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Member postings for Andy48

Here is a list of all the postings Andy48 has made in our forums. Click on a thread name to jump to the thread.

Thread: LiPo over-voltage
09/07/2020 14:37:22
Posted by Dickw on 09/07/2020 13:12:29:
Posted by Andy48 on 09/07/2020 11:09:03:
Posted by Tim Kearsley on 09/07/2020 08:54:59:
 
.............................

Either way, I believe a poor connection in the balance lead could result in overcharging on a balanced charge. Far easier, and it seems, safer to normally do a standard charge, and only if the battery shows more than 0.1 or 0.2v difference between cells to finish off with a balance charge.

...........................

Edited By Andy48 on 09/07/2020 11:11:23

I must admit to being a bit surprised at your reference to 0.1 or 0.2v difference. I have just put a couple on charge and the 3s battery has a difference of 0.029v between highest and lowest cell, and for the 10s the difference is .026v. Balancing starts as soon as the charger starts and I would expect cells to be closer at the end.

If any battery shows as much as 0.1v at the start of the charge I would assume a faulty connection or a suspect batery and act accordingly.

Your system obviously works for you, but I don't believe my chargers measure cell volts while balance current is flowing, as a modern battery management IC should take care of that, so I will continue balance charging. each to his own I suppose.

Dick

Sorry, I meant 0.01v

However, this also begs a question as to how closely cells have to be balanced? I've checked many new batteries and found even the best have some variance in the IR.

 

Edited By Andy48 on 09/07/2020 14:44:24

09/07/2020 11:09:03
Posted by Tim Kearsley on 09/07/2020 08:54:59:
 

But this doesn't make logical sense. If the charger is displaying a Voltage of, say, 4.35V then it "knows" that the offending cell is over-Voltage - how else can it be displaying it? I can understand the similar scenario where some high resistance connection results in the charger "seeing" a falsely low Voltage, but then it would display that false reading wouldn't it?

Tim.

 

Two possibilities. It could be I moved the battery thereby restoring a good connection before I looked at the charger, or it is possible that the poor connection corrected itself just before I looked at the charger.

Either way, I believe a poor connection in the balance lead could result in overcharging on a balanced charge. Far easier, and it seems, safer to normally do a standard charge, and only if the battery shows more than 0.1 or 0.2v difference between cells to finish off with a balance charge.

Pity really, because my chargers do quite a fast balanced charge.

Out of interest, my charger will not charge unless the balance lead is connected, and it always does a cell count first to check.

Edited By Andy48 on 09/07/2020 11:11:23

08/07/2020 22:16:10
Posted by Allan Bennett on 08/07/2020 20:37:39:

There's obviously many different makes/types of chargers being considered here. Mine displays individual cell voltages throughout the charge, and I've never seen any cell go above 4.20v -- if it did, the charger would have stopped and given an 'over voltage' error message. If a pack is out of balance it holds the first cell to reach 4.20v while the other cells catch up. Like Chris, I don't understand how any charger can display a cell voltage over 4.20v and not figure out that something's wrong.

Simple, because at the time it does not realise the cell voltage is over 4.2v due to a poor connection.

08/07/2020 19:47:03
Posted by Chris Bott - Moderator on 08/07/2020 18:41:15:

I don't understand Andy48. If it was reading over 4.3 on the charger screen then it knew it was going past 4.2 and shouldn't have charged it further.

If a bad connection meant that the reading in the charger was actually 4.2 when the battery was over 4.3 then you'd have seen 4.2. I'm missing something, aren't I?

It was reading under voltage when it started, however, I think the poor connection corrected itself shortly before I checked the voltages again. I'm not sure I understand either, cCould be I moved the battery, and this corrected the bad connection. I just know it happened, and I will be a lot more circumspect before using balance charge again.

08/07/2020 18:30:41

I have two good quality double chargers, and yes one of my cells did overcharge. Fortunately it has the option of displaying individual cell voltages, and when I connected it, one cell looked a little low, about 0.3v which was a little unusual. Thankfully I kept checking the charger whilst it was charging, and it was then I noticed that one cell was now reading over 4.3v. The rest (it was a 5S) we just over 4.0. A poor connection was the problem. I must have used these chargers hundreds of times now without any problem until this event. This particular battery was (and still is) in good condition, and individual cell voltages remain very close to each other during flight and at the end of a flight.

Thankfully (1) I had the charger set to show individual voltages, and (2) I was monitoring it frequently. Otherwise I would almost certainly have had a fire.

