What is on your onboard charger wishlist?

[lowCo2]

I bought my FFE a couple of weeks ago and this is my first post. Thanks to all for the useful posts over the years. I wish I had found this site before buying the car!
At the moment I'm getting by quite well with the included 120v charger which easily completes overnight. In April I will switch to PG&E's EA tariff and to get the best rates I will probably need a 240v charger.

Because I have modest energy demand (~20 miles per day) and I feel I'll get the more value out of the car the longer the battery survives, I believe the ideal charging system would have modes to:
1) minimize the charging rate such that charging would complete within the off-peak charging period (perhaps with a 1kw minimum) ("low heat mode")
2) if full charge cannot be achieved in the off-peak charging period I would be willing to cease charging at the end of off-peak (basically, if the following day I only need 30% of charge why pay higher rates to charge to 100%? I would be happy with 60%) ("cheap mode")
3) charge to less than 100% to improve battery longevity ("part-fill mode")
4) charge at the highest possible power ("fast mode")

Anyone else see value in these objectives?

Of course my #1 objective is that the charging algorithm is 100% predictable and reliable...

 

[WattsUp]

3) charge to less than 100% to improve battery longevity ("part-fill mode")

With the FFE, the battery is never actually charged to 100% capacity. Unlike the "maximum charge" mode of the Leaf, a full charge for the FFE represents somewhere less than 95% of the total battery capacity, as near as we can surmise.

The stated total capacity of the FFE battery is 23 kWh. The total usable capacity of the FFE battery seems to be 19.5 kWh (by all accounts of "wall-to-battery" and "battery-to-wheels" record-keeping that folks here have done). If we also assume there is a buffer of around 10% that is never discharged (this is a guess, but probably in the ballpark), then we can make the following estimate of the total stored energy on a full charge:

2.3 kWh (10% buffer) + 19.5 kWh (usable) = 21.8 kWh (total)

This result of 21.8 kWh is just about 95% of the total stated capacity.

 

[WattsUp]

Btw, you could achieve most of your objectives with a programmable EVSE (with the exception of the "part fill" mode, since the EVSE doesn't know the SOC). The EVSE can control when the power is available, and at what level.

 

[sefs]

I bought my FFE a couple of weeks ago and this is my first post. Thanks to all for the useful posts over the years. I wish I had found this site before buying the car!
At the moment I'm getting by quite well with the included 120v charger which easily completes overnight. In April I will switch to PG&E's EA tariff and to get the best rates I will probably need a 240v charger.

Because I have modest energy demand (~20 miles per day) and I feel I'll get the more value out of the car the longer the battery survives, I believe the ideal charging system would have modes to:
1) minimize the charging rate such that charging would complete within the off-peak charging period (perhaps with a 1kw minimum) ("low heat mode")
2) if full charge cannot be achieved in the off-peak charging period I would be willing to cease charging at the end of off-peak (basically, if the following day I only need 30% of charge why pay higher rates to charge to 100%? I would be happy with 60%) ("cheap mode")
3) charge to less than 100% to improve battery longevity ("part-fill mode")
4) charge at the highest possible power ("fast mode")

Anyone else see value in these objectives?

Of course my #1 objective is that the charging algorithm is 100% predictable and reliable...

The FFE has a 6.6 kW charger. Even if we use the 19.5 kWh capacity for conservatism, the 6.6 kW charger works out to be charging at a rate of about 0.3C. 0.7C is the upper limit of what is generally accepted to be completely safe for Lithium Ion batteries. So even with "fast-charging" we aren't even getting close to straining the battery. Ford has really set up the FFE to be charged "completely" whenever you can. Like WattsUp said, it locks out the upper and lower portions of the charge to maximize the longevity of the battery. I wouldn't have any concern about charging at 6.6kW every night. It's exactly what I do. I'm actually in the design phases of adding an additional 3.7 kW charger to the FFE to speed up charging. If you wanted to be overly cautious (unnecessarily cautious in my book) you could go with a lower power level II EVSE. Clippercreek makes variants all the way down to 2.8 kW for their level II chargers. That would assure you finish charging in the off peak window if you were dead set on not charging at 6.6kW.

