Sena S10 battery replacement

[Biggles]

My Sena S10 comms units have recently been going flat after only a couple of hours.  They're just under 4 years old and have done a fair few hours, so I'm OK with that.  I'm especially happy that it is possible to replace the batteries, even though it's a daunting prospect for a klutz like me when it comes to soldering.

I found a Youtube clip (as you would expect), that sets the job out very well.  They recommend using solder paste which I'd never heard of before.  So I bought some- the smallest dispenser being about 100 times as much as I needed.  Ditto the shrink tubing.

The batteries are on eBay, post free from China, and have the same number (602248) and size as the originals and cost $19.57 for the pair including postage.  They arrived in less than two weeks.  Even better, they are 650 mAh whereas the originals are 560 mAh.
https://www.ebay.com.au/itm/2pcs-3-7V-650-mAh-Li-polymer-rechargeable-Battery-Li-Po-ion-602248-for-GPS-mp4/252827890467?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

This afternoon I bit the bullet and did the job.  It's minor brain surgery but not rocket science, if you get my drift.  The torx bits I had were too big at T-10 and my 2 SNCM too small; you need T-8, but a 2mm straight blade removed the screws without damage.

If anyone else wants to do the job, I'll save you some bux.  For $5 including postage I'll send you more than enough solder paste, shrink tubing (1.5mm) and double-sided tape to do the two sets.  Or if you live in Perth, you might buy Brock a beer to lubricate the lock on his shed- worth asking...   

This is the original battery with the leads cut short to make the soldering of the new ones easier.  They actually plug onto the PC board but I couldn't get the plug to release so did the join in situ.

[Brock]

Had to read up on solder paste, as I have never used it. I would just use an electronic temp controlled iron, which I have. The soldering job wouldnt be very hard, but its getting harder every year as the eyes fade

[Biggles]

Had to read up on solder paste, as I have never used it. I would just use an electronic temp controlled iron, which I have. The soldering job wouldnt be very hard, but its getting harder every year as the eyes fade

I used my flash new eyes!   

But I did work under a magnifying glass to help the precision.
My 4mm 25w iron did the job. The solder paste only needs a touch with the iron.

[ST2UP]

Thanks Bill, I have kept your little how to up my sleeve as I suspect ours that are 5 yrs old are getting to the end of there lives.

Cheer

[Biggles]

Thanks Bill, I have kept your little how to up my sleeve as I suspect ours that are 5 yrs old are getting to the end of there lives.

Youtube has a vid on S20s also, although I didn't look at it.  I suspect the layout is similar.

Regarding reassembling the unit, there is a very good double ridge gasket which slides out and in neatly but should be checked for alignment before closing up.  One of the "how-to" videos says to removed the rubber socket cover before opening the unit, but you can safely ignore that, as it comes away with the back plate and slides back on easily.

[Brock]

I have replaced the Speaker/ear plug connector on the SMH10, that was fun

[Biggles]

After living with carbon/zinc, NiCd and NiMh cells forever, I was curious to see how many tiny cells would be in one of these Lithium polymer cells.  And polymer!? That's plastic, isn't it?

So I conducted a scientific dissection.

The bits in the second shot are just to hold the sheet flat.

It has a unique organic/metallic smell (probably toxic- I'll let you know).

So- no cells, just a flat coil, a bit like a capacitor.

Laid out reasonably flat, it's 300mm long.  I deduce the higher mAh jobbie would have one more layer.

[Gadget]

!!!!!WARNING WARNING WARNING!!!!

Don't get the lithium wet with water (or sweat) it responds with an explosively hot  burn and can cause a fire you can't put out until the lithium has finished burning.

 http://www.cdc.gov/niosh/ipcsneng/neng0710.html

Sent from my SM-G930F using Tapatalk

[Biggles]

That's a good warning, Gadget.  I deduce the cell contents is bonded in some way, since the MSDS lists it as "SOFT SILVER-WHITE METAL. TURNS YELLOW ON EXPOSURE TO AIR AND MOISTURE" in its pure form.  As per the photo, it's black in this application, but certainly has been known to spontaneously combust.  I treated it with care, knowing that history, and was well ventilated.
Have we got a skull and crossbones emoji?

[Bodø]

can cause a fire you can't put out until the lithium has finished burning.

I have seen thins in action... and it took its time too.

[Gadget]

https://youtu.be/U3hb9JVmZfA

Sent from my SM-G930F using Tapatalk

[Biggles]

We've just returned from a weekend trip that involved about 7 hours of battery time, and there was still power available.
So the refurb appears to have been well worthwhile.
The available data suggests at least 300 cycles are available before the capacity drops below 80%.  I guess I got something like that, but certainly no more.
One oddity I came across is the optimum charge voltage is around 4.1, yet the phone chargers and the USB connection put out 5.0 volts.  The indications are the lithium cells are fairly intolerant of higher voltages, which makes one wonder why the mobile phone manufacturers make 5 volt chargers.  Do they want to limit battery life?

[DavidP]

Good to hear :-)

The 5v is just what USB normally is, but the smarts in your phone tightly regulate it down to the correct voltage.  Some fast chargers put out 9v or 12v and the phone takes care of the rest (simple explanation :-) )

Sent from my SM-T710 using Tapatalk

[Gadget]

What DavidP said.

There are IC regulators which control both voltage and current. Batteries are susceptible to both over voltage and over current. The main problem is the overeating of the cells during charging which affects the chemical processes.

Re 5 Volt standard allows for voltage drop over the cables and joints and still have enough to maintain constant voltages at the batteries.



Sent from my SM-G930F using Tapatalk