I wanted to share with you guys something that for the longest time I thought was kinda shameful or at least would be frowned upon around here…but has been working for me so flawlessly that now I think it’s worth making a post on it.
First of all, this is not for everyone, but I think that I fall in a weird category as a builder: I have the tools, know-how and time to DIY as many components on my boards as I can, but at the same time my budget is kind of low for the type of builds I make. This “cheap performance” balance is only possible due to remmnants of old hobbies and willingness to spend way too much time troubleshooting and getting to the perfect product via iterative design (aka, breaking shit). Once this is out of the way, let’s begin:
I use LiPos on all my boards. Why? Well, here are some of the reasons:
Performance: Much higher discharge on smaller packs. I can get fantastic performance out of a small pack if I don’t need the range.
Chargers: I got high quality balance chargers for previous hobbies (FPV drones), which I can use to charge up all my boards, really quickly.
Cheap-ish: Sourcing cells, buying a spot welder and building packs sound like fun, but it is not economical to do all that for just one time. Replacing dead cells can also be a problem on lithium ion packs, while replacing LiPos is as easy as buying a new pack, which is just a fraction of your whole battery.
This leads to the main drawback of using LiPos on street boards. How the heck do I mount them? Well, let’s see what I want to achieve:
Quick-swap: I have to take the batteries out of my board in order to charge them. Also, I want to be able to pop a fresh set from my backpack if I feel like riding for longer.
Security: I don’t want to start a fire. I’ve puffed, punctured, slashed, burned, overcharged, overdischarged and all around abused LiPos back when I flew drones. I know the consequences, I know how to handle them, but I really don’t want to piss them off.
Looks: It’s a street board, I don’t want no ugly case on top of it!
So, finally here’s what I’ve been doing for the past 3 years and have never, ever failed me:
Stainless steel wire: Bent into shape in order to form a “bridge”
Marine wood screws: I know, inserts are more elegant. I press my own decks, I choose to mutilate them so they know who’s boss.
Kevlar-reinforced straps: Inexpensive but tough. These are the ones that I used to hold LiPos on my drones crashing at +100km/h
3D printed anti-slip holders: To stop the batteries from ejecting on hard (de)accelerations.
3D printed PETG shield: Stops pebbles, curbs and general road shit from damaging the cells.
EVA foam: Used to cover the packs, adding some cushioning and making them non-slippery
These pictures show different iterations of two boards (mine and my GF’s). Both of them are using Turnigy 5S 5000mAh packs in series. I build a board for a friend using 4x 3S 5000mAh packs and it looks like this:
I think this method has the advantages of being inexpensive, secure and flexible. A dedicated enclosure for both batteries and ESCs (btw, my ESCs are inside 3D printed TPU enclosures fixed with inserts to the deck) certainly looks sleeker, but for me it’s just not worth it. Think of it as the refined version of the tupperware method.
Love it! DIY is not only about mere customising, I consider it too as an opportunity to save money where all available parts on the market simply offer more than you need. So to get what you want with compromises where you (and often only you) would accept them in order to calm down your purse (or your wife)
Which Lipos would you recommend with regard to the best cost-performance ratio? I am dreaming about a light budget mountain board
Thanks! Yeah, I really think DIY is a gigantic spectrum, from this “save as much as you can” to “completelly-illegal-face-melting-monster performance” xD
For esk8 I have almost exclusively used Turnigy 25-35C 5000mAh cells, both in 2x5S and 4x3S configurations for 10 and 12S respectively. Lately hobbyking has been running low on stock, and for two new builds I’m planning for family members I have bought chinnahobbyline 3S 5000mAh packs. They are supposedly 55C (take that with a grain of salt, LiPo manufacturers inflate their C ratings a lot and they are usually only useful to compare packs of the same brand). CNHL is a reputable brand in the FPV space known for their cost-performance ratio and if these higher capacity packs are as good as their drone packs…oh, boy, these are gonna be really sweet on a eMTB.
Good setup. TBH, the batteries are protected on all the important sides. Only issue would be water. Good to see someone else using Lipos for a change. I also use Lipos with a bluetooth BMS for easy charging. What are your cut offs?
I have them set up pretty high to avoid damaging cells. Sag is not an issue on these packs, so my cutoffs are 35/33 for 10S and 42/39,6 for 12S (3.5 and 3.3V per cell). Since I always balance charge, I think I could squeeze a little more, but never had the need!
Interesting! Well, I try to immediately stop riding if I notice the cutoff kicking in unless I’m really close to home…I thought it was high because I used to absolutelly shred my batteries on drones, but in that use case you’d be lucky to get 50 cycles out of a pack
Yeah. RC LVC doesn’t really translate to esk8. The equivalent esk8 usage would be going uphill 30 degrees full blast and emptying the battery in 20 minutes. In those circumstances, 3.5v might well mean you still have 50% battery left due to voltage sag.
But for the most common esk8 usage which is very start/stop in terms of amp usage, 3.5v most likely means that you have used all your capacity and are damaging your cells.
Wellllll, that’s not so difficult with a proper MTB aaand it’s a lot of fun too
… with a 12s1p 5Ah lipo setup as minimum.
I do cut off at 3.6V usually as well.
Below 3.5V it’s like 100m too much and the one or other cell can drop below 3V every other second. Personally not worth the risk in my opinion.
I do 3.6V soft cutoff and 3.3V hard cutoff, with an additional voltage alarm set at 3.6V. I’d rather have the extra range and limp my way home than have the ESC cut off for me and leave me stranded (MTB so no way to kick). The voltage alarm goes off early due to sag, and that lets me know when to start easing the power. Then that gives me about 2-3 miles before the battery gets to 3.55V, which is usually plenty to get back.
That being said I’ve never actually run it below 3.55V yet, but I’d rather be in control of when it shuts off than have the board do it for me.
Yeah I have same setup… 4 x 3s turnigy nano tech 25 to 50c 5000mah… for a street board. Set my soft cutoff to 44. Try not to go below that ever because I have killed 2 sets of lipo batteries back when I was still a total noob by overdischarging and also leaving my board in hot cars. I also switched my batter indicator to volts instead of percentage… as reccommended by Namasaki on here. He says it’s more accurate and after trying it I would never go back
Like the battery hookup to the board. Some graph I saw showing lipos doing like 15% more cycles I think it was, with them compressed, which you’re already kinda doing. I think it was a lot of pressure evenly distributed
