# [EVDL] Question about charging efficiency of BEV



## EVDL List (Jul 27, 2007)

If you're talking efficiency of charging a battery at home, then
transferring the energy to the car battery, not great.

The MPPT charge controller on the solar array is upwards of 98 to 99%
efficient, but the charging efficiency of a stationary house battery bank
is somewhere in the 85% range. Then, there's the issue of getting the
power out of the battery to the other battery -- since the voltages almost
certainly won't be the same (unless you have a contactor bank to
reconfigure the house battery to higher than 48 volts, the highest
practically allowed by NEC code), you'll need some sort of DC-DC boost
converter -- maybe in the 90%+ range if it's a good one. Or, a DC-AC
inverter, plus the standard AC battery charger. If you could have the
solar array and house battery bank at the same DC voltage as the EV
batteries, then the only loss would be charging and discharging the house
battery bank, but it's still not really attractive.

Another alternative, and the one more commonly used, is to do a batteryless
PV system -- around 95 to 97% DC-AC efficiency, then charge the EV from AC
same as normal. You then have the effect of a 100% efficient battery
(because it is an administrative battery rather than a physical battery).
Of course, you still have the losses of the AC-DC battery charger.

Z



> Larry Gales <[email protected]> wrote:
> 
> > I understand that charging an EV from a wall-plug is about 85% efficient.
> > That is, if you car gets 4 miles/KWH, then it gets about 3.4 miles/KWH
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Folks,

I'm using the Manzanita Micro PFC-20B charger. On their website they 
say it is from 88% to 96% efficient - with the 88% being the earlier units.

The Zivan charger is rated at 92%.

The Elcon charger is rated at 93% (they say above, but that's probably 
marketing).

So worst case so far is 88% for older models, and up to 96% efficiency 
for newer models.

YMMV. 

Cheers,
Peter

On 1/22/12 3:09 PM, Zeke Yewdall wrote:
> If you're talking efficiency of charging a battery at home, then
> transferring the energy to the car battery, not great.
>
> The MPPT charge controller on the solar array is upwards of 98 to 99%
> efficient, but the charging efficiency of a stationary house battery bank
> is somewhere in the 85% range. Then, there's the issue of getting the
> power out of the battery to the other battery -- since the voltages almost
> certainly won't be the same (unless you have a contactor bank to
> reconfigure the house battery to higher than 48 volts, the highest
> practically allowed by NEC code), you'll need some sort of DC-DC boost
> converter -- maybe in the 90%+ range if it's a good one. Or, a DC-AC
> inverter, plus the standard AC battery charger. If you could have the
> solar array and house battery bank at the same DC voltage as the EV
> batteries, then the only loss would be charging and discharging the house
> battery bank, but it's still not really attractive.
>
> Another alternative, and the one more commonly used, is to do a batteryless
> PV system -- around 95 to 97% DC-AC efficiency, then charge the EV from AC
> same as normal. You then have the effect of a 100% efficient battery
> (because it is an administrative battery rather than a physical battery).
> Of course, you still have the losses of the AC-DC battery charger.
>
> Z
>
>


> Larry Gales<[email protected]> wrote:
> >
> >> I understand that charging an EV from a wall-plug is about 85% efficient.
> >> That is, if you car gets 4 miles/KWH, then it gets about 3.4 miles/KWH
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks much for that valuable information. The reason I am looking at
battery-to-battery efficiency is that an EV is often at work or on the road
during the day when the sun shines, and is more likely back at home at
night. So if this is an off-grid house, the only supply of electricity is
from the house battery that has been charged during the day.

As far as matching DC values, it appears to me that the house battery might
well be an old discarded EV battery that has lost 20% of its charging
capacity but still has a very long life as a storage battery for the house,
and would likely have the same DC values.

If this is the case, are we looking at 0.85*0.85 = 72% efficiency for the
overall
PV-to-battery-to-EV-battery trip?

Thanks,

-- Larry






> Zeke Yewdall <[email protected]> wrote:
> 
> > If you're talking efficiency of charging a battery at home, then
> > transferring the energy to the car battery, not great.
> ...


