Jokani
Active member
@sailaboutvic Did you compress the Calbs or insulate them? Trying to workout whether I need/want to?
270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
sailaboutvic
Well-known member
before I balance them I did have a strap around then while charging ,
Once fitted I used two double strap the cells are 4 on 4 up against the grp battery box one end the other end I have a ply wood side that separate the cells from the starter battery another ply wood the other side of the starter battery then the straps around the lot top and bottom . Batteries are solid.
Photo before job was finish .
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Jokani
Active member
Thanks that's helpful.
sailaboutvic
Well-known member
We have no need to insulate as we our in the Med , if it got that cold I be headed back to the uk haha
sailaboutvic
Well-known member
Gary I know you was thinking about Eve cell aluminium,
I'm no expert and don't pretend to be but if your going to use aluminium cells I would put some thing in between each cells mate if they going on a boat , on land their probity be ok .
I'm no expert and don't pretend to be but if your going to use aluminium cells I would put some thing in between each cells mate if they going on a boat , on land their probity be ok .
Kelpie
Well-known member
The cells appear to come very well packaged. Other than the extra space taken up, would there be anything wrong with reusing this in A permanent installation? Perhaps too much movement between the cells?
My other idea was to use GRP sheet. I have an old dinghy to dispose of, lots of thin flat sheet...
My other idea was to use GRP sheet. I have an old dinghy to dispose of, lots of thin flat sheet...
sailaboutvic
Well-known member
I think using the plastic from a dinghy tube would work in between each cell,
I would just make sure they can't move once under way .
I used the type of strap one uses to secure things like on roof rack , the once with a ratchet, you can get them really tight .
and if by any chance they did slack off a bit you just ratchet them up again.
Others have use ply wood side and threaded bars but you still have to stop them from moving around .
I cut four slits in the GRP side and put the strap through them first then around the end ply on the batteries so there was no way they could move .
I would just make sure they can't move once under way .
I used the type of strap one uses to secure things like on roof rack , the once with a ratchet, you can get them really tight .
and if by any chance they did slack off a bit you just ratchet them up again.
Others have use ply wood side and threaded bars but you still have to stop them from moving around .
I cut four slits in the GRP side and put the strap through them first then around the end ply on the batteries so there was no way they could move .
Poey50
Well-known member
If you are talking about aluminium cased prismatic cells then 0.5mm fibreglass sheets are thick enough against any blue plastic wrapped surface and underneath. Thicker than this and you just fill space unnecessarily.. You do need to immobilise the cells as you don't want to put stress on the soft aluminium terminals. Tensioning helps with longevity. I don't recommend Vic's method as the tension is variable. The plywood ends with metal bars works well as you can get a consistent tension. You don't want to over or under tension. Insulation is not a good idea. The method I used was gleaned from many previous builds and still holds up I think.
sailaboutvic
Well-known member
If I may add one more suggestion, it's a mistake that could had cost me dearly .
Being a total novice even after months of research, when my batteries turned up there where all spot on , I nearly never bothered to buy a power supply to balance them .
While waste £60 on a power supply only to be used once when the voltages where all spot on , plus another thing to store on board .
Here the thing the voltage don't start to stray until they get nearly full charge , what ever you do top balance the cells .
Being a total novice even after months of research, when my batteries turned up there where all spot on , I nearly never bothered to buy a power supply to balance them .
While waste £60 on a power supply only to be used once when the voltages where all spot on , plus another thing to store on board .
Here the thing the voltage don't start to stray until they get nearly full charge , what ever you do top balance the cells .
mitiempo
Member
Sailaboutvic
Passive balancing should be the only balancing needed. If you do a proper top balance when you get the cells they should stay very close in balance as long as the charging doesn't get too high. Active balancing should never be necessary.
Passive balancing should be the only balancing needed. If you do a proper top balance when you get the cells they should stay very close in balance as long as the charging doesn't get too high. Active balancing should never be necessary.
Jokani
Active member
Coincidentally, I ended up ordering the same batteries as you CALB SE200's, I was put off the aluminium. Hopefully they are already somewhere between here and China, but only ordered a week ago.
sailaboutvic
Well-known member
Thanks for that ,
But I respectfully I disagree with you , heavy charge and discharge can see cells stray over time , this isn't just an option it information from people who been uses lithium over time and seen it happen.
If that was the case why spend hundreds on bms when all you need to do is balance once and only charge them to say 13.8v and don't discharge them less then 12v . Add an alarm and away you go.
