Joined
·
12,622 Posts
This is part 1 of an advanced mod. It's dangerous working on the HV battery pack and associated components. Don't do it if you are not happy.
Grid charging has been done before in various forms, so thanks go to Mike Dabrowski, Armin Kusig and James Frye for their work in this area, which is still very much ongoing, I recommend you follow developments at Mike's site, especially with regard to pack balancing
I decided to implement the grid charging and simple balancing mod on my two cars to pre-empt problems that may arise as the packs age, and to help with my wife's short 5 mile commute which hits the battery hard on a daily basis.
Safety first. I ensured pack was off before starting, and allowed capacitors to discharge on the controller. I checked voltages were safe with a meter and used the one hand technique with rubber gloves when fishing down between the battery pack and motor controller. It's a real tight squeeze with no room to maneuver
Having read the various posts an this site about grid charging, and the fact that a low current 300ma charge may also help re-balance a failing pack I opted for the simple series charger.
A 300ma series charge applied to the pack (overnight) should be safe for the cells for a limited period say <12-18hrs. As individual cells reach full charge they will start to warm up, but 300ma should be low enough not to cause any gassing or other problems. As all the cells reach full charge you eventually end up with a fully charged and balanced pack hopefully.
The main advantages I can see is you start the next day with a fully charged and balanced pack (probably slightly warm as well) allowing full assist from go.
For the project you need a simple safe way of connecting to the battery pack, and bringing this connection out to a socket which can be connected to a 175v 300ma approx constant current charger.
I wanted it to look as discrete/standard as possible, in fact you can hide the charging socket fairly easily
It has to be very safe, for this reason I included 400v 3A diodes in the +/- charge leads adjacent to the pack connections so that the High voltage present could never appear at the socket or in fact outside the HV compartment. I lose a volt in the diode forward voltage drop but it's a small price to pay.
UK Insight's have a nice place above the rear number plate to mount a socket, it's fairly well protected from the weather and can be fitted with a sealing cap.
http://www.solarvan.co.uk/insight/chargingproj01.jpg
http://www.solarvan.co.uk/insight/chargingproj02.jpg
I used a 3 pin 3A 250v connector and 6amp 3 core arctic flexible cable for the project.
http://www.solarvan.co.uk/insight/chargingproj03.jpg
http://www.solarvan.co.uk/insight/chargingproj04.jpg
I routed the cable through the blanking grommet in the rear panel around the right hand side into the hv compartment. Cable ties etc to keep it all neat and safe.
http://www.solarvan.co.uk/insight/chargingproj06.jpg
The cable eventually is threaded through until it is between the HV battery pack and the motor controller. This is where it gets tricky
The lack of room means you can't easily connect to the + side of the pack in situ.
See Mike's labelled diagram.
http://www.solarvan.co.uk/insight/chargingproj12.jpg
You can't get at that nice screw he has arrowed on the + side without removing the battery pack
Well I couldn't anyway. However you can get to the other end of that orange wire, which is fitted with a 6.4mm 1/4 standard spade connector and connects to one side of the pre-charge resistor.
http://www.solarvan.co.uk/insight/chargingproj05.jpg
http://www.solarvan.co.uk/insight/chargingproj13.jpg
Basically I piggy backed onto here and used one of those 'Lucar' spade double adaptors to connect. It's difficult to get in here with big hands and remove and re-connect the spades, but it can be done, be careful of the pre-charge resistor, the terminal is quite weak and will bend, as will it's mounting if you use too much force.
http://www.solarvan.co.uk/insight/chargingproj14.jpg
http://www.solarvan.co.uk/insight/chargingproj07.jpg
http://www.solarvan.co.uk/insight/chargingproj08.jpg
The - terminal is easy as it sits atop the pack, and is the main negative lead. Note the diodes in my wires close to the pack to prevent voltage flowing back to socket.
http://www.solarvan.co.uk/insight/chargingproj09.jpg
I also connected the earth wire to the earth point on the controller case which is connected to the vehicle chassis.
http://www.solarvan.co.uk/insight/chargingproj10.jpg
Now I put it all back together again, double checked the connections, tested the diodes and continuity to the socket and threw the main switch.
