For some reason Hifei capacitor boards have cutouts each side that would take an automobile battery lead when a cutout much smaller would make battery connections much easier and avoid the pitfall that I have fallen into. I am using gauge 8 wire from my batteries to the Hifei capacitor board and then to the 8mm bullet connectors on the ESC connection. My boat has two 4s batteries in series each side, then paralleled to the ESC connection. This afternoon I soldered the Hifei capacitor board each side, inline with the battery supply to the ESC connection. I connected everything up and everything worked fine. Leaving the four batteries insitu and connected to each other in series, I disconnected the two positive leads from the ESC connection and securely stowed them. As I had an important phone call to make I rested the hatch back on the boat. Approximately 45 minutes later I could smell a burning odour. When I lifted the hatch a cloud of smoke emerged, with a thin layer of black soot over everything. The right hand capacitor board was totally destroyed. The heat totally melted the ESC on/off switch as well as cosmetic damage to the battery supply leads.
I must presume that the factory test the capacitor boards prior release so can assume that in soldering my gauge 8 wires to the capacitor board that excess solder has shorted out the capacitors on the board. I am very experienced at soldering so this is not down to carelessness or lack of ability on my behalf. I believe the capacitors are rated at 63 volts so my 32 volt supply should not have caused the capacitors to self destruct. I will source another capacitor board but in hindsight, view these boards as liable to be a source of future problems. I could have totally destroyed a very, very expensive boat even before it sees a drop of water. I am hoping that the ESC has not suffered any internal damage. I did a cell check of the two batteries on that side and all cells were fine. I believe that the battery supply wires will be OK but as the ESC switch is destroyed along with the attached wires almost back to the ESC case then I may possibly delete the switch.
I am not impressed as I see the design of the Hifei capacitor board as a very poor design, as the cutouts where the battery wires are soldered to are far too large and in reality should be sized to be a snug fit. I now have a very messy cleanup job to complete. I am thinking that when I solder in the new capacitor board I will use thin offcuts of brass tubing soldered to the battery leads to increase the diameter of the gauge 8 wires to match the oversize cutout diameter on the board.
I must presume that the factory test the capacitor boards prior release so can assume that in soldering my gauge 8 wires to the capacitor board that excess solder has shorted out the capacitors on the board. I am very experienced at soldering so this is not down to carelessness or lack of ability on my behalf. I believe the capacitors are rated at 63 volts so my 32 volt supply should not have caused the capacitors to self destruct. I will source another capacitor board but in hindsight, view these boards as liable to be a source of future problems. I could have totally destroyed a very, very expensive boat even before it sees a drop of water. I am hoping that the ESC has not suffered any internal damage. I did a cell check of the two batteries on that side and all cells were fine. I believe that the battery supply wires will be OK but as the ESC switch is destroyed along with the attached wires almost back to the ESC case then I may possibly delete the switch.
I am not impressed as I see the design of the Hifei capacitor board as a very poor design, as the cutouts where the battery wires are soldered to are far too large and in reality should be sized to be a snug fit. I now have a very messy cleanup job to complete. I am thinking that when I solder in the new capacitor board I will use thin offcuts of brass tubing soldered to the battery leads to increase the diameter of the gauge 8 wires to match the oversize cutout diameter on the board.
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