Most bms have active balances I guess smart don't for the same reason you have to solder bit of wires on and poke wires in holes and open module rather then incase them ,
to say a few cents , at over €300 plus you wouldn't say they cheap
It only take a wire thats worked it self loose, a bit of dirty or some corrosion to knock cells out of balance and on a boat that spend most of its time shaking in a damp environment it wouldn't take much.
mitiempo
Member
I did not say do not balance. I stated that ACTIVE balancing should not be required on a top balanced bank. And there are many BMS available for much less expense than hundreds. In addition to the Electrodacus I have (159 Cdn) there is the OverkillSolarBMS available for about 150 US. If I hadn't purchased the Electrodacus I would have bought the OverkillSolar BMS.
In my experience very few BMS have active balancing. Most have passive balancing. The two above are both passive.
If you have loose wires I doubt any type of automatic balancing will be a real help.
sailaboutvic
Well-known member
Again with respect we need to be very careful ,
for once we have a thread that's been informative and no argument and with that in mind let me clarify what I said .
I didnt say that you suggested not to balance. I be grateful if you read my posting again.
As regard to a bad connection how ever it may arise, it was referring to your suggestion that if the cells are porper balance its the only balance needed ( your words)
It was an example , that just because cells are balance it possible for lots of reason for cells to drift, has I said heavy uses over time for one.
I agree there are bms for much less money then I paid for the smart 123 and better too which is what I tried to get over here , before buying do your research.
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GHA
Well-known member
Raspberry Pi/LiFePo4 sounds like a match made in monitoring heaven, save mV readings and temperature of every cell once a second with alarms etc. I've a board slowly coming along which should do all that with headers to mount a Pi zero and rj45 sockets for a breakout boat at the batteries .
Anyone else doing this?
Easier than you might think and a Pi Zero has very little power consumption so can be left on 24/7.
Anyone else doing this?
Easier than you might think and a Pi Zero has very little power consumption so can be left on 24/7.
Poey50
Well-known member
Vic, what kind of voltage differences are you getting between your cells?
You're not having a happy time with your 123Smart BMS. So far I've been ok with mine but you are living aboard and cycling your battery whereas I have used ours very little because of the pandemic so I don't know what is normal usage yet. Are you using solid core wire for connecting the boards together? Those wire grippers are actually pretty good with solid core and pretty much impossible to pull out unless you have a small release key. If you are worried about damp on the boards then additional conformal coating may be a good idea. Only some of the higher range BMS's offer active balancing - REC and Orion Jnr being two. Most offer passive balancing and some do this at a more limited rate than the 123Smart.
You're not having a happy time with your 123Smart BMS. So far I've been ok with mine but you are living aboard and cycling your battery whereas I have used ours very little because of the pandemic so I don't know what is normal usage yet. Are you using solid core wire for connecting the boards together? Those wire grippers are actually pretty good with solid core and pretty much impossible to pull out unless you have a small release key. If you are worried about damp on the boards then additional conformal coating may be a good idea. Only some of the higher range BMS's offer active balancing - REC and Orion Jnr being two. Most offer passive balancing and some do this at a more limited rate than the 123Smart.
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Poey50
Well-known member
Just a note on using aluminium cased prismatic cells for an LFP build.
I've mentioned a few times that with additional space and money I would have bought plastic cased cells - Winstons would have been my choice but at the time of purchase these were x 3 the cost of my imported blue cells. However the rejection of - to misquote Poirot "the little blue cells" is often somewhat ill-informed and this comes about from not properly distinguishing between three separate issues in relation to the aluminium casings - oxidation, galvanic corrosion, and electrolytic corrosion.
Just in case it isn't yet clear, I'm no expert so open to other information but this is how I understand it.
OXIDATION. Exposure of aluminium to the air leads to an oxidised layer that helps to stabilise the surface. It may not be pretty to look at but is not alone going to do long term harm to the metal. This presumably is why aluminium boat topsides are left exposed.
GALVANIC CORROSION. This needs the presence of another metal higher on the galvanic scale and an electrolyte. The only place where this could happen on a blue cell is where the aluminium terminal meets a copper busbar plus moisture. This is no different from using plastic cased cells and can be protected against by use of Ox-gard or anything which excludes damp.
ELECTROLYTIC CORROSION. This, I think, is the potentially serious one for these cells but can readily be guarded against. As said at the start of this thread, the blue plastic is thin and barely adequate to isolate the positively charged case. Any stray current finding its way to earth can cause damage to the case with potentially serious consequences. There is a photo of this on the original post caused by cells sitting on painted wood that had got wet. But if the cells have additional insulation between them and under them so the blue coating is not relied upon and the battery compartment is not wet then there should be no problem.
