Lithium Batteries / charger for Boat

[a_bow_nut]

I have a three bank charger that we can make a deal on if you are interested but it will not work on lithium batteries.

The one thing that kept me away from lithium was that they do not like being used in cold temperatures.

[SkunkedAgain]

Are the LiPO4 or whatever that formula is, different than the Lithium batteries that I use in my ice gear? My lithium batteries that I use in my fish finder and other things have always worked well for me in the cold, but I don’t know if they are the same chemistry as they big ones that they use for boat batteries… Oh hey I just checked my ff and it is a LifePO4 battery, so I know they have worked well for me for a couple years of ice fishing, so I hope the boat ones are good… Just seen the Cabela’s Lithium batteries are around $750 each today for one 12 V with 100 amp hours… So I pulled the trigger on the Amazon batteries before the sale ended… Got 2 batteries and a three bank lithium charger for $677, so I figure someone will tell me I could have gotten them cheaper, but this was the best deal I had seen, so I hope they work well… Sorry I didn’t see your charger offer until after I had ordered this one, but if it won’t do lithium I guess it wouldn’t have worked for me. Thanks for the offer.. Jeff

[Bduck]

I have the NOCO 2 bank smart charger in my boat maintaining a 12v wet cell and an AGM. As soon as the life of the wet cell extinguishes, I’ll replace it with another AGM. Over the past 2½yrs I’ve replaced 5 wet cell batteries with AGMs in my vehicles as winter was taking its toll on them. Also, installed a NOCO GEN II smart maintainer for each vehicle. These small maintainers have a selector mode for the type of battery it will be maintaining and cost about $50ea. NOCO has been a good investment for all of my batteries especially with my diesel truck that sits out in the elements not getting the run time it used to. Battery life with my truck ranged from 4-if lucky 6yrs.

[BYUHunter]

The Minnkota onboard chargers are lithium capable. They are also capable of charging dissimilar circuits, for instance your 12v starting battery and your 24v trolling motor system, simultaneously without the need to separate.

As for your AH question, battery life all depends on the size of the boat, how much wind, how hard you’re running the electric, etc. 100 AH is a good sized battery and should last a long time.

I have a 36v 100 AH LiPo in my boat. The Minnkota was not capable of charging a Li of that much voltage, so I had to buy a dedicated golf-cart battery charger, but for two 12v, you’ll be fine with a regular onboard charger.

[SkunkedAgain]

@Bduck

I have the NOCO 2 bank smart charger in my boat maintaining a 12v wet cell and an AGM. As soon as the life of the wet cell extinguishes, I’ll replace it with another AGM. Over the past 2½yrs I’ve replaced 5 wet cell batteries with AGMs in my vehicles as winter was taking its toll on them. Also, installed a NOCO GEN II smart maintainer for each vehicle. These small maintainers have a selector mode for the type of battery it will be maintaining and cost about $50ea. NOCO has been a good investment for all of my batteries especially with my diesel truck that sits out in the elements not getting the run time it used to. Battery life with my truck ranged from 4-if lucky 6yrs.

Thanks for the feedback on the NOCO chargers, I had heard they were pretty decent, but I never know how much I can believe from internet sources, I prefer the locals I know, so your info is of much more value to me… Thank you… I think the price I got on the lithium batteries was about the same as the AGM’s so I took the leap and I’m hoping for the best… Later J

[Therapist]

I was talking to the guy at Backwater Sports, they are the Minn Kota Service center in North Orem. I was thinking of replacing my 36Volt system with Lithium batteries when the current Wet cells die. He did not recommend using Lithium because the tend to burn your motor out. He said if you do go to Lithium, do not run the motor over 80% . Now I did not ask if he was talking older motors with brushes or both with or w/o brushes, but thought that was an interesting piece of information that no one talks about !! I still have 2-3 years left on my current batteries, so I am not gong to worry about it. But do some more research on it before you invest, might save you not only the price of Lithium batteries, but also a new motor !!!

[SkunkedAgain]

@BYUHunter

The Minnkota onboard chargers are lithium capable. They are also capable of charging dissimilar circuits, for instance your 12v starting battery and your 24v trolling motor system, simultaneously without the need to separate.

