jray3
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Re: Add DC quick charger?

Mon Mar 25, 2013 5:41 pm

Don wrote: I would suspect it's up to the car... I would guess .. The commercial stations must be looking ...I suspect it's looking at lots of variables, ... it looks like it checks the charge current ..
Don

From what I've read, Don, you're correct on all of the above. BUT- I've yet to hear a reason why bulk fast-charging could not be performed on occasion with little or no ill effect, IF the operator takes care to stay within limits. The hobby and race-duty chargers like Manzanita Micro's do not apply an arbitrary voltage- they apply precisely what is programmed in terms of voltage, amperage, and hold time at constant voltage for a finishing charge (set to zero for bulk charging). We know that Mitsu went very conservative on our cell voltages, not providing a high-charge option for extended range.
http://www.gs-yuasa.com/us/technic/vol5 ... _1_021.pdf
GS Yuasa tested these cells by charging to 4.10V in three hours. Mitsu has us charging to 3.955V in 6 to 21 hrs... (and provides no guidance on whether 21 hrs or 6 hrs makes any difference in battery longevity)
Exactly how much more energy could be stored with that extra 0.145 V is hard to tell, but the above-linked graph shows how flat the discharge curve is at high voltage, and makes 10 Ah or 20% look possible.
It's like we're forced into the 80% charge at all times without a boosted option for those heavy-duty days. Bottom line though, this is a warranted product, which much be "idiot-proofed" to the greatest extent possible. Nissan was reminded of this by their hot climate customers (who received no warning from their cars that heat damage was occurring ).

Lastly, it appears to me from several sources that the length of spent at high state-of-charge has a greater effect on pack longevity than exactly how high the peak voltage is, yet I see no cars or EVSE pursuing that control strategy. (Bring SOC to a certain level, say 50% ASAP, then restart charging X minutes before a planned departure in order to minimize time at high SOC.) :? Of course, this would increase the importance of periodic balancing charges.
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

Don
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Re: Add DC quick charger?

Tue Mar 26, 2013 10:17 am

Is your plan to build a quick charger, or are you more interested in charging to 4.1 volts per cell in order to gain a few extra miles of range?
jray3 wrote:GS Yuasa tested these cells by charging to 4.10V in three hours. Mitsu has us charging to 3.955V in 6 to 21 hrs... (and provides no guidance on whether 21 hrs or 6 hrs makes any difference in battery longevity)
I've changed my thinking on this after reading everything I could find over the past year regarding the care and feeding of lithiums and I suspect it really doesn't make much difference in their longevity. So long as you're charging at 0.5C or less (and some say as high as 0.7C) the cells really don't care, and our 3300 watt, 10 amp onboard charger is only capable of about 0.2C, so either a 6 or a 21 hour charge is really slow, relatively speaking. Even a 3 hour charge would still be less than 0.5C
Exactly how much more energy could be stored with that extra 0.145 V is hard to tell, but the above-linked graph shows how flat the discharge curve is at high voltage, and makes 10 Ah or 20% look possible.
True, but I wonder what the existing BMS attached to the battery would think when you try to recharge the cells above 3.9? - I'll bet our BMS isn't programmed to like that at all. The tests you refer to probably were not done with the current BMS setup active. I would imagine they either used no BMS at all for those tests, or one they had programmed for 4.1 volts
It's like we're forced into the 80% charge at all times without a boosted option for those heavy-duty days. Bottom line though, this is a warranted product, which much be "idiot-proofed" to the greatest extent possible
Yes, we're forced into an everyday 80% charge and then if you're quick charging them, you get only 80% of that 80% . . . . and even then, they recommend you not do it everyday. I think quick charging is done at about 2C (100 amps) isn't it?

I'd feel lots better about the whole idea if we had the SCiB cells which were specifically created with the idea of quick charging them

At any rate, your experiments will be a real learning process - I'm sure you'll keep us posted on how it goes and what you find

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

jray3
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Re: Add DC quick charger?

