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[DonTom]

1C means you either fully charge or discharge the battery in 60 minutes.

2C means you either fully charge or discharge the battery in 60/2=30 minutes.

3C means you either fully charge or discharge the battery in 60/3=20 minutes.

4C means you either fully charge or discharge the battery in 60/4=15 minutes.

etc.

Zero batteries are warrantied for 1C charge and up to 10C discharge rate as I understand it. Of course the C rating of the battery is wholly dependent on amps. Amps are the real power of the battery. The different packs may operate at different voltages, but they only accept a certain number of amps. This means all the batteries between manufactures are quite different, and the goal of each charging station is to provide amps to the batteries at whatever voltage the vehicles use. Energica bikes operate around 280-320V. The bikes are fine with accepting around 80+ amps at that voltage range. 80x280=2380W=23kW at completely dead. As the voltage rises, and the amps delivered remain the same, more kW are delivered. After all, 80x320=25600W=25.6kW.

Energica states that their nominal (usable) pack size is 11.7kWh or 11700Wh. If we take the median voltage, ~300, then we get 11700kWh/300V=~39Ah. The fact that it's dumping in upwards of 80 amps on a ~39 amp hour pack is fucking phenomenal. That's over 2C.

Thanks for that info.  One more question. How long will it take to charge a 11.7 KWH battery with an average charge power of exactly 11.7 KW?  Will it be an hour or more than an hour? And if more than hour, by about how much?

-Don-  Reno, NV

[MVetter]

The question is flawed. You charge by delivering amps. The voltage rises from low to high. *IF* you were to deliver exactly 11.7kW to the battery from empty to full it would mean you are delivering MORE amps during the empty stages and FEWER amps during the fuller stages. REMEMBER: Watts = Volts x Amps

[DonTom]

The question is flawed. You charge by delivering amps. The voltage rises from low to high. *IF* you were to deliver exactly 11.7kW to the battery from empty to full it would mean you are delivering MORE amps during the empty stages and FEWER amps during the fuller stages. REMEMBER: Watts = Volts x Amps

That's why I used the word "average". I know it will not be steady at all, but power is power and I don't see why the question is flawed.

In fact,  the CCS chargers even show us how much power we are charging at--and in watts. And so does the bike. That's how I knew the HD charger here in Reno is set to 15KW max. Both the CCS charger as well as my SS9 displayed the 15 KW until it got near the end when it had to lower.

-Don- Reno, NV

[MVetter]

1 hour

[Doug S]

It would be a fair amount more than an hour -- depends on a bunch of things, but 1-1/2 hours might not be a bad guess.

First, there's charging inefficiency. The fact that the batteries heat up means every joule of energy put into the battery does NOT result in a joule of energy in the battery -- some of it is lost to heat (you can use kWh for your energy units if you wish). Typical batteries only store about 80% of the charging energy put into them.

That's assuming you're DC charging, so the charger power loss is off the bike. If the charger is on the bike (level 1 or 2 charging), there's another loss term due to the charger inefficiency.

One more factor is the end-stage charging current taper. Below some SoC value, say 20%, and above some other value, say 85%, the charging current MUST taper down or you'll irreparably damage the battery. You can only charge a "1C" battery at the 1C rate between these values. That stretches out the charging time if you start very low or end very high.

[DonTom]

It would be a fair amount more than an hour -- depends on a bunch of things, but 1-1/2 hours might not be a bad guess.

First, there's charging inefficiency. The fact that the batteries heat up means every joule of energy put into the battery does NOT result in a joule of energy in the battery --

That is exactly what I assumed. If it took one hour to charge a one KWH battery, there is no way for the battery to get hot, as that would be 100% efficient. The heat proves there is power waste. How much in charge time that makes, I have no idea.  But I would expect it to be better than your 1.5 hours, but I really do not know. 1.5 hours means 50% is wasted in heat, and I doubt it is that inefficient. But perhaps it could be when we are at 2C and above as that must create a lot of heat while it is charging. IOW, I assume that the efficiency decreases as the charge rate is increased.

The SS9 battery has less warranty time than other electric bikes. It charges a lot faster (~25 KW), which means it gets a lot hotter.  I assume that is why the warranty is less.

-Don-  Reno, NV