Just asking for the cheapest solution for a 14s @48v BMS for 245 Nissan leaf G2 batteries, I just want to hook seven of them together and get 56V, but buying 35 BMS’s Would get very expensive, I took a picture of what I got and I have eight of these with seven batteries in a module and with a BMS as an example, The rest of the batteries I have coming big battery had a blowout sale, I would appreciate any suggestions, David Poz suggested a watchmon 4, but I have no idea how much that would cost and I think it’s coming from Australia so if anybody has any suggestions I’m all ears, thank you for your time Jeff
14s 48v Nissan leaf G2 BMS
- Thread starter yah
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Ampster
Renewable Energy Hobbyist
Okay let's start out by clarifying how many modules you will have in total? Each module is 8 volts and I assume you are going to put a bunch of them in parallel and seven of those groups in series to get 56 volts. That would be XP14S where X equals the number of modules in parallel. 14S is the number of cells because each module has two cells in series inside the module.
On a hunch I divided 245 by 7 and came up with 35 so I may have guessed the answer. If that is the correct assumption you could do it as one big battery pack with one BMS or 35 small packs each with their own BMS or something in between. I think there is some likely hood that some of these maybe damaged or have reduced capacity that you may want to develop a strategy to test them in some fashion. How are you planning on using them?
On a hunch I divided 245 by 7 and came up with 35 so I may have guessed the answer. If that is the correct assumption you could do it as one big battery pack with one BMS or 35 small packs each with their own BMS or something in between. I think there is some likely hood that some of these maybe damaged or have reduced capacity that you may want to develop a strategy to test them in some fashion. How are you planning on using them?
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A friend of mine has this on his 5th wheel 48V Leaf battery system:
Been working perfectly for well over a year.
It's not inexpensive, but it's reasonable compared to other high end BMS. It's also infinitely cheaper than an indoor battery fire.
Been working perfectly for well over a year.
It's not inexpensive, but it's reasonable compared to other high end BMS. It's also infinitely cheaper than an indoor battery fire.
Ampster
Renewable Energy Hobbyist
If he wants to go with a pack that big there is no way any meaningful balancing can be done by a normal BMS. That many Leaf modules is over 100 kWh of capacity.
Yeah. At that point, you're just relying on monitoring. There are some 4A (peak) balancers that I'll be using, but they work all the time independent of the BMS.
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I've used 7 of these on a smaller unmanaged 24V. Every time I checked the cells manually, they were within a .01V range. I used the charge controller to manage the pack voltage and just crossed my fingers with the low end.
I also have the confidence in having tested all 420 cells.
Ampster
Renewable Energy Hobbyist
Back to the original question the least expensive solution is a multimeter and you are the BMS. If you have the time that @snoobler took to test each cell and bin them your odds will increase to have a pack that you can depend on. Buss bars alone are going to set you back some. I figure over 60 feet of copper and over 700 holes in those buss bars.
Thank you so much for the replies and yes 245 batteries is hopefully what I’m going to have to work with I initially had 56 batteries plus the 192 batteries that came today still in containers And yes there is a few dings and dents on them so who knows if they are damaged until I open them up.
And the three Nissan leaf batteries i’ll use for something else since I couldn’t use them in a pack of seven.
Iplanning on using them with Solar.
And I would like to have one BMS control everything just because spending money on 35 BMS’s would be kind of costly.
To test the batteries I bought a sm8124 Impedance meter and a Load tester the one with the purple fan in Will Prowse video
The batteries are supposed to be 70% with the loss of 30% and I hope these last me until I’m old and gray or at least until the solid state batteries are dirt cheap.
And again thank you to everybody for all the information,
Ampster You’re right I probably will spend a butt load on copper bus bars, and I hope you’ll let me know what you think on the set up thank you for your time Jeff
And the three Nissan leaf batteries i’ll use for something else since I couldn’t use them in a pack of seven.
Iplanning on using them with Solar.
