Charging and OBC discussion split from Nissan Ariya thread

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
jlv said:
DaveinOlyWA said:
Or simply a marketing ploy to ease range anxiety that Tesla already knew was overblown. Having 80 amp charging at home was nothing more than a monumental waste of money and EVERYONE lost a ton when they sold those cars because the double chargers were literally worthless.
THIS ^^

I knew a guy that bought a P85D back when I got my LEAF. He got the double charger and put in 80A charging at his house. But his car would charge at work during the day at 30A, and he rarely needed to charge at home. Two years later he told me the double charger and 100A circuit was the biggest waste of money because he never used them. But he was ego driven (hence spending $130K on the P). I wouldn't be surprised if he has a Taycan now.

My home has a 300 Amp (or is it 320 ?) service drop, and I recently installed a second electric panel that has ~ 16 free breaker slots for now. I thought about installing a 72 kW Supercharger, but in the end decided that a 10 kW EVSE that uses a 14-50r already in place, regulated down to 6 kW to match my PV, would work best for me.
 
Indeed! If people want to discuss OBCs and L2 EVSE max output in the US/North America (at home, in public, at work, etc.), there should be a separate thread.
 
SageBrush said:
GRA said:
Oh, please, are you seriously suggesting that a 48A EVSE install is that much more expensive than 40A?

Not really a suggestion, but a fact of life if an electrician is called for the job.


An electrician will be just as needed for a 40A install. 48A costs more due to bigger wire and the breaker may be marginally more expensive, but the major expense is if it's necessary to upgrade the service entrance.
 
GRA said:
SageBrush said:
GRA said:
Oh, please, are you seriously suggesting that a 48A EVSE install is that much more expensive than 40A?

Not really a suggestion, but a fact of life if an electrician is called for the job.


An electrician will be just as needed for a 40A install. 48A costs more due to bigger wire and the breaker may be marginally more expensive, but the major expense is if it's necessary to upgrade the service entrance.
It has nothing to do with material costs. You don't know what you are talking about.
 
So, I did a thing. Ran the pack down to 22% SOC, then plugged in at 9:30 PM and by the time I arose the next day at 5:40 AM, the charge was complete and I am only pushing 24 amps. Now the charge light was still on but not blinking so maybe another balancing bump was being prepped but SOC was 99.9% based on the new and improved BMS per LEAF Spy. So I gained roughly 200 miles in a partial overnight charge which is yeah, a bit meaningless if TOU is a concern but the grand scheme of things says home charging pretty much fits for nearly everything but that we already knew.

So now we discuss "our wants" and NEWSFLASH!! Those wants apply AND fail just as equally when choosing gassers. We want range but we also want reliability, cheap ongoing costs and cheap fuel. So gassers are more of a compromise than going EV. "We" shouldn't have to be reminded of that.

So your memories of "old reliable" that went 300,000 miles is human nature as we tend to either remember mostly good or mostly bad when thinking of the past. Odds state that if talking about a gasser, it was mostly bad and we chose to gloss over that fact.
 
GRA said:
Given the large 90kWh (87kWh usable) pack (and somewhat for the smaller 65kWh, 63 usable) the charging rates seem too low, particularly L2.
Larger batteries allow for lower charging rates.

A battery is a queue for energy.

https://en.wikipedia.org/wiki/Queueing_theory
 
SageBrush said:
GRA said:
SageBrush said:
Not really a suggestion, but a fact of life if an electrician is called for the job.


An electrician will be just as needed for a 40A install. 48A costs more due to bigger wire and the breaker may be marginally more expensive, but the major expense is if it's necessary to upgrade the service entrance.
It has nothing to do with material costs. You don't know what you are talking about.



Riiiight, a licensed electrician isn't needed to install a 50A circuit (to code). :roll:
 
WetEV said:
GRA said:
Given the large 90kWh (87kWh usable) pack (and somewhat for the smaller 65kWh, 63 usable) the charging rates seem too low, particularly L2.
Larger batteries allow for lower charging rates.

