Batteries, types and LiPo questions etc

DVT Dweller · Post by **DVT Dweller** » Mon Apr 06, 2015 9:23 am

Ok it's possibly best if I give the background here. I've been rebuilding one of my battery locos and as part of the rebuilding its had a new MFA motor and gearbox fitted:

http://www.mfacomodrills.com/gearboxes/919d_series.html

I've now fitted a roundhouse locoglyde ESC to convert it from manual to RC, planet t5 rx and a 5A auto reset circuit breaker.

Now the power pack it previously had fitted to a smaller motor was 10x AA rechargeable cells. When I came to test the loco I fitted 10 none rechargeable Panasonic AA's but with a heavy test, 2 steam locos dead on the hook, it soon drained the batteries.

This gives me 2 options, reduce the workload or increase the battery capacity. The main problem being the limited space 93mm x 85mm x 50mm. This rules out lead acids, I could potentially fit 'C' 5000mah cell but these look ver expensive and will they be upto the job?

I've also be nagging poor Shane (pendo) about LiPos. I'm slowly getting to understand the simple things Xs is number of cells in series Xp being cells in parallel but I don't understand all the discharge rates Xc etc.

I've managed to find these online:

http://cellpacksolutions.co.uk/online-s ... tery-pack/

But they don't appear to have a balance lead for charging? The racing style packs:

http://www.rcsmart.com.my/products/Gens ... r%29/11713

Seem to be much longer but fitted with balance plugs. I know there are horror stories about LiPos bursting into flames and I'm interested to hear of any experience people have had with them, be that years of faulty free running or fireballs. Basically as much info as you guys know would be really helpful.

Steve

tegfan railway · Post by **tegfan railway** » Mon Apr 06, 2015 10:57 am

those prices seem a bit steep, I buy most of my Lipos from Hobbyking (UK Warehouse) or BRC/Robotbirds (same company)

http://www.hobbyking.com/hobbyking/stor ... ipoly.html

DVT Dweller · Post by **DVT Dweller** » Mon Apr 06, 2015 2:46 pm

tegfan railway:109824 wrote:those prices seem a bit steep, I buy most of my Lipos from Hobbyking (UK Warehouse) or BRC/Robotbirds (same company)

http://www.hobbyking.com/hobbyking/stor ... ipoly.html

I know what you mean, I've been searching through to try and find what I want at a reasonable price. But all the standard packs seem to be much longer in construction.

Post by **ge_rik** » Mon Apr 06, 2015 3:04 pm

tegfan railway:109824 wrote:those prices seem a bit steep, I buy most of my Lipos from Hobbyking (UK Warehouse) or BRC/Robotbirds (same company)

http://www.hobbyking.com/hobbyking/stor ... ipoly.html

I use Hobbyking (and also eBay). Hobbyking have a useful search tool which enables you to set parameters such as size, capacity etc.
http://www.hobbyking.com/hobbyking/stor ... ration.asp

Regarding LiPos - I've been using a variety for a couple of years now and have had no problems (as yet). I don't tend to fast-charge mine - I think most of the problems come when car and plane users stretch the charging guidelines to their limits.

My latest builds have used 18650 LiPos (the type used inside most laptop battery packs) with a battery protection board. Gives you the flexibility of placing batteries in whatever configuration you choose.

Here's a post showing my latest battery conversion:
http://gardenrails.myfreeforum.org/about9532.html

Rik

Big Al · Post by **Big Al** » Mon Apr 06, 2015 11:53 pm

A good place to buy Batteries http://www.componentshop.co.uk/batterie ... -car-packs

DVT Dweller · Post by **DVT Dweller** » Tue Apr 07, 2015 12:11 pm

Thanks gents,

I'm slowly getting there on what's what so to speak, the bit I'm struggling on now is finding something of the capicity of the Cell pack one I put up earlier but of a similar size. Though the lack of ballance lead and to another extent the price put me off it.