And I would like to have one BMS control everything just because spending money on 35 BMS’s would be kind of costly.
To test the batteries I bought a sm8124 Impedance meter and a Load tester the one with the purple fan in Will Prowse video
The batteries are supposed to be 70% with the loss of 30% and I hope these last me until I’m old and gray or at least until the solid state batteries are dirt cheap.
And again thank you to everybody for all the information,
Ampster You’re right I probably will spend a butt load on copper bus bars, and I hope you’ll let me know what you think on the set up thank you for your time Jeff
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One BMS lead per parallel cell group. Given the size it MIGHT help to break them up into a sensible number of separate batteries for better control. Maybe 5? Make sure you sort your modules to ensure your parallel groups are the same capacity, but you probably already know that.
Is it possible to take 7 Nissan leaf batteries, That would make 56V or around, Like I have set up on the shelves in the picture, but Use one BMS and instead of 7 Nissan leaf batteries
Use it for 35 batteries that are grouped in 7,
So another words use one BMS for 5 groups of 7, to save On buying as many BMS’s And up the BMS from what I have now at 60A to 150A or 200A
Like Snoobler said
Would that work or would it be a balance issue?
Thank you for your time and Jeff
Use it for 35 batteries that are grouped in 7,
So another words use one BMS for 5 groups of 7, to save On buying as many BMS’s And up the BMS from what I have now at 60A to 150A or 200A
Like Snoobler said
Would that work or would it be a balance issue?
Thank you for your time and Jeff
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Ampster
Renewable Energy Hobbyist
I am having a hard time following you. I count 8 groups in that picture which would be 64 volts. In your statement you say five groups of seven. That would be 40 volts. There is no reason you can't stack them as high as you want to in parallel. When in parallel they will all be at the same voltage.
Maybe some of the confusion is because of that green connector plate? Are you going to use those? Do they connect the cells in series or parallel? I count seven cells in a stack.
Before I can intelligently answer your question about what size BMS I need to know what you are powering? That will determine whether a 60, 150 or 200 Amp BMS is needed.
Maybe some of the confusion is because of that green connector plate? Are you going to use those? Do they connect the cells in series or parallel? I count seven cells in a stack.
Before I can intelligently answer your question about what size BMS I need to know what you are powering? That will determine whether a 60, 150 or 200 Amp BMS is needed.
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Thanks for the quick reply Ampster, you’re right there are seven batteries together with the circuitboard in front is so you don’t half to run wires from the batteries to the BMS, I was lazy. They sold the BMS and the circuitboard for $65 opposed to $55 just by the BMS so I thought what the heck.
And there is eight BMS’s And 8) 7packs like in the picture. I think the max I can charge one of the seven packs or the whole thing is 58.8v but I usually charge it up to 57V even, And the BMS’s is 60 amp.
for the batteries I have complete that are on the shelves that you seen in the previous picture I would like to remove the circuit board and the BMS‘s and add the Batteries to the rest of the batteries that I got in today and hook them all together to make a big 48 V system and that’s if I went with a central BMS.
My set up is:
66) 250W solar panels used from Satan solar
4) midnight solar classic 250
1) midnight solar classic 150
2) SMA SI6048 off grid inverter Which is capable up to 12,000W joining the two,
Which I’ll probably would never come close to ever using that much it’s just that I needed two of them to make 240 Which I’ll probably would never come close to ever using that much it’s just that I needed two of them to make 240v
So I’ll be running 12 panels per midnight solar classic 250
And also running 18 panels for the one midnight classic 150
about the last post that I made I was referring to just using less BMS’s and keeping the system at 48V it was just an example instead of having a BMS on every seven batteries, maybe skip a seven pack every other one or every five or every seven while still making at 48V.
