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[motorrad36]

Why couldn't we charge faster than normal (my normal is 120v off a wall plug) from a J-1772 station -> accessory power port by the motor? Same place the delta-q chargers plug in. Is it because there is no "charger" in-line that tells the station what amount of kWh to pump out? As you can see, I do not necessarily get the ins and outs of EVs.

[kasmtk]

Output from J station AC
Input on charge input DC




Sent from my iPhone using Tapatalk

[Crissa]

The J-station doesn't actually charge the battery, your on-board charger does.  (This is different than a DC fast charging station.)

So unless you change the on-board charger, that's your limitation.

So yes, some bikes do charge faster from J-station than the standard outlet with with the 3, 6, and 12 KW chargers on-board.  But unless you have that charger on board, you don't.  That's why some people carry that extra charger on-board!

-Crissa

[DonTom]

Why couldn't we charge faster than normal (my normal is 120v off a wall plug) from a J-1772 station -> accessory power port by the motor? Same place the delta-q chargers plug in. Is it because there is no "charger" in-line that tells the station what amount of kWh to pump out? As you can see, I do not necessarily get the ins and outs of EVs.

With all Zero chargers (except the 2020 Zero SR/F) the current decreases as the voltage increases, keeping the wattage output the same regardless if 120 VAC or 240 VAC is used.

But this is because of the design of the chargers, has nothing to do with the j-1772. You get the same charge rate at 120 VAC as 240 VAC or a J-1772. Slow!

With the SR/F or Energica the charge current will stay the same  as the voltage is doubled, giving double the KW charging as the voltage doubles. That means charge twice as fast from 240 VAC or from a J1772 (which uses 240 VAC).

Older Zeros as well as the HD LW will drop the current  as the voltage is increased,  which IMO, is a bad idea. But must be cheaper to build as the charge wattage is half  on 240 VAC.  Why a 30K$ bike would do this amazes me. With cheaper Zeros, I can understand.

-Don-  Reno, NV

[Crissa]

That's not how chargers work, though, Don.

They're rated in wattage. Because that (and the heat it creates) is the limiting factor.  So if you raise the voltage the current has to go down.

Nothing is wasted.  You're still using the full wattage of the charger, unless your charger is much bigger than your supply (which is what the J-station is supposed to communicate).

-Crissa

[DonTom]

That's not how chargers work, though, Don.

They're rated in wattage. Because that (and the heat it creates) is the limiting factor.  So if you raise the voltage the current has to go down.

Nothing is wasted.  You're still using the full wattage of the charger, unless your charger is much bigger than your supply (which is what the J-station is supposed to communicate).

-Crissa

I never said any power (wattage) is wasted. This is NOT about efficiency. But here are the facts. In your Zero charger, the current goes down as the input AC voltage goes up, keeping the charge time the same as the output DC wattage is the same with double the AC input  voltage. Same with the Harley LW when charged with 240 VAC vs. 120 VAC.

In the SR/F or my Energica the output DC wattage DOUBLES as the AC input voltage doubles. These are FACTS, not opinions. That means on 240 VAC, my Energica will charge in half the time as on 120 VAC. On your Zero, the charge time will not change regardless if you use 240 VAC or 120 VAC. Again, these are the facts, not my opinion.

There is more than one way to design an EV  charger.

-Don-  Reno, NV

[TheRan]

Expanding on what kasmtk said, a charger is essentially an AC to DC converter. It takes the 110 to 240 volts from your mains outlet (or whatever a charger station kicks out) and converts it to a lower DC voltage that it puts straight into the battery (with some monitoring and adjustment for the current). That voltage is going to be close to the voltage of the battery (I think 92v in the case of Zeros). The accessory charging port is a straight shot to the battery for that voltage to go, so if that voltage is too high and AC (i.e. connecting a charging station or the mains to it) then not only will it not charge it will cause some serious damage to the battery.

If you're wondering why AC won't charge a battery, think of DC like a foot pump and you're inflating a tyre. Now for AC imagine if every time you lifted your foot up to give it another pump and push more air into the tyre it instead sucked the air back out that you just put in it. A battery is a bit more complicated because instead of sucking current back out of it you're instead pushing it in the wrong way (so I guess you could think of it like someone pushing on the outside of the tyre when you lift your foot) and that damages the battery, sort of like how you could damage the check valve on the pump by forcing air into it.

[Crissa]

In the SR/F or my Energica the output DC wattage DOUBLES as the AC input voltage doubles. These are FACTS, not opinions. That means on 240 VAC, my Energica will charge in half the time as on 120 VAC. On your Zero, the charge time will not change regardless if you use 240 VAC or 120 VAC. Again, these are the facts, not my opinion.

No, the total wattage of the device doesn't increase.
The SR/F comes with a 3kW charger, the older Zeros come with a 1.4KW charger standard.  The Energica comes with a giant charger in comparison (in wattage, weight, and volume).

Raising the input voltage doesn't change how much the charger can accept.  Your Energica can't charge at more than the station can provide - even if it is 240v, if the station only allows 1.4KW (like the portable granny charger J-stations) your 240v charger will run at a lower current.

-Crissa

[DonTom]

The SR/F comes with a 3kW charger,

And what happens when you use 120 VAC on a SR/F? Are you saying it will still charge at 3 KW?

Well, think about this. 20 amps times 120 VAC is only 2,400 watts capable. But the norm is to not  go over 16 amps continuously (only a few minutes above 16 amps should be considered acceptable) with household current. The 80% safety rule is on current draw. That leaves 1,920 watts available from a standard AC outlet.