----------



## EVDL List (Jul 27, 2007)

> The Zivan charger is rated at 92%.

I find this very hard to believe, unless there has been a
serious design change. We are still talking about the NG
series Zivan chargers, right?

A long-time EAA member (recently past away), took readings
of my S10 Blazer EV conversion Zivan 240VAC NG5, 240VAC K2,
and 120VAC K2 on-board chargers. They all had a lower than
70% pfc reading. And with some AC line noise and current 
spikes, the Manzanita Micro PFC models just do not 
have/create.

Which explains why the above Zivan models would not work on an
EVII Avcon through an EAA Avcon adapter box. The Automakers 
forced EVII to include a circuit to sense non-pfc chargers
and turn off the charging (Automakers did not want those pesky
conversions using public EVSE). MM PFC chargers worked fine
with the above configuration.

With my many charger experiences, I found any charger running 
off 240VAC from an EVII ICS-200 Avcon that did not have a pfc 
rating of 90& or higher, would trip that circuit and stop the 
charging cycle 1.5 minutes from the start.

I know all those old Avcon EVSE are either already replaced
with J1772 EVSE or soon will be. But I use the above 
experiences, and the readings from said EAA member's Fluke 40
digital meter to say, the Zivan was a far cry better than the
old not-much-better-than-a-bad-boy chargers of yester-year
(i.e. K&W BC-20). But they only used 60% of the AC cycle, had
noise and current spikes, and a only a little better pfc 
rating (on mine they had a about 68% pfc reading). 

They were great way back then, but would not buy one today,
not when we have such good charger designs out now. Go with
a charger with a high pfc rating, and more of the AC current 
your charger draws from it's source actually goes into the
pack ( = fast and better recharging).

Can anyone post a URL of where I can see where Zivan states 
the pfc ratings for their chargers are 92%?


{brucedp.150m.com}






> Peter C. Thompson wrote:
> > Hi Folks,
> >
> > I'm using the Manzanita Micro PFC-20B charger. On their website they
> ...


----------



## EVDL List (Jul 27, 2007)

> Larry Gales wrote:
> 
> > I understand that charging an EV from a wall-plug is about 85%
> > efficient.
> ...


----------



## EVDL List (Jul 27, 2007)

> Peter C. Thompson wrote:
> 
> > I'm using the Manzanita Micro PFC-20B charger. On their website they
> > say it is from 88% to 96% efficient - with the 88% being the earlier
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Bruce,

I was quoting directly from the websites, so I can't vouch for the 
reality of those numbers. Especially since I never got a chance to try 
out the Zivan for my car.

For the Zivan number, I originally got it from the ElectroAuto site, but 
for this, I'm going directly from the Zivanusa.com site:
http://www.zivanusa.com/NG3BatteryCharger.htm
They are claiming 85-90% efficiency.

Which model are you using?

Cheers,
Peter

On 1/23/12 1:57 AM, Bruce EVangel Parmenter wrote:
>> The Zivan charger is rated at 92%.
> I find this very hard to believe, unless there has been a
> serious design change. We are still talking about the NG
> series Zivan chargers, right?
>
> A long-time EAA member (recently past away), took readings
> of my S10 Blazer EV conversion Zivan 240VAC NG5, 240VAC K2,
> and 120VAC K2 on-board chargers. They all had a lower than
> 70% pfc reading. And with some AC line noise and current
> spikes, the Manzanita Micro PFC models just do not
> have/create.
>
> Which explains why the above Zivan models would not work on an
> EVII Avcon through an EAA Avcon adapter box. The Automakers
> forced EVII to include a circuit to sense non-pfc chargers
> and turn off the charging (Automakers did not want those pesky
> conversions using public EVSE). MM PFC chargers worked fine
> with the above configuration.
>
> With my many charger experiences, I found any charger running
> off 240VAC from an EVII ICS-200 Avcon that did not have a pfc
> rating of 90& or higher, would trip that circuit and stop the
> charging cycle 1.5 minutes from the start.
>
> I know all those old Avcon EVSE are either already replaced
> with J1772 EVSE or soon will be. But I use the above
> experiences, and the readings from said EAA member's Fluke 40
> digital meter to say, the Zivan was a far cry better than the
> old not-much-better-than-a-bad-boy chargers of yester-year
> (i.e. K&W BC-20). But they only used 60% of the AC cycle, had
> noise and current spikes, and a only a little better pfc
> rating (on mine they had a about 68% pfc reading).
>
> They were great way back then, but would not buy one today,
> not when we have such good charger designs out now. Go with
> a charger with a high pfc rating, and more of the AC current
> your charger draws from it's source actually goes into the
> pack ( = fast and better recharging).
>
> Can anyone post a URL of where I can see where Zivan states
> the pfc ratings for their chargers are 92%?
>
>
> {brucedp.150m.com}
>
>
>
>
>