For those that think it essential to balance charge every time, I would ask why? There is certainly a danger of having the same problem I had, and the possibility of a fire due to overcharging.

Its simple really, check the cell voltages and if there is a difference of more than a couple of tenths of a volt, then do a balance charge, but check individual voltages regularly, otherwise do a normal charge..

Thread: Outdoor Workshop
06/07/2020 19:58:54

I've recently finished insulating my new garden shed. I strenghened the floor with a layer of flooring chipboard followed by a plastic click-lock laminate. I didn't bother with insulating the floor as most heat is lost through the walls and roof with only 10% lost through the floor. I reduced that further with the extra thickness of chipboard and the plastic flooring.The floor has never been cold. Walls and roof are both insulated and it has double glazed windows and door. The roof is hot roofed with a rubber roof membrane. All the joins in the wall and roof are sealed against draughts.

I just heat it with a oil filled radiator which has a built in timer. Never needed it on anything but the lowest setting, and it was quite cheap to buy.

Thread: LiPo over-voltage
06/07/2020 19:46:02

I posted about the danger of this just 2-3 weeks ago. It only happens with balance charging, due to a bad connection somewhere between the balance plug and the charger.

For this reason it seems far better to NOT balance charge unless the cells actually need it, and then do a normal charge followed by a balance charge, watching the individual cell voltage frequently.

As for your overcharged battery, as Richard says, I'd also be inclined to discharge it and then send it for recycling. Better safe than sorry, for what such a battery costs.

Thread: Self adhesive trim
03/07/2020 21:15:07
Posted by wingcoax on 03/07/2020 16:15:53:

Does anyone remember the packs of self adhesive trim sheets you could get about 20 years ago? What happened to them? They were a good way to decorate your models without a lot of masking or cutting of covering.

Water decals. You can buy water decal paper that you use in an ink jet printer - try Amazon. Then design your own decals. Once printed spray with clear acrylic lacquer and then use like any other water decal.

Thread: Onboard Voltage Sensor
03/07/2020 17:22:34

deleted

 

 

Edited By Andy48 on 03/07/2020 17:22:54

Thread: propellers
30/06/2020 18:05:04

26p a propeller is awfully cheap. I would expect to pay at least £1-2 each for them. You might find the ones you have got are very flimsy, and not very safe.

Thread: Motor Braking
28/06/2020 14:36:01

Not made any difference with mine. It will only hang down when the glider is going slow enough and folds out of the way when landing.

28/06/2020 13:35:42

Were life that simple! An electric motor will have various stopping positions depending on the number of turns. Try turning the motor, unconnected of course, by hand and you will feel them.

Thread: Unable to save settings for S8R
27/06/2020 21:15:23
Posted by Allan Bennett on 27/06/2020 20:32:20:
Posted by Andy48 on 27/06/2020 19:55:04:

Probably nobody's made too much effort over this is because there is the LUA script on the tx which does the same job, and so much easier to use, and of course the settings can easily be tweaked down at the field.

I know that all sorts of things can be tweaked on the trannie, but I don't like doing any of that at the field because (a) the screen is difficult to see in bright light and (b) the screen is difficult to see because I don't carry my reading glasses with me frown

Using LUA script to configure my S8R was a revelation, but I much prefer OTX Companion and FreeLink on my laptop in the workshop. If any tweaking is needed after a flight, I just make a mental note of it and do it later at home.

Hmmm. If you don't take reading glasses down to the field, how do you carefully check a model over before the first flight to ensure nothing has come amiss during transport?

I've never had a problem with seeing the screen even in bright light and there are some things I do need to change occasionally down at the field. I always carry a spare of glasses in my field box.

27/06/2020 19:55:04
Posted by Steve Balaam on 27/06/2020 16:40:23:

In response to Ron Gray. The original FRSKY config software has not been able to save settings back to the Rx for a couple of years, FRSKY haven't bothered to fix it. I've had to depend on Mike Blandford's program and the LUA script. I tried an early version of FreeLink that never worked. I've now managed after some effort to get the new version working with Windows 10 by configuring it to working in Windows XP compatibility mode. I had to do this both on my PC and Laptop. There are no explanatory notes telling users to do this. Users should not have to struggle to get these programs to work, the RX's are difficult enough to set up when things are working normally. In my humble opinion these programs are not yet fit for purpose and shouldn't have been released, hense my comment Ron took exception to.

Probably nobody's made too much effort over this is because there is the LUA script on the tx which does the same job, and so much easier to use, and of course the settings can easily be tweaked down at the field.

