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[Doctorbass]

Hello guys, i made a video showing the test i made to find what current each 3.3kW units are drawing at various AC voltages

I decided to do that after i had trip some circuit breaker when using dual unit( 6.6kW total)  on some charge station that operate at 208V and not 240V. My  2 units draw  at 208V  a total of 36A  witch exceed the rated 30A max... witch cause problem with some charge station...

I also posted all the data here so you can  select witch voltage you want to know the current or even the efficiency because i also measured and calculated the DC  power output!  (I did those measurement at 52% SOC)

Enjoy! 

Doc

[Electric Terry]

Wow awesome data Doc!!

With efficiencies between 90 and 96%, you could save a bit of energy just charging with the supercharger vs the onboard charger alone every night!!  These ultra high frequency switching chargers are expensive, but their efficiency is outstanding!!  Totally worth it.  Also means if you only have a certain amount of power available from a charge station, more of that power goes into the bike, and less wasted as heat, meaning you actually charge at a faster rate. 

I'd love to see more data at 215 and 220 VAC if you get a chance.  Looks like it was above average high efficiency at 215 and below average at 220, and just wondering if those results repeat the same way.  But not important, the general result is that it will pull 1600-1650 watts from the AC source from 80-180 VAC input, and what is incredible is almost exactly 3500 watts on the money from 185 volts all the way to 240 VAC!!   Cool!!   

[Keith]

Very nice. I will probably do something similar with my DeltaQ chargers, I just bought AC and DC power meters. It seems most chargers are constant current and that means the power increases as the battery charges. Is this true with the Diginow? Or does it output constant power so that the DC current is less when the battery voltage is high?

[MrDude_1]

Great info! thanks for taking the time to do this and sharing!

[Doctorbass]

Very nice. I will probably do something similar with my DeltaQ chargers, I just bought AC and DC power meters. It seems most chargers are constant current and that means the power increases as the battery charges. Is this true with the Diginow? Or does it output constant power so that the DC current is less when the battery voltage is high?

Thanks Keith,
I did that test at 52% SOC witch is an average or ( close to nomimal voltage of the battery) but i could repeat it at 25% and at 75% or different % request.

I guess you meant you understod that most charge are constant current  AT THE OUTPUT right?.

because according to the data i have the power seem to remain the same.... i other words the regulation seem to be constant power "first" witch create the problem i have....

I would love to see those charger to draw steady 14.5 or 15A AC for voltages lower than 240V...

Because when you decide to use 2 of these the current draw MUST be 30A or less because many of the charge stations are on 208V ac and not 240V ac... and that test confirm that when these run on 208V ac they will exceed the common 30A current

Doc

[Doctorbass]

Wow awesome data Doc!!

With efficiencies between 90 and 96%, you could save a bit of energy just charging with the supercharger vs the onboard charger alone every night!!  These ultra high frequency switching chargers are expensive, but their efficiency is outstanding!!  Totally worth it.  Also means if you only have a certain amount of power available from a charge station, more of that power goes into the bike, and less wasted as heat, meaning you actually charge at a faster rate. 

I'd love to see more data at 215 and 220 VAC if you get a chance.  Looks like it was above average high efficiency at 215 and below average at 220, and just wondering if those results repeat the same way.  But not important, the general result is that it will pull 1600-1650 watts from the AC source from 80-180 VAC input, and what is incredible is almost exactly 3500 watts on the money from 185 volts all the way to 240 VAC!!   Cool!!   

Terry witch data would you see at 215 and 220V?  i can do the test on demand   just ask !

Doc

[Electric Cowboy]

Hey guys, we have a new firmware coming out that will be constant power constant voltage for better results. It will also have a very slow ramp and allow for Bluetooth control AND load sharing between the chargers.

Sent from my Nexus 6P using Tapatalk

[togo]

there's no bluetooth or serial input/output in the
modules that have been provided with the first SCv2,
so you won't get those features without buying or
building new control modules.

but yes, being able to control the bricks is really
good.  i've been able to dial down the bricks'
current from when plugged into 240vac and
3-brick input exceeds my bike's 1C limit or to
dial down the charge rate when a station can't
deliver what it promises.  (I don't have the
bluetooth like anton but I did add a the ramp up
and the manual override to my dev board.)

[protomech]

With efficiencies between 90 and 96%, you could save a bit of energy just charging with the supercharger vs the onboard charger alone every night!!

Let's assume 20k miles ridden per year @ average 120 Wh/mile at the wall. 2.4 MWh is a lot of energy!

