G3 Forum

Trackwork, Electrification & Control => Battery Power => Topic started by: 753 on May 26 2019 15:53

Title: Battery Pack
Post by: 753 on May 26 2019 15:53
I would like advice on battery packs


I found these batteries with the idea of making my own pack, six of these would give 19.2V at 3300mah for £36.00. Can anyone see any problems with this idea?


Title: Re: Battery Pack
Post by: John Candy on May 26 2019 19:46
I am not in favour of Lithium cells for two reasons.
Firstly, (unless they have been improved in recent years) they decay from the moment they are produced (i.e. have a limited shelf-life) and the charge they can hold deteriorates with age (not just with use).
I had a Polk brand Lithium pack supplied for use with a railcar kit supplied by GRS some years ago and after only three years it was totally "dead" ... and I hadn't even used it!
By comparison, NiMH cells will last for up to 1000 re-charges and seem to go on and on and on!
Secondly, there seems to be an increased risk of fire associated with the storage and re-charging of Lithium cells.
My recommendation is to use NiMH cells from a supplier such as "Strikalite".

Title: Re: Battery Pack
Post by: Peaky 556 on May 26 2019 22:37
If it’s a combination of great weight and value for money that appeals, then you can’t beat sealed lead acid cells!
With two “bricks” you can get your 19V but 4500mAh, for a cost of about £25-28.
Shape may be a problem for you, and lifetime seems to be around 3-4 years in my experience.
Regards, Tim
Title: Re: Battery Pack
Post by: cabbage on May 27 2019 08:30
The main problem with both Lithium Ion and Lithium Polymer batteries is the "cliff edge voltage". Most commercial packs include a voltage detector that cuts off the battery before this voltage is reached. Once the voltage falls below this - it will not charge again...

Both Li-ion and Li-poly packs require specific "intelligent" chargers and using a Lithium cell pack is not advisable in a loco since they get VERY hot during charging.

I have the knowlege and training to build large Lithium cell systems and my advice is DON'T.

I would agree with Tim that an SLA brick is better for a G3 loco.


Title: Re: Battery Pack
Post by: 753 on May 27 2019 09:40
Thanks for the advice, I have little experience with powering G3 locos, so your input is appreciated.

Title: Re: Battery Pack
Post by: LankyTank on May 27 2019 12:19
For guidance & wisdom, I usually talk to Steve Foster at www.fosworks.co.uk - he's the guy who took over from Peter Spoerer

No connection/interest, just a satisfied customer. Saves making expensive mistakes.


Note, other R/C gurus are available - just that I've not dealt with them.
Title: Re: Battery Pack
Post by: John Branch on May 27 2019 19:38
I have stuck to either Strikealight or Turginy AA NiMH cell packs. The Turginy ones are marketed by Hobbyking, and come in all shapes, sizes and voltages.  You can buy cells individually or in ready-assembled packs, which is usually cheaper.  for example a Turginy 5-cell (6v) 2.3Ah pack is around £7.  The packs are good as they are shrink-wrapped and the cells are tagged-both good things to have.  Using AA based cell packs gives you  more flexibility when it come to stuffing them in restricted spaces- down a boiler for instance.

I have used Lead-Acid bricks as well, and they are good, but a bit inflexible in outline.

or you could go for graphine..............