The usual recommendation is to connect a battery temp sensor to one or other terminal post (Victron to +, Balmar to -). This is fine for lead acid as the temperature of the lead post closely represents the internal plate temp.
However, whereas my Daly BMS inside my drop-in lithium casing registers 24°C via Bluetooth when my lithium 4 cell unit is charging at say 120A, the thermistor cable from the negative terminal back to the Balmar external alternator regulator shows about 50°.
Now, I do realise that the terminal temp is actually just the heat from the high current flow inwards through the stainless bolt and fitting -- which is probably much higher than the actual lithium cells "on the other side" of the BMS. So, shouldn't the thermister cable end actually be connected directly to the top of say, the centre lithium cell so it matches with the true BT app reading? ... or maybe glued to the side of one lithium cell?
Btw, I know that temperature compensation is not needed when charging lithium batteries, and that the BMS has safety shutdown for high temp (factory default at 60°). But the Balmar regulator is designed to current limit battery charging according to battery heat. As a pre-set temp gets near the battery's shut off, it limits charging current to prevent a BMS hi-temp shutdown ... which would surge blow the alternator when current has nowhere to go.
So, I figure to move the cable INTO the box and bolt it to the top of the BMS to battery negative bus.
However, whereas my Daly BMS inside my drop-in lithium casing registers 24°C via Bluetooth when my lithium 4 cell unit is charging at say 120A, the thermistor cable from the negative terminal back to the Balmar external alternator regulator shows about 50°.
Now, I do realise that the terminal temp is actually just the heat from the high current flow inwards through the stainless bolt and fitting -- which is probably much higher than the actual lithium cells "on the other side" of the BMS. So, shouldn't the thermister cable end actually be connected directly to the top of say, the centre lithium cell so it matches with the true BT app reading? ... or maybe glued to the side of one lithium cell?
Btw, I know that temperature compensation is not needed when charging lithium batteries, and that the BMS has safety shutdown for high temp (factory default at 60°). But the Balmar regulator is designed to current limit battery charging according to battery heat. As a pre-set temp gets near the battery's shut off, it limits charging current to prevent a BMS hi-temp shutdown ... which would surge blow the alternator when current has nowhere to go.
So, I figure to move the cable INTO the box and bolt it to the top of the BMS to battery negative bus.