> Peter C. Thompson wrote:
> >> Hi Folks,
> >>
> >> I'm using the Manzanita Micro PFC-20B charger. On their website they
> ...


----------



## EVDL List (Jul 27, 2007)

> of my S10 Blazer EV conversion Zivan 240VAC NG5, 240VAC K2,
> and 120VAC K2 on-board chargers.

I also had a Zivan NG3 in the Escort wagon EV I owned for a short
while. 

I believe Roger addressed my concerns in his post which was
after ours.


{brucedp.150m.com} 

--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Question-about-charging-efficiency-of-BEV-tp4319186p4321541.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

If the PV's pack voltage is always above that of the EV's pack
couldn't a speed controller and inductor be used to charge the EV?

-- 
David D. Nelson
http://evalbum.com/1328
http://2003gizmo.blogspot.com

_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Hi Bruce,
Power Factor (PF) is not the same as efficiency.
You can easily have a supply that is more than 95% efficient
but has a PF below 60%.
The PF only tells how much current and voltage are in phase
and linearly correlated, while efficiency tells how much
energy is turned into work and how much is lost.

There is a relation in that a lower PF unit often has a worse
efficiency, but that is not always true.

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Bruce EVangel Parmenter
Sent: Monday, January 23, 2012 1:57 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Question about charging efficiency of BEV

> The Zivan charger is rated at 92%.

I find this very hard to believe, unless there has been a serious design
change. We are still talking about the NG series Zivan chargers, right?

A long-time EAA member (recently past away), took readings of my S10
Blazer EV conversion Zivan 240VAC NG5, 240VAC K2, and 120VAC K2 on-board
chargers. They all had a lower than 70% pfc reading. And with some AC
line noise and current spikes, the Manzanita Micro PFC models just do
not have/create.

Which explains why the above Zivan models would not work on an EVII
Avcon through an EAA Avcon adapter box. The Automakers forced EVII to
include a circuit to sense non-pfc chargers and turn off the charging
(Automakers did not want those pesky conversions using public EVSE). MM
PFC chargers worked fine with the above configuration.

With my many charger experiences, I found any charger running off 240VAC
from an EVII ICS-200 Avcon that did not have a pfc rating of 90& or
higher, would trip that circuit and stop the charging cycle 1.5 minutes
from the start.

I know all those old Avcon EVSE are either already replaced with J1772
EVSE or soon will be. But I use the above experiences, and the readings
from said EAA member's Fluke 40 digital meter to say, the Zivan was a
far cry better than the old not-much-better-than-a-bad-boy chargers of
yester-year (i.e. K&W BC-20). But they only used 60% of the AC cycle,
had noise and current spikes, and a only a little better pfc rating (on
mine they had a about 68% pfc reading). 

They were great way back then, but would not buy one today, not when we
have such good charger designs out now. Go with a charger with a high
pfc rating, and more of the AC current your charger draws from it's
source actually goes into the pack ( = fast and better recharging).

Can anyone post a URL of where I can see where Zivan states the pfc
ratings for their chargers are 92%?


