Sweet Sue II

[ashley needhamParticipant @ashleyneedham69188]

A couple of my odd craft have aircraft esc’s and If the battery gets low or the esc hot, they drop to half power, or less, thus giving you warning. However unless the esc blurb says so, I would like an audible warning bleeper as well, just in case…

Ashley

[BanjomanParticipant @banjoman]

Ashley,

The ESC instructions explicitly state that power will drop to half if the voltage drops below the set value or, indeed, the ESC gets too hot; taken in conjunction with what Dave M says about never yet having run down a LiPo to the point of triggering a low voltage reaction, I'm not unduly worried to go belt-only, but as I'd already also ordered the additional alarm, I might perhaps just as well include the braces of it in the circuit?! We'll see. In any case it is, I thiink, a simple in-line unit, so easy to plug in or remove as one's fancy takes one.

Speaking of ordering stuff, today the first of four outstanding orders for this build showed up in the post. Funnily enough it turned out to the last one made, but what with everybody and their uncle (and aunt, and cousin, and the bloke they sat next to back in 5th grade) currently ordering on-line like billy-oh, the Post Office and courier companies are having trouble keeping up, I believe.

In any case, this was the second (and smaller) of two Sweet Sue II-related orders from Albatros Modelbouw up in Mechelen, and in it was a 3S LiPo extension balancing lead …

… and also some protective covers for male JST-XH connectors.

Furthermore, there was a grubscrew-fastened aluminium tiller for a 4 mm rudder shaft …

… and two pushrod swivel nuts (also grubscrew-secured).

To be continued …

Mattias

Edited By Banjoman on 16/04/2020 11:47:49

Edited By Banjoman on 16/04/2020 11:48:18

Edited By Banjoman on 16/04/2020 11:49:05

[Ray Wood 3Participant @raywood3]

Hi Mattias

Lipo's are only batteries at the end of the day, when the boat slows down, bring her back in as you would with any other form of battery, it's a lot easier to spot with an aeroplane because they stop wanting to climb.

I do charge on a fire brick, but never had any issues (touch wood)

Regards Ray

[BanjomanParticipant @banjoman]

Hello Ray,

Yes, they are indeed batteries, but at least to the novice user of them perhaps not quite as "only" as the ones with which one is already familiar, given all the dire warnings and strict injunctions with which they come. Of course I understand that manufacturers and sellers of something that could carry a risk must underline and to some extent exaggerate said risk, both to cover their own behinds and to make sure that users are aware.

In any case, yesterday afternoon, the chap from UPS brought me my package from ComponentShop (while maintaining appropriate distance, natch!), in which was first and foremost a LiPo (cue thunderclap and some menacing music) …

… but also a LiPo guard bag (soon to be replaced, but more on that once the postman has been along today with a further parcel).

Here in Belgium, the DIY shops were allowed to reopen on Saturday, so yesterday afternoon I popped along to one and bought some fire-resistant bricks, of which here's a sample …

… with which I created a sort of secure storage facility in a part of the garage (which is heated in winter, so always at room temperature) where there's nothing else immediately above or in front that wouldn't be able to survive the heat of an incident. I will make this neater with a small metal cabinet from Ikea, once they too are open for business again.

Am I being overly cautious here? I'm sure I am (if I weren't, I wouldn't have bought a LiPo in the first place), but I'd rather err with a very large margin on the side of safety – if nowt else it'll help me sleep at night!

And while we're being cautious, here's the low voltage alarm as already discussed

I also took the opportunity to stock up Deans type connectors, regular, mini and micro …

… and finally there was the programming card for the ESC.

To be continued …

Mattias

[Bob Abell 2Participant @bobabell2]

Don`t like the look of that little pile of Dynamite, Banjo

Fire bricks etc

I used to charge my Fire Sticks in a biscuit tin and wearing me Dad`s old Tin Hat

All the best

Bob

[BanjomanParticipant @banjoman]

Bob,

I'm sure a tin hat is much better than a tin foil one, eh wot wot?!?

That pile'll just be for storing the stuff. I plan to do all charging out of doors (there's a handy electric outlet on our back terrace) in a protective box on top of some fire bricks.

Just call me Granny Cautious!

Mattias

[Ray Wood 3Participant @raywood3]

Hi Mattias,

Don't worry about Lipo batteries, although if you read the instruction !!! I can't see how your battery pack could be charged any other way with balanced charging plug supplied.

We know examples of fire's thanks to social media, YouTube etc, but you also find people who burnt down the house with a barbecue in the Garden !

If they were that dangerous they wouldn't be sold commercially in my view, relax & build the boat 😀

Regards Ray

[Bob Abell 2Participant @bobabell2]

I am very impressed with the way that batteries have developed over the past twenty years

What will they be like in five year`s time?

Day`s to come?

