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[DonTom]

Good to know, but what I was getting at is that it’s a less powerful charger than the 6.6 kW HK-J at the relatively low voltages that Zero’s operate. 5.3 kW at 116 vdc (46A) vs 9.2 kW (80A) on the HK-J 84V, leaving aside whether you would ever actually want to draw that much power from one.

After you have it programmed for a Zero, I would expect it to charge about the same as a Zero charger at the same KW spec at the same SOC.

-Don-  Cold Springs Valley, NV

[flynnstig82r]

After reading the "New TC chargers coming to market" thread on this sub-forum, I now see what you mean. At $1,500 for the 6.6 kW version, though, a DigiNow SC setup or even a 6 kW charge tank starts making a lot more sense. If it were $800 I would consider it.

*mod edit* added link for context

[talon]

That's what you want it to do. You want the charge current to drop off near the ends. That's why they usually spec charge rates to 85% SOC. They must slow down near the top. If it doesn't, either the battery gets damaged or worse--catches fire or explodes.

4.6 KW sounds like a lot at 99% SOC! Perhaps too much, if anything. I charge at 1.3 KW at above 95% SOC when I start with ~7.9 KW.

Your BMS will not allow that 5.3 KW at the top!

-Don-  Reno, NV

Don, the battery limits the current by rising in voltage. It slows itself down in normal charging conditions by *being* at a higher voltage, not the charger slowing down. The charger does not slow it down as it fills, the physics of the battery does. (Side note:  yes chargers do have limits and the CC/CV charge process technically limits current by changing the charge voltage) A battery can measure 116VDC while charging and that does not mean it is anywhere near 99% SOC. I believe they usually spec charge rates to ~80-85% because that is typically after where the CC (constant current) part of the charge terminates--and every battery is different past that point (even the same battery under different conditions) and the charge current has reduced itself by almost half on the curve. But as an example:  as a battery degrades, it may begin and continue measuring 116V as early as 60% (perhaps earlier) while undergoing a fast charge all the way until it is at 100%. 4.6kW would be very little for most SR batteries "at 116V" because 116V is not necessarily equivalent to 90-100% while charging.

[DonTom]

Don, the battery limits the current by rising in voltage. It slows itself down in normal charging conditions by *being* at a higher voltage, not the charger slowing down.

What did I say that made you think I didn't understand that?


But it ends up being the same difference, the charge rate (charge current) goes down a lot near the end regardless of the cause.


But I am no expert on EV chargers. I cannot claim I totally understand exactly how they work.


So  one thing perhaps you could explain to me  is the programming of the charger. What  is it programed to do at various rates?  Didn't I hear here that it switches from CC to CV?  Where at and why?

And since the current drops down a lot near the end, why was it necessary for my non-CANBUS external chargers to totally turn off at 95% SOC? What would happen if they just let them charge to 100 SOC since the charge current will automatically drop down anyway?

-Don-  Reno, NV

[talon]

It just sounded like you assumed the charger itself had to lower its output when its output dropping is just a byproduct. "your bms will not allow that 5.3kW at the top" "4.6kW sounds like a lot at 99%". multiplying the constant charge current by the maximum voltage of the battery is a good quick check of peak charging power, and it seemed that you took that for 99%=~116V while charging.

I don't know elcon's general programming specifically, but I know at some point it is basically a CC/CV charger with extra protections hopefully based on best practices. CC/CV is pretty simple--it just describes two limits while charging and how it approaches them. Most power supplies that have a current limit and adjustable voltage are already capable of CC/CV, albeit with possible overshoot.

If you want a fully charged battery at 116V (or so), 116V would be your CV setting. If you pick a certain rate in amps (say 30 amps) to charge that your charger and battery are capable of (wiring, bms, contactor, cells, etc.) this would be your CC setting, or limit. To push this current, the charger switches "on and off" and dumps charge very rapidly, effectively "setting" a voltage output. This voltage output is of course still tied from charger to battery terminals so the power that is coming out is only a slight voltage differential along the power wires from the battery voltage, with lots of current. Even though you set it to output 116V, the current is too low to maintain that voltage while charging the battery. By monitoring and carefully controlling that rapid switching, the voltage differential is varied and causes ONLY enough current so that it does not surpass your 30Amp CC limit. If at any point the voltage reaches the set CV limit, the charger is still rapidly switching--but only to maintain that voltage now, and no higher. As this goes on the battery is depositing charge and the current begins to lower because the voltage differential is smaller because the switching duty cycle doesn't need to be as high to maintain that voltage. Switching between CC and CV is more or less automatic as they are both limits. Some chargers may bounce between CC and CV a few times (typically lower quality) when hitting their limits, and they may overshoot their CV target in tiny pulses. That being said, by design I believe diginow's elcons "bounce" and reduce their power level (by lowering voltage which causes lower current) a few times when approaching full and I'm told this has something to do with balancing.

Ideally it would pay attention to charger, battery cell, and ambient temperature (to reduce the charging rate), balance (to give the BMS whatever conditions it can best balance at before reaching CV and stop charging in an emergency if one cell rises too fast), voltage lift while charging (to see if the battery is even hooked up and how much impedance is there), and voltage measurement independent of the power wires.

I imagine your non-canbus chargers did that primarily because of not communicating and knowing the balance. The difference in voltage between 95% and 100% is so slight that a charger has to be very careful if even one cell was out of balance. The BMS and DC/DC converter put a small load on the battery and perhaps higher when it starts to balance which may add to this complexity?

I'm no expert either, just hopefully adding to the discussion and understanding.

[dannsky]

Has anybody here used the above mention hack?  I would like to know what it does and if it would be useful for what I want to do. And that is to be able to charge without using the OBC and  with the key removed. I want to be able to enable and disable (by unplugging the OBC)  the extra 1.3 KW OBC charge as required.

Does the above switch  simply close the contactor (even when key is removed) or does it do more or something else?

The reason I am asking is because I purchased a couple of 3.3 KW Econs today, all programmed up for my Zero SR.  There could be times where I need to leave with the key and cannot charge at the 7.9 KW because many J Stns have a 6.6 KW (or less) limit.  I have my two 3.3  Elcons wired to the motor controller via Anderson Connectors.

I realize there are other ways to solve this problem, such  as the ChargePoint I used here today. It says it  can do "6.6 KW per port", so all I would need is to use both ports, using two J adapters (I do own four of them, but I have three in Reno right now). That's the very best way when possible. But I want some flexibility of my charge rate, so I can always charge as much as possible without "busting" as they say in Blackjack.

BTW, at the above mentioned J-station (my Plugshare linkg above). I did try the full 7.9 KWs to see what would happen. The chargepoint was working and even showed that I was charge a 7.X KW. It worked great for about two minutes at that rate  and went dead. It self re-set, so no harm done. I simply unplugged and re-plugged back  in at 6.6 KW (I disconnected the OBC and left the key on).

I will use my two old 2.5 KW chargers on my DS, and charge it at 6.3 KW from now on. No real issue there, but I am getting very close to 1C on that bike.

So what does the above switch actually do? I want to make sure I understand what it does before I add it to my Zero SR. Anybody here using it?

-Don-  Auburn, CA

Greetings friend! My number of wires of my connector (2014 ZeroS) is different from what is shown in your photo. What can I do to activate an additional charger without turning on the regular (OBC)?

[DonTom]

Greetings friend! My number of wires of my connector (2014 ZeroS) is different from what is shown in your photo. What can I do to activate an additional charger without turning on the regular (OBC)?

Just turn the bike on and leave the key in. I don't know of another way if your bike is different than shown.


-Don-  Reno, NV