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Old 06-18-2020, 03:06 PM   #265 (permalink)
S Keith
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Originally Posted by mvrroking View Post
Excuse my language I meant the sticks, the battery sticks is what I've been cycling in order to find the faulty/low capacity one. What percentage diff would cause an imbalance if there is such a thing in these packs. I am aware that the center sticks tend to not dissipate heat well damaging their longevity, so I'm looking forward to replacing those.
There isn't a simple answer to your question. Too many variables. In some cases, a very large deviation can be tolerated. In other cases, a very small deviation is unacceptable.

You have yet to provide any meaningful data upon which a decision can be based. You have provided capacity values under very low current (5W or 10W max power, meaning about 0.8 or 1.4A, respectively. For sticks that will be called upon to charge at 50A and discharge at 100A, your tests have no meaning.

There's also the issue of DECREASING capacities with cycling. That indicates one or more of the following:
  1. Sticks are bad
  2. Stick capacity will not benefit from cycling
  3. You are not cooling the sticks, and each cycle is terminating early because the stick is getting hotter.

Since I suspect you're going to insist on hammering your scrotum with a pickaxe, here's some guidance:
  1. Start a google sheet or something to record your data.
  2. Conduct ONE charge/discharge cycle with 20 minute wait. Charge at the highest current available to you up to 6.5A (5A is typical of most B6 type chargers; 2A is too low). Discharge to 6.0V at the maximum current available. ALWAYS CHARGE WITH COOLING.
  3. Record the Charge and discharge capacities reported.
  4. Conduct ONE CHARGE of the stick at up to 6.5A.
  5. Let the stick rest for 7 days.
  6. Record resting voltage.
  7. Record internal resistance if the charger supports it (connection quality must be very good - no alligator clips).
  8. Conduct ONE DISCHARGE of the stick at maximum current available.
  9. Record discharge capacity.
  10. Repeat for all 20 sticks.

The above might give some meaningful data.

Honda sticks fail primarily in self-discharge, i.e., one or more more cells in a stick just lose their ability to hold charge. This creates an imbalance at the cell level that quickly causes the pack to code. NOTE that it's not at all uncommon for ALL cells in a stick to suffer from excessive self-discharge.

The misleading thing is that almost all Honda sticks will cycle up to what appears to be a very good capacity; however, their inability to retain a charge means they're useless.

Last edited by S Keith; 06-18-2020 at 03:16 PM..
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