How do you get 3 KW charging from 120 vac with their supplied 120 VAC input cable when only 2,400 is possible before the CB trips and only 1,920 watts is safe?  Or are you claiming the SR/F cannot charge with 120 VAC?

I am claiming it will then charge at HALF the 3 KW, or ~1.5 KW,  which proves my point that the current does NOT decrease at 240 VAC to get the spec of 3KW.


-Don-  Reno, NV

[BrianTRice@gmail.com]

The Calex chargers on Zero S/DS/FX (Gen2) models target a certain amount of power (1.3kW or 650W for FX) and draw half the current at 220V than they do at 110V AC.

The Rapid Charge Modules on the SRF draw 3kW at 220V and 1.5kW at 110V if I recall right, and target / limit to a current level (13-14A presumably).

[Crilly]

There are two types of chargers for ev vehicles.  Built in chargers, and stand free chargers.  All chargers  supply the voltage required for the vehicle.  One volt to what ever is required. Hundreds of volts if required.  Then all convert to direct current.

My Prius prime will charge at 1200 watts at 110 volts and 2400 watts at 220 volts. 5 hours and 2.5 hours.
My SR/F well charge at about 1200 watts at 110 volts and up to 6000 watts at 240 volts. 10 hours and 2 hours.
My Livewire well charge at (good question).  It takes up to 13 hours to charge at 110 volts.  On 300+ volts of dc current it takes about an hour.

[Crissa]

The SR/F comes with a 3kW charger,

And what happens when you use 120 VAC on a SR/F? Are you saying it will still charge at 3 KW?

Seems I already answered this.

Raising the input voltage doesn't change how much the charger can accept.  Your Energica can't charge at more than the station can provide - even if it is 240v, if the station only allows 1.4KW (like the portable granny charger J-stations) your 240v on-board charger will run at a lower current.

-Crissa

[DonTom]

Seems I already answered this.Raising the input voltage doesn't change how much the charger can accept.  Your Energica can't charge at more than the station can provide - even if it is 240v, if the station only allows 1.4KW (like the portable granny charger J-stations) your 240v on-board charger will run at a lower current.

All J1772 stations are 240 VAC. So to avoid confusion, talk about home charging where we have a choice to use either 120 or 240 VAC.

BTW, most J1772 charge stations on the road  are good for more than 7KW. Some less, some more. But they are all 240 VAC and that voltage doesn't change much.

My Energica on a J charger that can provide 7 KW will charge at 3 KW. Your Zero on-board charger will charge at HALF that rate, around 1.4 KW using the same J 7 KW capable charger. You have to wait twice as long as my Energica on a 7KW J station.

But your Zero as well as my Energica on 120 VAC will charge at the same rate of around 1.4KW. We both wait the same on 120 VAC.  But  I charge twice as fast as you do using my bike on the exact same J-1772 7 KW charger.

And that is FACT. So if the current does the same in both types of chargers, try to explain the double power of watts into my Energica compared to your Zero at 240 VAC. 

It is less confusing if we discuss home charging such as a 240 VAC drier outlet  compared to a 120 VAC home outlet. The we both know there is NO communication of any type between such. I charge twice as fast as you do on 240, but we both charge the same rate on 120 VAC. You want to try to explain how that is possible?

It's the design of the Zero J-charger in the bikes. Zero and the 30K$ Harley does it the same way. No decrease in charge time with 240 VAC compared to 120 VAC. Half the charge time with the Zero SR/F or my Energica on a 7KW J plug than your Zero or a  Livewire. That is because your current drops as the voltage increases. My Energica doesn't. The SR/F doesn't.

BTW, think about what happens when you increase the voltage across a resistor. The draw current increases in proportion.  But in your Zero charger, it is designed to draw less current as the voltage is increases to keep the wattage the same at any voltage, 90 to 240 VAC.   Uses a special circuit in the charger to do such to keep the power down.


A better example. Zero Delta Quick chargers. they are 1.4 KW at 120 VAC or on 240 VAC no difference in charge times.

Compare to my external Elcon  charger. 1.25 KW at 120 VAC in.  2.5KW when 240 VAC is on the input. Half the charge time on 240 VAC because the current did NOT drop.


-Don-  Reno, NV

[Crissa]

A better example

...What are you even talking about?

That your higher wattage charger charges at a higher wattage is not news.

Why do you seem to think that a lower wattage charger should be able to charge at a higher wattage while charging, just because you're running at a higher voltage?

That's not how this works.

-Crissa

[TheRan]

My Energica on a J charger that can provide 7 KW will charge at 3 KW. Your Zero on-board charger will charge at HALF that rate, around 1.4 KW using the same J 7 KW capable charger. You have to wait twice as long as my Energica on a 7KW J station.

But your Zero as well as my Energica on 120 VAC will charge at the same rate of around 1.4KW. We both wait the same on 120 VAC.  But  I charge twice as fast as you do using my bike on the exact same J-1772 7 KW charger.

And that is FACT. So if the current does the same in both types of chargers, try to explain the double power of watts into my Energica compared to your Zero at 240 VAC. 

It's not so much that the Energica is charging twice as fast on 240v, it's 120v that's cutting the charging rate in half. It has a 3kw charger so it's going to charge at 3kw as long as it doesn't exceed the current limit required for the voltage. If the Zero only has a 1.4kw charger then of course it's not going to charge at a higher rate than that even if it has current to spare, if it instead had a 3kw charger then it would charge twice as fast at 240v. If we imagine that the Zero had half the current limit it does then it would behave like the Energica does, it would charge at half the rate on 120v and would require 240v to charge at full speed.