ON BOARD CHARGER

[FiddlerJohn]

The on board charger increases a single phase AC for home to 360 V to charge the main battery.

Construction
The on board charger monitors input and output voltages, current and pilot signal. If detecting the abnormal conditions, the on board charger should stop a charge. The three temperature sensors are mounted at the inside of the on board charger to monitor the temperature of the inside circuits of the on board charger. When the temperature of the inside circuits of the on board charger becomes high, the cooling request signal should be sent to the EV-ECU to drive the electric motor unit cooling system. When the temperature abnormally becomes high, the charge should be stopped.
System configuration

When the charging cable is connected between the vehicle and the power point for home use with the electric motor switch in the "LOCK" (OFF) position, the electric power should be supplied from the power supply for home use to the on board charger. The on board charger where the electric power is supplied sends the charge activation signal to the EV-ECU. The EV-ECU receives the charge activation signal and turns on the EV control relay to activate the EV-ECU. The EV-ECU also turns on the on board charger relay to activate the on board charger. The activated on board charger measures the input power supply voltage for home use. The activated on board charger measures the input power supply voltage for home use, which is sent to the EV-ECU. The EV-ECU issues the on board charge voltage command and the on board charge current command to the on board charger and then, charging the main battery starts. When knowing that the charge conditions of the main battery are sent from the BMU through the CAN and detecting the fully charged conditions, the EV-ECU should stop the charge.

CHARGING CABLE
The charging cable is mounted on the vehicle as an accessory of the vehicle. Connecting the cable between the vehicle and the home socket can make the main battery charged. There is the switch in the regular charging plug of the charging cable. The switch is turned ON/OFF, depending on the regular charging plug release button status. When the regular charging plug is correctly connected with the vehicle, the switch should be ON and the signal should be input into the EV-ECU. When the regular charging plug release button is pressed from that status, the switch should be turned OFF and the signal should be input into the EV-ECU. This allows the EV-ECU to detect the insertion status of the regular charging plug.

The charging cable has the charging circuit interrupting device. When connecting the charging cable with home sockets, the AC power supply should be input into the charging circuit interrupting device. At that time, the READY indicator (green lamp) of the charging circuit interrupting device should be lit. When connecting the charging cable with home sockets and the vehicle, the charging circuit interrupting device should send the pilot signal to the on board charger. This allows the on board charger to detect the supplied currents and charging should be enabled. When the main battery starts to be charged, the CHARGE indicator (orange lamp) of the charging circuit interrupting device should be lit. When the main battery is finished to be charged, the CHARGE indicator (orange lamp) should be extinguished. The charging circuit interrupting device has the function detecting whether earth leakages exist or not; also the charging circuit interrupting device has the function detecting charging cable abnormalities. If detecting abnormalities, the charging circuit interrupting device should shut down the AC power supply and should light or blink the FAULT indicator (red lamp) of the charging circuit interrupting device.

 

[jray3]

Thanks John, that contained some details that surprised me, like the double-conversion charging process (AC-DC-AC-DC?).
Have you looked into adding a second charger, either onboard or offboard to increase speed, as some of the Gen 1 LEAFers are now doing with a Brusa charger?
THX,
Jay

 

[FiddlerJohn]

... the double-conversion charging process (AC-DC-AC-DC? )... Have you looked into adding a second... Brusa charger?

The the double-conversion process allows the step up transformer to be very small because the inverter frequency is very high.

This design might mean that the input could be any frequency -- maybe even DC like from a PV solar cell array. Since 240 VAC has a peak at (240)√2 = 240x1.4 = 336VDC, the PV array should be less that 336VDC open circuit Voltage. The input protection of the OEM charger has something like a metal-oxide varistor (MOV) that shorts and blows the input fuse when the input excesses some high value (maybe 385 Volts peak to ground). Then the array would need the hardware and software to handle the EVSE protocol.

... Have you looked into adding a second... Brusa charger?

Only in my dreams. To parallel a Brusa charger with the OEM to provide 6.6 kW charging would be a great project, but it's too much for me. I could handle the cost, the mechanical changes and the electrical issues, but the CAN bus scares me. We would need of team of experts, like we have in this forum, to pull that off.