As for your AH question, battery life all depends on the size of the boat, how much wind, how hard you’re running the electric, etc. 100 AH is a good sized battery and should last a long time.

I have a 36v 100 AH LiPo in my boat. The Minnkota was not capable of charging a Li of that much voltage, so I had to buy a dedicated golf-cart battery charger, but for two 12v, you’ll be fine with a regular onboard charger.

Appreciate the info, guess I already pulled the trigger on the NOCO charger, so I hope it will work well… Understand the usage sets the life on the charge, but was looking for an estimate of if this would be big enough… I have a 18’ Tracker so it’s not terribly heavy, but it does have a wind profile that will probably catch more breeze than my old tri-hull… so it will take more power, but I also plan on using it as an aid, not the main propulsion, more for steering and anchoring purposes and slow trolling… I think my old wet cell battery was a 72 amp hour and I haven’t used it on this boat, but on the old one, it was a little weak to last all day, but that was on a 12 V motor and a single battery, so with two at 100 amp hour I’m thinking it should have a fair amount of power…

I’ll have to try and see if the charger will work without disconnecting the jumper, that would sure be a lot easier and part of the reason I got the on board charger, but if it won’t the battery is easy to access…  Is this the reason folks use a battery cut off switch?  Or is it to avoid shorts that set your boat on fire??? Just wondered if you could put a switch between the batteries and cut that circuit off while charging them… Then I wouldn’t have to mess with the wires… sorry random thought… I’ll bet that would work… Anyway thanks for all the  info, I appreciate it… Jeff

---

@Therapist

I was talking to the guy at Backwater Sports, they are the Minn Kota Service center in North Orem.  I was thinking of replacing my 36Volt system with Lithium batteries when the current Wet cells die.  He did not recommend using Lithium because the tend to burn your motor out.  He said if you do go to Lithium, do not run the motor over 80% .  Now I did not ask if he was talking older motors with brushes or both with or w/o brushes,  but thought that was an interesting piece of information that no one talks about !!  I still have 2-3 years left on my current batteries,  so I am not gong to worry about it.  But do some more research on it before you invest,  might save you not only the price of Lithium batteries, but also a new motor !!!

Yikes I hadn’t heard anything like that… Hope I don’t find out the hard way… Wonder what the reasoning is with that?  Will the lithium provide the ampage too fast so it overheats the motor??? Hope this doesn’t turn out to be true, but I’ll have to watch how hard I push the motor, I wasn’t planning on using it at full power, but I know the spot lock sometimes gets over aggressive at trying to keep you on spot… Might need to watch out for that… Thanks for the heads up on that… Jeff

[Bassin_Blitz]

I just finished my third year with Lithiums, I can’t speak for the Li-time brand I have Ionics and they are awesome.

No issues

[Mr_J]

Jeff, I had a NOKO 3 bank charger in my boat (recommended by Scott T) it worked as it was supposed too. As mentioned it has a charging designator on each bank, so you need to be sure you have it set for the type battery you have. Keep in mind that you have to have one bank for each battery you charge. I have a Minn Kota in my new boat, can’t tell you much about that one.

rj

[BearLakeFishGuy]

Here is my take:

1. I’ve had the NOCO 2 bank charger for at least 9 years.  Works flawlessly.
2. I don’t believe the part about LI batteries burning out a motor.  12V is 12V.  Maybe you can run the motor for longer period since the batteries have more reserve capacity than lead batteries, but it simply cannot “burn out” a motor.  I’ve used LI batteries on very expensive (and very sensitive) equipment where we used lead batteries in the past.  We’ve never had an issue with ANYTHING except they LI batteries weigh less and they run longer.  
   3)  I have also used LI batteries in VERY cold, extended conditions and have not had an issue with them decharging anymore than lead batteries.

