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Created August 2017
Updated September 2018

 

Battery and tray Cleaning.

Following up on battery charging failures as a result of leakage current in the battery pack is not complete without a conversation about cleaning.

The conductive path from the battery posts to the chassis ground is not completely as a result of moisture after all fresh water is mostly non-conductive. Whats really happening is that a soup is being created n the battery tray after many years of charging and driving. The soup is a mixture of moisture, off gassed electrolyte, road dirt and dust. This creates a lovely film over all the batteries and in the bottom of the tray which is conductive and creates a conductive path across the tops of the batteries, down the sides of the batteries and the restraining brackets to the tray. Any abrasion, cracks or chips then provide a direct path to the chassis ground through the bonding strap. Except for this bonding strap the battery case is purposefully completely isolated from the chassis and by the barrier inside the tray from the batteries.

Cleaning the batteries is critically important in any pack maintenance, I soaked my batteries in a tray, scrubbed the sides tops and bottom with a brush, rinsed and dried. The same procedure also needs to be done to the battery tray. A pressure washer works well on it. more pictures attached. A close inspection of the nuts on each of the cells is warranted. I am of two minds with regards to the nuts and connectors. Remove and clean all of them or only the really ugly ones. I removed and cleaned most of mine and honestly a little surface corrosion on the visible area's of the nuts did not translate to corrosion on the mating surfaces. It's inevitable that some corrosion from the off gassing is going to happen but I think its cosmetic. I would suggest not removing the nuts just clean the tops with a tooth brush or similar. You do however need to place close attention to the straps between 12 volt modules and the sense wires on each module. When you have finished cleaning use a small torque wrench to tighten to 11 ft lbs. It is important that they be the right torque, it is such a small amount that it is easy to over tighten and possibly crack (worse) or shear off the stud.

Battery bath pressure wash battery pack