Battery LCD display showing single bar caused by backfeeding between multiple batteries on power sleds

Gear

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Master SeriesIs a used Master Series rig worth buying as a first big rig?191

BFDHow do I power my BFD receiver from my camera or sled?186

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2009Batteries/Power forum

17 years old. Gear and prices may have changed since.

DisputedParticipants disagreed and reached no conclusion. Read the findings as positions, not as an answer.

When multiple batteries are connected to a power sled without isolation, one battery can attempt to charge another, which the battery prevents by displaying a single bar on the LCD as a protective measure
Installing a diode in series with each battery prevents backfeeding and eliminates the single bar display issue
The problem occurs when batteries are wired in parallel configuration, not when they are in series
Different battery chemistries have different discharge curves, and mixing them increases the likelihood of voltage mismatches that trigger backfeeding
A 7 amp 20 volt diode is suitable for most applications, but powering RED cameras requires a higher capacity diode such as 10 amps due to increased current draw
The single bar display does not indicate a battery failure; the battery continues to function normally and the LCD returns to normal after recharging
Diodes can be installed in power jumpers or other connection points without requiring major modifications to the sled

The backfeeding problem primarily occurs in 12 volt parallel configurations and with Y-cable connections that put batteries in parallel
Installation procedures and exact component specifications were discussed but no confirmed photographic documentation of completed installations was provided in the thread
Some users reported the issue occurring intermittently or only under specific conditions such as cold temperatures or after extended periods without use
The presence of an existing diode in some sled models did not always prevent the problem, suggesting inconsistency in original component specifications