[Therapist]

@BearLakeFishGuy

Here is my take:

1. I’ve had the NOCO 2 bank charger for at least 9 years.  Works flawlessly.
2. I don’t believe the part about LI batteries burning out a motor.  12V is 12V.  Maybe you can run the motor for longer period since the batteries have more reserve capacity than lead batteries, but it simply cannot “burn out” a motor.  I’ve used LI batteries on very expensive (and very sensitive) equipment where we used lead batteries in the past.  We’ve never had an issue with ANYTHING except they LI batteries weigh less and they run longer.  
   3)  I have also used LI batteries in VERY cold, extended conditions and have not had an issue with them decharging anymore than lead batteries.

i had never heard anything like it also,  but when Carl, the service tech, told me that, I began rethinking Lithium.  I think it needs to be researched more.  About chargers,  I’ve had a 2 bank Minn Kota on my 1996 Skeeter ( which is for sale by the way ) for the last 15 plus years and have loved it.  When I purchased my Pontoon this past summer I went looking for a charger for it,  36 volt plus the starting battery.  Found a used NORCO 4 bank and it has been doing a good job so far.  Will really give a test this coming year !!  It will not charge Lithium, so another reason that I probably will stay with wet cell batteries !!

[mjlevie]

@Therapist

I was talking to the guy at Backwater Sports, they are the Minn Kota Service center in North Orem.  I was thinking of replacing my 36Volt system with Lithium batteries when the current Wet cells die.  He did not recommend using Lithium because the tend to burn your motor out.  He said if you do go to Lithium, do not run the motor over 80% .  Now I did not ask if he was talking older motors with brushes or both with or w/o brushes,  but thought that was an interesting piece of information that no one talks about !!  I still have 2-3 years left on my current batteries,  so I am not gong to worry about it.  But do some more research on it before you invest,  might save you not only the price of Lithium batteries, but also a new motor !!!

I’ve heard this in the past.  Just did a quick search on Minn Kota’s site and found this.

https://minnkota-help.johnsonoutdoors.com/hc/en-us/articles/6477037780631-Selecting-Lithium-Batteries-for-Trolling-Motors

It doesn’t look like lithium batteries should be a problem with a minn kota trolling motor.

I’ve been using Li-time lithium with mine this year and have not had any problems.  I can get about 8 hours trolling on calm days with my 16 foot boat with a 24v system 100 ah.  One of the big advantages is that they charge much faster than either lead acid or AGM. Hope this helps.

[system]

@SkunkedAgain

I didn’t take notes when this conversation was had before so wondering if you’d mind repeating some of this info???
First off for a trolling motor 24 volt, how many amp hours of power do you need to run all day?  (Will 100 amp-hours work?)
*Second on an online bank charger on a boat, if you have 24 volt trolling motor and a 12 volt starting motor would I need a 3 bank or two bank charger? If a 3 bank do you have to unhook the jumper wires so the batteries can be charged one at a time? This assumes I am using 2 12V batteries wired in series to make the 24V…  *
Third, I think, Has anyone had any experience with LiTime lithium batteries?  Are they any good?  I see they have a cyber Monday deal where you can get two for $475… I think that is about half of what they were last time I looked, so since I need new trolling batteries, i think I’m going to take that plunge… Let me know what you think… Thanks Jeff

---

Are the Noco Genius a good boat charger?

not sure about lithium, I’ve heard good and bad but currently run two 12 volt AGM’s and need to replace one this spring, so will probably stay that way.   I can run all day (6-8 hours) at medium high throttle with my 22’ tritoon and minnkota terrova 80# with that set up.   I can definitely vouch for the NOCO, they are great. I have one on my cranking battery and a 2 bank on my trolling motor batteries.  I installed a plug that lets me run an extension cord to it and plug it in easily at the end of the day and it charges them right up and maintains them for longer spells between boating. been very happy with them.

[dubob]

I’ve had several boats over the years and currently have a Thunderjet with two outboards and a 24v electric motor.  I have a two bank charging system for the two AGM electric trolling motor batteries.  Each outboard has it’s own marine, wet cell cranking battery.  I have never had, or seen a need for a charger for my outboard cranking batteries.  As long as one of the outboards is running, it’s cranking battery is being charged by the outboard.  I typically get 7 years plus out of my cranking batteries and I have never used a charger on them - ever.

The only issue that I’m aware of with lithium batteries and cold weather is that you can not charge them when it is cold.  If they are charged, they work just fine in cold weather.  My Vexilar has a lithium and has worked just fine in -20 degree weather.

I am not impressed with the lighter weight of lithium when it comes to being used in a fishing boat.  Your outboard could care less if you carry a few extra pounds of wet cell battery weight.  And I seriously doubt you can tell the difference in your boats performance by shaving a few pounds of battery weight.

