Thursday, April 29, 2021

Re: [electricboats] Draft Schematic-Please give input

I like your diagram.  I have a couple questions.   

You show the shunt for the monitor between the BMS and the neg lead.  That makes sense but it can't be done that way on a battery like a Battleborn with its internal BMS.  So I wonder which way is better?  Should the BMS be considered a part of the battery?   So the battery is in effect a box with all the BMS components inside. 

You show a separate negative lead to the BMS from the charger?  Does your BMS have a seperate neg input fro the charger?

What BMS are you planning this with?

Thanks, Dan Pfeiffer

 

On 2021-04-29 10:06 am, oreillygb@hotmail.com wrote:

First Draft of Schematic. Using Lishen 202Ah. I decided to go with the BMS only actively controlling the charge side of the circuit and opted for passive monitoring on the load side. Using a victron 712 for monitoring and hopefully can connect it to a relay to shut off charge circuit at predetermined voltage. Guys please tell me what I have missed.

Couple of points.

1) Passive Load monitoring. I have decided to go this route as i understand that the load BMS can turn off for 2 reasons, obviously first is if whole bank drops to a lower than 20%SOC and secondly if single cells fail. From my perspective if I have a single cell failure I would rather still be able to use the other 15 cells than have no power. If I let my bank drop to below SOC of 20% that's on me.
2) Want to keep house bank separate for now, mainly as if I have to shut off my 48v bank for low SOC I don't want to have to worry about all my electronics being offline.
3) I want a separate relay to shut off charge current so that I can set this manually. When I come back from a sail i want to be able to top bank up to about a 70% SOC for storage. Then on the day I want to sail I can top it off o 90%

No comments:

Post a Comment