| Joined: | Thu Apr 12th, 2012 |
| Location: | Denham, United Kingdom |
| Posts: | 293 |
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GeoffR wrote:Can't remember the details of the battery, 28V obviously but I need to find my notes for the rest. Once the cell voltage is below the minimum the charger shuts down and won't charge the battery. Doesn't matter what power source, Ground Power, APU or Engines, once discharged below minimum the cells are toast. It is one big battery and they, there are two, live in fire proof vaults vented overboard.
Robert wrote:Once a battery has gone below a predetermined, critical voltage, NOT to zero, then it can become unstable and dangerous to attempt to re-charge it, that's why if a battery has gone below the critical voltage, the correct charger should refuse to charge it.Absolutely correct, and very expensive when a set of cells costs $64,000! Boeing reasoned, correctly in my opinion, that it was better to allow a complete discharge than have the battery die just short of an airport. A 787 costs rather more than $64,000.
Well those spares or replacements are pretty expensive as well!
How many cells in the set? Voltage and Amperage? Can't they recharge from the engines?