both BMS and Balancing Charger?

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Dec 9, 2022
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Hello,
I'm new in the battery world. I've found online a 12S (44.4v) battery with 28000mAh and 25C which does not have an integrated BMS. Talking with the seller, he said that I would need a smart charger. For me the space it's not crucial but the price is as I'm on a tight budget.

The battery costs 378USD but the smart charger alone is around 300USD which is quite a lot. A similar battery with integrated BMS is around 500USD.
The battery will be connected to an ESC which will drive a 44.4V - 100A nominal current motor electric motor

I need some help regarding the following questions:

- from what I've understood, I either need a BMS or a Balance Charger, and not both?
- Would it be better to buy a battery with a BMS as it also controls the battery while connected to the load?
- Is the BMS not necessary while using the battery so I'm better off purchasing a smart charger?
- Doing the math it would be cheaper to buy a battery integrated BMS for 500 usd and buy a "dumb" charger for 70USD, as the dumb charger also weights a lot less.
- Would you suggest buying the 378USD 12S(44.4V) - 28000mAh battery and than buying a BMS to go with it? if yes what are the parameters I need to look out for?
- Why do some people, when referring to 12S, say that the voltage is 48V and not 44.4?

Thanks,
 
I recommend posting links to the specific items you are considering. This will help us help you understand what exactly the items are, and how they can be used / charged / etc.

Posting your system specs that it will be used on, and conditions the system will be used under (speed, riding style, terrain, weight, hills, wind/etc., etc), and the range required at the speed you need to go, will also help us help you ensure the battery can actually provide the power the system will need, and the capacity to give you the rainge required.
 
This is how most of the lithium batteries are used in the RC toys. The ESC has only a undervoltage protection for the whole batterie.
There is no over current or single cell under voltage protection.

I would also not recomnend using batteries without bms for a daily driver.
 
dominik h said:
This is how most of the lithium batteries are used in the RC toys. The ESC has only a undervoltage protection for the whole batterie.
There is no over current or single cell under voltage protection.

I would also not recomnend using batteries without bms for a daily driver.

??? - Sure there is. Every single cell lithium device I have ever taken apart has a BMS and every single cell BMS I have ever tested has low voltage and over voltage protection. I have a small box of them. Stop over at Aliexpress and see the dozens of different single cell BMSs. They sell for around 50 cents each so they are cheap enough to put in everything.
 
Yes, that might be, but in the RC world, you have only the balance wires coming out of the battery and you have to use a charger wich does the balancing during charging.
 

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dominik h said:
Yes, that might be, but in the RC world, you have only the balance wires coming out of the battery and you have to use a charger wich does the balancing during charging.

In the RC world are you putting several hundred to several thousand watt hours of lithium between your legs? No.

Run a BMS.
 
dominik h said:
...
I would also not recomnend using batteries without bms for a daily driver.
 
dominik h said:
Yes, that might be, but in the RC world, you have only the balance wires coming out of the battery and you have to use a charger wich does the balancing during charging.

Agreed, but the RC world is a small, specialized and very different application that you don't see used any where else. It uses very specific batteries with specific chargers where every ounce matters. (I have 9 RC airplanes....)
 
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