Help with building a DIY 18650 pack UK

Most common batteries in esk8s are 10s3p, 10s4p and 12s3p and maybe 12s4p with lower kv motors.

Higher is always better. I use a 10s pack that consists of 5.0ah/60-120c Lipos And it supposedly can handle 300a cont to 600a peak. Running dual 190kv motors with Vescs set at 60a motor max and 50a battery max each. 15/36 gears and 83mm wheels. And I still get some voltage sag when driving hard up a 10% grade. But it’s only 1v from total pack voltage.

So I’ve done a bit more research in my spare time and found what I think look like good cells, I found that I should find my idea voltage by doing 8600/170 (my motor KV) and found that I should be packing about 50V which points towards me upgrading to 12S (if I’m correct), I am now wondering if it is worth going for a higher discharge cell (about 30A) and sacrificing some capacity (having 500mah less) or is it worth going for a lower discharge (20A) and keeping capacity higher (3000mah)

Where does the 8600 come from?

What you need is at least 5000mah and 30c. That should give you abt 12 mile range with 12s 5000 mah and 60c would be better.

How are you working out the C rating for the cells, these are the two main cells I’m looking at at the moment

  1. http://www.gearbest.com/batteries/pp_399870.html
  2. http://www.gearbest.com/batteries/pp_399862.html

Thought you wher talking about Lipos

oh sorry no I’m on about making an 18650 battery pack

I think Samsung or LG are the go to cells. Not sure I would trust imr

This should be taken with a grain of salt though: it only applies to motors with 14 poles. There are hub motors out there with 28 poles for example. Also 10S is the sweet spot for the VESC - higher is pushing it and only recommended if you absolutely need the added speed.

Okay I’ll stick to the 10s then I’m just not sure how many of the cells to put in parallel and of which cell

what’s your opinion on what cell to go for in this instant then?

Well, the imr is claiming 30a but I find that hard to believe. I would search for reviews before buying that one. They could easily be over rating it. Or they might mean 30a peak.

If I had to build a pack again I’d go for samsung 30Q cells. Preferably in a 10S4P configuration.

@Maxid Is there any reason, apart from the price, why Samsung 30q became the preferred cells in this forum? Don’t the LG hg2 cells offer the same (or better) performance?

They perform almost as good as hg2 but at a lower price. High capacity and high current capabilities combined with very little voltage sag compared to for example 25Rs. (I am using 25Rs and regret not getting the 30Q because of voltage sag) Just compare 25Rs or HG2s with the 30Q on this site: http://lygte-info.dk/review/batteries2012/Common18650comparator.php

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I have found that the 30Q cells are only £1.50 cheaper than the hg2 cells (as the hg2 are on sale) I’m leaning more towards the hg2 at this point but have never used them before, are they worth it do you know?

If you don’t care about the money go for HG2. But 1.5 at 40cells is 60pounds

sorry I meant for a pack of 8 as in a pack of 8 hg2 is £1.50 more than a pack of 8x 30q