Good quality marine batteries will give you many years of excellent service if properly maintained.

But hey, it’s your money.  Spend it on whatever you want.

[SkunkedAgain]

@Bassin_Blitz

I just finished my third year with Lithiums, I can’t speak for the Li-time brand I have Ionics and they are awesome.

No issues

Thanks for the encouraging info on them… J

---

@Mr. J

Jeff, I had a NOKO 3 bank charger in my boat (recommended by Scott T) it worked as it was supposed too. As mentioned it has a charging designator on each bank, so you need to be sure you have it set for the type battery you have. Keep in mind that you have to have one bank for each battery you charge. I have a Minn Kota in my new boat, can’t tell you much about that one.

rj

Thanks Richard, it’s supposed to get here this weekend, then I’ll have a better idea of what it looks like and how it will work.  Thank you very much for the heads up… Sounds like the 3 bank was a good idea… Thank you… Jeff

---

@BearLakeFishGuy

Here is my take:

1. I’ve had the NOCO 2 bank charger for at least 9 years.  Works flawlessly.
2. I don’t believe the part about LI batteries burning out a motor.  12V is 12V.  Maybe you can run the motor for longer period since the batteries have more reserve capacity than lead batteries, but it simply cannot “burn out” a motor.  I’ve used LI batteries on very expensive (and very sensitive) equipment where we used lead batteries in the past.  We’ve never had an issue with ANYTHING except they LI batteries weigh less and they run longer.  
   3)  I have also used LI batteries in VERY cold, extended conditions and have not had an issue with them decharging anymore than lead batteries.

Scott, I think I like all 3 of your points and I have seen the same results with my limited small battery experience, so I tend to agree with what you have provided, not to mention that it was exactly what I wanted to hear… Thanks Scott… Later Jeff

---

@Therapist

@BearLakeFishGuy

Here is my take:

1. I’ve had the NOCO 2 bank charger for at least 9 years.  Works flawlessly.
2. I don’t believe the part about LI batteries burning out a motor.  12V is 12V.  Maybe you can run the motor for longer period since the batteries have more reserve capacity than lead batteries, but it simply cannot “burn out” a motor.  I’ve used LI batteries on very expensive (and very sensitive) equipment where we used lead batteries in the past.  We’ve never had an issue with ANYTHING except they LI batteries weigh less and they run longer.  
   3)  I have also used LI batteries in VERY cold, extended conditions and have not had an issue with them decharging anymore than lead batteries.

i had never heard anything like it also,  but when Carl, the service tech, told me that, I began rethinking Lithium.  I think it needs to be researched more.  About chargers,  I’ve had a 2 bank Minn Kota on my 1996 Skeeter ( which is for sale by the way ) for the last 15 plus years and have loved it.  When I purchased my Pontoon this past summer I went looking for a charger for it,  36 volt plus the starting battery.  Found a used NORCO 4 bank and it has been doing a good job so far.  Will really give a test this coming year !!  It will not charge Lithium, so another reason that I probably will stay with wet cell batteries !!

Thanks for the encouragement about the charger, I’m looking forward to not pulling the batteries to charge them… J

---

@mjlevie

@Therapist

I was talking to the guy at Backwater Sports, they are the Minn Kota Service center in North Orem.  I was thinking of replacing my 36Volt system with Lithium batteries when the current Wet cells die.  He did not recommend using Lithium because the tend to burn your motor out.  He said if you do go to Lithium, do not run the motor over 80% .  Now I did not ask if he was talking older motors with brushes or both with or w/o brushes,  but thought that was an interesting piece of information that no one talks about !!  I still have 2-3 years left on my current batteries,  so I am not gong to worry about it.  But do some more research on it before you invest,  might save you not only the price of Lithium batteries, but also a new motor !!!

I’ve heard this in the past.  Just did a quick search on Minn Kota’s site and found this.

https://minnkota-help.johnsonoutdoors.com/hc/en-us/articles/6477037780631-Selecting-Lithium-Batteries-for-Trolling-Motors

It doesn’t look like lithium batteries should be a problem with a minn kota trolling motor.

I’ve been using Li-time lithium with mine this year and have not had any problems.  I can get about 8 hours trolling on calm days with my 16 foot boat with a 24v system 100 ah.  One of the big advantages is that they charge much faster than either lead acid or AGM. Hope this helps.