Bob

[Ray Wood 3Participant @raywood3]

Hi Bob,

Yes great for our modelling, but slightly less practical for cars at the moment ! My mate is an RAC man and is spending an increasing time recovering cars that ran out of battery, but is it a breakdown as such ??

Regards Ray (diesel powered)

[BanjomanParticipant @banjoman]

Hi Ray,

Oh, I think I will continue to worry slightly and build that boat

And indeed things such as barbecues and fire places (both of which we have here at home) can cause fires (and probably do much more often than LiPo:s). Back in the 1980s, an aunt of mine made a very serious error: she'd enjoyed a cosy wood fire of an evening, and then, being (too) tidy, removed the (as she thought) burnt-out ashes before going to bed. The ashes she put in a plastic (!) bucket, which she then pushed under a chair in the entrance hall, intending to take it out to empty next morning. However, she woke up in the middle of the night (actually, the cat woke her up!), with flames coming up the stairs from the hall to the second floor, where she slept! She had to climb out through a window, and was lucky to survive! If it hadn't been for the cat, who knows how it might have ended?! The fire brigade managed to save the house, although it needed extensive repairs.

From which I learned (a) never to clean out the grate (or the barbecue, for that matter) on the same night as it was used, and (b) to use a proper, made-to-purpose steel ash can with a heavy lid and a bottom raised to two inches above the floor for storing (even cold) ashes until final disposal (on the compost heap, usually).

As for the balancing dervishes and all that, my charger does have a mode (called Charge) expressly for the purpose of charging LiPo:s without a balancing lead. But I'm not going to use that mode, am I now?!

Thanks again, though, for your encouraging words and kind help

Mattias

Edited By Banjoman on 21/04/2020 10:37:02

Edited By Banjoman on 21/04/2020 10:38:09

[Ray Wood 3Participant @raywood3]

Hi Mattias,

I don't know very much about electrics but should your battery be rated 30C for fast discharge ??I

I bought one some time ago thinking was ok but the boat was very slow but for a long time !!

I'm sure DM will let us know in due course 😀

Regards Ray

[Ray Wood 3Participant @raywood3]

Hi Mattias

Forget my last, I see it's 35C 😯 senior moment !!

Regards Ray

[BanjomanParticipant @banjoman]

Hello Ray,

Yup, 'tis 35C – and as it happens the exact same brand and spec as the packs that Dave M. put into his two prototype boats a few years ago. So, there's precedent

Mattias

[Dave MilbournParticipant @davemilbourn48782]

Ray

Not necessarily for your benefit but you've raised a point about the terminology applying to batteries.

The C rate indicates the theoretical current which could be sustained while discharging the pack over a period of one hour until it was exhausted, so the C rate for a 2600mAH pack is 2.6A. The 35C discharge rating gives a value for the maximum current discharge rate that the pack will deliver. So Mattias' 35C pack can discharge at a rate up to 35 times the C rate, which is 35 x 2.6A or 91 Amps. That could be maintained, however, for just one thirty-fifth of an hour.

Dave M

[Ray Wood 3Participant @raywood3]

Thanks Dave,

Like most things in life I learned that the hard way 😀 bought what to me looked like all my other batteries of course it wasn't !!

Still none of us are exercising our batteries of any sort at he moment !! SWMBO suggested I dig a hole in the Garden & hope for rain 😯,

Regards Ray

[BanjomanParticipant @banjoman]

Well!

Yesterday afternoon, the postman turned up with a nice, big package, that had taken a full week (!) to travel the +/- 14 miles (!!) from Albatros Modelbouw in Mechelen – but then I read in the paper yesterday that what with lockdowngenerated on-line ordering, the Post Office has to handle the same volumes now, week in, week out, as it usually only does in the run-up to Christmas (which might incidentally also explain why I've not yet recieved my copy of the May issue of MB).

In any case, there it was, and first out of the box was this beauty: a Robbe RO-Safety dedicated LiPo charging and storage box:

According to the specs it is good for simultaneus storage of up to the equivalent of two 6S 5,000 mAh packs, so my little 3S:er had plenty of elbowroom, all to itself.

For the details on the features and specs, see **LINK**. Obviously there's only one way to really know if it does what it says on the box (ha!), and I most sincerely hope I'll never find out, but in any case it is a pretty nice piece of kit. Rather more pricey than the usual soft LiPo bags, but I'm happy enough to have spent that on peace of mind.

Furthermore, there was a couple of packs of Z-Poxy finishing resin (and no, I don't expect to use all that on this build; I'm just stocking up, is all) …

… and glassfiber cloth in 25 and 100 gram/m2 weight respectively.

I also recieved a receiver …

… and a Hitec HS-81 servo.

After my days work was done (I'm still working full time from home), 'twas time to set uip out on the back terrace, and fully charge the LiPo, which went completely hassle free, I'äm delighted to say …

… and then to bind the receiver, solder on a Deans plug on the powefr leads of the esc, connect it to the LiPo and set it up with the programming card (another doddle — that card was well worth he money!) and finally test the motor-and-esc set-up.

