I'm pretty new to this but it doesn't seem too complicated. I do have 1 question I don't seem to be able to find the answer to...
I currently have 3 group 31 AGM batteries connected in series. I need 36v and no more than 60a, it's currently fused at 60a. I have a Noco marine charger with 3 leads 10a each connected to each battery to charge. The boat is 24' and heavy and I use the trolling motor constantly. I pretty much drain the 110ah batteries every day. I doubt I'm really getting advertised power based on what I see and what I've found online. I can charge these batteries overnight and be ready to go in the morning if I have a power source but that's not always easy or available. I either have to pull the boat out of the water and plug it in to utility power or use a my Honda 1000 and run it all night and that makes it hard to sleep when camping on the boat. I'd like to get to the point where I don't have to mess with the generator or charging the batteries at all on a 3 or 4 day trip.
Also the savings on weight is huge for a boat. When I added the 3 group 31s I noticed it was much harder to get the nose all the way on the trailer because of the additional weight forward, which is really the only place I have.
My idea is to get 12 280ah or 310ah cells to make 36v. My big question is this... I'd like to use the existing Noco 12v 3 lead marine charger. I guess this means I will need to wire these batteries with 3 4s 100a BMSs to basically build 3 12v batteries and hook each up in series as if they were independent batteries. This seems easy to do, much like I have the 3 AGM batteries wired but then to monitor the batteries with a BlueTooth BMS I'd have to look at all 3 BMSs for capacity. I wouldn't be able to use a single shunt as I'd have to be charging the batteries in groups of 4 for 12v. I hope I'm making this clear... Would I be able to just monitor 1 of the 3 batteries and do the math by 3 or could that be way off?
It seems a better way would be to use a single 12s 100a BMS with BT but then I wouldn't be able to use the current charger. I'd have to get a charger capable of 36v and I have found 1 waterproof 36v charger at 10a which would work , but I don't see how I could use the existing charger because I'd have to charge groups of 4 at 12v and that wouldn't work with a single12s BMS would it?
I've seen a couple threads where people are asking about this for a 36v trolling motor but they don't have all the details I was hoping for. Hopefully someone else has done this and can offer some advice before I get in too deep on this.
I'm attaching a jpg of my initial plan, 3 groups of 4 cells for 3 12v batteries connected in series and 3 BMS but I'd really like a way of monitoring the ah use and capacity so I know how much I have left.... NOTE - I couldn't figure out how to change the scale so where you see 18' it's really 18" and where you see 2'9" it's really 2.75" I was in a hurry and just really needed to see it things fit and wanted to draw a quick diagram to get my thoughts straight... If there's a better way or if a 12s 36v BMS is a better route please let me know. Also if I messed up the wiring let me know this is my first shot at this with a BMS in the mix....
I'm planning on making a custom battery box out of marine board HDPE to house this and have a lid to cover up all the exposed terminals. How concerned do I need to be about ventilation because of heat?
Thanks in advance...
I currently have 3 group 31 AGM batteries connected in series. I need 36v and no more than 60a, it's currently fused at 60a. I have a Noco marine charger with 3 leads 10a each connected to each battery to charge. The boat is 24' and heavy and I use the trolling motor constantly. I pretty much drain the 110ah batteries every day. I doubt I'm really getting advertised power based on what I see and what I've found online. I can charge these batteries overnight and be ready to go in the morning if I have a power source but that's not always easy or available. I either have to pull the boat out of the water and plug it in to utility power or use a my Honda 1000 and run it all night and that makes it hard to sleep when camping on the boat. I'd like to get to the point where I don't have to mess with the generator or charging the batteries at all on a 3 or 4 day trip.
Also the savings on weight is huge for a boat. When I added the 3 group 31s I noticed it was much harder to get the nose all the way on the trailer because of the additional weight forward, which is really the only place I have.
My idea is to get 12 280ah or 310ah cells to make 36v. My big question is this... I'd like to use the existing Noco 12v 3 lead marine charger. I guess this means I will need to wire these batteries with 3 4s 100a BMSs to basically build 3 12v batteries and hook each up in series as if they were independent batteries. This seems easy to do, much like I have the 3 AGM batteries wired but then to monitor the batteries with a BlueTooth BMS I'd have to look at all 3 BMSs for capacity. I wouldn't be able to use a single shunt as I'd have to be charging the batteries in groups of 4 for 12v. I hope I'm making this clear... Would I be able to just monitor 1 of the 3 batteries and do the math by 3 or could that be way off?
It seems a better way would be to use a single 12s 100a BMS with BT but then I wouldn't be able to use the current charger. I'd have to get a charger capable of 36v and I have found 1 waterproof 36v charger at 10a which would work , but I don't see how I could use the existing charger because I'd have to charge groups of 4 at 12v and that wouldn't work with a single12s BMS would it?
I've seen a couple threads where people are asking about this for a 36v trolling motor but they don't have all the details I was hoping for. Hopefully someone else has done this and can offer some advice before I get in too deep on this.
I'm attaching a jpg of my initial plan, 3 groups of 4 cells for 3 12v batteries connected in series and 3 BMS but I'd really like a way of monitoring the ah use and capacity so I know how much I have left.... NOTE - I couldn't figure out how to change the scale so where you see 18' it's really 18" and where you see 2'9" it's really 2.75" I was in a hurry and just really needed to see it things fit and wanted to draw a quick diagram to get my thoughts straight... If there's a better way or if a 12s 36v BMS is a better route please let me know. Also if I messed up the wiring let me know this is my first shot at this with a BMS in the mix....
I'm planning on making a custom battery box out of marine board HDPE to house this and have a lid to cover up all the exposed terminals. How concerned do I need to be about ventilation because of heat?
Thanks in advance...
