BMS vs Balancer vs Protector

I'm in planning stages of a small solar setup I'll be using on a sailboat. 100-200 amp solar panel, 100amp hour, lifepo4 battery. I'm very confused about bms... Seems many bms advertised with balancer and protector. Does that mean i don't need a balancer or would i still be better off having one? Then there's a protector... Is that something i should have separate?

Thanks for everything!

Some googling lead me to a video that somewhat answers one of my questions. From that video i learned that active balancer maybe connected in parallel with a bms. Sounds like bms has balancing capability but it isn't nearly as efficient as an active balancer..

They are all different devices for different purposes. A BMS is a 'battery management system', which takes care of monitoring the cells and cut off the charger when the cells get too hot or too cold, and prevent overcharging and discharging. A balancer is a device that (actively or passively) keeps individual cells in balance, i.e., at the same voltage/state of charge between them. Whether you need this one or not depends a lot on load and how fast you discharge/charge - for typical solar installations I would say you don't need one. Most BMS systems have the functions you would expect from a protector, but not vice versa - for example a typical battery protector only protects against over discharge by disconnecting the inverter from the battery.

SailCS33 said:

Some googling lead me to a video that somewhat answers one of my questions. From that video i learned that active balancer maybe connected in parallel with a bms. Sounds like bms has balancing capability but it isn't nearly as efficient as an active balancer..

Click to expand...

You are correct, both (usually) balance. But an active balancer usually has a much higher current. A BMS' prime role is cell level protection and management, balancing is one part of this, and not the most important one.

I think most of us are too concerned about exact cell balance unless you are an experimenter / builder of battery packs and are interested in the exact performance parameters. I use Daly BMS's and so far have performed faultlessly protecting the packs that I experiment with. Build your set-up , use / cycle it and forget about it unless you get degraded perforfance , then investigate. If you can get to the individual cells , perform a cell test once or twice a year and if necessary , balance the cells.