Additional Battery Pack RS-HS

[a.patrick]

Hi everyone!

I am riding a RS HS v2 and i am thinking about building an additional battery pack since the original 24s4p configuration with the LG M50LT should at max deliver around 40A. I am not a very fast or aggressive rider but in EUC world i very often get readings higher than 40A when accellerating.

But it is also when going down a hill, i get readings in the app telling me the battery will be charged up to around 20A. And that isn't good for those packs too.

I am aware that those readings in EUC World may not be that accurate, so i will order a volt and ampere meter, build a plug so i can get the readings from the battery-mainboard connector directly to get confirmation.

So i am playing with the thought of building another 24s2p Pack with Samsung 50S (if i get them somewhere), change those XT60s to XT90s and even change to bigger wires that are going into the mainboard. I am still looking for a good BMS. And i hope it fits in that shell somehow 😅.

So my goal is to have more range and safety. What are your thoughts on that? 

Does anyone here have any experiance in that kind of work?

 

Regards, Patrick

[Chriull]

1 hour ago, a.patrick said:

am riding a RS HS v2 and i am thinking about building an additional battery pack since the original 24s4p configuration with the LG M50LT should at max deliver around 40A.

They deliver a much higher max current - 40A is the maximum continous current they can deliver according to the datasheet.

1 hour ago, a.patrick said:

I am not a very fast or aggressive rider but in EUC world i very often get readings higher than 40A when accellerating.

This is phase (motor) current which is normally much higher than battery current.

Afaik EUC World also shows battery current for begode wheels, but thats an calculated/estimated value...

1 hour ago, a.patrick said:

I am still looking for a good BMS.

You need one that can be syncronized with the other bms, so in case of single cell overvoltage all bms stop charging.

1 hour ago, a.patrick said:

So my goal is to have more range and safety. What are your thoughts on that? 

For safety in regards to fire and/or malfunctions one should be very experienced and skilled with battery pack building.

In an EUC battery have to withstand very harsh conditions. 

[Chriull]

And a link to details of bms by gw wheels:

 

[alcatraz]

For more range you could try and look into making a big powerbank with a dc-dc converter and charge while you ride.

It won't be enough to ride on an empty internal battery but it will slow down the depletion.

As for safety, as Chriull said, if you're not riding in extreme conditions. Be it very high/low ambient temp, long fast climbing, regular wet riding, or perform insane accelerations/emergency braking....

Then you're fine with the amperage. Chriull also taught me about the difference in motor and pack amps. 

Still the fact is that we essentially ride around on cells commonly found in phone powerbanks which is a bit scary. High amp cells are going to be a nice upgrade one day.

Personally for peace of mind I'd install balance wires on the packs (or make the heatshrink removable, but taped up) so you can monitor the voltages every few monts. That way you can sleep without a worry.

If you're patient to perform an over-voltage charge cutoff test, then you can even leave the wheel unattended on the charger. (I would. I haven't done such a test yet. I'm going to.) 

[TantasStarke]

The RS19 already uses high capacity cells so your only option is to find more room internally to fit more cells. People have made additional packs for wheels like the EXN, where you add a 24S1P pack to the mix to give it an extra 450Wh.

Looking at a teardown there is a lot of extra space on the non-control board side, could definitely fit a 24S1P pack in there, maybe even squeeze in a 24S2P pack giving the wheel 2700wh and essentially making an EXN.

Here's a video on the 3150Wh EXN mod 

 

[RagingGrandpa]

On 4/11/2022 at 12:23 AM, alcatraz said:

For more range you could try and look into making a big powerbank with a dc-dc converter and charge while you ride.

^ the most practical option for an MSuper.
https://forum.electricunicycle.org/topic/19450-do-you-use-a-backpack-battery/

[alcatraz]

5 hours ago, RagingGrandpa said:

^ the most practical option for an MSuper.
https://forum.electricunicycle.org/topic/19450-do-you-use-a-backpack-battery/

Holy crap!