 

[WattsUp]

I'm actually in the design phases of adding an additional 3.7 kW charger to the FFE to speed up charging.

Interesting sefs. Could you elaborate on what you mean by this... are you referring to augmenting the on-board charger? I mean, are you actually planning to modify your FFE? :shock:

 

[michael]

I continue to believe that "part fill" mode is very desirable. I understand that the FFE uses only a part of the total capacity, but I am convinced that keeping as close to 50% as an average as practical will result in improved battery life.

A programmable EVSE is not a substitute, since the TMS doesn't work when the EVSE isn't providing power. Like Tesla and Nissan, Ford should allow the option of a partial fill.

I also like the idea of a slow charger. Of course in shared charger situations, this is bad since it ties up the shared charger. I have a 3 KW portable that I use during the day at work. There are plenty of 220 outlets so I don't tie up the scarce 6 KW charging stations.

 

[sefs]

I'm actually in the design phases of adding an additional 3.7 kW charger to the FFE to speed up charging.

Interesting sefs. Could you elaborate on what you mean by this... are you referring to augmenting the on-board charger? I mean, are you actually planning to modify your FFE? :shock:

The idea came to me when looking through the Leaf forums and saw that they had added a Brusa 3.7 kW charger to boost the charging ability of their 2012 3.3 kW Leafs to that of the level of the 6.6 kW Leafs. It looks to be pretty involved, but I have been pouring through the service manual and learning a lot about the control and operation of the various systems involved. Right now, I'm researching what data is available through the EV-CAN bus that I can collect and translate for an additional charger(s). Also, I'm investigating the data that feeds back to the battery control module. I don't want to inject more current, have the BECM see too high of current and open the charging contacts. Anyways, still in the early stages, but I'd love to be able to charge at 20 kW

If anything, it would be great to gather more information to augment the instrument cluster on state of charge and other statistics.

 

[paw160]

sefs... I like your ambition, but I just want to give a word of caution... what you are doing could be very dangerous. It does sound like you are doing you homework on this though.

What kind of electric service are you going to power this from? At 240VAC you are looking at >40Arms.

I could see how the Leaf could boost from 3.3kW with a 3.7kW to 7kW total. That's a pretty common 30A 240V circuit.

 

[sefs]

sefs... I like your ambition, but I just want to give a word of caution... what you are doing could be very dangerous. It does sound like you are doing you homework on this though.

What kind of electric service are you going to power this from? At 240VAC you are looking at >40Arms.

I could see how the Leaf could boost from 3.3kW with a 3.7kW to 7kW total. That's a pretty common 30A 240V circuit.

Thanks for the caution, safety is the top priority. I have a 70 amp clippercreek EVSE. I'm looking at either adding a Brusa (http://www.brusa.biz/index.php?id=154&L=1) that would add 3.7 kW (this is what the Leaf owners have already done), or a EMW Smartcharge 12000 (http://emotorwerks.com/tech/electronics) that could possibly add up to 12 kW. As far as my background in power electronics, I'm an electrical engineer by trade; but this project is still in the preliminary stages.

Keeping with the onboard charger wish list topic of this thread, mine would be:
1. Ability to monitor volts and amps going into the vehicle.
2. Ability to limit current drawn by the on board chargers.
3. Be able to charge at least 10 kW. (Making RV outlet and welder outlets that much more useful to me.) At 20kW, full charging could be complete in a little over an hour. Not that you would want to charge near 1C all the time, but the option could be very beneficial.
4. Be able to charge at 16 and 24 amps 120V to make NEMA 5-20 and TT-30 outlets more useful.
5. Not really a charger wish, but have the ability to have more detailed state of charge readout while driving.

 

[paw160]

Sounds like a very cool project. It would be nice to get more detailed information out of the battery. Watching the charge curves would answer a lot of questions about capacity and charge state.

Looking forward to reading about your progress!