Help with MCM5 340wh 84v battery upgrade

[pressbyron]

Hey!

I bought a mcm5 v2 340wh wheel as a starter wheel. I quickly outgrew it and want more range. Accodring to wheellog my wheel has 84v when fully charged.

Is there any plug and play solution that I can put in the side compartment of the wheel? Know there is a empty space there from other threads/videos. Would something like this work out of the box with a connector splitter? https://www.aliexpress.com/item/32862150354.html

I'm not sure if one can mix 64 and 84 volt? I have not found any 84 volt battery? As far as I understand this one has a built in BMS so connecting it in parallell with another battery would be safe as the bms prevents the batteries charging eachother?

Is this a stupid endeavor since I know very little about batteries?

[RagingGrandpa]

I think MCM5 340wh is 67V.
You can confirm it by counting the number of pins in the charging connector: 67V is 3-pin, 84V is 4-pin, 100V is 5-pin.

WheelLog needs to be configured for the EUC voltage in its settings menu- it cannot determine it automatically, so that is why yours is reporting something near 84.

8 minutes ago, pressbyron said:

Is there any plug and play solution that I can put in the side compartment of the wheel?

Only if there were a Gotway pack from a larger-battery 67V MCM5. I'm not aware of one

8 minutes ago, pressbyron said:

can mix 64 and 84 volt?

No.

8 minutes ago, pressbyron said:

this one has a built in BMS

correct...

8 minutes ago, pressbyron said:

so connecting it in parallell with another battery would be safe as the bms prevents the batteries charging eachother?

No.

Even if you charge your new pack through the 'output' of the Gotway pack, it still needs its own protection from cell overvoltage- so the new pack certainly needs a BMS attached to it.

Hope this helps

Edited May 5, 2021 by RagingGrandpa

[Scottie888]

Considering the (low) cost of a new 84v 800wh MCM5v2, it almost doesn't make sense to try to upgrade the battery of your 340wh. Its likely someone will buy it as a learner/beginner wheel so if it were me, I'd sell it & order the 800wh. I don't know if yours is the V2 but if not, the V2 is a big upgrade over the V1 as well & its worth the upgrade for that alone.

That's what I'd do if it were me. If I knew then what I know now, I'd have done most things differently but the one thing I would still do is to own the MCM5v2. Its an awesome wheel & I love it to death. Its my fav do it all 'slow' (if one can call 30-40kph a snail). As expected, ts not great for bumpy whoops, doesn't have much >40kms & I wouldn't take it much past 40kph but its good to great in everything else. 

Its a keeper & definitely worth it to get the 800wh V2 version. To me at least.

Edit:O I remember reading someone did do a diy upgrade of theirs to >1k wh. Do a search on the MCM5 & I'm you'll find it. PM him & if you ask nicely, its likely he'll point you in the right direction if you really wanna get your hands dirty

Edited May 5, 2021 by Scottie888

[Camenbert]

On 5/5/2021 at 8:21 PM, Scottie888 said:

Considering the (low) cost of a new 84v 800wh MCM5v2, it almost doesn't make sense to try to upgrade the battery of your 340wh.

I disagree, I bought my 280Wh MCM5 v2 only $490 including EU taxes (easy half the price of a 800Wh),
and the best cells on nkon.nl are cheap. The 67V is just barely slower.

So the true is exactly the opposite, it's way cheaper to buy the entry-level and upgrade the battery, if indeed you are a bit DIY.
If you consider the sag of lithium batteries increase after 3yo or so, it's not bad to upgrade the battery anyway.

There is a subject on this forum about such MCM5 upgrade, click on the links of Oneleg to see the space available :

Bottom line, you can add 32 cell on the side, with it's own bms, and preferably using the same cells as the main pack.
Or upgrade the whole battery, you can then reuse the gotway bms. Both case it require a very good execution.

 

On 5/5/2021 at 7:11 PM, pressbyron said:

Would something like this work out of the box with a connector splitter? https://www.aliexpress.com/item/32862150354.html

Using chinease-no name-cheap-from-aliexpress batteries is a receipt for disaster !

I wont want this one for a ebike, so on a single wheel moving at 37 Kmh

You'll have to find one 16S2P with good brand cell, a bms that support regen braking, somehow waterproof, there is no cheap battery for euc...

Edited May 18, 2021 by Camenbert

[yuweng]

Only today i see this thread  All above statements are very true  If you donno DIY or anyone close doing li-ion battery pack then it will be best to just sell off existing & get a new one as the labor costs & 18650/ 21700 are damn expensive nowadays !

Spoiler

 

You can get up to 1300WH with 18650 according to taobao store but not with 21700. i think they fit 60 cells on the top & 40 cells at the side.

On my DIY path, i choose what they claim is zero-cycle Tesla 18650. Try sourcing from your local recycled EV batteries. My 67v mcm5 170WH, self upgrade to 1Kwh with 84v controller & BMS total cost just a mere USD600+ 

Having said that, down the road i have a few failure from inexperience though i have some electronics experience but not on battery packs.

1. Nickel strip becomes loose contact/ strip off bcos of constant falling/ crashing@MTB trail. Lesson learned : Whole battery pack has to be securely tight. Install extra forms & make sure whole battery pack cannot move at all. Vibration is the No. 1 killer of battery packs on EUC !
2. Once out riding you will get caught on unexpected rain. Slowly but surely, sooner or later, one or few cells will fail bcos of water entry. Use silicone glue to seal off all possible water entry on the battery pack at the first place. Water is the No. 2 killer of battery packs on EUC ! Get a back pack cover to cover the top of the EUC to prevent water entry from the top when raining.

 

 

 

 

[pressbyron]

From the responses i think I will just buy another EUC
Thinking about the mcm5v2 800WH or the nikola+.

Buuut that will be next summer since my girlfriend thinks i'm wasting money 
Did not think I will outgrow this one so fast 

[Camenbert]

A professionally made 16S2P with genuine cells will add the missing Wh for less than delta price between a new mcm5v2 800Wh and your old one...

Edited May 18, 2021 by Camenbert

[redsnapper]

4 minutes ago, pressbyron said:

Did not think I will outgrow this one so fast 

I think you will find that you will be forever looking at other wheels no matter which wheel you have! It is a madness for which there are few cures - poverty is one but with unpleasant side-effects. Building and/or DIY upgrading li-on batteries is not for the faint of heart (as it presents not insignificant risks of harm for the inexperienced)... Upgrade your machine - rinse - repeat! 

[tvu213]

I did have a thread asking about upgrading the battery for my 84V 460Wh Gotway. I built another battery pack with a bms on it then parallelly connected the old and the new one (both must be fully charged and at the same voltage for connecting). I am testing the range of the wheel after connecting the two battery packs. The first impression is that the battery is really "bigger" in terms of range. The thing is that I have to modify the shell so that I can keep the added battery pack inside.

[tvu213]

On 6/14/2021 at 9:45 PM, tvu213 said:

I did have a thread asking about upgrading the battery for my 84V 460Wh Gotway. I built another battery pack with a bms on it then parallelly connected the old and the new one (both must be fully charged and at the same voltage for connecting). I am testing the range of the wheel after connecting the two battery packs. The first impression is that the battery is really "bigger" in terms of range. The thing is that I have to modify the shell so that I can keep the added battery pack inside.