'm working further towards making a hardware kit to upgrade the Leaf with an extender.


You mention in the video that you've reduced (~ 50%) the coil currents of the main power relays of the add-on battery.
Are you concerned that the contact resistance of the relay will increase to a point where the relay life may shortened or
that a problematic relay contact voltage drop, e.g. at 100+ amps, may occur?


These particular relays are supposed to be rated to full engagement down to 80mA, and I've tested this before on the bench. So far I've kept an eye on it and it doesn't seem to be an issue, nothing is getting warm even when pounding the car. Obviously a relay fail-open or fail-closed scenario would be pretty devastating, so you have to check these things.


Thanks for your feedback. Keep-up the great project. It's impressive.
Leaf SL MY 9/13: 66K miles, 50 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 charges to 100% > 1000, max battery temp < 95F (35C), min discharge point > 20 Ahrs

Return to “Engineering”