Originally Posted by Weldergary
Thanks for the information. I understand that I can remove the white wire, leave the solenoid in place a use the post to continue installing the Orion DC-DC battery charger to charge the lithium battery. The Orion is designed to protect the alternator from burning up.
On the subject of alternator protection;
1) Be careful with using the statement 'The Orion is designed to protect the alternator from burning up.' The alternator 'protection' Victron is referring to is the B-B charger limits the current draw to a fixed amperage (not exactly but see #2), AS OPPOSED TO COMPLETELY UNREGULATED current draw if wired directly. There is NO ACTIVE ability to safeguard the alternator inherent in their charger OR ANY OTHER to prevent the user from putting a large added load on the vehicle that overloads the alternator. It is incumbent on YOU, the purchaser, to make sure that your vehicle has the capacity to deliver an additional 50A that your 40A charger will demand from your vehicle system.
2) A B-B with a capacity of 40A, means that it can charge the battery at 40A. If charging an LFP battery, with a max charging voltage of around 14.6V, that delivers (40A x 14.6V) 584W. Because the charger is only ~93% efficient, it must draw (584W/.93) 628W to deliver that 40A, HOWEVER, the reason you have a B-B charger is that the engine voltage is often lower than the LFP needs to charge and the B-B will draw more amps at low voltage and boost the voltage to make the 40A output. If you have a 'smart' (better called 'variable voltage') alternator, the vehicle system voltage likes to run around 12.4-13.2V most of the time. IF (and I'm calculating worst case) the vehicle alternator is only putting out 12.4V, the delivery of 628W/12.4V will draw 50.6A from the vehicle. The key question is, does your alternator have that much reserve (capacity above and beyond the vehicle needs) capacity?
3) What is the alternator's reserve capacity? At idle? At highway speed? At high RPM as when climbing a hill? You need to know all of these and they are all different. An alternator performance curve will show output at given RPMs. Rated capacity is at 6000 alternator RPM. This is not CONTINUOUS output.
IDLE: Capacity at idle is around 1/3 of rated capacity and almost all of it is used by the vehicle. If you run your B-B at idle, it will overload your alternator. Your alternator can tolerate the heating for a short period of time IF the engine/alternator is cold. It will tolerate a lot shorter period of hot. It will likely not tolerate it for long enough to charge your battery in almost every case. TBL, don't charge at idle. Have some way to prevent it if you idle for long.
HIGHWAY SPEED: Your CONTINUOUS capacity at 2000 engine RPM/6000 Alternator RPM is about HALF THE RATED CAPACITY. This is where you want to charge. Be careful about getting in a situation where your engine speed is above or below it.
HILL CLIMBING: Not only is your engine RPM and engine heat generation high, but your alternator efficiency drops from ~75% @ engine 1400RPM, to around 60% at highway speed to below 50% at high speed. This loss results in much more heating of your alternator, causing its available capacity to drop from 1/2 rated back to 1/3-1/4 of rated capacity. Just as if idling, the alternator will be overloaded and if left long enough, will burn out.
In the high and low-speed operation, the vehicle should have a manual shut-off to unload the B-B. It's just like you're admonished to shut off your A/C to prevent overheating the engine on a hill climb or passing.