On-Board Charger

[iamjustinpowell]

Hello everyone...

Just curious if anyone has experimented with replacing the 3.3 on-board charger with a 6.6kw charger? Because of my driving style it would help me greatly to be able to recharger my HVB faster. Just curious if any MOD freaks out there have looked into it.....

[larryh]

The current on-board charger applies 3 kW of power to the HVB using an external 240 V charger.  The remaining 0.43 kW of power is lost by the AC to DC converter and used by the on-board electronics, to charge the 12 V battery, and to power the fans.  This is close to the optimal in terms of maximizing the useful lifespan of the HVB.  Charging at a higher rate would heat up the HVB much faster and shorten the HVB's lifespan.  In order to charge the HVB at a faster rate, you would need to retrofit a more efficiently cooling system for the HVB.  Currently, the car uses air cooling for HVB.  Car's that charger at faster rates generally use liquid cooling. 

Edited August 16, 2014 at 06:29 PM by larryh

[Dan's Energi]

Nah, the Leaf has been using a 6.6 and L3 (super charging) for a while and there's no noticable degregation on their air (no fans) cooled batteries reported from folks in the northern states.  I mention the northern states because there are Leafs in hot states that have lost range - but that's due to high ambient temps.

 

I'm someone who also owns a Volt with a 3.3 and I've been asking (begging) Chevy to put a 6.6 in it.  Chevy still hasn't :(  Yet, the Volt has a great battery cooling system and does not use the full capacity of it's battery pack (charging to 100% also causes degredation).  Hopefully Ford comes out with a 6.6.  If they do, I think we'll see even more Volt owners coming to the Energi.

[larryh]

There is degradation with super charging the Nissan Leaf.  Nissan does not recommend doing it all the time.  You can read the following paper that discusses the affect of various charging rates on lithium-ion battery capacity:

 

http://electricvehiclewiki.com/images/b/b0/Capacityfade_jpspaper2.pdf

 

The more current used during charging, the faster the degradation. 

Edited August 16, 2014 at 09:25 PM by larryh

[Dan's Energi]

I'm pretty sure I never said anyone recommended using the L3 all the time.  However there's a lot of Leaf owners who use it - a lot.

 

The cases of folks using L3 and having hurt their batteries are few and far between.  Again, keep in mind that the Leaf has a lesser battery cooling system and uses ~100% of it's pack yet there's no widespread L3 deaths.  Meanwhile there's lots of heat related deaths indicating which is more likely to harm the cells.

[larryh]

The Nissan Leaf battery used an inappropriate cooling system given the battery's chemistry.  The chemistry used by the Leaf Battery experiences significantly faster degradation at higher temperatures than the batteries used by other manufacturers.  So an appropriate cooling system is critical for the Leaf, especially for owners in the southern states. 

 

Furthermore, Nissan failed to disclose its own recommendations that owners avoid charging the battery beyond 80% in order to mitigate battery damage, and failed to disclose that Nissan’s estimated 100 mile range was based on a fully charge battery, which is contrary to Nissan’s own recommendation for battery charging. 

 

The Fusion Energi does not allow you to charge the HVB to full capacity, i.e. 7.6 kWh.  Constantly charging a lithium ion battery to 100% SOC will shorten its lifespan.   If you want to maximize the life span of the HVB, you do not want to subject the battery to high temperatures.  In addition, you want to charge the battery right before using the car and only put in sufficient charge to get you to your destination. 

Edited August 17, 2014 at 02:15 AM by larryh

[Dan's Energi]

The Nissan Leaf battery used an inappropriate cooling system given the battery's chemistry.  The chemistry used by the Leaf Battery experiences significantly faster degradation at higher temperatures than the batteries used by other manufacturers.  So an appropriate cooling system is critical for the Leaf, especially for owners in the southern states. 

 

Furthermore, Nissan failed to disclose its own recommendations that owners avoid charging the battery beyond 80% in order to mitigate battery damage, and failed to disclose that Nissan’s estimated 100 mile range was based on a fully charge battery, which is contrary to Nissan’s own recommendation for battery charging. 

 

The Fusion Energi does not allow you to charge the HVB to full capacity, i.e. 7.6 kWh.  Constantly charging a lithium ion battery to 100% SOC will shorten its lifespan.   If you want to maximize the life span of the HVB, you do not want to subject the battery to high temperatures.  In addition, you want to charge the battery right before using the car and only put in sufficient charge to get you to your destination. 

I don't really understand if that's a counterpoint, it seems inline with what I said.

 

Whatever, it's all good. :hat_tip: 

I  want a Roush edition FFE   :rating:

[larryh]

The above posts are information that I have come across recently while investigating lithium-ion batteries and degradation in capacity over time.  People might find it of interest.  The previous post comes from the lawsuit filed against Nissan.  When Nissan tested the Leaf Battery at high temperatures, they did cycle testing over the course of a few months, continuously charging and discharging the battery.  They observed no significant degradation in battery capacity.  The problem is that heat related degradation, causing undesirable chemical reactions, takes place constantly over time.  The only way to determine the degradation in battery capacity over the years is to actually test the battery for that length of time, which is not practical.  Hence the unexpected premature failure of the Leaf batteries.  Their test procedures were faulty. 

Edited August 17, 2014 at 12:10 PM by larryh

[Hybridbear]

The above posts are information that I have come across recently while investigating lithium-ion batteries and degradation in capacity over time.  People might find it of interest.  The previous post comes from the lawsuit filed against Nissan.  When Nissan tested the Leaf Battery at high temperatures, they did cycle testing over the course of a few months, continuously charging and discharging the battery.  They observed no significant degradation in battery capacity.  The problem is that heat related degradation, causing undesirable chemical reactions, takes place constantly over time.  The only way to determine the degradation in battery capacity over the years is to actually test the battery for that length of time, which is not practical.  Hence the unexpected premature failure of the Leaf batteries.  Their test procedures were faulty. 

Similarly worrying is the fact that Ford used similar test procedures when assessing its Li-ion battery chemistry. I hope the Fusion Energi batteries hold up well.