EVTV says $2,295.00 for the NLG513 16A Brusa charger.
http://store.evtv.me/products.php?cat=15

I can imagine a parallel 3.3 kW charger that senses and matches the OEM current. The parallel 3.3 kW charger should be controlled by the CAN bus, but my tenancy would be just hardware control being careful to allow the BMU to still function.

 

[siai47]

It doesn't appear that the I-MiEV likes a parallel charger. I have tried this and when you increase the total input power above about 5 KW, the vehicle charger shuts down. I think that the battery current sensor is sending a signal to one of the controllers that the vehicle charger is inputing too much current and therefore it shuts down to protect it. That being said, I do charge with a 12 KW charger directly into the traction battery by making a connection at the inverter where the pack cables enter. I have a 175 amp anderson connector mounted on the car to connect the charger which is a Manzanita Micro PFC-50B. To do this, you must place the car in the "ready" mode to get the HV contactors to close. As far as the car is concerned, you are driving down a steep incline and are in the regen mode. You won't see it on the dash display as the car would normally be in park, however if you move it into any drive position, you can see the display move almost half way into full regen---12 KW is delivering about 32 amps back to the traction battery. Even at that level you are only charging at less then 1C rate. When in park, the BMU is accurately recording "KW in" so the SOC indicator is working correctly. An additional benefit to this method is with the car in the "ready" mode, you can use the vehicle A/C to provide cold air into the pack (if your car has the battery warmer or QC option) during charging. The only downside to this is that I don't believe the battery balancers can work until there is a lower current input. When you charge normally, the charger current falls off and (I am again guessing) the balancers are switched on. The balancers can't shunt high currents, therefore can't operate at high charge levels. I also think that's why QC charging terminates at 80% or so. I never charge above 80% (voltage limited) with the 12 KW charger. I will only do this a couple of times before I do a full charge with the vehicle charger to allow balancing. I haven't had any problems to date. I you want to charge off a solar system and have a voltage regulator on it set so you cannot exceed a specified voltage---say 355 or so--then you could use this method. Just make sure that you balance the pack once in a while. Many people who don't charge to 100% aren't balancing and don't even know it.

 

[jray3]

I have tried this and when you increase the total input power above about 5 KW, the vehicle charger shuts down....That being said, I do charge with a 12 KW charger directly into the traction battery ... To do this, you must place the car in the "ready" mode to get the HV contactors to close.

SIA47- U DA MAN!

I've daydreamed on this, but hadn't taken the plunge, as my PFC20 charger would only increase charging speed by 45%, not the 360% that you've achieved. (and require manual retuning each time I swap it between EVs)


Did you just cut the inverter leads and splice in the Andersen, or make a longer pigtail or 3-way connection? It appears that this method could also allow one to export power from the iMiEV, whether for emergency household/business backup power, or EV-to-EV resuscitation..

Dateline: 2014 NEDRA Nationals, Kent, WA. Today, EV Racers silenced their generator sets and transferred 24 kW of charging current directly from an i-MiEV into the White Zombie dragster using a Manzanita Micro PFC75, while the MiEV replenished itself at a sedate 3.3 kW rate between heats.

 

[PV1]

Solar/battery range trailer is now an option for you. Awesome. Would you mind sharing where you tied into the high voltage system?

 

[siai47]

I connected the PFC-50 at the inverter. There really isn't any other good place to do it. I removed the inverter and put a hole in the left front of the housing. I threaded it and put in a water tight SO cord strain relief. This allowed me to make a larger radius turn into the connections inside the inverter then trying to go through the small access cover. From the inverter I ran a #4 SO cord over to the QC port area and installed a 175 amp anderson connector (Way overkill but I use this connector on all my other stuff). To charge, I put the car in the "ready" mode to close the HV contactors and switch on the A/C to duct cold air to the battery during charge. 80% from turtle takes just about one hour drawing 50 amps off the AC line. I might start going to 90% and keep an eye on the balance on the batteries. Even at this charge level, the battery is still only seeing 2/3 C rate which is pretty easy on the battery. I know the PFC-50 (like all PFC'S) is a non-isolated charger but the I-MiEV HV circuit does not use the vehicle grounds at any point in the system. If a ground was occuring, the battery ground fault detector would pick it up. I can't find any AC or DC voltage potential on the vehicle to ground. I also sent the charger back to Manzanita Micro to have the modifications for J1772 control added to it. It should help charge times when on the road. When visiting friends I just hope they aren't drying clothes or cooking dinner when I show up with my 50 foot 6/3 extension cord.

