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Battery parallel connection ?

Started by mowhoong December 27, 2012
Parallel connection on lantern batterys will have higher current, but it wi=
ll cause self dicharge to other battery with lower voltage. My solution to =
solve this problem was to add one diode to each battery, but I do not know =
why this method was not used on commerical battery pad ? Can any members of=
 this group give me me advice. Thank you and happy x'mas to all members.

Regards
On Wed, 26 Dec 2012 21:57:27 -0800 (PST), mowhoong
<mowhoong@hotmail.com> wrote:

>Parallel connection on lantern batterys will have higher current, but it will cause self dicharge to other battery with lower voltage. My solution to solve this problem was to add one diode to each battery, but I do not know why this method was not used on commerical battery pad ? Can any members of this group give me me advice. Thank you and happy x'mas to all members.
Diodes have a forward voltage drop. Depending on the diode type and current the loss may be as much as half of a cell voltage. The diode also dissipates power which isn't generally a good idea buried in a battery pack. If the cells are identical (cells manufactured at the same time, on the same line, are close enough), isolation isn't worth the loss in useful energy.
On Wednesday, December 26, 2012 9:57:27 PM UTC-8, mowhoong wrote:
> Parallel connection on lantern batterys will have higher current, but it will cause self dicharge to other >battery with lower voltage.
Not usually true; the exception, is if your cells spontaneously develop short circuits (like whiskers in NiCd or bent plates in lead-acid). Discharging a battery cell, ideally, raises its internal impedance, doesn't cause leakage.
> My solution to solve this problem was to add one diode to each battery, but I do not know why this >method was not used on commerical battery pad ?
Diodes have significant effective resistance, it lowers the voltage and current the battery can deliver.