What’s a better solution for a system with an alternator and two coexisting battery banks (one AGM engine start, and the other one lithium service)?
Option 1 using a Orion-Tr Smart DC-DC Charger Isolated
Option 2 using a Smart BMS CL 12/100
asked
Alternator and lithium batteries
Two remarks:
In 95% of all cases the non-isolated DC-DC charger is sufficient and cheaper. You should carefully re-consider your design and check if the isolated charger is really necessary. It seldom is.
Please be aware that the Smart BMS only works with Smart LiFePO4 batteries manufactured by VE, because the BMS communicates with the batteries via a VE-proprietary protocol. The BMS does not work together with any LiFePO4 battery by some manufacturer. Maybe this already rules out that option.
Hi @AINOA there are lots of questions here that go to the overall design of your install.
First up I would want to consider if the Smart BMS CL 12/100 is the right BMS for your environment. The smart BMS CL 12/100 won’t talk to a GX device, won’t give you state of charge and won’t directly disconnect the load on low voltage.
Assuming the Smart BMS meets your needs the next thing to consider is the alternator quality and whether it has any regulation. The smart BMS CL 12/100 does not have inbuilt charging profile. The output voltage for some alternators is all over the place - this may be okay for you starter battery but not your house battery. The Orion Smart charging profile isn’t perfect but it’s better than nothing.
Lastly, with regard to the Smart Orion the the non-isolated will work in the majority of cases. One main advantage of the isolated smart Orion is that you can put a shunt on the output to monitor the charging current. Hope this helps.
Thank you both for your prompt responses. It clarifies some of the doubts I had. My current setup is for a sailboat with all AGM house and starter banks. Current alternator is a Balmar high output regulated with a multi-stage voltage regulator with an AGM profile. This alternator goes into a battery bank isolator that separates starter and house banks. By replacing the house with lithium, the idea is to leave the alternator only charge the starter, and disconnect the house from the alternator and isolator and then use the DC-DC charger to charge the lithium house. I’m assuming that this setup will charge the lithium to 100%. My doubts were about the efficiency and safety of charge into the lithium bank, and whether the smart BMS was a better way to go.
A BMS is not a charger. You will need both a BMS and a charger.
A BMS monitors the battery and protects it from over or under voltage, excessive charge and discharge currents and low/high temperatures. It does this by DISCONNECTING the battery from the charging sources and loads. It does NOT regulate charging current.
What you end up with for a BMS will depend on what batteries you buy. Some "drop-in" lithiums have a BMS built in, some like the Victron Smart lithiums need an external BMS. The Victron lithiums and a compatible BMS is only part of the solution. You will also need battery protects to shut down charging and discharging based on control lines from the BMS.
As for charging, the Orion line is a good choice. Note that The Orion line includes CHARGERs and CONVERTERs. you should pick a CHARGER model. You can parallel multiple Orion chargers if one isn't sufficient.
