LiPo battery setup

Hi everyone,

I’m building my own electric skateboard and the last bits I need are the enclosure and battery. I’ve got everything else. The battery seems to be the most expensive part of the build and I want to get out on the board now. The weather in the UK is incredible and I want to be out enjoying it!

I’m thinking of throwing in some LiPo batteries in so that I can get out and about. I know I’m not going to have the distance or speed of a Li-ion setup, but it’s better than nothing.

Any advice on the batteries I should buy along with a suitable charger? I’ve got a single 6374 motor with FOCBOX (awaiting delivery).

Thanks, Daniel

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Personally happy with 4x 8000mah flight Max (30c). Would not get turnigy nano-tech or multistar or super cheap ebay brands. Anything above 30c should be fine. Anything around or above 8000mah should be fine (even 2x) if you are not going for distance.

If cash isn’t an issue, the turnigy Graphenes offer good value when comparing it to other high c lipos.

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Do you have a link to the ones you’re using? I’d prefer to go off of a recommendation based on experience.

Thanks, Daniel

Found them :slight_smile:

compare how much would you spend on lipos and see what you can get for the same money with a custom made li ion pack

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They are rather expensive now. I bought them for 55 euro via their European warehouse about a year ago with JST-XH connectors. The xt-90 version was 20 euro more expensive.

They are listed cheaper via the Hobbyking eBay stores as opposed to their official website.

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@acido It’s definitely cheaper to buy some run of the mill LiPo batteries than a custom made pack. I’ve already got a balance charger so all I would need is some newer batteries. I’ve got some old 1600mAh RC car batteries but I don’t want to link loads of them together.

@telnoi According to the HobbyKing website they’re £27.61 a pack which seems like a good price. I’ll get 2 of them and will use them on a budget board which I can lend to friends when I no longer need the batteries.

You’ll want somewhere in the 8-12S range so will need to link these in series to boost the voltage. When you link in parallel you add the capacity (mah) but the voltage stays the same (can’t connect say 3S to 4S in parallel cause it will dump charge from the 4S into the 3S until all the cells are over voltage, can hook them in series though effectively a 7S). I use 2 5Ah 5S 20C (turnigy) and don’t have any issue but I don’t draw a ton of amps either being a small dude on flat land:

For two 5Ah 5S turnigy 20-30C batteries the price of the batteries is around $40-50 a piece so about $100 for 185Wh, compare with a li-ion you’ll typically get twice the Wh for three times the price.

So I think I’ll now get 3 of these as they seem cheap and will be perfect(?) for a temporary build:

Any recommendations on a balance charger where I can plug all 3 batteries in at once and charge together rather than charging them individually? My current LiPo charger requires me to charge individually which is a little bit of a faff.

Thanks, Daniel

Balance board should solve that.

Can’t seem to find any bullet connector versions but I presume it’s something like this?:

Yah, you’d just have to solder your own connectors or replace the lipo connectors.

Most balance boards are xt60. I personally soldered xt60 to 90 connectors.

I get 37+ Volts out of my old 3 X 3S set up … it’s comparable speed wise to a 10S li- ion pack… would go 2 X 6S tho 15305528037378739365336611779992

Regarding the parallel charging board might be worth getting the kind with built in fuses to avoid accidentally dumping charge too quickly from one battery to another. Typically you want the batteries total voltage to be within 1 or 2 tenths of a volt when hooking up to the parallel board. This is the one I use for my quadcopters but only works for 3S or 4S batteries nice side is it has the voltage display built in so just plug in the main lead and I can check voltage on each of them before plugging in multiple batteries. Personally just using 2 chargers for my 5S (was charging in sequence before getting a second charger, but between the quad and skateboard I need to charge a lot of things).

@telnoi I thought that would be the easiest solution. I’ll do whatever I need to get it working.

@CougarKiller It’s good to know what sort of power I’ll be getting from this cheaper solution. I’m not massively worried about power levels right now because I just want to get out and play!

@wafflejock I’ve decided to go with the below option because of the exact reason that the previous didn’t have fuses. A small system error could cause a big problem. I feel this HobbyKing option is suitable for the job:

Could someone recommend an anti-spark switch I could use? I don’t really want to have a makeshift key. I’d like the setup to be fused in order to prevent damage on the FOCBOX. I’ll be ordering all these parts from HobbyKing as it’s easier, so if they’ve got an option then that would be fantastic.

Thanks, Daniel

Cool looks good on the parallel board, still good to check the voltage before you hook them up to avoid blowing the fuses. Regarding antispark I think the homemade loop key is sort of the only option. There are a few variations using 3d printed parts and bullet connectors or 3d prints around the anti-spark xt-90 but don’t think you can buy ones premade (luckily they’re easy to make). You’ll want to have XT-90 male/female connectors anyhow for hooking the batteries in series etc. so probably worth it to just get a box of those some silicone 12 gauge or 10 gauge wire the loop key is just a matter of hooking one wire in a loop onto the XT-90 antispark (buy one of these separate from the ‘extra’ xt-90s) and putting some heatshrink on there. If you have to replace battery connectors at all just make sure you cut and tape up each lead separately easy to forget and cut across both leads shorting the battery through your tool (possibly welding it to the leads causing bigger problems).

I’ll go with the anti-spark option then providing that doesn’t cause any damage to the speed controller. I’ll place my order tomorrow.

Out of interest - which charger would you recommend for £30-£40 on the HobbyKing website? Got an extra £6 to spend for free delivery and can’t figure out what to get!

Yah insofar as I know you don’t actually need the antispark either it’s just nice to have to avoid burning up the connectors when there is a spark from the initial inrush current into the capacitors on the ESC. I used my first VESC for a while without one and it worked fine but I had to replace my xt-90s after a while because the sparking charred the connectors over time (also just unnerving to hear and sometimes see the spark when hooking things up). Another plus with the anti-spark is you can just remove it if the board is going haywire assuming you have it in a place that is easy to grab and you have your wits about you when you need to pull it, other nice things are no one can just jump on your board and hit a button and go and unlike the switches/buttons there’s very little room for failure with an anti-spark (switches/buttons can fail closed/on or open/off)

Regarding chargers the imax b6 is widely used and pretty much trusted option

Personally I use a couple of keenstone chargers, one is basically a clone of the b6 but lets you do 80W instead of 50W, newest one I got goes up to 500W. With the 80W one with 5S*4.2V ~= 20V, 80W/20V = 4A I can really charge at 3.6A or so before it starts to overheat itself. The 500W one I’ve brought up to 5A (1C) with no problems (it has a fan inside, only downside with that one is it needs DC input no AC->DC transformer inside).

Hmm, xt90-s has been working fine for over a year with constant unplugging for charging. I got rid of the anti-spark switch, cause it’s just another component that can blow up if the amp draw is too high. Not gonna happen with a single drive, but personally a big fan of simplicity. Up to you. If you’re in the EU I can send you a working anti-spark switch for 15 Euro.

As for a chargers, ISDT is brilliant. They are a bit more expensive, but less so than equivalent charger offering similar amp ratings. Charging my lipos at 14a with a q6 plus.

Yah I should mention it was really bad with 12S I was initially running but at 10S the spark was less of an issue really.