Everything went swimmingly well: the motor runs nice and smooth, forwards and backwards, and is very quiet, too.

All in all a very successful afternoon, which I then rounded off again, back out on the terrace, by running the storage mode (dis)charging programme on the LiPo, to take it back down to 3.8V per cell. As I won't be using it very much during next stages of the build, I figure it'll be better that way; it can still be used for any occasional testing needed, and then topped up every now and then back to said 3.8V/cell storage voltage.

A couple of things rather struck me during the charging and discharging process.

Firstly, the LiPo didn't increase its temperature in any way that could be detected by simple touch, which of course was reassuring.

Secondly, with the press of a few buttons, the charger very neatly displayed a lot of measurements, including current voltage per cell, which meant that progress was easy to follow, which in turn also felt very reassuring.

All in all, I rather think I've been getting me boxers in a little more of a twist over this whole LiPo thingummy than what was really necessary – but then again, I feel much happier with having been perhaps overly cautious than the opposite.

To be continued …

Mattias

[BanjomanParticipant @banjoman]

I forgot to say about the charging and storage charging that the former was done at 1C, so that it took just over half an hour to get the battery up to full charge, while the discharging down to storage level was a rather slower process.

The max current setting for the Storage mode is 1.0A, which is what I selected, but the charger decided for itself to run the process at 0.5A, going down gradually to 0.2A for the final balancing act; that thus took neigh on three hours, but it was a lovely evening to sit reading out back, enjoying the garden, while the book I'm currently (re-)reading is thick enough, too, to last me rather longer than that, so all in all, no worries …

To be continued …

Mattias

Edited By Banjoman on 22/04/2020 08:03:40

[Eddie LancasterParticipant @eddielancaster]

Hi.Mattias, if you have to be in lockdown you couldn’t have a better place or view, do you get a good dawn chorus there?

Regards.

Eddie.

[BanjomanParticipant @banjoman]

 

Hi Eddie,

That is absolutely true, and my wife and I are well aware of how fortunate we are; both able to work from home, a comfortable house with a lovely garden (and a nice workshop, too ) and on top of that the village bakery and pharmacy are still open for business, plus we live more or less at the nexus of a network of walking paths that take us straight out into the open countryside whenever we want a constitutional (which is expressly allowed under Belgian lockdown rules, as long as one keeps one's distance to anyone one happens to meet). Here are a couple of photos from a nice 6 mile walk we made last week:

And yes, we do indeed have a lovely dawn chorus! We get quite a number of birds in our garden, and this time of the year they're of course really at it!

Cheers,

Mattias

Edited By Banjoman on 22/04/2020 10:13:43

[Bob Abell 2Participant @bobabell2]

Hello Banjo

With reference to the US Civil War book cover illustration

I`ve read a lot about this war. I can`t get over the way they used to march into the face of shot and shell, shoulder to shoulder, packed like sardines and suffer enormous casualties!

It seems to be so stupid?

The sad highlight of the war was Gettysburg of course, but there were plenty more

I was in Kentucky, Tennessee, North Carolina, Virginia and Atlanta a few times in the 90`s and kept a look out for signs of the battles and there were plenty

It took them quite a few years to realise the unnecessary slaughter and adopted WW1 strategy of trench warfare

Bob

[BanjomanParticipant @banjoman]

Hi Bob,

I remember reading in another book on another conflict (Peter Englund's book on the battle of Poltava in 1709, during the Great Nordic War, to be precise) that the main point of battlefield tactics and behaviour in the era before widespread use of precision, long range, high rate-of-fire and (not least) smokeless fire arms was not primarily to kill or maim as many as possible of the enemy, but rather to get them to break and run by the psychological pressure of a massed advance.

Furthermore, given the lack of workable means of communication, what with all the smoke and noise, dense grouping was pretty much the only way to keep units reasonably together, and may well have helped the individual withstand the fears involved.

In most cases, I think the casualty figures also make it clear that the precision and rate of fire was low enough that you usually stood a sufficiently decent chance of coming through alive and unhurt that the odds would not have seemed too long for those involved.

One my my big regrets from travelling in the US, also back in the 1990s, is that I did visit the battlefield at Gettysburg, but only stayed for about two hours. But I didn't know then what I do now, about neither the battle itself, nor how well-preserved the place is, and we had further to go that day, so basically only saw the museum and the view from the top of Cemetary Hill.

And if you haven't read Shelby Foote's three-volume work on the US Civil War, it is seriously recommended!

Mattias

Edited By Banjoman on 22/04/2020 11:07:51

[Bob Abell 2Participant @bobabell2]

Hi Banjo

My trips to USA was for meeting customers and machine installation

Visited….Salisbury,,,,Nashville…..Atlanta……Springfield, Gatlingberg

I was with the Boss at the time. but he showed no interest

Pity really

Bob

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