Monday, June 3, 2013

DC to DC converter

One last touch and that is the addition of a new DC to DC converter. This unit will tap the full 96 volt battery pack and convert that voltage down to 13.4 volts to charge the 12 volt battery that is still required to run the original 12 volt circuits in the van. In my first Omni conversion since I did little or no night driving and the other 12 volt loads were small I just ran a "total loss" system. When I noticed the battery needed charging I hooked up my 12 volt charger to it. This was required about once every two weeks. The 2001 Caravan is a different story. It has power brakes and the 9.5 amp vacuum pump is a bit more of a load. I found the battery needed charging almost every other day. So after learning my $100 lesson from buying a cheep converter I now have that problem resolved for a mere $350.

Another problem that needed to be solved was a way to monitor the temperature of the motor. Since the original sensor wires for this on the motor had been pinched off inside the motor housing I went with an indoor/outdoor thermometer. Must stay below 120 degrees or damage could result to the field windings.

With the readout mounted on the dash and the outdoor sensor tapped to the motor housing I will get the information I need to see if the motor is over heating. Not likely but good insurance. 

Have about test 30 miles on the vehicle to date and seems to be doing well. Looks like top speed will be about 45 mph. Although I have not tested this out yet I believe the range will be about 15 miles. This is a tricky one because I don't want to find out the range the hard way and get stranded! I am "opportunity" charging the pack after almost every trip to keep the 8 year old batteries happy. Note: For every 8 minutes of run time it takes 120 minutes of re-charging time. That is about one trip to town and back. Will continue to collect data and  post more feedback as I get more experience with it this summer. 

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