There is a battery link test that can be done to check the conductance of the link connection. Connect a milliamp meter in the 0.001 amp range in parallel with the battery link. Only connected to the battery post, not to the end of the link or the post connection.
Here we are testing the resistance of the link connection to the battery post as per A=E/R. This test is done with the battery charger on adjusted to about 5 ampere. When I do this test, I apply and wear electrical safety equipment, which includes electrical gloves, a electrical rubber blanket or a neoprene 1/8 inch rubber mat that covers all the battery connections except the one that is being tested. Also cover any metal on the car and use a rubber floor mat to stand on. It is also important to torque the battery connection to the specifications for that type of connection. These normally run from 50 to 100 in.lbs. (inch pounds). I used a standard in.lb. torque wrench that I will initially adjust and then slip over a electrical rating neoprene rubber tube over the handle. In initially installing battery links for the first time, I will use a standard insulated ratchet and socket to tighten the nut to where you think is good. I have train electrical technicians to do this initial tightening and many thought the torque would be at least 50 inch lbs. It was not! Testing out the torque with a torque wrench show the torque valve to be 10 to 15 in.lbs under specifications. After you do the initial hand tightening, connected the amp meter adjusted to 0.001 amp and turn on the battery charger to 5 amps. You will see that the ampere reading may be between 0.1 to 0.001 amps. Tighten the links fasteners to the specific torque level which may read 0.08 amps. You than torque all the other links to the same valve. After a load is apply to the battery, it is common for the battery line resistance to increase. It is recommend after the first 5 mile drive, is to check the torque level again. My batteries which is a standard auto post type, will lose about 5 in.lbs. Re-torque again and the loss may be 1 to 2 in.lbs in about a week. In about a month, the torque value will be in about 1 in.lbs. I now only check the torque value every six months when I water and clean the batteries. Roland ----- Original Message ----- From: Mark Hanson<mailto:marke.han...@hotmail.com> To: ev@lists.evdl.org<mailto:ev@lists.evdl.org> Sent: Monday, January 06, 2014 5:26 AM Subject: [EVDL] Keeping LiFePO4 battery terminals tight every 10k miles Hi Folk's, last night a overvoltage battery balancer #22 shut down the charger at 4.0V. At first I thought it was a bad OV balancer detector but after replacing the circuit it still did it so I put a scope across the battery cell and noticed the charging pulsed waveform going from 3.3V to 4.0V 60 hz when adjacent cells were fairly solid (signifying a high impedance condition). I thought I had a bad cell but after sanding under the copper strap & adding 3M dielectric grease & torquing back down, it charged perfectly with no faults, back to low impedance. I found a few other battery terminal bolts not tight after 20k miles (even with sealing paint on terminal bolts CALB 130). So it's best to tighten terminal bolts on lithiums every 10k miles it seams. I used to tighten terminal bolts on old lead GC batteries every 500 miles but didn't think it was necessary with lithiums but apparently they need it as well just less often. Best Regards,mark -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140106/46bb23a0/attachment.htm<http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140106/46bb23a0/attachment.htm>> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140106/da3b52aa/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
