Replace Lipo with Lion?

Hi,

After about 450 flights and 10 months my VBCt battery, now handle only about 14-15 flights (screen brightness = 0) and discharged to about 14-15% of capacity. Is it allowed to replace stock 6000 mAh 1S lipo with 2S Lion battery?



Edited 2 time(s). Last edit at 05/30/2022 04:30PM by Jock_rst.

Hi,

even with Screen Brightness 0, Sun Brightness is 100 and the ambient light sensor will make the display as bright as can be.

To see what the battery can still do, charge, then leave the radio switched on at 100 % and check like every hour.
I bet it will last almost three hours until it shows 0 %, then, it will dim the display, capacity will jump up to 10 %, and the radio will last even longer

The only drawback, below 15 % the radio starts chiming (nagging, others say), which can be annoying.

I'd rather add a second 1s (make sure it fits the bay, the case must still close without pressure required) than switch to a different chemistry.
The radio's charging circuit is designed for a 1s LiPo and it's characteristics, including switch-off mechanisms, safety mechanisms, temperature monitoring etc.

Kind regards

Eddi

Born to fly ...
forced to work.

Eddi E. aus G. Wrote:
-------------------------------------------------------
> Hi,
>
> even with Screen Brightness 0, Sun Brightness is
> 100 and the ambient light sensor will make the
> display as bright as can be.
>
> To see what the battery can still do, charge, then
> leave the radio switched on at 100 % and check
> like every hour.

In passive mode while model is not connected - battery works much longer but in real conditions - sunlight day, my average statistic about 14-16 flights (4-5 mins per flight) radio discharged to 13-16%. I'll try to replace stock batt with two 5000 mAh packs with hi C rating. Bad case - total weight of radio will be increased, total WH (watt hours) will be about 36 Wh vs 22 Wh of stock 1s 6000 mAh.



Edited 1 time(s). Last edit at 05/30/2022 09:35PM by Jock_rst.

HI again,

WAIT!

First, the model connected makes no difference. The radio module is one of the least consumers in the loop.
The display is the largest consumer.

Then, please use original batteries or batteries with low C rating.
C rating is only necessary up to the point where you need it (2 amps means .3 C in a 6.000 mAh battery, or .5 C in a 4.000 mAh battery).
A high C rating makes absolutely no sense, to the contrary, the cell chemistry will not last as long as in low C rating batteries, which are made for longevity, for marathons, not for sprints, like our flight packs.

With two original batteries, you have 44 Wh or almost double the runtime.

Also, whatever you do, make sure the batteries fit the bay, by their dimensions. What you do not want is, apply constant pressure on the main board, with the bottom case bolted down. Over time, worst case, the 6-layer board may take damage when it shrinks and expands ever so slightly, with temperature and moisture, and with the battery applying pressure on it, bending it, and eventually over stressing the conducting paths on and inside the board.

Just a wee word of warning.

Kind regards

Eddi

Born to fly ...
forced to work.

Eddi E. aus G. Wrote:
-------------------------------------------------------

> Also, whatever you do, make sure the batteries fit
> the bay, by their dimensions. What you do not want
> is, apply constant pressure on the main board,
> with the bottom case bolted down. Over time, worst
> case, the 6-layer board may take damage when it
> shrinks and expands ever so slightly, with
> temperature and moisture, and with the battery
> applying pressure on it, bending it, and
> eventually over stressing the conducting paths on
> and inside the board.
>
> Just a wee word of warning.
>
> Kind regards
>
> Eddi

Thanks Eddie for detail explanation! Currently purchase original lipos is too hard here, due to situation =(
Sure, only compatible batts by dimension - no any overpushing to the motherboard. Thanks for tips. Btw - may be is it possible to add option to disable ambient light sensor?

After investigation i will try to use Panasonic NCR18650B 3300 mAh Lion batts.

Pros:
More life cycles (500+)
6600 mAh 2S pack with less weight vs 6000 mAh 2S lipo
Less cost
Overcharge / discharge protection
18mm dia, perfect fit in to VBCt case

Would be great if Mikado can produce original Lion 2S battery pack for VC / VBCt. Lipo is degradated after 100-150 cycles (about 400-500 flights = about 120 charge cycles of TX) and significatly lost capacity. To buy new tx battery pack every year is not good for me.