{brucedp.150m.com}






> Peter C. Thompson wrote:
> > Hi Folks,
> >
> > I'm using the Manzanita Micro PFC-20B charger. On their website they
> ...


----------



## EVDL List (Jul 27, 2007)

Dump charging also has the advantage that you can come home, do a quick dump charge whilst picking up a spouse or kid, and then be able to drive an errand. As Lee says it could take a long time to do a full charge that way, but is hard to beat for a few quick Ahr.



________________________________
From: Lee Hart <[email protected]>
To: Electric Vehicle Discussion List <[email protected]> 
Sent: Tuesday, January 24, 2012 10:50 AM
Subject: Re: [EVDL] Question about charging efficiency of BEV

...
> Best efficiency will be when the solar bank can be
> configured to match the EV's pack, but you lose charge control

You're thinking of doing it as a "dump charger"? Just wire the two packs 
in parallel, and let the higher one charge the lower one? This would 
normally be the home pack. It's hard to beat it for efficiency. The 
house and car packs would also function as one during a power outage or 
other emergency.

The initial dump charge current can be pretty high; but it usually isn't 
a problem if the two packs are nominally the same voltage. You might get 
a brief peak of 100 amps when first connected and the house pack is full 
and the car pack is dead; but the current drops very quickly as the two 
voltages move together.

Dump charging would not be a good option if the house pack has a higher 
nominal voltage than the car pack. It's also slow; though the initial 
current is high, it drops so fast that it would take all night to 
transfer even half the charge from the house to the car. ...
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.sjsu.edu/mailman/private/ev/attachments/20120124/4fe722e3/attachment.html 
_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > You're thinking of doing it as a "dump charger"? Just wire the two packs
> > in parallel, and let the higher one charge the lower one? This would
> ...


----------



## EVDL List (Jul 27, 2007)

Well, with lead acid you are probably right. I just did a run where my
CycleAnalyst recorded 6081Wh used from the pack. When charging the pack to
full my Killawatt meter recorded 7.11kWh. This is an 85.5% efficiency.
Using a Zivan NG1 and a LiFePO4 pack.

When I had a lead acid pack of 6V batteries I got 4mi/kWh. When I installed
the Li pack, the same driving style netted over 6mi/kWh when measured from
the wall.



> Chuck Hursch <[email protected]> wrote:
> > On 1/22/2012 1:23 PM, Larry Gales wrote:
> >> I understand that charging an EV from a wall-plug is about 85% efficient.
> >> That is, if you car gets 4 miles/KWH, then it gets about 3.4 miles/KWH
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > On 1/24/2012 2:06 PM, Willie McKemie wrote:
> > > [a "dump charger"] is something I've been thinking about... I'd be interested in hearing
> > opinions on
> ...


----------



## EVDL List (Jul 27, 2007)

Back in September I had a couple of TS-LFP40AHA cells to play with. I
discharged one to 2.500V at ~8A. After ~19hr rest the OCV was 3.021V.
The other cell was sitting at 3.339V and at the same temperature. I
hooked the two in parallel through one of the battery straps and the
other through ~ 3 feet of 1 gauge wire with a 50A 50mV shunt in the
middle. The initial current was ~28A which quickly dropped to ~22A and
then slowly declined from there. When the current had dropped to ~15A
the voltage difference between the cells was 0.15V when measured at
their respective terminals. When the current had dropped to 10A one
cell was at 3.245V and the other was at 3.228V. After about 5 minutes
the current had dropped below 9A.

Unfortunately I didn't have an Ah counter to measure how much charge
was transferred and I don't know what the SOC of the "full" cell was.
I had to return the cells to the owner about a 1/2 hour after the
above test so I don't have any better data than that.

I suppose if there was no shunt between the cells the current could
have well been higher since the shunt initially caused a 0.028V drop.



> Willie McKemie <[email protected]> wrote:
> >
> > Since LFP cells are nearly fully charged at ~3.4v and nearly fully
> > discharged at ~3.2v, It looks like one might nearly fully charge a
> ...


----------

