Improving Daly 250A BMS

[walter-]

I ran a load test yesterday on a 250A Daly smart BMS without fan.
I depleted a 4S 272Ah bank at about 2kw.

After 30 minutes or so; the BMS cables started to heat up.
Not extreme but they reached about 45°C. Measured with an infrared thermometer; but it felt hotter.
The 2AGW Cables for 30cm, on 180A would loose about 0.1 volt; which is about 20W Produced heat (each).

Would it make sense to add a second extra wire to the BMS terminals? And how to best connect it?

Note: battery would be used in an RV with biggest consumer a 1800W microwave/oven combination. So it will occasionally run the higher loads for 30 minutes (but not constant the highest load).

Walter

 

[InMyImage]

I’m assuming each of the packs in 4s configuration at also 4p or 12v. If you were only discharge the bank at 2kw that would be:

2kw = 2000w
2000w / 12v = 166.67 amps
166.67 amps / 4 packs = 41.67 amps per pack.

If you have 250amp Daly BMS on each pack that should be more than capable of feeding the 41.67 amps for each pack.

Will recently ran 270+ amps through one recently without any problems even though it was above the rated capacity of the BMS.

 

[walter-]

To be clear; my setup is just 12V 4S.

If you say no issue; what temperatures did you see?

Walter

 

[InMyImage]

To be clear; my setup is just 12V 4S.

That’s what I assumed.

what temperatures did you see?

I don’t remember the temps, but the wires and busbars were not “hot” to the touch. The BMS fan kicked on occaisionally. I recommend watching the video. I don’t think he starts with the BMS until about a third of the way into the video. I aslo believe he’s using the “dumb” version of the BMS. He has noted before that he doesn’t normally use the “smart” versions because he has heard of them having issues (at least some of that opinion was sourced from this forum)