First battery build...did I just order the wrong BMS?

[Terrapin]

Hey all, thanks for the help so far.

I decided tonight to pull the plug and build my first LPO LFP 12v. I am following Will's lead and just ordered a smart BMS based on one of his videos. I did not look close enough and I think I was supposed to order a "4S". does this indicate the number of 3.X volt cells I am putting in series to make the +/-12v battery? My invoice was Emailed showing a "3S" designation.

This was the description of the listing of the item on batteryhookup.com:

Li-ion/Lifepo4 3s-20s 100a BMS W/ LOW TEMP CUTOFF​

If there's a mistake I need to correct please let me know....

Thanks

 

[Dzl]

Can you link to the actual BMS you bought? The title you quoted says 3s to 20s does this indicate multiple models or one model that can work with a wide range of options. Some BMSes work with a broad range of pack sizes, some do not.

If you ordered a 3S BMS this is not for LiFePO4 (also side note: not sure what LPO refers to (maybe just a term I don't know), but the most commonly used/understood abbreviations for lithium iron phosphate on this forum are LiFePO4 or LFP)

 

[Terrapin]

Can you link to the actual BMS you bought? The title you quoted says 3s to 20s does this indicate multiple models or one model that can work with a wide range of options. Some BMSes work with a broad range of pack sizes, some do not.

If you ordered a 3S BMS this is not for LiFePO4 (also side note: not sure what LPO refers to (maybe just a term I don't know), but the most commonly used/understood abbreviations for lithium iron phosphate on this forum are LiFePO4 or LFP)

Hi thanks,
Here is the order page:

Li-ion/Lifepo4 3s-20s 100a BMS W/ LOW TEMP CUTOFF

--------------------Here are 100a BMS units. We carry 3s-20s and both Lithium Ion (Li-Ion) and Lithium Iron Phosphate (Lifepo4). The lithium ion version also works with Lithium Polymer (Li-Po) since they both have the same parameters. (WIRING DIAGRAM BELOW!) Some of the BMSs arrived without the...

batteryhookup.com

here is a pasted copy of the order confirmation.
Shopping cart

Product image	Description	Quantity	Price
1	Li-ion/Lifepo4 3s-20s 100a BMS W/ LOW TEMP CUTOFF4s LifePo4	1	$74.99
1	Bluetooth Module for Battery Hookup BMS	1	$7.99

Scroll for more items
Cost summary

Description	Price
Subtotal	$82.98
Discount DIY	- $4.14$4.14 off total order price
Shipping	$8.00
Total	USD $86.84

 

[Terrapin]

LFO was a dyslexic moment

 

[Dzl]

Maybe you got the right one, its a confusing order screen, if your look at the end of the first line item it mentions (4S LiFePO4):


This appears to be the default selection in the dropdown list on the product page so if you didn't deliberately select a model, this is probably the model you got.

 

[chops728]

Log in to your account and look at your order --it will tell you exactly what you purchased
should look like this for Lifepo4

Li-ion/Lifepo4 3s-20s 100a BMS W/ LOW TEMP CUTOFF - 4s LifePo4
Fulfilled January 4, 2021
Track shipment

 

[grizzzman]

No worries. I put the correct one in the cart. It matches your order.

 

[Terrapin]

Log in to your account and look at your order --it will tell you exactly what you purchased
should look like this for Lifepo4

Li-ion/Lifepo4 3s-20s 100a BMS W/ LOW TEMP CUTOFF - 4s LifePo4
Fulfilled January 4, 2021
Track shipment

I could be right then...It was the default. I thought the "3S" designation could be for different build using only 3 cells. It reminded me how i heard configurations of batteries are wired with a quantity and a designation of"P" for parallel, or "S" for series. So seeing 3S I was left wondering if that BMS was for a build for 9volts from 3.2 cells or 23v from four...or whatever.

 

[Terrapin]

Maybe you got the right one, its a confusing order screen, if your look at the end of the first line item it mentions (4S LiFePO4):
View attachment 34047

This appears to be the default selection in the dropdown list on the product page so if you didn't deliberately select a model, this is probably the model you got.

Thx again. I hope they call b4 shipping. I ended up sending an Email to them to plz call to confirm what's up and what my confusion is. I do wonder what those designations are if not how many cells it's intended to balance and manage it seems strange that there are no other designations regarding usage, volts, amps. dimensional sizes....nada..... Anyways I will add a resolution post , or maybe a better titled one to steer questions to it better. It's the seller linked in the blueprints here so I can't be the only one this will hit.

 

[Dzl]

I could be right then...It was the default. I thought the "3S" designation could be for different build using only 3 cells. It reminded me how i heard configurations of batteries are wired with a quantity and a designation of"P" for parallel, or "S" for series. So seeing 3S I was left wondering if that BMS was for a build for 9volts from 3.2 cells or 23v from four...or whatever.

Yes, you are right about the meaning of P and S, just misreading/misinterpreting the title (I think). Looks like you got the 4s version (4 x 3.2 = 12.8)


The 3S-20S is just referencing that they have a range of models from 3S to 20S

 

[grizzzman]

Just plain stupid if you ask me.

 

[Terrapin]

Yes, you are right about the meaning of P and S, just misreading/misinterpreting the title (I think). Looks like you got the 4s version (4 x 3.2 = 12.8)
View attachment 34063

The 3S-20S is just referencing that they have a range of models from 3S to 20S

Ahha! and the solar powered lighbulb above my head turns on. Now I see it designated after "cutoff". Cool beans. Thanks for walking me through it Dzi. Safe travels and bright sunshine on your roof.

 

[Terrapin]

Just plain stupid if you ask me.

Confused the begeebers out of me... It's not hard. I am great with physical stuff but when you can't see electricity I tend to figure I got it wrong.