So you asked what am I powering well I use about 20 kW a day, I typically am running 300 to 400WAH and I live by myself so I’m not always running the washer and dryer.
and you said I could run them in parallel and make them long, what about this idea imagine I had a big ass shelving rack and nice and long with seven shelves And I put 35 batteries on each shelf and take four pieces of all thread and bolt the 35 batteries Together and I do this on all seven shelves and then connect the seven shelves on the end together to make 56 to 58v For a 48 V system, and use one high amp BMS, just a thought I have a long way to go and learning every day.
Thanks for your time Jeff
And there is eight BMS’s And 8) 7packs like in the picture. I think the max I can charge one of the seven packs or the whole thing is 58.8v but I usually charge it up to 57V even, And the BMS’s is 60 amp.
for the batteries I have complete that are on the shelves that you seen in the previous picture I would like to remove the circuit board and the BMS‘s and add the Batteries to the rest of the batteries that I got in today and hook them all together to make a big 48 V system and that’s if I went with a central BMS.
My set up is:
66) 250W solar panels used from Satan solar
4) midnight solar classic 250
1) midnight solar classic 150
2) SMA SI6048 off grid inverter Which is capable up to 12,000W joining the two,
Which I’ll probably would never come close to ever using that much it’s just that I needed two of them to make 240 Which I’ll probably would never come close to ever using that much it’s just that I needed two of them to make 240v
So I’ll be running 12 panels per midnight solar classic 250
And also running 18 panels for the one midnight classic 150
about the last post that I made I was referring to just using less BMS’s and keeping the system at 48V it was just an example instead of having a BMS on every seven batteries, maybe skip a seven pack every other one or every five or every seven while still making at 48V.
So you asked what am I powering well I use about 20 kW a day, I typically am running 300 to 400WAH and I live by myself so I’m not always running the washer and dryer.
and you said I could run them in parallel and make them long, what about this idea imagine I had a big ass shelving rack and nice and long with seven shelves And I put 35 batteries on each shelf and take four pieces of all thread and bolt the 35 batteries Together and I do this on all seven shelves and then connect the seven shelves on the end together to make 56 to 58v For a 48 V system, and use one high amp BMS, just a thought I have a long way to go and learning every day.
Thanks for your time Jeff
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Ampster
Renewable Energy Hobbyist
I think the first thing to be figured out is what configuration is mechanically practical. One pack consisting of 35 modules in parallel combined with six others of the same size is a lot of space and weight.. Seven of those groups in series is not going to be practical to be managed by a typical BMS. The weight alone is something to consider. I have six modules in parallel and they are heavy.
Or some configuration of smaller packs in parallel with others for ease of maintenance.
Or some configuration of smaller packs in parallel with others for ease of maintenance.
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Ampster
Renewable Energy Hobbyist
The other issues now that I understand the big picture is whether to have both inverterss share one pack, or have each inverter have its own pack or have each inverter share two packs each. As mentioned earlier perhaps a battery monitoring system would be more cost effective because a BMS could never balance packs of that size. If there was drift then the OP could install balancers.
Hello Ampster,
You’re definitely right about taking up a lot of space I figured from the freight each unit is 600lbs x 4=2400 pounds And so I figure 12 1/2 pounds per battery and the thickness of the battery is an 1 3/8”
Then times that by 35 and you get 48 inches or 4 foot and that would take up one shelf weighing 437 1/2 pounds and then of course I would need seven shelves not to mention all the charge controllers and the SMA inverters, but the nice thing is the house is on a cement
Slab.
As far as space I can always make it work since I live alone I would have nobody to complain about it except for myself for the size of the batteries taking up space.
But as far as saying that I want to make sure that whatever I buy is going to do the job for a BMS or balancing, i’m guessing it’s starting to look like either I get on AliExpress or Alibaba and make a deal for 27 BMS’s or Pay more money and go with Batrium, Orion, or REC
I don’t know, my little pea brain is rattling around, so what might be your thoughts on this Ampster, thank you for your time Jeff
You’re definitely right about taking up a lot of space I figured from the freight each unit is 600lbs x 4=2400 pounds And so I figure 12 1/2 pounds per battery and the thickness of the battery is an 1 3/8”
Then times that by 35 and you get 48 inches or 4 foot and that would take up one shelf weighing 437 1/2 pounds and then of course I would need seven shelves not to mention all the charge controllers and the SMA inverters, but the nice thing is the house is on a cement
Slab.
