Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Paralleling tool batteries?
#1
Could you mind paralleling tool batteries? Would that work or could there be a problem with their internal BMS? Could get some new very cheap ones containing 14 Sony VTC5 cells configured 14S1P. Sounds so interesting to me  Angel
My Powerwall Build Thread

Maniac_Powerwall: 1x 14S100P 18650 LiIo, 6x 345W LG panels, MPP Solar PIP5048GK, Batrium Watchmon4 BMS
Reply
#2
There'd be no issue paralleling them. They would work just as if they weren't going through the BMS. This would be the same as multiple packs with their own bms. Would be a lot like daromer and others who have multiple strings with several Batrium units on them. You are just paralleling the absolute ends of the individual strings.

The only issue would be if 1 or more packs go offline due to over-discharge. Then the other packs would get hit with higher amp load. However, all things considered, this happens even with standard builds with multiple strings connected.
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#3
Ok. I think I get a bunch of these.
My Powerwall Build Thread

Maniac_Powerwall: 1x 14S100P 18650 LiIo, 6x 345W LG panels, MPP Solar PIP5048GK, Batrium Watchmon4 BMS
Reply
#4
Would be an interesting setup. Just use old chargers and replace the charging boards with at least some leds to show if it's connected or not. To make them a little more "smart" could add some coulomb counters (shunts) in each one to see which packs are getting weak.
If going that route, would be easy to add the shunt, use an attiny chip to do the readings and then connect all them together using i2c (similar to the way batrium longmons are connected)
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#5
I think I will add some wires with XT connectors because it is cheaper than buying a lot of connectors or chargers. Just solder them to the existing BMS or connector pins. I ordered 15 now. Wich is 14s15p. Not very much but somehow cool. Maybe I'll do a portable power supply. Not sure. Wich kind of shunts would you use and what kind of hardware (Maybe some links?) I am not very firm in these kind of stuff  Sad 

They are some McChulloch 58V batteries like this:

My Powerwall Build Thread

Maniac_Powerwall: 1x 14S100P 18650 LiIo, 6x 345W LG panels, MPP Solar PIP5048GK, Batrium Watchmon4 BMS
Reply
#6
Another thing:

Will or can the voltages be different on the different strings? Mustn't they not be equal always? For sure one cell in one string could be low causing the BMS to open the circuit and lead to a higher drain on the other strings.

Wouldn't we configure the strings quite equal with let's say 2 strings of 14S100P with one Longmon each of the 28 packs and only 1 shunt and 1 trip breaker?

Or did you just write the same in your first post? What would your idea with different shunts give us? Would you use it to indicate health or prevent the packs going offline?
My Powerwall Build Thread

Maniac_Powerwall: 1x 14S100P 18650 LiIo, 6x 345W LG panels, MPP Solar PIP5048GK, Batrium Watchmon4 BMS
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)