EMF
100 kW
Here is a simple project if you don't like keeping an eye on things whilst your batteries charge. I found on Google, this really nice DC current sensing relay, made by CR Magnetics, that has a couple sets of contacts in it - one open, one closed. You can configure yours however you want as far as amp scales and time delay span, etc. I made mine a latch low with a 1 to 10 amp adjustable scale. It takes a loss of power to the relay to get it to reset. These are made to order and take 2 weeks to get. My model number was CR5395-LL-ACV-110-A-CD-ELR-I
The nice thing to me is, the sensor is an aperture so you don't have to worry about damaging delicate electronics if you decide to cram 20 amnps thru it. I also, set an "ice cube" relay to isolate the function of shutting down the charger from the built in relay on the sensor. I just control the isolation relay with the current sensor.
Since the isolation relay has 2 NC contacts, I used one to feed power to the charger and also the current sensor, but I put a switch in series so I can power the charger and keep the sensor shut off until I set my Mastech. Once I see the settings are right, I close the switch on the toggle and it goes into "monitor" mode as the current sensor is energised at this point. The other NC contact, I used to break the positive connection going from the battery charger to my packs.
My A123 packs are 2 sets of 10s 4p with a series wire between them to achieve 66 volts. I also found a VERY nice 2 pole circuit breaker rated at 40 amps that will protect my bike power system with one pole. The other pole I use to break the series connection and thus have two 36 volt packs that I charge all at once with the Mastech, by using a "Y" connection. the charger cord has a 10 amp fuse with a diode to keep from backfeeding the charger if all else fails.
I can no longer find these HY5020 chargers and it looks like they are discontinued, (at least Mastechs site no longer lists it on their product page) so you better take good care of one if you are lucky enough to have one.
The other nice thing about this shut down relay is it can be moved from one charger to another if you like, as it is stand alone.
The folks at CR Magnetics are first class! Even the girls that answer the phone can answer technical questions about the products. I asked could I loop my wire thru the aperture more than once to manipulate the amp cut-off and she knew I could. http://www.crmagnetics.com/newprod/ProductView.asp?ProdName=CR5395
I set mine for one amp and then ran the wire thru the aperture two times and the relay works like a charm, shutting down the Mastech at 500ma. Since both the 110 and the DC is cut off with the ice cube relay, I am sure the charger is safe.
I see now that DigiKey and McMaster-Carr are also distributors, since I bought mine. I think I paid 84 dollars for it. Maybe these other places are cheaper. I don't know.
I made a little video of it in use that I will have on You tube once they process it and I can put in a link in a bit.
Edit: Video link http://www.youtube.com/watch?v=oEJdpg-521Y
The nice thing to me is, the sensor is an aperture so you don't have to worry about damaging delicate electronics if you decide to cram 20 amnps thru it. I also, set an "ice cube" relay to isolate the function of shutting down the charger from the built in relay on the sensor. I just control the isolation relay with the current sensor.
Since the isolation relay has 2 NC contacts, I used one to feed power to the charger and also the current sensor, but I put a switch in series so I can power the charger and keep the sensor shut off until I set my Mastech. Once I see the settings are right, I close the switch on the toggle and it goes into "monitor" mode as the current sensor is energised at this point. The other NC contact, I used to break the positive connection going from the battery charger to my packs.
My A123 packs are 2 sets of 10s 4p with a series wire between them to achieve 66 volts. I also found a VERY nice 2 pole circuit breaker rated at 40 amps that will protect my bike power system with one pole. The other pole I use to break the series connection and thus have two 36 volt packs that I charge all at once with the Mastech, by using a "Y" connection. the charger cord has a 10 amp fuse with a diode to keep from backfeeding the charger if all else fails.
I can no longer find these HY5020 chargers and it looks like they are discontinued, (at least Mastechs site no longer lists it on their product page) so you better take good care of one if you are lucky enough to have one.
The other nice thing about this shut down relay is it can be moved from one charger to another if you like, as it is stand alone.
The folks at CR Magnetics are first class! Even the girls that answer the phone can answer technical questions about the products. I asked could I loop my wire thru the aperture more than once to manipulate the amp cut-off and she knew I could. http://www.crmagnetics.com/newprod/ProductView.asp?ProdName=CR5395
I set mine for one amp and then ran the wire thru the aperture two times and the relay works like a charm, shutting down the Mastech at 500ma. Since both the 110 and the DC is cut off with the ice cube relay, I am sure the charger is safe.
I see now that DigiKey and McMaster-Carr are also distributors, since I bought mine. I think I paid 84 dollars for it. Maybe these other places are cheaper. I don't know.
I made a little video of it in use that I will have on You tube once they process it and I can put in a link in a bit.
Edit: Video link http://www.youtube.com/watch?v=oEJdpg-521Y
The circuit looks like Greek to me. 