As far as space I can always make it work since I live alone I would have nobody to complain about it except for myself for the size of the batteries taking up space.
But as far as saying that I want to make sure that whatever I buy is going to do the job for a BMS or balancing, i’m guessing it’s starting to look like either I get on AliExpress or Alibaba and make a deal for 27 BMS’s or Pay more money and go with Batrium, Orion, or REC
I don’t know, my little pea brain is rattling around, so what might be your thoughts on this Ampster, thank you for your time Jeff
Ampster
Renewable Energy Hobbyist
You can get an Orion Jr for $500 and I have used one for 5 years. I dont know much about the others. I am writing this from a Supercharger on the I5 in Central California returning from a quick trip to Los Angeles. My pack is only a few days old and I wanted to check on it i just went to the connect.orionbms.com sight and saw my pack is charging at 27 Amps and voltage is 53.5 after dipping to 52 volts overnight.
have the WiFi Connect installed and I love the information. Your situation might be different with used cells. You may want some redundancy by splitting your pack into pieces. If I were in your position the most I would do would be 4 packs, two for each inverter.
I will have to give more thought to this but some of it should relate to your goals. How do you value redundancy versus having one big pack that would be hard to disassemble if one cell in the middle of a 48 inch long group went bad? That is a lot of interconnects to unbolt before you took the pressure off the allthread holding all 35 together.
Hello Ampster,
I think you’re right again having 4 feet of batteries with a bunch of wires in case one does go bad that would probably take a whole afternoon to fix.
I’m willing to go with what you suggested use two packs on one inverter and two packs on the other but do you think an Orion Junior would work on four packs or would I need two Orion juniors, Thank you for your time Jeff
I think you’re right again having 4 feet of batteries with a bunch of wires in case one does go bad that would probably take a whole afternoon to fix.
I’m willing to go with what you suggested use two packs on one inverter and two packs on the other but do you think an Orion Junior would work on four packs or would I need two Orion juniors, Thank you for your time Jeff
schmism
Solar Addict
were you happy with the techdirect BMS for the leaf modules? I also have a Leaf pack coming.
My plan was to go 40-60A BMS on each 48v pack and run each pack to a buss bar for the inverters. Ill have 2x 3K inverters so I anticipate a max current draw off the bus of ~125a. In theory you can spread that over as many single stack packs as you have. Its a bit more complex as multipul packs feeding a single bus, there are voltage considerations concerning the wire distance from each pack and location of each inverter.
The other way is to run several leaf modules in parallel (buss bar down the front) and then series these stacks with the BMS lead on each stack. (you can see this version here
)
I think for as many modules as you'll have then it makes sense to put 4 or 6 in a P stack and limit the number of 100-200A BMS you need.
My plan was to go 40-60A BMS on each 48v pack and run each pack to a buss bar for the inverters. Ill have 2x 3K inverters so I anticipate a max current draw off the bus of ~125a. In theory you can spread that over as many single stack packs as you have. Its a bit more complex as multipul packs feeding a single bus, there are voltage considerations concerning the wire distance from each pack and location of each inverter.
The other way is to run several leaf modules in parallel (buss bar down the front) and then series these stacks with the BMS lead on each stack. (you can see this version here
I think for as many modules as you'll have then it makes sense to put 4 or 6 in a P stack and limit the number of 100-200A BMS you need.
@yah Looking forward to your build! Not sure if you have seen this setup but he went big, really big with the number of parallel cells, 20p or so.
He has a few videos on his system but this one I believe has a nice overview that might give you some decent ideas on how you approach yours.
Good Luck!
He has a few videos on his system but this one I believe has a nice overview that might give you some decent ideas on how you approach yours.
Good Luck!
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