Small LiPo battery question

[justinwebb]

Anyone ever used a LiPo battery that wasn't the lego box?  I've been looking for a small battery to fit in some MOC's and the battery box's are far too large.  There are some smaller 7.4v batteries out there that might work and just wire on the lego plug to the receiver.  Hoping others might have tried this and have a battery that is small and works well as there are tons out there.  

[MAB]

Yes, I have. Most of the ones designed for quadcopters work fine. I bought a 7.4V, 2000 mAh one from an aliexpress seller. I guess it is about 8 cm long, by about 3.5cm x 1.5cm cross section. Weight is about 100g or so. I think it was about £8 GBP, so $9-10 USD.

You'll need a "2S" (2 cells in series) for the correct voltage. The C rating (related to discharge rate / time) doesn't matter too much if you are driving a normal train - the drain rate is normally lower than a quadcopter or heavy RC car. One thing to watch out for is that some of the better RC car ones can come in quite a heavy protective casing - you don't want that (bulk and weight). Go for one that is essentially just the battery and connectors. They will usually be sold as "for quadcopter" or similar.

 

I wouldn't go for anything below 1000 mAh and definitely not below 500 mAh unless you want to be switching batteries a lot.

 

You will also need a charger.

 

 

Edited August 8, 2017 by MAB

[dr_spock]

On 8/7/2017 at 2:15 PM, justinwebb said:

Anyone ever used a LiPo battery that wasn't the lego box?  I've been looking for a small battery to fit in some MOC's and the battery box's are far too large.  There are some smaller 7.4v batteries out there that might work and just wire on the lego plug to the receiver.  Hoping others might have tried this and have a battery that is small and works well as there are tons out there.  

It might be a good idea install a shutoff and/or warning circuit so that you don't damage your LiPo from discharging it too low.  You can find inexpensive low voltage warning devices for drones on places like eBay.