OpenGD77

How about a battery voltage calibration setting?
That way my radio might actually show 100% when it stops charging instead of 94%.
It seems to be about 0.1 volt low compared to the actual battery voltage.

KI5GZK wrote: ↑

Thu Nov 12, 2020 6:55 am

How about a battery voltage calibration setting?
That way my radio might actually show 100% when it stops charging instead of 94%.
It seems to be about 0.1 volt low compared to the actual battery voltage.

So what voltage does your battery reach at top of charge ?

I presume < 8.2V

What it usually seems to do is charge to about 8.2 volts, and then when the charging stops, the voltage will drop down to around 8.1 volts fairly quickly.
The voltage displayed on the radio is about 0.1 volts lower than the actual battery voltage as measured with a DVM.

Yes.

But most online resources about Lipo charging state the charger has to charge a 2S battery to 8.4V for it to be 100% charged.

e.g.
https://blog.ampow.com/lipo-voltage-chart/

Even Wikipedia shows the fully charged voltage of a Lipo as 4.2V per cell

https://en.wikipedia.org/wiki/Lithium_p ... _of_charge


If your batter is not at 8.4V its not 100% charged, and we even make a 0.2V allowance , and show 100% at 8.2V

Setting a lower voltage to equal 100% would give a false impression that the battery was fully charged when its not.

Its not uncommon for "intelligent" batter chargers to to cycle the battery voltage somewhat, if the radio is left in the charger, so just because its in the charger it doesn't mean the battery is at 100% charge.

The official charger is not very good, and is not "intelligent" its just an OpAmp. I have no idea why they didn't use a custom battery charger chip. Probably cost.

Yes, the official charger isn't great and charges rather slowly. That is why I replaced the board with a TP5100 charge module.
It charges much faster, but unfortunately it doesn't seem to charge all the way to 8.4 volts, and I have tried more than one of them.

I don't mind sacrificing a little capacity for the quicker charging, but it would still be nice to see it display 100% charge even if it was lying to me.
It's kind of like when you fuel up you car. You want it to show full and stay there for a little while, just because it's more satisfying.

KI5GZK wrote: ↑

Thu Nov 12, 2020 7:31 pm

Yes, the official charger isn't great and charges rather slowly. That is why I replaced the board with a TP5100 charge module.
It charges much faster, but unfortunately it doesn't seem to charge all the way to 8.4 volts, and I have tried more than one of them.

I don't mind sacrificing a little capacity for the quicker charging, but it would still be nice to see it display 100% charge even if it was lying to me.
It's kind of like when you fuel up you car. You want it to show full and stay there for a little while, just because it's more satisfying.

There is an option in the Display settings called Battery. Change it to V
Then it displays the voltage, and you don't need to worry about not seeing 100%

BTW.

My TP5100 top out at about 8.35V . All 3 of them

Yeah, I am aware of the voltage display option, I guess I just prefer the percentage because everything else I own with a battery works that way.

My tp5100 seems to top out around 8.28 volts and drops to around 8.23 volts shortly after the charging stops while still on the charger and with no radio attached. When I attach the battery to the radio it shows 8.1 volts and 94%.

Perhaps if I buy a dozen more of these boards I'll find one that works a little better.

KI5GZK wrote: ↑

Thu Nov 12, 2020 9:34 pm

Yeah, I am aware of the voltage display option, I guess I just prefer the percentage because everything else I own with a battery works that way.

My tp5100 seems to top out around 8.28 volts and drops to around 8.23 volts shortly after the charging stops while still on the charger and with no radio attached. When I attach the battery to the radio it shows 8.1 volts and 94%.

Perhaps if I buy a dozen more of these boards I'll find one that works a little better.

Probably one of the components has an effect on the voltage, and they probably use components with sloppy tolerances