Tue Mar 26, 2013 10:45 am

Thank You Don,
I'd most prefer to add CHAdeMO in the OEM configuration, as there are enough stations around Seattle now to make it worthwhile (I can't get home from Seattle without a 3 hr charge). Also, as I've managed EVSE installations in my day job, I find myself acting as liason between the Seattle EV Assoc and Ecotality on getting more BLINK DCQC deployed.

Exporting HVDC from the iMiEV is another big motivation in pursuing an unconventional setup. As an EV Drag Racer, I'd love to have the ability to pull 16 kW from my iMiEV to top off a car at the track, and also the ability to hook up my big UPS unit (designed aroud a 240V battery) to power the house during a blackout.

Having the Manzanita Micro charger (which can also operate as a DC-DC converter) in Karmann Eclectric means that I already have most of what's needed for DCFC in my garage. Imagine the stock charger pumping into the pack while the pack also receives 20A a through the Karmann or from the wall. I already simultaneously pull 16A and 20A from the wall when charging both cars, and the house's 200A service handles it just fine without adjusting other loads. That would allow an 8.1 kW charge rate for the iMiEV, theoretically bringing the pack from 0% to 80% in 95 minutes. Again, it's not a real 'need', but would increase utility of the car.

And then there are those rare days, like heading up to Mt. Rainier, where an overcharge could make the difference between using the iMiEV and taking a gasser. HowEVer, my pusher trailer project still has top priority, as it offers much more than even a 20% range boost from overcharging and would not involve any hacks to OEM systems. A lot of this may wind up being a thought exercise, but I'm learning stuff and not spending much (yet). As the wife says, she'd rather be a 'garage widow' than a 'bar widow'. :roll:
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

Don
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Re: Add DC quick charger?

Tue Mar 26, 2013 10:51 am

You're married to a wise lady :D

I like the idea of your pusher trailer, since it leaves the car stock (thus not tampering with the warranty) and is only used on an 'as needed' basis . . . . plus, you can use it on more than one car, which is a really big advantage for you

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

jray3
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Re: Add DC quick charger?

Tue Mar 26, 2013 10:53 am

Don wrote:
Exactly how much more energy could be stored with that extra 0.145 V is hard to tell, but the above-linked graph shows how flat the discharge curve is at high voltage, and makes 10 Ah or 20% look possible.
True, but I wonder what the existing BMS attached to the battery would think when you try to recharge the cells above 3.9? - I'll bet our BMS isn't programmed to like that at all. The tests you refer to probably were not done with the current BMS setup active. I would imagine they either used no BMS at all for those tests, or one they had programmed for 4.1 volts

Yes, and depending on the design of our BMS, it would either start burning up current through a shunt as the voltage rose, or command the contactor to open (probably once all BMS modules signaled high V).

It's like we're forced into the 80% charge at all times without a boosted option for those heavy-duty days. Bottom line though, this is a warranted product, which much be "idiot-proofed" to the greatest extent possible
Yes, we're forced into an everyday 80% charge and then if you're quick charging them, you get only 80% of that 80% . . . . and even then, they recommend you not do it everyday. I think quick charging is done at about 2C (100 amps) isn't it?
Don


I'm pretty sure that the Aerovironment and Blink DCQC installed along I-5 thus far are limited to 50 kW, and they have been logged at averaging only 30 kW into a LEAF.
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

Don
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Re: Add DC quick charger?

Wed Mar 27, 2013 2:56 pm

Some interesting facts about the pack

"Mitsubishi tested the cycle life of the pack under standard (50 A) and quick charge (120 A) conditions using the JC08 driving pattern and found that the pack retained 84% of capacity with quick charging and 83% with standard charging after 1,000 cycles."

Mitsu considered a 'standard' charge rate of 1C and even that doesn't seem hard on the pack - Our L2 Max charge rate of about 0.2C appears to be little more than a 'trickle' charge by comparison. Safe to say there will be very little difference in pack lifespan whether we recharge with 120V @ 8 amps or 240 volts @ 14 amps . . . . either is relatively tiny by comparison

Also interesting is they report the same (slightly better actually) lifespan using a 120 amp (2.4C) Quick Charge

Lastly, their test results are for a period of only 1,000 cycles, which is less than 3 years usage for some of you guys - We'll be delving into relatively unknown territory here before too long . . . . at least, some of you will

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

nsps
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Re: Add DC quick charger?