A battery is a queue for energy.

https://en.wikipedia.org/wiki/Queueing_theory


A larger battery allows for lower C rates given the same charging rate, but requires a higher charging rate to achieve the same C rate. Drivers care about how long it takes to put X amount of range in their battery, and how much range that battery can provide. The latter is independent of charging rate. The max. L2 C rate for the 90kWh Ariya will be about C/12.5. For the 82 kWh ID.4 it's about C/7.5, and for the 98 kWh Mach-E it's somewhere in the range of C/8.9-9.33; the uncertainty exists because some companies seem to list the max. current from the wall, and others use the net rate into the battery.
 
GRA said:
WetEV said:
GRA said:
Given the large 90kWh (87kWh usable) pack (and somewhat for the smaller 65kWh, 63 usable) the charging rates seem too low, particularly L2.
Larger batteries allow for lower charging rates.

A battery is a queue for energy.

https://en.wikipedia.org/wiki/Queueing_theory


A larger battery allows for lower C rates given the same charging rate, but requires a higher charging rate to achieve the same C rate. Drivers care about how long it takes to put X amount of range in their battery, and how much range that battery can provide. The latter is independent of charging rate. The max. L2 C rate for the 90kWh Ariya will be about C/12.5. For the 82 kWh ID.4 it's about C/7.5, and for the 98 kWh Mach-E it's somewhere in the range of C/8.9-9.33; the uncertainty exists because some companies seem to list the max. current from the wall, and others use the net rate into the battery.

Totally missed my point. Try again.
 
SageBrush said:
WetEV said:
Totally missed my point. Try again.

He did indeed. Makes me wonder if he really has ever installed an off-grid PV+battery system.

I don't see any reason to doubt that he sold them. Don't need to understand all the details to sell.
.
WetEV said:
GRA said:
Given the large 90kWh (87kWh usable) pack (and somewhat for the smaller 65kWh, 63 usable) the charging rates seem too low, particularly L2.
Larger batteries allow for lower charging rates.

A battery is a queue for energy.

https://en.wikipedia.org/wiki/Queueing_theory

TLDR: Larger battery means a slower charge rate can support the same driving pattern.
 
WetEV said:
I don't see any reason to doubt that he sold them. Don't need to understand all the details to sell.
*All* the details, no.

But a half-assed salesperson would ask about PV generation and home consumption in order to size the battery.

In case it is not obvious, PV generation is akin to charging and consumption to range
 
SageBrush said:
WetEV said:
I don't see any reason to doubt that he sold them. Don't need to understand all the details to sell.
*All* the details, no.

But a half-assed salesperson would ask about PV generation and home consumption in order to size the battery.

In case it is not obvious, PV generation is akin to charging and consumption to range

Batteries are queues for energy.

A larger battery means that less PV generation can supply the same loads. The real trick is finding the minimum total cost.

Need to understand? Get a program that spits out an answer, don't need to understand the calculation, just plug in the numbers and read the result(s).
 
WetEV said:
Batteries are queues for energy.

A larger battery means that less PV generation can supply the same loads. The real trick is finding the minimum total cost.
One might even call a battery an energy storage medium
 
WetEV said:
GRA said:
WetEV said:
Larger batteries allow for lower charging rates.

A battery is a queue for energy.

https://en.wikipedia.org/wiki/Queueing_theory


A larger battery allows for lower C rates given the same charging rate, but requires a higher charging rate to achieve the same C rate. Drivers care about how long it takes to put X amount of range in their battery, and how much range that battery can provide. The latter is independent of charging rate. The max. L2 C rate for the 90kWh Ariya will be about C/12.5. For the 82 kWh ID.4 it's about C/7.5, and for the 98 kWh Mach-E it's somewhere in the range of C/8.9-9.33; the uncertainty exists because some companies seem to list the max. current from the wall, and others use the net rate into the battery.