 

[jray3]

I connected the PFC-50 at the inverter. There really i I also sent the charger back to Manzanita Micro to have the modifications for J1772 control added to it. It should help charge times when on the road.

Ha, it is indeed a small world; I beta-tested the J1772 modification for Manzanita, so mine is still external to the PFC20 charger as a "smart box". Never got mine to work with public EVSE, I think due to intermittent ground faults in the flooded pack. it's going back for revision.

What's the downside to connecting at the HV contactors on the pack?

 

[RobertC]

I connected the PFC-50 at the inverter.

What a great idea!
Is the PFC-50 mounted in the car?
Also, I was wondering if by having the AC blow cold air into the battery pack and it is hot out, is there a possibility of condensation in the pack?
I recently DC Quick Charged from 40% to 80%.
The whole charge took about 13 minutes.
I monitored the charge using Canion.
The AC ran full blast and shut off after 8 minutes or 68.5%.
The DC Quick Charge ran at about 115A for the first three minutes and started to ramp down and was down to about 60A when the AC shut off.
The battery pack average temperature only went up about 6 degrees Fahrenheit.

 

[siai47]

There is nothing wrong with using the QC contactors for charging with the PFC charger. When I first did this, my car didn't have the QC contactors which it does now. I am going to be switching to using them as it gives me an option to get high voltage DC back out of the Anderson connector without having the car in the "ready" mode. As to condensation, I suppose you could get it if you got the pack really cold. I have tried that with the leased car (no use having problems with the one I own) and have been able to get condensation on the outside of the two aluminum access covers under the car. Removing the covers showed no condensation inside the covers. It's a lot like when you are using A/C in a very humid enviornment. The glass might condense on the outside, but the humidity is lower inside the vehicle (and pack) therefore it doesn't condense inside. If you look at the internal ducting of the cold air in the pack, the bulk of it is directed between the stacks of batteries with the area of the access covers really getting hit with the cold air. Also, the plastic construction of the rest of the pack isn't going to allow heat transfer to the outside as quickly as the aluminum covers. The PFC isn't mounted in the car, it's something I can throw in there if I need to use it.

 

[RobertC]

There is nothing wrong with using the QC contactors for charging with the PFC charger. When I first did this, my car didn't have the QC contactors which it does now. I am going to be switching to using them as it gives me an option to get high voltage DC back out of the Anderson connector without having the car in the "ready" mode. As to condensation, I suppose you could get it if you got the pack really cold. I have tried that with the leased car (no use having problems with the one I own) and have been able to get condensation on the outside of the two aluminum access covers under the car. Removing the covers showed no condensation inside the covers. It's a lot like when you are using A/C in a very humid enviornment. The glass might condense on the outside, but the humidity is lower inside the vehicle (and pack) therefore it doesn't condense inside. If you look at the internal ducting of the cold air in the pack, the bulk of it is directed between the stacks of batteries with the area of the access covers really getting hit with the cold air. Also, the plastic construction of the rest of the pack isn't going to allow heat transfer to the outside as quickly as the aluminum covers. The PFC isn't mounted in the car, it's something I can throw in there if I need to use it.

Summer is over here in New Jersey, but I am going to run an air conditioning duct into my garage and install an exhaust fan for next summer since I have found that ambient temperature greatly determines the battery pack temperature, and keeping my garage cooler will help the battery pack (and the rooms above the garage). Also, based on your excellent research, next summer I am going to divert air conditioning to my battery pack when driving on hot days.