Edited 7 time(s). Last edit at 06/01/2022 09:57PM by Jock_rst.

Now two versions are almost ready for testing.

7000 mAh 1S for V Control
14000 mAh 1S for VBCt

Because in V Control is parallel circuit for two packs, we like to increase capacity for our packs.

Manual grading cells (3500 mAh per cell), spot welding, nickel metal for cells connection.



Edited 2 time(s). Last edit at 06/02/2022 07:27PM by Jock_rst.

Hi again,

I have no information about the discharge curve of the original cells, but I have information from the manual, about the voltage monitoring.

If I take the data sheet I found, on these cells, and the voltage curve, I guess you will run in to issues at < 10 °C (you will hardly ever be over the warning threshold of 3.5 V), and the usable capacity will be less than 50 % even in 25-40 °C conditions (3.5 V threshold at 1 C load).
Of course, at max. 2 amps or thereabouts, you'll never be at 1 C load, but the graph makes me believe that the readout will probably bob up and down at low percentages (low, for psychology ...), and that the warning will occur way earlier than expected.

I personally can not find anything wrong with the original batteries, and over years now, I only charge when necessary, not whenever there's a charger available. And even then, the charging circuit and logic is designed in a way to preserve the battery, do not overcharge, do not charge if almost full already etc.

Anyway, I'm curious what you find.

Kind regards

Eddi

Born to fly ...
forced to work.

Oh, and about the light sensor: you could try masking it with opaque tape, for starters.

Born to fly ...
forced to work.

Eddi E. aus G. Wrote:
-------------------------------------------------------

> Anyway, I'm curious what you find.
>
> Kind regards
>
> Eddi

1) Most lipos (stock Gens Ace in VBCt too) are degradated after ~150 charging cycles.

2) From my experience:
I've started expluatation my VBCt in May 2021 with 37-43 flights to 15% of TX discharging and now i have only 13-15 flights to 15% discharge. Don't know exactly about how many TX cycles (VBCt has no charging counter), i think about 120-140. Total about 450 flights on my both helis.

Currently from 95% of TX to 43% for 5 flights.

3) Lion provide about 500+ cycles without significantly lost capacity and current output.

4) Hi current Lion can handle screen consumption better than stock Gens 1 C tx lipo pack.

5) 4 x 3500 mAh Lion in parallel to get about 14000 mAh with same weight as two 6000 lipos.

Overall - main reason - long work cycle within one charge. I've did not like charge my radio after one flying day. Purchse new tx lipos every year did not like too.

I know that screen is main power consumer in VBCt, but we can't replace screen to something more quality and enorgomic.



Edited 8 time(s). Last edit at 06/07/2022 01:57PM by Jock_rst.

First testing sample. Unfortunately currently have no shrink film with appropriate Dia. Will buy it asap.

Weight 206 grams. Two connectors for dual channel balancing.



Edited 1 time(s). Last edit at 06/07/2022 09:21PM by Jock_rst.

First test of 14000 mAh Lion battery was successfully passed!

60 mins on maximum screen birghtness and connected model. Battery was discharged from 90% to 80% - 10% total.
In real conditions with lighting sensor i think power consuption will be less.

I think about 11-12 hours on one fully charged 14000 mAh battery or 130-150 flights.

Power consuption with maxumum screen brightness and RX - 1.2 A/h
Power consuption with lighting sensor and RX - ~0.7 A/h

No battery heating detected. 28 C working temperature.

Charge current form VBCt to battery - 1 A for discahged battery (~30%)

There is not too much space to fit 4 pcs of 16850, but possible.

A little bit heavy, but may be try to make 10500 mAh version and remove second power connector. Cells can do autobalancing.



Edited 9 time(s). Last edit at 06/08/2022 03:41PM by Jock_rst.

Simulator test

About 3 hours in simulator (ambient semi dark environment) by usb and Wi-Fi connected. After ~17 hours in full off mode. Battery was discharged on about 2%



Edited 4 time(s). Last edit at 06/09/2022 02:57PM by Jock_rst.

hello,
how did you charge the cell's?
about the vbct conector or outsite the vbct?

Wolfgang

ikarus991 Wrote:
-------------------------------------------------------
> hello,
> how did you charge the cell's?
> about the vbct conector or outsite the vbct?