Gens make a 4s2p 3300mah pack:

http://www.fast-lad.co.uk/store/gens_33 ... anguage=en

Now if I'm correct the 35c rating means the pack can happily chuck out 115A only 100A more than the motor will draw so in that way there's more than enough when the motor is under heavy load but this still only give a just over an hours running time at 2.5amps. Would it be possible to wire a pair of these packs in parallel to give 6600mah? Or could this lead to problems? Or does anyone know of anyone that can build bespoke packs with a larger capacity?

Steve

Superbiker_uk · Post by **Superbiker_uk** » Tue Apr 07, 2015 12:59 pm

Have you tried this supplier?

http://www.strikalite.co.uk/prodcat_typ ... /index.asp

DVT Dweller · Post by **DVT Dweller** » Tue Apr 07, 2015 3:47 pm

Superbiker_uk:109876 wrote:Have you tried this supplier?

http://www.strikalite.co.uk/prodcat_typ ... /index.asp

I tend to use strikealite for all my power packs. Brilliant customer service every time and never had any problems either. But I've noticed he seems to have the same fear of LiPos that seem s to be doing the rounds in 16mmers. I've dropped him an email anyway.

Busted Bricks · Post by **Busted Bricks** » Tue Apr 07, 2015 5:34 pm

Does the ESC have a Low Voltage Cutoff suitable for use with Lipo cells? If you discharge them too much they will be ruined.

godsteam · Post by **godsteam** » Tue Apr 07, 2015 9:37 pm

Steve

Your first link was for Li-ion batteries which are different to Lipos, I don't think they need a balance lead.

Godfrey

Post by **ge_rik** » Tue Apr 07, 2015 10:01 pm

DVT Dweller:109880 wrote:
Superbiker_uk:109876 wrote: I've noticed he seems to have the same fear of LiPos that seem s to be doing the rounds in 16mmers.
There are scare stories but the way I look at it is that li-ions / lipos are now used in most everyday electrical devices - including e-cigs, mobile phones, power tools, vacuum cleaners and the tablet I'm writing this on. A li-ion/lipo powered loco is just another device.

If mistreated, then lipos can be hazardous, but then so can canisters of butane and boilers full of scalding steam.

Rik

DVT Dweller · Post by **DVT Dweller** » Wed Apr 08, 2015 10:12 am

godsteam:109910 wrote:Steve

Your first link was for Li-ion batteries which are different to Lipos, I don't think they need a balance lead.

Godfrey

Godfrey,

I honestly hadn't noticed that. Thank you for pointing it out

What do we know about Li-ion cells then? Are they suitable for out use?

Steve

godsteam · Post by **godsteam** » Wed Apr 08, 2015 10:35 am

Steve
I have tried to understand the difference between the two types of battery but I am still a bit confused.
I notice that the power tool industry has largely changed over to the Li-ion batteries now.
So needing a power source for some small 3volt motor loco's for the grandchildren to use on my railway I opted for the Li-ion 18650 cell. They seem to perform much better than the NiMH AA cels I had been using. Ultrafire cells, holders and chargers are available on ebay at very reasonable prices.

Godfrey

Post by **philipy** » Wed Apr 08, 2015 10:56 am

I know nothing about this subject, so I went searching.
This link gives a fairly detailed comparison. I have no idea if it is accurate though!
http://batteryuniversity.com/learn/arti ... al_battery

DVT Dweller · Post by **DVT Dweller** » Wed Apr 08, 2015 10:03 pm

Thanks guys, really does look like we are heading in the right direction. I'm assuming that as Li-ion cells have an in built circuit board and therefore are self balancing?

I need to research into charging and find out if there is a supplier of packs in the UK other than those that supply in the thousands from China. Or failing short of that its having a go at building my own...... Gulp.

Post by **philipy** » Thu Apr 09, 2015 6:51 am

By sheer chance and coincidence, I just saw this on the Beeb:

http://www.bbc.co.uk/news/science-environment-32204707

Now, the fast charging and flexibility would be a real advantage, if they do manage to go commercial with it.

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Batteries, types and LiPo questions etc

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