BMS question - multiple small BMSs like a single big BMS

[Vanarian]

Guys a question occured to me :

How do you mount your BMS and what models do you use?

I've seen a lot of positive on bestechpower so this might be a good start. But as I've seen that they have many models, I've also noticed that the bigger voltage and amperage one'd want, the bigger their units are.

For bikes and/or longboard this is not an issue since you'd expect a flat wide unit to accomodate the deck easily. But since I work on inlines, I can't use a wide unit. I'd need something narrow or a bit adaptable.

Hence my question : Can you use multiple little BMS to manage your battery pack like a single bigger one would?

Batteries are seried and paralleled, does this stop from using multiple little ones? For example 2x 5S BMS instead of 1x 10S or 4x 3S BMS instead of 1x 12S BMS.

This is one of the basics but I lack this basic

 

[torqueboards]

I don't think much use BMS on this side of the forums. I like the thin long BMS which you can put on the side of battery packs. A thing more people would enjoy the charging aspect of the BMS but to actually limit the amp output to less sucks.

Are there any BMS in which let's say max amp output of 60A Cont that it will restrict the battery from pulling more than 60A Cont? Ex. You won't be going like 20mph and pull more then 60A Cont and it drops and suddenly your speed haults.

 

[agraham]

For Justin_le's project he used three packs in series, each with a built in bms so it seems the answer is yes you can do that.
http://endless-sphere.com/forums/viewtopic.php?f=35&t=49557&start=75#p904577
I'm not sure if they are disconnected and charged individually or if they can be charged while still connected together.

 

[agraham]

I like the thin long BMS which you can put on the side of battery packs.

Where do you get these?

A thing more people would enjoy the charging aspect of the BMS but to actually limit the amp output to less sucks.

The limiting is good as long as the limit is correct. Voltage sag is bad for your batteries and too much current is bad for your windings and esc. That said it would make more sense for your esc to do the limiting.

 

[Vanarian]

Ok thank you for the infos

Well it's true that balancing cells when charging and setting safe levels of maximum discharge should suffice but I feel that a BMS helps preventing batteries from unbalancing and possibly cause over discharge while commuting, which can help ensure a longer cycle for the battery pack ?

Please let me know what you think.