Thank you, that is a great reference… If you noticed in the comments it recommended not running your motor above 85% power with Lithiums kind of in line with the above comments… I really appreciated your run time recommendation, that was kind of what I was looking for… I don’t hardly ever get more than 8 hours at a time to fish… Wish I did, but not often if ever, and I doubt I would use the motor full time for that long of a trip…  Thanks a bunch this was very helpful… J

---

@chubby chaser

@SkunkedAgain

I didn’t take notes when this conversation was had before so wondering if you’d mind repeating some of this info???
First off for a trolling motor 24 volt, how many amp hours of power do you need to run all day?  (Will 100 amp-hours work?)
*Second on an online bank charger on a boat, if you have 24 volt trolling motor and a 12 volt starting motor would I need a 3 bank or two bank charger? If a 3 bank do you have to unhook the jumper wires so the batteries can be charged one at a time? This assumes I am using 2 12V batteries wired in series to make the 24V…  *
Third, I think, Has anyone had any experience with LiTime lithium batteries?  Are they any good?  I see they have a cyber Monday deal where you can get two for $475… I think that is about half of what they were last time I looked, so since I need new trolling batteries, i think I’m going to take that plunge… Let me know what you think… Thanks Jeff

---

Are the Noco Genius a good boat charger?

not sure about lithium, I’ve heard good and bad but currently run two 12 volt AGM’s and need to replace one this spring, so will probably stay that way.   I can run all day (6-8 hours) at medium high throttle with my 22’ tritoon and minnkota terrova 80# with that set up.   I can definitely vouch for the NOCO, they are great. I have one on my cranking battery and a 2 bank on my trolling motor batteries.  I installed a plug that lets me run an extension cord to it and plug it in easily at the end of the day and it charges them right up and maintains them for longer spells between boating. been very happy with them.

That is exactly what I’m hoping to be able to do, have an easy recharge method set up… Have been doing things the clunky take far too long method and really would like to clean things up to a single cord to plug in and be done.  Thanks for the input on run time as well… Sounds like if your batteries are 100 amp hour that we will be right where I hope to have my system set up.  Thanks for the input… J

[SkunkedAgain]

@dubob

I’ve had several boats over the years and currently have a Thunderjet with two outboards and a 24v electric motor.  I have a two bank charging system for the two AGM electric trolling motor batteries.  Each outboard has it’s own marine, wet cell cranking battery.  I have never had, or seen a need for a charger for my outboard cranking batteries.  As long as one of the outboards is running, it’s cranking battery is being charged by the outboard.  I typically get 7 years plus out of my cranking batteries and I have never used a charger on them - ever.

The only issue that I’m aware of with lithium batteries and cold weather is that you can not charge them when it is cold.  If they are charged, they work just fine in cold weather.  My Vexilar has a lithium and has worked just fine in -20 degree weather.

I am not impressed with the lighter weight of lithium when it comes to being used in a fishing boat.  Your outboard could care less if you carry a few extra pounds of wet cell battery weight.  And I seriously doubt you can tell the difference in your boats performance by shaving a few pounds of battery weight.

Good quality marine batteries will give you many years of excellent service if properly maintained.

But hey, it’s your money.  Spend it on whatever you want.

Hey Bob, I think you put your finger on the cold issues with Lithium, I think the recharge is probably the issue.  Now you mentioned this, I had heard that you need to take your batteries inside to charge during the winter, so I’ll bet this is the concern with them… Wonder what temp is considered cold where you need to do this???

As far as recharge of cranking battery, I have my electronics on that circuit and I think I might need to change this, but that is typically what runs my cranking battery down and it’s not an every trip deal, but once in a while and mostly after the boat sits for awhile, that I have to recharge that one… Plus that battery is old and tired and time to replace it…

On the AGM/Lithium cost issue, I was looking at both when I decided to go Lithium, AGM was $189 to $239 lithium and I had heard 5 year life verses 10 plus years so I figured $50 for 5 years was worth it.. Weight only plays in when installing and working on the batteries to me, not the boat performance, it’s a save my back issue to me.  You know I’m cheap, so I likely wouldn’t spend extra just to be trendy… I think your dislike of the lithium is probably tied to the crazy price that they used to be, but now they have dropped to close to AGM prices I’ll bet more will start to adopt them… I couldn’t justify $500 per battery, but two for that price put me over the edge… We’ll see, maybe I’ll be eating crow, but sounds like quite a few folks really like the lithium, so I hope to be happy as well…