Here's a similar project using the PFC-50 and a first generation Toyota RAV4 EV. It looks like the PFC charger sat in the trunk and a 50A 240V marine connector was used to connect the car to AC power.
http://www.evnut.com/docs/rav_docs/rav4evpfc50.pdf
Interestingly, since the RAV4 could be charged while running (and so could your i-MiEV), they were also able to put an 11kW generator on the back as a range extender.
Unlike your application, it doesn't look like they were able to do anything about the increased heat from charging, and heat is an enemy of the NiMH batteries that were in the RAV4 as well.
Your 12kW charger is between a Level 2 and a Level 3 charger. Your Level 2.5 charger could be installed at many residences or businesses without upgrading their electric service. The 12kW charger would cost less than a Level 3 charger, make use of the DC Quick Charge port, and could deliver 50 miles range in one hour.

 

[fjpod]

Better check your local building codes first. It may be illegal to run a duct from your living quarters into a garage. The concern, of course, is the accidental flow of carbon monoxide into the ductwork and throughout your house.

Sure a garage can get warm...maybe you can set up an exhaust fan. As long as the car is not in direct sunlight, isn't that enough protection?

 

[siai47]

I owned a Rav4-EV and had done the modification to connect the PFC to it. In normal use it wasn't needed as the Rav's 6.6 KW "Magnacharger" was reasonably quick at charging. The problem was going on a trip. There was no public charging infrastructure in place. The "EVSE" side of a Magnacharger was as big as a house and had to be used to make the onboard charger work (thanks GM :evil: ). The PFC 50 was smaller and had almost double the output of the onboard Rav charger. The connection and operation of the modification was almost identical to what I did with the I-MiEV. Although you couldn't cool the pack on the Rav manually, if the batteries reached a specific temperature the cooling fans would come on as the Rav (like the I-MiEV) had to be in the drive mode to make this work. Already owned the PFC from the S10-E days (same Magnacharger problems) and my Kurbwatt (talk about a huge forklift size offboard charger) so it was a no brainer. Looking back, we have come a long way with EV's in a few short years!

As to cooling the garage, the inspector would most likely have a fit. My parents house years ago had heat in the garage and the outlets had gravity dampers on them. The airflow from the furnace blower would open them when there was pressure in the ductwork and they would close when the blower stopped. Maybe an inspector would buy something like that. I use a 12K BTU, two-hose, portable room air conditioner to cool the garage here in Florida and keep it at 77 degrees.

 

[RobertC]

Better check your local building codes first. It may be illegal to run a duct from your living quarters into a garage. The concern, of course, is the accidental flow of carbon monoxide into the ductwork and throughout your house.

Sure a garage can get warm...maybe you can set up an exhaust fan. As long as the car is not in direct sunlight, isn't that enough protection?

Thanks. I checked the code. My idea won't work.
My garage is insulated and is 11' 6" high. It really holds the heat in the summer and even the two rooms above it are warmer.
The battery pack is almost always warmer than the ambient temperature. If my i-MiEV is in my 95 degree garage, then my battery pack is going to be at least 95 degrees.

As to cooling the garage, the inspector would most likely have a fit. My parents house years ago had heat in the garage and the outlets had gravity dampers on them. The airflow from the furnace blower would open them when there was pressure in the ductwork and they would close when the blower stopped. Maybe an inspector would buy something like that. I use a 12K BTU, two-hose, portable room air conditioner to cool the garage here in Florida and keep it at 77 degrees.

It looks like the two-hose, portable air conditioner is the way to go. My garage does not have windows, so I will have to cut two holes in the wall for vents.
Thanks for the advice.

 

[jsantala]

I had some time here, sitting at a gas station, charging at 3 kW, so I googled for the second charger option and found this old thread.

siai47's system of plugging into inverter input and adding a new charger sounds really good. I found this charger that would fit the bill quite nicely, namely the TCCH-288-18 model, which would charge at about 6.5 kW and take about 31 amps from the wall at 230 VAC:

http://www.evassemble.com/index.php?main_page=product_info&products_id=26:1e3ab89ca93a449528d6c1e0922726bd

I've order several chargers from this company and they've delivered. I wouldn't recommend those KP chargers, since one broke on me and they are not suitable for outside use. I have a TCCH 2.5kW charger in my DIY build right now working perfectly.

The Type 2 stations which are gaining popularity around here in northern Europe and deliver up to 3 x 32A 230VAC. Technically I could even get three of these chargers and charge at close to 20 kW in many places which don't have CHAdeMO. Better still, they wouldn't have the problems I've been having with CHAdeMO lately.