Tested socket and no voltage present
http://www.solarvan.co.uk/insight/chargingproj11.jpg
Last photo for part 1 shows socket with plug installed. I am now waiting for a few more components to arrive, including my nice psu and I'll start on the charger side. Hopefully next week.
I'll update asap. Peter
Grid charging has been done before in various forms, so thanks go to Mike Dabrowski, Armin Kusig and James Frye for their work in this area, which is still very much ongoing, I recommend you follow developments at Mike's site, especially with regard to pack balancing
I decided to implement the grid charging and simple balancing mod on my two cars to pre-empt problems that may arise as the packs age, and to help with my wife's short 5 mile commute which hits the battery hard on a daily basis.
Safety first. I ensured pack was off before starting, and allowed capacitors to discharge on the controller. I checked voltages were safe with a meter and used the one hand technique with rubber gloves when fishing down between the battery pack and motor controller. It's a real tight squeeze with no room to maneuver
Having read the various posts an this site about grid charging, and the fact that a low current 300ma charge may also help re-balance a failing pack I opted for the simple series charger.
A 300ma series charge applied to the pack (overnight) should be safe for the cells for a limited period say <12-18hrs. As individual cells reach full charge they will start to warm up, but 300ma should be low enough not to cause any gassing or other problems. As all the cells reach full charge you eventually end up with a fully charged and balanced pack hopefully.
The main advantages I can see is you start the next day with a fully charged and balanced pack (probably slightly warm as well) allowing full assist from go.
For the project you need a simple safe way of connecting to the battery pack, and bringing this connection out to a socket which can be connected to a 175v 300ma approx constant current charger.
I wanted it to look as discrete/standard as possible, in fact you can hide the charging socket fairly easily
It has to be very safe, for this reason I included 400v 3A diodes in the +/- charge leads adjacent to the pack connections so that the High voltage present could never appear at the socket or in fact outside the HV compartment. I lose a volt in the diode forward voltage drop but it's a small price to pay.
UK Insight's have a nice place above the rear number plate to mount a socket, it's fairly well protected from the weather and can be fitted with a sealing cap.
http://www.solarvan.co.uk/insight/chargingproj01.jpg
http://www.solarvan.co.uk/insight/chargingproj02.jpg
I used a 3 pin 3A 250v connector and 6amp 3 core arctic flexible cable for the project.
http://www.solarvan.co.uk/insight/chargingproj03.jpg
http://www.solarvan.co.uk/insight/chargingproj04.jpg
I routed the cable through the blanking grommet in the rear panel around the right hand side into the hv compartment. Cable ties etc to keep it all neat and safe.
http://www.solarvan.co.uk/insight/chargingproj06.jpg
The cable eventually is threaded through until it is between the HV battery pack and the motor controller. This is where it gets tricky
See Mike's labelled diagram.
http://www.solarvan.co.uk/insight/chargingproj12.jpg
You can't get at that nice screw he has arrowed on the + side without removing the battery pack
http://www.solarvan.co.uk/insight/chargingproj05.jpg
http://www.solarvan.co.uk/insight/chargingproj13.jpg
Basically I piggy backed onto here and used one of those 'Lucar' spade double adaptors to connect. It's difficult to get in here with big hands and remove and re-connect the spades, but it can be done, be careful of the pre-charge resistor, the terminal is quite weak and will bend, as will it's mounting if you use too much force.
http://www.solarvan.co.uk/insight/chargingproj14.jpg
http://www.solarvan.co.uk/insight/chargingproj07.jpg
http://www.solarvan.co.uk/insight/chargingproj08.jpg
The - terminal is easy as it sits atop the pack, and is the main negative lead. Note the diodes in my wires close to the pack to prevent voltage flowing back to socket.
http://www.solarvan.co.uk/insight/chargingproj09.jpg
I also connected the earth wire to the earth point on the controller case which is connected to the vehicle chassis.
http://www.solarvan.co.uk/insight/chargingproj10.jpg
Now I put it all back together again, double checked the connections, tested the diodes and continuity to the socket and threw the main switch.
Tested socket and no voltage present
http://www.solarvan.co.uk/insight/chargingproj11.jpg
Last photo for part 1 shows socket with plug installed. I am now waiting for a few more components to arrive, including my nice psu and I'll start on the charger side. Hopefully next week.
I'll update asap. Peter