[joekitch]

note this is for 2x volt's worth of battery with some of the very conservative top and bottom limiters reduced, so around 36kw

Damien was messing around with chademo fast charging his 2x volt packs in his Panzer but i don't know if he ever settled on a safe maximum charge rate

assuming i have proper cooling capacity to keep the cells in their optimum temperature range, what's the safe maximum charge rate the chevy volt batteries can take from a theoretical CCS setup?
Can it do bonkers fast like 150 kW because of how overbuilt the batteries are, or is something more like 60kW that fastest anyone has dared to try?

 

[john61ct]

What voltage we talking, Ah capacity?

In other words how do those kW convert to C rate?

 

[brian_]

What voltage we talking, Ah capacity?

In other words how do those kW convert to C rate?

Wouldn't it just be the voltage and capacity of a Volt pack? Some people use fractions of a pack or parallel strings, but the question was simply about the Volt pack. There are two generations of Volt, but they have same voltage (the 360 V of a 96S pack) and nearly the same capacity (about 16 kWh or about 44Ah).

 

[Isaac97]

KW can convert to C rate as long as you know the KWh number - 16 for a single Volt pack.
CHAdeMO (at least the normal versions) can only push ~50kw maximum. That would be ~3C for a single Volt pack.
Tesla, with their 250Kw v3 superchargers, and 75KWh packs (in Model 3 LR) reach 3.33C. And they're engineering specifically for charge rate.

 

[john61ct]

So 44Ah , assuming internal cell temps are >25C, you should not suffer much longevity reduction doing say 3-5C

So @360V that's 50-80kW

Personally I'd only be going higher (faster) if I really had a compelling reason, you're already talking a complete refill in only 10-20min

With relay racing or something where replacing the pack frequently was NBD then preheating the cells to 35-40°C would reduce damage done.

For ordinary road touring, I'd rather keep under 20A, stop for a leisurely meal, in order to get better longevity.

And if the cells are worn, or under 20°C, that becomes more important.

 

[joekitch]

80kw is probably all i need?
Which should get that empty to full in 30 minutes target with a 36kw pack

this thread is to determine if someone's found an upper limit through experimentation

 

[rmay635703]

The Volt itself peaks the entire pack @48kw from 20-80% SOC

 

[brian_]

The Volt itself peaks the entire pack @48kw from 20-80% SOC

That's an interesting point: while the 48 kW limit is probably determined by the electrical output capacity of the Voltec drive system (with the engine driving one or both motor/generators as motors, or regenerative braking), rather than the battery's ability to accept charge safely, it does establish that 48 kW charging is feasible.

 

[john61ct]

At such high C-rates, the natural "trailing amps" phenomenon will kick in much earlier

depending on the chemistry and age/wear of the pack, might even be before hitting the CV setpoint

which will also happen at a much lower SoC% than charging at normal rates.

None of this behaviour is the result of charge regulation circuitry

just the physical chemistry's interaction between SoC and the resistance / impedance, charge rate, voltage, etc.