I've purchased connectors and connect to the VBCt motherboard as stock lipo battery. Still testing battery life time from one charge.

Currently 7.5 hours.
6.5 h in the siumulator with light sensor
1 hour on maximum load with max screen brightness and connected model

Now 65%

I saw and read that!
my question was how you charge the cells.
via the charging socket in the vbct or externally

Wolfgang

ikarus991 Wrote:
-------------------------------------------------------
> I saw and read that!
> my question was how you charge the cells.
> via the charging socket in the vbct or externally


First charge was externally (for testing capacity). Next charge will be via charging socket of the Vbct

Question:

Is it possible to use 12v 4A power supply to charge my Lion pack via VBCt? Is VBCt motherboard allow 4A current?

Hi,

the radio needs 12 V DC/1.5 A to charge properly.
You can even charge from a 4s LiPo, or from a 12 V jack in your car, mind polarity.
But higher amp rating won't speed up the job, the on-board charger is designed for slow charging, for safety reasons, and to ensure the longevity of the battery.

Kind regards

Eddi

Born to fly ...
forced to work.

Eddi E. aus G. Wrote:
-------------------------------------------------------
the
> on-board charger is designed for slow charging,
> for safety reasons, and to ensure the longevity of
> the battery.

Thanks Eddie for the info.

p.s. i need custom firmware for speed up charging

14000 mAh Lion test results:

Start charge: 90%
Final charge: 5%

Simulator via USB: 10 hours
Flights: 3 hours

Test conditions:
Simulator with lighing sensor (semi dark environment)
1 flying hour with max screen brightness - light sensor was oriented to sunlight
2 flying hours with light sensor

Active options: wifi (1 hour), active idle, voice

Total work time: 13 hours
Days: 7



Edited 3 time(s). Last edit at 06/14/2022 06:21PM by Jock_rst.

The main problem - to use full capacity of Lion need cutoff on 2.6 v, but in the VBC / VBCt cutoff on the 3.2 volt.

Would be great to add cutoff voltage option in the radio settings. Or just two selectable options: Lipo (3,2) and Lion (2,6)

It can be included in to Pro App bundle. Who need it - know for what.



Edited 5 time(s). Last edit at 06/14/2022 09:49PM by Jock_rst.

Hi,

I like and appreciate the efforts and suggestions you make, but there's one thing to be kept in mind: every radio (not only VBar Control) has been designed and then tested for product safety, emc and radio specifications, to comply with CE, RED and FCC regulations, with it's original design, including the battery.

We have learned that small changes like longer wires, different wire layouts, different components can affect the operation of the electronics, or the overall way how the radio emits all kinds of electromagnetic emissions.

Although this does very likely not affect health or operational safety, technically, with any modification not specified in the manual or approved by us, you're on your own. They could render the radio illegal by the standards defined in different countries.

Then, there are specifications of all kinds of components on the mainboard, which are designed to work with certain voltages, and where the voltage regulation is fine-tuned to the power supply and it's characteristics. Change it, and components could run on edge, eventually malfunctioning.
Why should circuits designed for running at 3.3 V (which still work at cutoff-voltage of 3.2 V under load) suddenly work at 2.6 V, for example?

You can very well argue, bring in all sorts of buts, but as a company, and in a legal manner, this does not matter.

And another thing from my point in support: right now, we have next to no aftersales service items left.
Means, if you damage your mainboard accidentally, even for money, there could be no replacement, for the time being.

Don't get me wrong, but better enjoy your products and more so, your flying, instead of tinkering it kaputt eventually.

When there's time, we will think about a different battery layout, check and if necessary change the charging circuits and/or software, and then it will maybe even be available as an upgrade, together with software, like when switching from NiXX cells to LiPo.
But right now it's not the time to jump at it, I'm sorry.

Kind regards

Eddi

Born to fly ...
forced to work.

6 days radio on hold (14.06 - 20.06) - no sim, no flights. Self discharge about 3%.

Finally tested on the field in real conditions:

42 flights from 100% to 11% battery.

So, not too much flights as expected. Relatively close to the stock 6000 1S lipo battery.



Edited 1 time(s). Last edit at 08/08/2022 11:28AM by Jock_rst.