Wed Mar 27, 2013 6:40 pm

Don wrote:Also interesting is they report the same (slightly better actually) lifespan using a 120 amp (2.4C) Quick Charge


Yes, I found that quite surprising since the manual actively discourages frequent use of Quick Charge.

peterdambier
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Re: Add DC quick charger?

Fri Mar 29, 2013 4:55 am

Regen switched off when battery is full.

I have seen the question earlier and can confirm - leaving home with charged battery, climbing over the hill and rolling down the other side, regen gets reduced half way down and finally cuts off before I reach the bottom - except when the heater is on. The BMU is watching and talking to the motor controller and to the CHAdeMO charger.

Concerning electricity germany is a third world country. Many of our households have 3 phase 35A each. Some have 25A single phase. We can do L2 at home but that is it. There is a 20kW charger for us nevertheless:

http://www.e8energy.de/produkte/strom_l ... @fast.html

They can charge from 400V/32A 20kW or 400V/16A 10kW using CHAdeMO and I know they have been experimenting with some 650V DC from solar arrays. I have learned from the evtv.me forum the Lithium Iron Phosphates love quick charging but the'll explode from trickle charging. There is no doubt 80% quick charging is better for long live than regular charging 100% is.
Peter and Karin Dambier, DL2FBA, www.piraten-fraktion-bergstrasse.de

JoeS
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Re: Add DC quick charger?

Fri Mar 29, 2013 8:34 am

peterdambier wrote:Concerning electricity germany is a third world country. Many of our households have 3 phase 35A each. Some have 25A single phase. We can do L2 at home but that is it.... I have learned from the evtv.me forum the Lithium Iron Phosphates love quick charging but the'll explode from trickle charging...
Peter, I think you're short-changing your country as Germany's use of solar/wind to displace fossil fuels is showing the world that it can be done on a large scale. Now, it's just a matter of upgrading each home's electrical capacity… (I know, I know, easier said than done).

As much as I like their topics, I long ago gave up sitting through evtv's ramblings. I had never heard of any issues regarding slow charging of any type of Lithiums. This was confirmed a couple of years ago at a presentation at our local electric auto association meeting when I point blank asked the chief scientist of a Lithium battery development startup if there were any problems charging too slowly? - The answer was NO. Since I primarily charge using L1, do you happen to recall which episode of evtv this assertion was made (or did the assertion pertain to really minute unregulated input trickle currents)?

Back on topic, I too would be interested in adding CHAdeMO to my Mitsi, although so far for over a year L1/L2 has been more than sufficient for our daily drives.
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

peterdambier
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Re: Add DC quick charger?

Sat Mar 30, 2013 4:57 am

Not only the video but the blog as well.

http://blog.evtv.me/2012/10/charge-fast ... oking-car/

Next more on CHAdeMO is

http://blog.evtv.me/2013/01/2066/

From those two it looks to me like CHAdeMO will make it. There are already hackers trying to reengineer the CANBUS data exchange and the hardware is open. For SAE you have to buy a bugged (property crippled) computer to read the documents and swear not to leak any of the information in the unreadable documents.

May be I am a bit discouraged with our electricity mess in germany but on the other hand we are very close to completely autonomous households not even connected to the mains.

In our county I am spreading the idea of factory outlets for electricity so people can bring their batteries (i-MiEVS) and get their power without feeding networks and bureaucracy for one third of the price. Imagine we are paying 33 cents per kilowatt hour. Dollar cents and Euro cents are close enough to compare. Gas is expensive but they try their best to "keep electricity competitive".

Trouble is we dont have enough capacity in the wires and 3-phase does not save us. The future will be DC and I guess DC charging will get its own grid.
Last edited by peterdambier on Sat Mar 30, 2013 9:39 am, edited 1 time in total.
Peter and Karin Dambier, DL2FBA, www.piraten-fraktion-bergstrasse.de

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