I've posted a question on the Lithium Batteries on a Boat Facebook Group to ask if anyone using these cells has experienced corrosion issues. Many have been using them for several years but, so far, out of 4,000 plus subscribers, not a single report.
I've mentioned a few times that with additional space and money I would have bought plastic cased cells - Winstons would have been my choice but at the time of purchase these were x 3 the cost of my imported blue cells. However the rejection of - to misquote Poirot "the little blue cells" is often somewhat ill-informed and this comes about from not properly distinguishing between three separate issues in relation to the aluminium casings - oxidation, galvanic corrosion, and electrolytic corrosion.
Just in case it isn't yet clear, I'm no expert so open to other information but this is how I understand it.
OXIDATION. Exposure of aluminium to the air leads to an oxidised layer that helps to stabilise the surface. It may not be pretty to look at but is not alone going to do long term harm to the metal. This presumably is why aluminium boat topsides are left exposed.
GALVANIC CORROSION. This needs the presence of another metal higher on the galvanic scale and an electrolyte. The only place where this could happen on a blue cell is where the aluminium terminal meets a copper busbar plus moisture. This is no different from using plastic cased cells and can be protected against by use of Ox-gard or anything which excludes damp.
ELECTROLYTIC CORROSION. This, I think, is the potentially serious one for these cells but can readily be guarded against. As said at the start of this thread, the blue plastic is thin and barely adequate to isolate the positively charged case. Any stray current finding its way to earth can cause damage to the case with potentially serious consequences. There is a photo of this on the original post caused by cells sitting on painted wood that had got wet. But if the cells have additional insulation between them and under them so the blue coating is not relied upon and the battery compartment is not wet then there should be no problem.
I've posted a question on the Lithium Batteries on a Boat Facebook Group to ask if anyone using these cells has experienced corrosion issues. Many have been using them for several years but, so far, out of 4,000 plus subscribers, not a single report.
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Poey50
Well-known member
The stage is set for you, GHA! I await results with interest.
Nicking bits of this along the way ..
sailaboutvic
Well-known member
We still experimenting we found whats works best at the moment , abs 14v float 13.5v seen to be about right dropping the abs on13.8v on sunny days , soon we be using less induction hob and mico waves the electric rad as already been put away so we won't be using so much then and I will set Abs to 13.8v no point charging higher if I don't need to.
once a month I increase charging to Abs 14.1v .
At 14.1v the different in cells are nothing , as it get close to 14.2 cells 3 slowly start to drift 14.3v would see cells 3 hitting 3.65 while the others are within 0.01 of each of the other cells
Whats strange and it may be normal is cell 3 is always .01/.02 behind all the other cells until it reaches 14.2v
I not tested at 14.4v as I know cell 3 will be pass 3.65v
See photos at 14v
Our 8 cells are in a 2P4S so we can use just one bms in reality each module it reading 2 cells as one, now if thats causing the different in reading as the cell get close to 3.65 dont know .
I wouldn't say I'm dissatisfied they seen to be working OK but for the money its more of a diy kit then a complete bms , Module are very easy to damage and as you know you have to go to the expense of adding relays to protect the batteries where many bms have protection build in .
If you add the full cost of the 123 plus relays you can buy a much better quality like the orion, which is what i would go for if I did it again.
Personally I don't thing 123smart are suitable for boats , on land sure even a RV .
once a month I increase charging to Abs 14.1v .
At 14.1v the different in cells are nothing , as it get close to 14.2 cells 3 slowly start to drift 14.3v would see cells 3 hitting 3.65 while the others are within 0.01 of each of the other cells
Whats strange and it may be normal is cell 3 is always .01/.02 behind all the other cells until it reaches 14.2v
I not tested at 14.4v as I know cell 3 will be pass 3.65v
See photos at 14v
Our 8 cells are in a 2P4S so we can use just one bms in reality each module it reading 2 cells as one, now if thats causing the different in reading as the cell get close to 3.65 dont know .
I wouldn't say I'm dissatisfied they seen to be working OK but for the money its more of a diy kit then a complete bms , Module are very easy to damage and as you know you have to go to the expense of adding relays to protect the batteries where many bms have protection build in .
If you add the full cost of the 123 plus relays you can buy a much better quality like the orion, which is what i would go for if I did it again.
Personally I don't thing 123smart are suitable for boats , on land sure even a RV .
