Legend Charging and other thoughts

[TorqueMaster]

I picked a Legend up before the year's end -- had been considering that great deal they had running, and an got an unexpected Christmas windfall, so I pulled the trigger. I've only had it out a couple of times, not enough to make a judgement on how it compares to the Equinox 600, other than having a bit more versatility in the setup.

I tried the same Aukey EP-B80 APTX-Low Latency Bluetooth earbuds I've been using on the 'nox. They paired just fine, and I liked that the Legend display shows a tiny "LL" next to the bluetooth indicator, verifying the low latency connection.

I've been charging it with a usb power adapter capable of 2.4 Amps, with a charge monitor attached, to see how the Legend behaves. Tests have been with the battery 1/2 to 3/4 full.
The most I saw it draw was roughly 1.4 Amps, and it seems to hold pretty steady there until it is close to full. When I saw it had dropped to drawing 1.2A, I checked, and the battery display had stopped blinking, indicating it was "full." I kept it charging anyway. Over the next 3 hours, the charge rate slowly dropped down to 200mA. Then it stayed at 200mA for another 2 hours, and I terminated the test.

I'm a little disappointed it didn't drop to zero. Most devices, when turned off, drop to zero when fully charged. While 200mA isn't a lot, it is way more than a trickle charge. I will not be leaving it charging any longer than overnight, and unplugging when full in the morning.

On the plus side -- I think when it first indicates it's "full", it's really only about 90-95% full. By not pushing it to 100%, the battery should have a longer service life before needing replacement. If you need to squeeze that last 5-10% into the battery, leave it charging the extra 3 hours.

One other nice touch -- as the battery is charging, the number of blinking segments is reduced as the battery gets closer to full.

 

[cellrdwellr]

Interesting observations TorqueMaster, I enjoyed reading your post. Thanks for sharing!

 

[Diga]

Thank you for that information TM.

Since the ground is frozen where I am, I've been doing all sorts of air tests with my Legend. Hey, it's not metal detecting but it's better than nothing

I just plugged in my Legend in with the 2 bars of charge. I'm showing 5.25V, 7.8W, and 1.5A. I'll go through everything the way you did and post back my results. I am however using a smart charger, so maybe it will stop the charge when full?


Also, I don't know too much about batteries or chargers, but are you certain that this type of battery shouldn't have a 200mA "trickle" charge even when full?

 

[TorqueMaster]

I guess it depends how smart your charger is. I suspect that means it can communicate with whatever it is charging, and deliver as much as the device requests. Rather than no communication and defaulting to 500mA or whatever.

Pretty sure 200mA is too much, it's a waste of power and probably just heating up the battery. It it were just 10 or 20mA, I wouldn't mind so much. And I think I mis-spoke -- I consider what it's doing should be called a maintenance charge, not a trickle. Trickle to me implies it actually needs more charging, and it is charging very slowly.

Maybe it sits at 200mA for a very long time before going to a true zero -- I thought 2 hours was enough for it to decide enough was enough.

 

[Diga]

2 hours seems excessive to me as well.

Mine has been dropping steadily in Watts and Amps since the Legend showed the full 5 bars. It's currently at 3.6W and 0.7A.

 

[Diga]

On the plus side -- I think when it first indicates it's "full", it's really only about 90-95% full. By not pushing it to 100%, the battery should have a longer service life before needing replacement.

I've now confirmed that as well. I've also confirmed a 200mA draw after showing 5 full bars. Here is what I'm finding so far:

12:00 Legend charged to full 5 bars at 1.5A
12:15 1.3A
12:30 0.7A
12:45 0.4A
1:00 to 2:15 0.2A


I'm going to keep it plugged in for a few more hours and see what happens.

Does anyone know if it's possible that the .2A draw is by design? If the draw should be going to zero or very close to zero, then I or someone else can PM Dilek on Facebook.

 

[Diga]

I hadn't looked at it since 2:15, but I just looked again at 2:40 and it's down to 0.1A

EDIT: Even though my charger says 0.1A, the charging bar indicator on the charger has stopped moving.

 

[Diga]

It's now 4:00 and I've stopped the test.

What I found is the Legend charges to around 90% to 95% when the Legend shows 5 full charging bars (just as TM found out).

For the next 1.5 hours, my Legend slow charged with reduced Amps to reach 100% charge. At that point, my charger was at 0.1A but its charging bars stopped moving. To me, that indicates that it was no longer sending charging current, or my Legend was no longer accepting charging current.

 

[TorqueMaster]

Thanks for the confirmation test and letting it go down to 100mA, for whatever reason mine never went that low.
Not sure why the monitors keep showing a current draw if there is none.

As I recall my Equinox never goes to zero, either, and Minelab recommends/implies it should not be left charging indefinitely.

 

[oldkoot]

Could the slight draw be from the clock that is on the Legend

this stuff is pretty interesting and thank both of you TorqueMaster and Digalicious for doing the testing great information

the clock would have to be getting power from somewhere to keep the time accurate

 

[Diga]

Since that last test, I checked to see what happened with my earbuds and phone. Well, the same thing happened with those. That is, the charger eventually settled at 0.1A and its charging bars stopped moving.

With that said, I may be paranoid, but when I leave the house, I disconnect anything that's being charged.

 

[TorqueMaster]

Since that last test, I checked to see what happened with my earbuds and phone. Well, the same thing happened with those. That is, the charger eventually settled at 0.1A and its charging bars stopped moving.

With that said, I may be paranoid, but when I leave the house, I disconnect anything that's being charged.

Could the slight draw be from the clock that is on the Legend

My earbuds, bluetooth speakers, and usb power packs all go to zero. If I remember, I'll turn my phone off-off tonight and see what it does.

The clock certainly needs some power, but that should be well less than 10ma, the minimum my monitor shows.

100mA would drain the battery in short order (days) if it was really using that while turned off, so it really seems like the charging circuits are continuing to push the current... somewhere.

 

[TorqueMaster]

When shut down (as "off" as it gets), my phone was still drawing 60-70mA when at 100% full. Bouncing around a bit. The charging circuitry must be using some/all of that, but not neccesarily sending it to the battery. It still has the ability to turn on the backlight and show a charging gauge, so it is not truly "off." Perhaps the charging circuits in the detectors are similar -- always active when receiving power from the charger -- and sucking down 100mA or more, but probably not overcharging the battery. Seems excessive though. I'll be unplugging when full, or as reasonably soon as possible after showing full.

 

[Diga]

TM,

That's pretty much what I'm seeing with my charger. That is, no matter what device I charge, when the device is fully charged my charger drops to 100mA and stays there. But, the charging indicator on the charger turns off. I would however be concerned if that charging indicator remained on