LiPo shopping list help!

Joined
Apr 30, 2011
Messages
410
Location
Bradford, UK
I'm going to make the jump to LiPo but I wanted to make sure I had the right bits and bobs on my list

8 x 6s 5000mah 20C Turnigy LiPo's to make 48V 20ah pack

Turnigy 4x 6s charger


What cables will I need to get these packs charged balanced and plumbed up. HELP!
 
Well without information on your motor or controller our info will be entirely based on a battery back with unknown requirements.

The batteries are a good choice for a pack and 12s is a simple setup for charging but the charger you post is really not the best. I beleive that each of the 4 charging sections can only handle 50watts so not only would you have to break your pack down every time to charge it but you would have to charge it in 2 lots after breaking the pack down.

My approach (Still in the implementation stage) is this

I will permanently wire my pack up on the parallel stage so in your case you would have 4 of the batteries permanently wired up into a 22.2v 20ah pack with all four power cables soldered or connected together and also all 4 balance leads connected together... cables i am using are... http://www.progressiverc.com/parallel-6x-balance-adapter.html x2 for making the 2 packs as above, and I’m making my own connectors to parallel the 4 packs at the power leads (mainly because it’s hard to find readymade ones that are suitable for high current.)

This way to charge all i need to do is remove the series connection between the 2 22.2v 20ah packs and charge them as 2 separate packs. This can be done with a relatively inexpensive charger and power supply such as http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6792 and http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16534.

This will charge your pack quicker than your above stated charger and also a lot easier and safer with not having to separate all your lipo bricks to charge. As for connectors it depends on your power usage but I’d recommend a minimum of 10awg wire and 60amp connectors unless you’re going to be hotrodding into motorcycle power territory. in using 10awg Turnigy silicone wire from HK and 65amp rated XT60 connectors also available from HK.

also worth considering is maintenance and protection for your packs... i also added to my shopping list 2x Celllog 8's http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10952 to connect to each of the 22.2v 20ah packs balance connectors to monitor cell voltages and provide a Low Voltage Alarm and i also bought 1x battery medic http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10328 for good measure and to allow me to balance both packs at the same time (1 on charger and 1 with the battery medic) to speed up any balancing that is needed.

Obviously these are not MUST HAVE items but if you want your pack to last you have to be careful that they don’t get over discharged or go too far out of balance.

I think that just about covers the things you will need.

Just another note... it is possible to rig your lipo up so you only have to connect to a charger and don’t have to worry about any disconnections between the packs but that will require a 14s charger which i believe to be too expensive to be worth the little less hassle (half the cost of the lipo just for a charger) and a more powerful and more expensive power supply to feed the large charger, in the end i settled on the above approach for best all-rounder.

Hope that helps you :)
 
Thanks for the info, really helpful. If I permanently wire them up to get 20AH packs, then how do I balance the cells individually?

The controller is 35A max, I'm not looking at superpower here, 1200W only. Looking for the simplest cleanest solution.
 
nonlineartom said:
Thanks for the info, really helpful. If I permanently wire them up to get 20AH packs, then how do I balance the cells individually?

The controller is 35A max, I'm not looking at superpower here, 1200W only. Looking for the simplest cleanest solution.

If you permenantly wire the packs up ast the power leads as well as wiring up the blanace leads permenantly with the cable i poseted from ProgressiveRC then you do not need to blanace each cell individually because the balance lead changes the 4x 5000mah cells into into 1x 20ah cell so the individual cells will not go out of blanace. this way you would only ever need to balance the 22.2v 20ah pack as 1 battery and you never need to break them up (unless you have a cell go bad on you). Hope that makes sence as im struggling to explain it as clear as i would like to lol :)
 
Ok that makes sense, sounds a little less daunting now. Can you get an off the shelf BMS to prevent under / over charging the 20ah pack?


alternativly, could I use a pair of HK101's, one on each 20ah 22V pack to keep them balanced / in check?
 
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