My first build, e-mtb trampa

ESK8 Builds
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@Stefanj about programming card for MAX6. I think it’s this card But i am sure there are many alternatives.

About your battery and charging system. I see you going for 4x4S batteries. Probably, 2x in series, and 2x parallel, so you will get 8S, 12Ah. It’s nice, but you have two/three options regarding charging it.

1 option - Pain in the ass :smile: you have your 4x batteries, you have to open the box each time, and charge every battery with 4S charger separately. One after another. It takes time, and you have to disconnect parallel and series wires each time. you have to buy charger with integrated power supply, but 4S balance charger is rather cheap.

2 option - less pain in the ass, but still :smile: you have your 4x batteries. you have to open each time box to charge it. you connected, all the balance wires into one plug (there are some threads regarding how to do that), so you have to connect one plug to the balance charger, and all power wires to one plug, same it goes to the charger. you got one big 8S battery, and you probably need 8S, charger. It’s not that cheap, and usually needs power supply (the charger is only charger, and that charger needs DC power supply to work)

3 option - best, but needs BMS - battery managment system. you connect all the balance wires to the bms, Power wires also ( this setup is the best with the 2x batteries. If you go with 8S i suggest to use 2x 16 Ah 10C Turnigy Multistar Battery) i don’t know about voltage sag with max6 esc, but i have those two batteries in my Trampa twin motor setup with VESC contollers, and i have no voltage sag. I have 6364 motor’s, and i am heavy as hell, and all working fine.

Anyway, you have your batteries, connected to the BMS. Pluses: BMS protects the ESC from too much current in case something go wrong, or motor short. You dont have spark, when you connect esc to battery You have charging port on the battery case, so you dont have to open the box all the time. You just connect XLR plug to the port on your box, and wait for the battery to auto charge. It’s the easy mode system, most commercial boards use these BMS prottects and balance each cell, from overcharge, or too much discharge.

I think 120 A BMS is enough for the ESC, but i am not sure, since i use 2x VESC

BMS - an example from Aliexpress

Charger - i can’t access the site from where i am, so not sure if the link is correct, anyway you need 8S 33,6 V BMS charger, 4-5 Amps.

You can look at my build thread, to see how i did my trampa boards, with BMS/LiPo batteries.

I want to add, that although i am heavy(120 kg), and i use pneumatics, My board have a range of about 18-20 km, with this 16 Ah, 378 Wh battery.

Ofc, that’s my opinion. Some will say, that if you go BMS, it’s best to use Li-Ion 16850 cells, like LG HG2, but that’s more expensive.

I suggest to get some information’s on this forum, mainy about batteries, cos rest is fairly easy :smile:

Good luck!

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Hey Tomash, A big thanks for the big help! Currently i’m gathering all the components for my first build. I’m sure i can find all the answers to my questions on this forum.

I think that bms is worth putting on my to-buy list as it would be easier to charge the batteries.

Thanks a lot!

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Hey @Tomash i’ve been thinking about your recommendation of the 2x Multistar High Capacity 16000mAh 4S 10C. I want to use these instead of my earlier Idea of using 4xZIPPY Compact 6200mAh 4s 40c. But the first question that pops into my mind is: 10c x 16ah = 160amp if u put these on max6 160a. Isn’t this a little too close of frying the ESC’s or is this still safe?

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Nope it’s not too close, because not matter what max Amp, battery can output, esc or vesc, won’t take more than it needs. If the esc is rated for 160 Amp, it usually means, that it can output that much current as it’s maximum value, or continues current for a very short amount of time. But it’ probably never do that, since motors are rated lower. Usually esc or vesc, take maybe 5-6 amps continues, and when it’s needed, usually at start or when go uphill, it take more, i don’t really know, but probably no more than 30 amps for vesc, and maybe more when you use esc. i don’t really know how much in case of ESC, cos i didnt ever used one. Anyway, then is when BMS comes in handy. If you have your discharge gated by bms (your power to the esc goes though BMS), the BMS limit your battery to it’s rating. Than mean if you have 120 A discharge rated BMS, it mean, it wont allow more current to flow to the esc, and can prevent the frying of esc or motor in case esc brake, or motor short’s out for whatever reasons.

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Probably best to do as Nowind suggests with the batteries. He probably has more experience with these things than anyone else on the forums. Most likely to end up with a gutless little vagina board with that low of a c rating.

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If this is your first time using the XT fittings, I would suggest going with the genuine yellow ones, although not a as pretty (unless you paint them) on a eMTB they are easier to solder with and come with caps for the solder points.

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Hehe, watch this video. I a almost sure it’s Nowind creation. Does he had BMS, i doubt that. But for sure he had Roxxy ESC. :smile:

But for sure, standstill gravel burnout’s and ESC fire are spectacular.

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@Tomash

Roxxys work great. Just need capbanks. Video above is without. Brakes are a little touchy. Didn’t seem nearly as bad with a gt2b compared to Quanum.

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:joy:

I’ve made my suggestion, but: you can only lead a horse to…

yeah that’s Jenso

Stefan there are different ways of looking at this but I think the 2300 likes Nowind has compared to the 28 Tomash has likely speaks volumes in this instance…

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I have a trampa with 2 ezrun 6 aswell. Powered with 4x 4s 6200mah 40C Zippy Compact. This guys deliver the power without much sag. Don´t cheap out on poor low C Lipos - take the big guys and you won´t have any problems when you encouter your first pothole in the woods :wink: If you only run on streets without hills, you might be ok with some multistars, but trust me, the zippys are an other league :wink:

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@TarzanHBK thanks, i have considered the cheap ones but i’m staying with the 4 zippycompact. Without the extra hassle of a bms(for now). I can allways put a bms inside later on…

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good decision! Look for @lowGuido video about a simple charging harness, to charge all lipos at once via balancer cables

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Do you mean this video or another from him?

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Ok, Just watched the video(@work, lol) and think i understand his method of charging. But how does this work with 4x zippycompact (2 in series, 2 pairs in parallel)? How does the balance cables need to be connected? Can somebody draw a diagram of this? This is the drawning i made this morning of the batteries…

1505140448202-761479789.jpg3328×1872 1.22 MB

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@Stefanj look at those two threads, maybe it wil help you:

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Perhaps I misunderstood the question (jst kinda buzzed through the comments), but I use this for charging multiple 3s packs at the same time. Works well.

IMG_0628.JPG3024×4032 1.96 MB

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Thanks for the help, probably going to charge them out of the board the first several times. @benjammin , whats the name of that card? I Will search it and buy it.

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JST 2s-3s from ProgressiveRC. Dk about using these tiny little jst connectors for your main power though. I use these for my headlights and whatnot.

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So i’m going to need a jst 4s parallel charging board? Like this one?

I think you misunderstood me, i’m not going to use the jst for main power. I will use it the first several times to charge the batteries outside the board untill i make the “in-board charging system”…

If that charging board is the right one, what charger do you propose to use for charging the 4 batteries (zippycompact 6200mah 4s) at once?