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we've got a question from Keith a fellow boater asking some questions about or the implications of having a lithium battery and how do you wire where should your alternator be connected when you have a lithium battery so Keith's question says Jeff I watch your video charging lithium batteries on my boat with an alternator why won't you wire the alternator directly to the house battery which is lithium and then install a DC to DC charging converter from that house lithium battery to the starter battery okay well um that's certainly the way that we would have done it if it wasn't a lithium so for example on my boat and we've done this on many boats not all boats are the same but uh you know for example on my boat um I have the alternator obviously it does have a switch so I can isolate the alternator but the alternator is directly connected to my house battery via switch and Via a fuse so I have two ways of disconnecting and and I have circuit protection and yeah that's that makes sense um and I have but remember in this setup a lead acid battery um in my case it's an AGM what you have is the alternator will never uh suddenly or how about this let me rephrase the battery will never disappear on the alternator the battery is really always going to be there a bad battery is still a battery uh it doesn't really behave all that well but it's still there it doesn't disappear the challenge with the lithium battery is it has Intelligence it's not just a battery it's lithium with a computer on top that computer is a BMS and that BMS can make decisions and it needs to be there just protect the battery that's why there's a computer on top and suddenly it could happen that your battery after the alternator has been running for a period of time the battery says you know what I've had enough I need I am disconnecting myself from that alternator and remember the alternator is not talking to the battery they're not exchanging information they're not talking they're not making sure each other one is right there's no communication right they're just sort of doing their thing and they're hoping the other one is going to be fine with it but there's no talking so if your lithium battery suddenly disconnects itself and the only thing connected to it is the alternator as we know and some of us remember and I learned the hard way at the beginning when I own my boat um if you ever disconnect an alternator from a battery Bank while the engine is running and the alternator is outputting so if you ever go to your battery switch and you can't do this and you turn the battery switch to off and it actually says on most battery switches never turn battery switch to off when engine is running there's a little disclaimer at the bottom of the switch if you do that you most likely will lose your alternator not lose like physically disappear but your ultimate is going to become damage and because you can't have an alternator lose a connection to a battery so the reason why we install these battery isolators on the output of an alternator when we have a lithium is so that there's always a place for the alternator to still dump current to even though it would suddenly lose the lithium battery because the BMS deemed that it needed to protect the battery and so that's the reason why with a lithium battery system um we often install battery isolators the FED type the modern type as a way to protect the alternator in the event and it's rare that the lithium battery would disconnect itself uh from the circuit um and now there are lithium batteries of course that have charging Parts ports charging circuits versus load circuits and so that's another thing you can do it gets more complicated but still doable but for the most part for the drop-in uh lithiums then we'll end up putting a battery isolator to make sure that we never lose a connection between a battery and an alternator even though the lithium battery disconnects itself so great question Keith and that's the why thanks for all for you for watching uh share with us how you do the lithium on your boat where were the pitfalls and issues that you were worried about and how did you solve it thanks for watching again so if you're curious again go on our website and find out more answers and solutions with this sort of setup and thanks for asking and thanks for all of you for listening and tuning in