Daly BMS
- Thread starter Dyotat100
- Start date
Frank in Thailand
making mistakes so you don't have to...
No it will not.
Sorry to say but the higher Amperage Daly BMS are failing a lot.
They seem to have no stock, each high Ampere unit is build after ordering....
At high current it's best to have the on/off switching outside the BMS.
Mosfets are great under 100A.
Higher better to use magnetic contractors.
Some complain about their power usage, 7 watts is OK for my 400A (cheap $50 China) contactor.
Good one (less power usage) is about 150-200 USD for the contractor only..
And you need 2....
One to stop charging and one to stop discharge.
You can place the stop charging contactor at the MPPT /solar that determines the current.(most mppt Solar controllers have -50A, PWM can be higher)
Higher voltage is lower ampere..
Sometimes you can simply turn off inverter, as stop discharge.
That is a low current (cheap) contactor/relay, or directly by the BMS
If you need to cut the main connection between battery and Inverter / MPPT...
You need a contactor that is capable of switching at that load.
Chargery is good China solution
Electrodamus is Canadian (max 24v)
DIYBMS is open source, and damn good product (that does require soldering and some programming/flashing. Adruino based)
All use contactors relays to connect/disconnect if needed.
Those contactors are your limit for current.
(Or switch smart, turn off the inverter
. )Ok thanks for the info.
What would you use for bms? No solar involved just a inverter/charger. I can go 2000w inverter but was planning 3000w. All new to this so I'm still learning. I don't mind buying the expensive contractors. Just need to know how to setup
What would you use for bms? No solar involved just a inverter/charger. I can go 2000w inverter but was planning 3000w. All new to this so I'm still learning. I don't mind buying the expensive contractors. Just need to know how to setup
Frank in Thailand
making mistakes so you don't have to...
Inverter / charger highly depending if it is combined unit, or 2 different.
Chargery and DIYBMS both use simple NO / NC relays to trigger something. (Normally Open / Normally Closed)
Those relays are not to be used to switch high current, but to switch something on or off.
If you have separate inverter who have a power switch, you simply can trigger that power switch.
(power switch is connection with 2 wires, usually the negative lead cut and place switch in between)
Same goes for the charger
If you can't turn them on / off, you need to cut the line towards the battery array for charging and from the array for discharge.
Usually the charge is lower current.
If it charges from AC, you can use AC contactor.
Discharge highest current
The same relay that is used to turn inverter on or off, is the same that turns contactor on or off, close the electric circuit, and the magnet that makes the +300A contact receive power (24v)
You get the 24v from the cells, it's usually between 18 and 36 volt margin.
No worries there for exact voltage.
And it's just that, electromagnet that push a core to make contact.
Plus.. why it's expensive, it have arc catcher.
With 300A 24v you can pull a nice arc, melting just about anything
The special setup prevent this.
There is difference between DC and DC breakers.
The cheap ones..
5 bucks from China..
Really nice for lights in your car or 12/24 v setup.
Don't switch 300A with them..
You be sorry.
I have used a while.. and all seems fine.. untill it doesn't.
No arc catcher..
And after a few switches there is constant arc, making the housing all crispy and smoking..
I didn't wait if it catch fire, just pulled the cables strong, and the melted housing released the contact...
Scarry moment
Huge difference between real breakers who have arc catcher and cheap ones who just connect or disconnect DC..
Side step
I will advise to use breakers, if only for safety reasons during maintenance. No sparks!
Chargery and DIYBMS both use simple NO / NC relays to trigger something. (Normally Open / Normally Closed)
Those relays are not to be used to switch high current, but to switch something on or off.
If you have separate inverter who have a power switch, you simply can trigger that power switch.
(power switch is connection with 2 wires, usually the negative lead cut and place switch in between)
Same goes for the charger
If you can't turn them on / off, you need to cut the line towards the battery array for charging and from the array for discharge.
Usually the charge is lower current.
If it charges from AC, you can use AC contactor.
Discharge highest current
The same relay that is used to turn inverter on or off, is the same that turns contactor on or off, close the electric circuit, and the magnet that makes the +300A contact receive power (24v)
You get the 24v from the cells, it's usually between 18 and 36 volt margin.
No worries there for exact voltage.
And it's just that, electromagnet that push a core to make contact.
Plus.. why it's expensive, it have arc catcher.
With 300A 24v you can pull a nice arc, melting just about anything
The special setup prevent this.
There is difference between DC and DC breakers.
The cheap ones..
5 bucks from China..
Really nice for lights in your car or 12/24 v setup.
Don't switch 300A with them..
You be sorry.
I have used a while.. and all seems fine.. untill it doesn't.
No arc catcher..
And after a few switches there is constant arc, making the housing all crispy and smoking..
I didn't wait if it catch fire, just pulled the cables strong, and the melted housing released the contact...
Scarry moment
Huge difference between real breakers who have arc catcher and cheap ones who just connect or disconnect DC..
Side step
I will advise to use breakers, if only for safety reasons during maintenance. No sparks!
