I would like to set the charge current lower than 5A

[Sandrosan]

Hello everyone,

My name is Sandro from Milan Italy and first of all sorry for my poor English. I own a Citroen C zero of 2011, I bougth it in 2017 and it has just 22000 km.
I made an EVSE using this PCB https://www.ev-power.eu/Electric-Cars/EVSE-kit-for-EV-charging-station-cable.html

because I need to adjust the charging current according to my Solar PV production and my home loads consumption.

Using that PCB the min charging current is 5A and the max is 14A with steps of 1A.
Lower than 5A the EVSE stops driving the OBC of the car, so there is no way to charge the car with less than 5A at 230V.
In winter my solar PV does not produce too much but I would like to use also the small solar production that is like 1 to 4 A (at 230V).

Is there anyone that has find out the way to charge the Imiev / C zero / iOn with lower current than 5A at 230V?
Thanks in advance to all will help me.
ciao
Sandro

 

[Gary12345]

Hi there !

The charger will just not run at such low amps and it is very inefficient. There is a 600w overhead during charging, this is from running the electronics, voltage conversion, water cooling pump, monitoring and balancing inside the battery, etc.

That means at 240v approx 2.5A is used by the car managing the charging. The longer you charge the longer you are wasting 600w, the more total power is wasted.

If you could make it charge at 4A
4A @ 240v = 960W consumed, minus 600W = 306W going into the car, very little. Below 4A almost nothing would go into the battery and it would take days to get any charge at all.

Put the 4A into your hot water tank!!!

Thanks.

 

[1kaspars]

Maybe 230V to 110V transformer could help?

 

[1kaspars]

Hi there !

(..)
There is a 600w overhead during charging, this is from running the electronics, voltage conversion, water cooling pump, monitoring and balancing inside the battery, etc.

That means at 240v approx 2.5A is used by the car managing the charging.
(..)

Car consumes 0,4-0,5A @333V while in ready mode and no other 12V consumers are on. While charging yes, i have seen 1,4kW goes in to the battery while 2100w from 230V wall outlet. I hope Canion have error in that reading.

 

[dracekvo]

I use 14A carger. 3000W.
If I see on canion, he show 2400W to battery.

 

[kiev]

Has anyone put a current clamp on the 12V output of the DCDC while charging?

i don't know the minimum output current, but 40A at 14.4VDC doesn't seem out of the question to supply power for

charging the aux battery,
holding relay coils,
power to all the ECUs that need to be active,
power to IP and other items on the CAN buss,
12 CMU boards,
2 Main contactors coils,
radiator fan as needed,
coolant pump as needed,
etc???

 

[Sandrosan]

Hi there !

The charger will just not run at such low amps and it is very inefficient. There is a 600w overhead during charging, this is from running the electronics, voltage conversion, water cooling pump, monitoring and balancing inside the battery, etc.

That means at 240v approx 2.5A is used by the car managing the charging. The longer you charge the longer you are wasting 600w, the more total power is wasted.

If you could make it charge at 4A
4A @ 240v = 960W consumed, minus 600W = 306W going into the car, very little. Below 4A almost nothing would go into the battery and it would take days to get any charge at all.

Put the 4A into your hot water tank!!!

Thanks.

Hi Gary 12345,

Thanks for your comments. I know the efficiency will be low, but better than noting. I will not use such low charging current for charging the battery completely but just to improve the SOC a bit.
Than let me think that 600W overhaed is too much and probably it will be just for limited time.
I already have done a hot watar tank controlled with 2 levels 600W and 1.2kW.

 

[Sandrosan]

Maybe 230V to 110V transformer could help?

Probably you are right. I will look for a scrap transformer with min 1kVA for some tests. Thanks for the tip!

However I would like to see if changing the duty cyle signal of the EWSE PWM can force the OBD to charge with lower current.

Maybe some of you in this fantastic forum already done it.
Sandrosan

 

[kiev]

It may not be possible to reduce the pulse width any further; it requires a 5% duty cycle for the EV-ECU/OBC to detect that an EVSE is connected and available.

In another thread is a diagram:
http://myimiev.com/forum/viewtopic.php?f=24&t=1497&start=110#p32608

 

[Sandrosan]

It may not be possible to reduce the pulse width any further; it requires a 5% duty cycle for the EV-ECU/OBC to detect that an EVSE is connected and available.

In another thread is a diagram:
http://myimiev.com/forum/viewtopic.php?f=24&t=1497&start=110#p32608

I remeber I have seen the pulse width and when the current was already 6 or 5 A the width was so tiny and the next step down switched the signal totally OFF. So I am afraid there is not way to go down playing with the signal.

Thanks very much Kiev, Iam going to read that thread carefully!

But I would not give it up and patiently wait otehr tips from this forum's memebrs.
Sandrosan

 

[Don]

Maybe 230V to 110V transformer could help?

That was my thought too - 120 volts @ 5 amps should solve his problem

All North American cars came with a 960 watt EVSE - 120 volts @ 8 amps, so charging at less than 1 kw is no big deal and I *think* the EVSE Upgraded Panasonic units can be set to 6 amps at either 120 or 240, so 5 amps at 120 would probably work - If not, he could set it to 6 amps

Don

 

[Sandrosan]

Thank you Don.
I will check with a trafo 230V / 110 V and let all of you know the results.
Sandrosan

 

[Sandrosan]

Dear all,
Thanks for your inputs.
I have used a 220 / 110 trafo 1500VA rated and it works! Thanks very much.
Supplying the EVSE at 110V the min current is around 3A on the primary side 220V that means some 700W.
So I can start charging at 700W when I use 110V trafo tat is good for me as my PV installation does not produce too much in autumn and winter of course.
It will be a very slow charge but better than nothing....