Thanks for the input Bob, appreciate that insight… Jeff

[brookie]

Okay, here is the next battery/charging question - charging 2 12 volt batteries in series. I have always had a 12 volt trolling motor, but am looking at a 24 volt so the 24 volt system is new to me. I know that 2 12 volt batteries in series make 24 volts. So how do you charge the batteries? Will a 2 bank 12 volt charger, one bank for each battery work? With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery? Do Li ion batteries make a difference here?

[wiperhunter2]

@brookie

Okay, here is the next battery/charging question - charging 2 12 volt batteries in series. I have always had a 12 volt trolling motor, but am looking at a 24 volt so the 24 volt system is new to me. I know that 2 12 volt batteries in series make 24 volts. So how do you charge the batteries? Will a 2 bank 12 volt charger, one bank for each battery work? With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery? Do Li ion batteries make a difference here?

The short answer is yes, one bank for each battery and no you do not need to disconnect the two batteries because they are hooked up different on the 24 v system vs 2, 12 v hooked up in series. Can’t help you on the  Li ion, I’m not ready to make that jump yet, until my old batteries go out.

[dubob]

@brookie

Okay, here is the next battery/charging question - charging 2 12 volt batteries in series. I have always had a 12 volt trolling motor, but am looking at a 24 volt so the 24 volt system is new to me. I know that 2 12 volt batteries in series make 24 volts. So how do you charge the batteries? Will a 2 bank 12 volt charger, one bank for each battery work? With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery? Do Li ion batteries make a difference here?

So how do you charge the batteries?  Hook bank 1 to battery 1; bank 2 to battery 2

Will a 2 bank 12 volt charger, one bank for each battery work?  Yes, that is the way they are designed to work.

With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery?  They do not have to be disconnected or have an on/off switch.  Hook separate banks to each battery - bank 1 to battery 1; bank 2 to battery 2

Do Li ion batteries make a difference here?  None whatsoever other than the charger must be compatible with lithium batteries.

[brookie]

@wiperhunter2

@brookie

Okay, here is the next battery/charging question - charging 2 12 volt batteries in series. I have always had a 12 volt trolling motor, but am looking at a 24 volt so the 24 volt system is new to me. I know that 2 12 volt batteries in series make 24 volts. So how do you charge the batteries? Will a 2 bank 12 volt charger, one bank for each battery work? With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery? Do Li ion batteries make a difference here?

The short answer is yes, one bank for each battery and no you do not need to disconnect the two batteries because they are hooked up different on the 24 v system vs 2, 12 v hooked up in series. Can’t help you on the  Li ion, I’m not ready to make that jump yet, until my old batteries go out.

Thanks Curt, was just a little afraid of putting 12V charger into a 24V system - wanted an outside opinion. (2 12V batteries hooded up in series is the 24V system)

---

@dubob

@brookie

Okay, here is the next battery/charging question - charging 2 12 volt batteries in series. I have always had a 12 volt trolling motor, but am looking at a 24 volt so the 24 volt system is new to me. I know that 2 12 volt batteries in series make 24 volts. So how do you charge the batteries? Will a 2 bank 12 volt charger, one bank for each battery work? With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery? Do Li ion batteries make a difference here?

So how do you charge the batteries?  Hook bank 1 to battery 1; bank 2 to battery 2

Will a 2 bank 12 volt charger, one bank for each battery work?  Yes, that is the way they are designed to work.

With a 2 bank charger do you need to disconnect the two batteries from each other to charge or have an on/off switch between or can they stay wired together in 24V and just hook up 1 12V bank to each battery?  They do not have to be disconnected or have an on/off switch.  Hook separate banks to each battery - bank 1 to battery 1; bank 2 to battery 2

Do Li ion batteries make a difference here?  None whatsoever other than the charger must be compatible with lithium batteries.

Thanks Bob, that answers all my questions. You guys are great. When you need answers, just go to the experience on BFT