I am having a lot of trouble finding a direct answer to the question of what is the recommended way to charge a Victron Smart 12,8/200-a lithium battery from an alternator.
Which should I use and why?
asked
Which should I use - Smart BMS 12/100, BMS 12/200 or Orion-Tr charger????
Unfortunately there is not a direct answer, all three are possible and will work. It comes down to a system design and overall approach and what you are trying to achieve.
The critical design consideration is to ensure that the high acceptance rate of the Lithium battery can be managed so that the alternator does not over heat and burn out. All three will constrain the demand on the alternator and current available for charging, The BMS 12/100 and BMS 12/200 do this based on the size of fuse installed, while the DC-DC approach it through a charger approach that constrains the maximum amount of charge current. The DC-DC will constrains to a maximum of 30A, as that is the largest unit available. The 12/100 is up to 100A and 12/200 up to 200A.
In my view it would come down to what is the size of the existing alternator, and what you are using as a BMS. If you are using a VE.Bus BMS then you could use either of the following
- External regulator that takes alternator temperature into consideration.
- DC-DC
- BMS 12/200 with the VE.Bus to BMS 12-200 alternator control cable (https://www.victronenergy.com/upload/documents/VE.Bus-BMS-to-BMS-12-1200-alternator-control-cable-EN.pdf).
If you are not using the VE.Bus BMS then the BMS 12/200 or BMS 12/100 are options.
The BMS12/200 works on the negative side; while the BMS12/100 works on the positive side.
So it comes down to what you need and want, they all work but in different ways.
The manuals for the BMS 12/100, BMS 12/200 and DC-DC are very informative about how they work and how they can be configured.
I can understand all the above points but what about all the fuss regarding charging profile for the battery??? BMS 12/100 and BMS12/200 will charge battery at whatever is coming out of the alternator. DC-DC follow set charging profiles.
Take a look at the manuals. They use the fuse as a shunt, so can constrain current flow.
From the 12/100 manual
Determine the rating of fuse (see figure and table 1). The fuse doubles as a shunt, thus the BMS CL will limit the input current according to the rating of this fuse. For fuse and corresponding current limit please see table 1. Choosing the right fuse will prevent overheating of the alternator and/or DC cabling.
yes i understand all that but the point is elsewhere Victron say that Lithium batteries 'need' to be charged using the correct charging profiles (ie, bulk, float etc). The 2 BMS choices don't do this whereas the Orion-Tr charger does. So confusing. Can't find a straight answer. It can't be both/ either as they are different so which is right???
