DALY BMS input current question

[NarrowboatLiving]

Hi, I purchased the 300A 4s.

Here are the specs for the different BMSs in the range.

If I am understanding it correctly it is 300A out + 150A in.

My charger is 200A connected to a 200A alternator

I can see from this chart that it is 300A out with discharge over protect of 450A

And 150A charge with 450A charge protect.

My question to anyone with experience with DALY BMS is can I charge my battery at 200A with this BMS? My plan was to charge at 0.5C (150A) but on occasion I may charge up to the full 200A 0.67C, cells are rated for 1C.

Thanks

 

[Reed Cole]

Do you know for sure if you can get 200A out of your charger? Usually there are conversion losses, you would need to feed the charger more than 200A for it to output 200A.

I don't have experience with Daly BMS but in general it's a bad idea to exceed the current rating of your components.

You would expect the BMS to shutoff if the rated current is exceeded, if it only shuts off at 450A it's not protecting your batteries, what would be the point? Maybe "overcurrent protection value" is referring to a surge rating?

A BMS that controls external relays might be a better choice for a 12v system with high current demands.

 

[NarrowboatLiving]

My charger with 150A alternator was charging at 140A max. with 200A alternator i would expect 185A through the BMS. I can set the current over protect to what ever i like. Say 190A for example to protect the battery. 450A was the default setting

charging at 140A for over 1 hour all the terminals and the BMS were cold, no warmth anywhere except for the alternator terminal

 

[Reed Cole]

Sounds like you have a good handle on things. It's weird that with the Daly BMS the charge rating is always half of the charge rating even though they are common port, seems like with most other BMS of that type charge and discharge are rated the same.