26/06/2020 20:49:01
Posted by Allan Bennett on 26/06/2020 17:38:22:

Thanks Ron, I suppose now might be the time for me to learn about lua scripts. I've seen that they come from OTX, rather than FrSky, and that I need to download them using OTX Companion. But how? I see nothing in Companion relating to lua scripts.

But the STK should work (it's worked for me in the past), so any other suggestions what I might be doing wrong, please?

Allan, you don't need to know anything about LUA scripts to use them. The scripts are on the OTX latest SD card. Download that and simply copy across the LUA scripts if you haven't already updated the SD card contents.

Check out the "How To Part 2", it goes through using the LUA script from the transmitter: **LINK**

Thread: The great i.c. / electric finger chopping debate
21/06/2020 22:35:36
Posted by Keith Miles 2 on 21/06/2020 19:07:20:

Yes, good safety advice.

I am simply making the point that there is far more complexity to setting up electric, especially scratch builds but, granted, less so with “buy and fly”. With IC all you have is an engine, fuel tank, and easier to ascertain prop sizes. Not so with electric which requires knowledge and care in matching components, plus soldering skills, plus care to avoid wiring or connection errors, burn-outs, fires etc. and a greater need for use, and correct setting, of safety features.

Edited By Keith Miles 2 on 21/06/2020 19:11:17

Eh? There is far more complexity to setting up electric? Since when?

Battery, motor speed controller and propeller.

First decide on the power required and choose the motor and battery combination. I standardise on battery sizes so only have a few. No more difficult than deciding which IC motor to choose. Look at the maximum current of the motor and make sure the speed controller is capable of handling that. Props? Electric really isn't at all fussy, a wattmeter is all that is really needed to see which prop is required.

I really don't understand the wiring and connection errors, the wiring is no more complicated than the average 9 year old handles in a science lesson. Burn outs??? Fires??? Get real. Never had either.

However, I do see many struggle with a new IC motor down at the field tinkering with them to get them running properly with fingers extremely close to the liquidiser blade. I've also seen a transmitter or two knocked when taking a model onto the field with the IC engine running.

20/06/2020 15:33:54
Posted by Keith Miles 2 on 20/06/2020 12:34:03:

Slightly off the specific topic but it seems to me that there are far more complexities associated with EP than IC, as these contributions would tend to confirm!

Not at all. Very simple really, arming plug for most models and arm on the field, foolproof kill switch for small foamies where an arming plug cannot be fitted.

In contrast, I never have to have my hand anywhere near the prop once it is turning.

20/06/2020 15:29:44
Posted by Tim Kearsley on 20/06/2020 13:52:47:

D'ya know, the more I read about Multiplex radio, the more I like it!

Tim.

The FrSky radios do a similar thing, if you change model it will not start until the throttle is set at 0, and you will get a warning. Also you can pre-set any of the switches or sliders so that it will warn you if they are not in the required start position not change to that model unless you override it or move the switches to the correct positions.

19/06/2020 12:42:08
Posted by Geoff S on 18/06/2020 22:01:15:

I've always used a toggle switch as first, a throttle cut on ic engines (on my Mux3030) and now I'm almost exclusively electric as a throttle disable on my Horus etc. Having read this about using a rotary control (much harder to operate inadvertently) I've just altered one model to use the 6 position rotary switch rather than the toggle. Always have voice warnings, too.

I've not only found a use for the 6 pos switch but freed up a toggle switch for something else

Geoff

Use one of the foolproof toggle switch systems mentioned earlier. Safer than the 6 position switch, even if it is voice activated, because you could leave that accidentally on and not hear the voice warning if someone nearby starts a noisy IC engine. The toggle switch system requires the switch to be moved a number of times within ,say, 5 seconds, and cannot be enabled or disabled unless the throttle is off. Voice alerts should also be added. Can't accidentally switch it off in flight either.

Thread: Horus RTC battery
18/06/2020 19:06:48
Posted by PatMc on 18/06/2020 15:55:24:

The Horus hadn't corrected overnight or when left on for about 20 minutes in a bedroom this morning. However left it switched on in the garden sun lounge the time & date were correct when checked after about 30 minutes.
Since the Taranis doesn't have GPS I've switched off the RTC adjust option.

I'm now wondering if selecting this option increases the drain on the RTC battery a) when there's no GPS b) when there is GPS.
If the drain is increased in b) it may be best to de-select the option once the clock has been updated.

Which Horus do you have?

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