The chargers appear to be 91% to 95% efficient, per Doc's notes. It's really curious that there's such a large dip at 220V. Let's assume we're at 93% efficient on average, so we lose 168 kWh per year.

The data sheet for the GWP EVC1300 claims 92% efficient at 110V, 94% efficient at 240V. it probably would be useful to run a similar test with the OBC, but it doesn't seem like the Diginow is markedly more efficient. 20 kWh/year saved is no small amount - enough for another 170 miles of riding - but also not a ton.

[clay.leihy]

there's no bluetooth or serial input/output in the
modules that have been provided with the first SCv2,
so you won't get those features without buying or
building new control modules.

but yes, being able to control the bricks is really
good.  i've been able to dial down the bricks'
current from when plugged into 240vac and
3-brick input exceeds my bike's 1C limit or to
dial down the charge rate when a station can't
deliver what it promises.  (I don't have the
bluetooth like anton but I did add a the ramp up
and the manual override to my dev board.)

Is there a website with specs, prices, etc?

Sent from my Z982 using Tapatalk

[Keith]

I guess you meant you understod that most charge are constant current  AT THE OUTPUT right?.

Right. There are two separate dimensions to this as I see it. One is what you measured, AC power consumption versus AC voltage at a given SOC. The other is AC power consumption at a given AC voltage versus DC output voltage which varies with the SOC. A charger that outputs constant current will draw an increasing amount of AC power as the battery charges. If a charger outputs a constant power, then then AC input power would also remain constant as the dc voltage varies with SOC. Of course power becomes low when constant voltage output is reached.

So either CC/CV or CP/CV charging could be done. Which one is better for the battery? CP would charge faster at low SOC than CC for the same maximum power. I don't know how the internal resistance of the battery varies with SOC but I'm sure it does. That would affect heating due to I^2R. There also might be other considerations with chemistry and such that would influence this choice. But disregarding the battery, it seems that constant power makes more sense. The AC input power required is then fixed and known, and the charging rate in kWh/h is constant rather than increasing with SOC. Right? Or does anyone really know?

BTW the legend for your chart shows five variables, but I only see three lines. Volts out is almost constant so unimportant and current out is not shown although it seems to have basically two constant values. So what I was asking is would the current out values stay constant or vary with SOC?

[Doctorbass]

Keith,

I've been confirmed that the way these "similar as Elcon "unit work depend mostly on witch firmware these have.

These suplied by Diginow have special firmware for the Zero.

From my understanding The firmware can only control the DC output witch affect the AC input btw.  The output  is constant power actually  for 3.3kW so the DC current is not constant.. it will vary depending on the SOC o fthe battery.. if voltage is higher, current is lower...   That's why i measured  all the value only at one SOC  and made all these in very short period to not have the SOC to vary so much so the ratio of Volt vs curret remain teh same.

In summary: My SCv2 are:
- constant output power
- input AC curent vary with input voltage.
- input power vary a little bit with Ac voltage input due to efficiency curve not linear
- Firmware monitor and control DC output.
- Hardware limit the max input power

Doc

[Keith]

Thanks for the clarification Doctorbass. I still wonder about which method is best CP or CC. I think CP means constant charge rate in energy v. time so it seems right, while CC means the rate gets higher near fully charged which means the battery is hotter right when you are going to use it. But is there a reason to charge more slowly at low SOC as CC does? Or is this just a side effect of a simple design that limits current to a constant value? Since the battery voltage doesn't change by very much, it isn't a huge difference but it would matter if trying to get the quickest charge while staying below a BMS power limit. Or is it staying below a current limit? Hmmm. Somebody knows...

Anyway I found a variac to borrow so I will collect the same data for the DeltaQ charger which I think is constant current. That means the AC input power will vary with both AC voltage and battery voltage so it will require multiple graphs.

[Electric Cowboy]

Guys, these are not elcons. They just use the same housing that Elcon and a few other companies use. We all have them built by the same company in china for us because they are the most reliable.

Dr. bass has earlier prototype units with unique hardware and software so the data provided is slightly different than the production units.

[Electric Cowboy]

Also about CC vs CP

CC is variable power out like you described which means it is variable power in as well. If a station can deliver 32A at 208v that's 6.5kw ish which means optimal output would be around 6.5kw so CP is ideal when limited by the ac power source.

If you have more power avaialable than the charging unit can deliver then CC is ideal to get the most.

Since we can deliver more power than some stations can give us CP is ideal. With the ability to control the power via your smart phone.

Sent from my Nexus 6P using Tapatalk