Author Topic: Undocumented JTV battery charger behavior  (Read 128 times)

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Offline snhirsch

Undocumented JTV battery charger behavior
« on: October 13, 2017, 08:50:22 AM »
Definitely a "top thing to know".  A few weeks back I inserted one of my JTV battery packs and noticed LED stayed solid red for a short time (charging state) before going off completely.  The battery was not at full voltage (typically around 8.4v no-load).  Long story short:  It turns out that battery was defective and had apparently developed a high internal resistance on one or more cells.  So it appears that the combination of charge current falling below a certain threshold while the battery voltage remains low results in the LED going out completely.  When I retried with my other battery everything worked as it should (solid red while changing, then slow blink).

Would have been nice if they documented the behavior, but hopefully this will save others some grief.

Offline GiRa

Re: Undocumented JTV battery charger behavior
« Reply #1 on: October 14, 2017, 02:02:26 AM »
That's actually documented: when the charger thinks that the battery is fully charged (100%) it will provide just a tiny stream of current to keep it there, turning off the led.
When it starts blinking it means that the battery is nearly 100% charged.

Offline snhirsch

Re: Undocumented JTV battery charger behavior
« Reply #2 on: October 14, 2017, 08:37:16 AM »
That's actually documented: when the charger thinks that the battery is fully charged (100%) it will provide just a tiny stream of current to keep it there, turning off the led.
When it starts blinking it means that the battery is nearly 100% charged.

I may not have explained it clearly.  When using a good battery, the LED has two states:  Steady on while charging and slow blink when at or near full charge.  With a properly functioning battery I never see a situation where it's inserted in the charger and the LED is completely off.

With a defective battery, the charger shows a steady (on) LED for a while then goes out completely.  The battery is not at full voltage and shows only 3 of 4 indicators when plugged into the guitar.  It also drains quite quickly.

Offline GiRa

Re: Undocumented JTV battery charger behavior
« Reply #3 on: October 15, 2017, 01:53:27 AM »
With a properly functioning battery I never see a situation where it's inserted in the charger and the LED is completely off.

If you leave the battery in the charger for some hours after it starts blinking, the led will shut off. This happens when the battery truly reaches a full charge.

Offline snhirsch

Re: Undocumented JTV battery charger behavior
« Reply #4 on: October 15, 2017, 08:30:34 AM »
If you leave the battery in the charger for some hours after it starts blinking, the led will shut off. This happens when the battery truly reaches a full charge.

I'll take your word for it, but have never seen this happen on mine - even after the battery is inadvertently left in for days.