Totally missed my point. Try again.


And you've failed to restate your original argument, but this time base it on a realistic premise, so you need to try again.
 
SageBrush said:
WetEV said:
Totally missed my point. Try again.

He did indeed. Makes me wonder if he really has ever installed an off-grid PV+battery system.


You're welcome to believe anything you wish. Why don't you enlighten all of us as to why, absent a need to upgrade the service entrance, you think it's far more expensive for an electrician to install a 60 vice 50A circuit, outside of extra costs due to larger wires (and conduit, if used)?
 
WetEV said:
SageBrush said:
WetEV said:
I don't see any reason to doubt that he sold them. Don't need to understand all the details to sell.
*All* the details, no.

But a half-assed salesperson would ask about PV generation and home consumption in order to size the battery.

In case it is not obvious, PV generation is akin to charging and consumption to range

Batteries are queues for energy.

A larger battery means that less PV generation can supply the same loads. The real trick is finding the minimum total cost.

Need to understand? Get a program that spits out an answer, don't need to understand the calculation, just plug in the numbers and read the result(s).


Well, sometimes. What is often the driving force in off-grid systems is days of autonomy you can meet the demand, usually 3 to a maximum of 10 (when I was designing these systems), and being able to replenish that autonomy given the solar/wind resource before it was next needed would determine the amount of generation required. Cottages and the like used only on weekends could use bigger battery packs and smaller PV arrays, because they had enough time in between demand to recharge for the next demand period, and you can usually cut out a few optional loads with minimal impact if you occasionally come up short. Full-time occupancy is a different matter - you've got to design the system so the PV generates an excess of the daily load, so it can replenish the batteries are while continuing to meet the daily demand after a period of low production.

At the time I was doing this, PV was 7 to 10 times more expensive per Wp than it is now, so we told customers to first spend money on buying the most efficient lights and appliances and, to the extent they were willing to do so, accommodate their activities to the system's needs; doing so was by far the least expensive option, rather than simply throwing money at the problem by buying more PV and batteries. Since the typical off-grid customer was a DIY type who had a strong environmental motivation and a belief that small is beautiful, plus limited funds, almost all of them were willing to make the necessary accommodations - things like waiting to do laundry until the pack was full on a sunny day, paying $2,500 for a refrigerator (that only required the output of 4 panels to run it vice 10-15 for a standard refrigerator), etc.

The economics have shifted considerably since then, most systems are on-grid now, and the typical mainstream customer is far less willing to learn how their system works, maintain it, or make the kinds of accommodations that my early adopter customers would, so system designs need to adapt to mainstream customers' expectations. Exactly the same process is needed to make BEVs mainstream - early adopter behavior and expectations are significantly different.

BTW, we did all our demand and generation calcs by hand or with a calculator, as such programs weren't available at the time. As there were typically far fewer and individually smaller loads, often DC rather than AC, this wasn't a problem. Actually, we encouraged our customers to do those calcs for themselves (but we'd check them over for errors, and make suggestions for options), because the more they knew about how the parts of their system worked together, the less expensive it would be to buy and operate.
 
GRA said:
What is often the driving force in off-grid systems is days of autonomy you can meet the demand, usually 3 to a maximum of 10 (when I was designing these systems), and being able to replenish that autonomy given the solar/wind resource before it was next needed would determine the amount of generation required. Cottages and the like used only on weekends could use bigger battery packs and smaller PV arrays, because they had enough time in between demand to recharge for the next demand period, and you can usually cut out a few optional loads with minimal impact if you occasionally come up short. Full-time occupancy is a different matter - you've got to design the system so the PV generates an excess of the daily load, so it can replenish the batteries are while continuing to meet the daily demand after a period of low production.

OK

Two identical houses with identical loads and solar exposure.

One house has a battery of size x.
The other has battery of size 2x.

Which house needs the larger PV array?

Show your work.
 
Back
Top