GRS kitbuilt Peckett converted to battery r/c (now + video)

[ge_rik]

I've been steadily building and converting battery r/c locos since I decided to abandon track power on the Peckforton Light Railway. I still have three track-powered locos awaiting conversion but recently converted my GRS kitbuilt loco to battery. I could have ditched the lead weights in the saddle tank and put the batteries in there but this would have required substantial dismantling, rebuilding and a repaint so I opted for an easier if less elegant approach.

I found room in the cab for three 18650 li-ion batteries, giving just under 12v.


I have so far been unable to find protected 18650s with solder tags and so invested in a protection board for a fiver from China


This not only protects against short circuit and over-discharge, it manages balance-charging and also includes an LED battery monitor to show battery level


With skates and pick-ups removed, the 0-4-0 LGB ToyTrain motor block now has quite impressive hauling power - much more than is actually needed.


She's controlled by a Deltang Rx65b receiver/controller but, as yet, I've not fitted a sound card.

BTW - the circuitry for the batteries and protection board is quite straightforward


Rik

[Big Jim]

Looks good Rik. A slap of matt black on the batteries might help hide them a bit.
Funny you should mention a Deltang unit as I am currently soldering up one for my Jessie rebuild.

[ge_rik]

Looks good Rik. A slap of matt black on the batteries might help hide them a bit.
Funny you should mention a Deltang unit as I am currently soldering up one for my Jessie rebuild.

It was a toss-up between black, grey or cream. Still not entirely decided - I think pink is a bit too obtrusive at present .......  :oops:

Rik

[ge_rik]

Short video of the Peckett in action

http://youtu.be/6JJhWHeFtSQ

Rik

[Peter Butler]

I just love your railway Rik. There are some beautiful scenic areas which look really mature and natural.
That little loco certainly has some power and the whole train looks right!

[ge_rik]

I just love your railway Rik.  There are some beautiful scenic areas which look really mature and natural.
That little loco certainly has some power and the whole train looks right!

Thanks Peter. If only I could move the house out of the way, I'd be able to get a few more filming locations

The trains are not typical of what I normally run on my railway - goods trains are usually restricted to ten wagons and passengers are usually a max of three coaches. I just fancied putting her through her paces.

Rik

[McRuss]

Hello Rik,

could you give as a link from where you bought the protection board?

Markus

[ge_rik]

Hello Rik,

could you give as a link from where you bought the protection board?

Markus

No problem, Markus
http://www.ebay.co.uk/itm/321060872067

You'll see the board also includes a heat sensor on a trailing lead. I've removed mine because I don't tend to fast-charge. I could have taped it to one of the batteries as an extra fail-safe, though.

Rik

[jim@NAL]

very impressive

[Big Jim]

You have got me all paranoid now. I have put fuses in the wiring plan for the Jessie, I just wonder if I need to use one of these as well.

[daveyrd11]

Wow that's so impressive, I love that haulage power! Those batteries must pack some serious punch for the size!
What's the running duration like?

[ge_rik]

Wow that's so impressive, I love that haulage power! Those batteries must pack some serious punch for the size!
What's the running duration like?

Not sure yet. They're rated as 2.3Ah and the loco draws around 0.5A so I assume it will be around 4 hours. I ran her for about an hour and a half the other day (with some pretty big loads as you see) and the battery monitor is still reading 100%. Not sure how accurate the battery monitor is and what the discharge curve is for these batteries but they do seem to hold their charge even if stored for a while - they're a lot better than normal NiMh when it comes to self-discharge.

Rik

[ge_rik]

I've just posted an entry on my blog about the conversion if anyone wants a bit more detail

http://riksrailway.blogspot.com/2015/03 ... co-to.html

Rik

[philipy]

Excellent write up Rik. Thanks a lot.

Philip

[daveyrd11]

Hi, Rik

I think this is a superb solution, I like that all the protection is built in to the loco, very professional!
I have a couple of questions please!
What do you use to charge, do you need a charger or will any supply do because the charging is controlled by the circuit you have built in?
What is the charging voltage?
Do you need to flatten this type of battery before recharging?

Cheers, Dave

[ge_rik]

Hi, Rik
I have a couple of questions please!
What do you use to charge, do you need a charger or will any supply do because the charging is controlled by the circuit you have built in?

Hi Dave
I am still using my Imax B6 charger as it provides an extra level of protection. This charger has come down in price dramatically since I bought mine (s@d's law) so I think it would be worth investing in one. I'd invest in a decent charger and not rely on the board (it is less than a fiver).

What is the charging voltage?

The charger handles this automatically and so this does vary as the charge progresses. There's plenty of advice out there but as a rule of thumb the general opinion is not to exceed the combined voltage of the batteries - ie 3 x 3.7 = 11.1v although I have seen advice that cells can be charged up to 4.2v.

It's important that the current is not too high. It seems that 1.5C is the upper limit when charging. C refers to the Ah rating of the battery. Mine are 2.3Ah (or 2300mAh) and so the maximum they are supposed to take would be 1.5 x 2.3 = 3.45A. I would never risk going as high as that. I tend to go for something less than 0.5C - I usually charge mine at 0.8A. The lower the current, the longer the battery is likely to last. Also, a lot of the cheapo li-ions you see for sale on eBay have wildly exaggerated claims about their capacity. I bought some advertised as 4Ah but when I tested them, they were only about 1.6Ah. So, it's advisable to play safe.

Do you need to flatten this type of battery before recharging?

Lithium batteries should never be flattened. It's suggested that a single cell should not fall below 3.0v but I would say 3.2v is the minimum. Below that and the battery could be ruined. That's why the Protection Board is so useful for unprotected batteries as it prevents the batteries from going below the safe level.

'Protected' li-ion batteries are a much safer option. They include their own circuitry which stops them from going below the safe level.

There's loads of advice on r/c forums about li-ions, but you need to read more than one source as some of the r/c modellers (especially the model car bods) are a bit gung-ho with what they suggest is acceptable.

Hope that helps

Rik

[daveyrd11]

Cheers Rik, you are a man of great knowledge! I think I may for a similar system in my tin turtle.

[ge_rik]

Cheers Rik, you are a man of great knowledge!

I wish....!

I think I may for a similar system in my tin turtle.

I'd imagine it would be ideal. I really like those tin turtles. I'm just constructing an IP plate Simplex -a sort of naked tin turtle.

Mind you, if there isn't room in your turtle for an 18650 or two, li-ions now come in all manner of sizes as they power the vast majority of electronic devices, from e-cigs, through tiny mp3 players to laptops.

Rik
PS - You might find this video interesting. It shows what can be achieved with minimal space - https://m.youtube.com/watch?v=6WdpCiD5fiY

[ge_rik]

What's the running duration like?

Hi Dave
Just been running her continuously for 5 hours with eight wagons in tow (Pictures are a bit blurry as it was dusk when I took them)





Had to bring her in as it's getting a bit dark. The battery monitor is showing 75%, however, the discharge curve for this type of battery is not linear and so that doesn't mean there's another 15 hours of running time left. I am curious to discover how long she will run for, so will continue the test tomorrow (weather permitting)

Rik

PS - Discovered that the protection board tends to cut off charging if I charge at more than 0.5A (even though the blurb says it can handle up to 8A).

[Big Jim]

Five hours, that's rather impressive.
I know what you mean about the life of Li on batteries. I have a few power tools that use them and the indicators always show full and 75% for much, much longer than the rest.