I installed the Smart BMS 12/200 with 2x30A fuses for having a maximum alternator charge current of 40A on my 15 years-old CamperVan Ducato 250. I thought that it will charge my 160Ah Victron Lithium-battery with 40A when I am driving on the highway, but it only charged with a maximum of 8A, why? I configured everything according to the manual and the Ducato-alternator can charge with a maximum of 120A... How is it possible to get 100% charge current instead of my 20% ? Thanks a lot!
Your alternator voltage is too low, you need an alternator capable of 14.4V or more to charge lithium through this type of BMS. Remember, the BMS adds some resistance to the charging circuit. The BMS does not include a voltage booster like an Orion DC to DC charger does. I do not know if a 15 year old vehicle will have a Smart type alternator where the engine ECU can limit the charge voltage, the Smart BMS 12/200 does not work with this type of alternator. You may need to consider adding an Orion DC to DC charger or if it is an older type alternator seeing if you can get a new voltage regulator for your alternator with a higher voltage set point.
As already mentioned is your alternator voltage to low.
The BMS doesn't pull current from the alternator, the current is based on the voltage difference between input and output, that's physics.
I bet if you put a high load on your lithium batteries then the current gets higher.
I don't think a bigger fuse will change the current.
Your problem is the low alternator voltage!!!
An alternator should deliver at last 14.2-14.6V.
Measure the voltage directly at the starter battery. If it also is only 13.6V then you should check the alternator.
The voltage of my starter battery is only 12,5V, maybe because of that the alternator doesnt charge the Lithium with 40A? I switched off all DC loads (fridge etc) and now Victronconnect shows me 100% charge current, but it is only charging with 23A. Why 23A are 100% ? Nevertheless, thats far more better than before! Maybe I should charge the starter battery with an external charger and try again if I get 40A when the alternator is only charging the Lithium because the starter battery is at 100%. Thanks a lot!
