Dan,

I've got the JK inverter BMS going happily on a 16S 48V pack of 304Ah cells. It should handle your 280a which is only 1C - but not sure the size of your cells though. I must admit that I haven't tried it on a motor for real. I've had the bms running for 6-9 months without worry so far. Offgridgarage YT has done various tests on it.?

?

R

On Sun, 1 June 2025, 12:03?pm Dan Pfeiffer via , <dan=[email protected]> wrote:

I may need a new BMS for my 16S 48V LiFePo4 battery that I built in 2021.? Looking for recommendations.? I am running a 12kW motor and max current is on the order of 280 amps.?

I have the Thunderstruck BMS (Dilthium Design) and it seems to have failed.? I can't get it to see more than 10 cells and voltage readings are incorrect compared to my meter (Fluke) directly on the batteries or on the harness end plug using the breakout board supplied with the BMS for testing.? My connections on the harness all seem fine.? I have tried to reset the BMS from the computer using the USB interface.? No luck.? I suspect there is something wrong with the BMS itself.?

This Thunderstruck BMS does balancing and charge controlling but does not control input and output for the battery.? That's fine but it means I can only use a charger that the BMS can tell to shut down.? So there is some advantage to a BMS with input output control?? It can disconnect charging without needing to have communications with the charger.? That seems useful? ?

So I am looking to see what others have done in this sort of installation.?

Thanks, Dan Pfeiffer
My Electric Drive Sailboat

On Jun 1, 2025, at 13:37, Paul J. Thompson via groups.io <bathroomdirectit@...> wrote:

?

I have 48V battery made up from the 280ah EVE cells and a REC 2Q BMS, it has external contractors (Bluesea 7700 bi-stable rated for 500A at up to 70V). You can pull as much power as the battery can supply for as long as it can. The Bluesea contractors also have a manual override should the bms not be cooperating for some reason.?

It's not the? cheapest way to go but I suspect one of the most reliable.? The REC can also seamlessly integrate into a Victron system if you have one.

--
Regards,

Paul J. Thompson
IT Manager - Bathroom Direct
(W)09 913 3110 (Mob)021 275 5001 (txt only please)

On Mon, 2 Jun 2025, 02:53 Dan Pfeiffer via , <dan=[email protected]> wrote:

I have a a 16S 48V battery with 280AH cells (Eve).?? They do have a 1C rating.? The highest load I have seen on testing is about 230A (making 6.8 knots). Typical operation is at 4 to 5.5 knots and less than 100 amps.? Occasionally I may have the need to punch through a wavy entrance for 3 to 5 minutes?? It's those situations that I might want max power.? That would be a bad time for the BMS to say "NO" and shut down output.? I generally like to size components with some headroom.?? I was thinking 300amps capacity was about where I wanted to be.? Not sure about that.

Info on my battery build here:


Thanks, Dan Pfeiffer

On 2025-06-01 2:28 am, Robert McArthur via wrote:

Dan,

I've got the JK inverter BMS going happily on a 16S 48V pack of 304Ah cells. It should handle your 280a which is only 1C - but not sure the size of your cells though. I must admit that I haven't tried it on a motor for real. I've had the bms running for 6-9 months without worry so far. Offgridgarage YT has done various tests on it.?

?

R

On Sun, 1 June 2025, 12:03?pm Dan Pfeiffer via , <dan=[email protected]> wrote:

I may need a new BMS for my 16S 48V LiFePo4 battery that I built in 2021.? Looking for recommendations.? I am running a 12kW motor and max current is on the order of 280 amps.?

I have the Thunderstruck BMS (Dilthium Design) and it seems to have failed.? I can't get it to see more than 10 cells and voltage readings are incorrect compared to my meter (Fluke) directly on the batteries or on the harness end plug using the breakout board supplied with the BMS for testing.? My connections on the harness all seem fine.? I have tried to reset the BMS from the computer using the USB interface.? No luck.? I suspect there is something wrong with the BMS itself.?

This Thunderstruck BMS does balancing and charge controlling but does not control input and output for the battery.? That's fine but it means I can only use a charger that the BMS can tell to shut down.? So there is some advantage to a BMS with input output control?? It can disconnect charging without needing to have communications with the charger.? That seems useful? ?

So I am looking to see what others have done in this sort of installation.?

Thanks, Dan Pfeiffer
My Electric Drive Sailboat