custom made battery box for eve LF280K cells

[toluxa1]

The BMS learns also. Once you cycle it a few times, it should provide the "seen" capacity.

Seplos just replied my message now. Do you think it's best to set it manually or just allow the BMS get the real capacity through full charge and discharge?
Also, if I'm discharging, do I discharge to 0%? Considering there is Low SOC parameters.

 

[houseofancients]

Seplos just replied my message now. Do you think it's best to set it manually or just allow the BMS get the real capacity through full charge and discharge?
Also, if I'm discharging, do I discharge to 0%? Considering there is Low SOC parameters.

real capacity as it will be as it says real and measured, and not a label value

 

[Rossman]

Seplos just replied my message now. Do you think it's best to set it manually or just allow the BMS get the real capacity through full charge and discharge?
Also, if I'm discharging, do I discharge to 0%? Considering there is Low SOC parameters.

Does anyone know if this is even true? With my BMS', I set the capacity at 280Ah when i put them into service, and the BMS has "learned" it's SoC from a full cycle (many full cycles), but it has never "learned" my cell capacity and changed the value from the 280Ah I specified.

edit: I have four packs and all of them behave the same way, I would expect some variance in them (though perhaps minor) at this point.

 

[Sanwizard]

Does anyone know if this is even true? With my BMS', I set the capacity at 280Ah when i put them into service, and the BMS has "learned" it's SoC from a full cycle (many full cycles), but it has never "learned" my cell capacity and changed the value from the 280Ah I specified.

edit: I have four packs and all of them behave the same way, I would expect some variance in them (though perhaps minor) at this point.

The parameter setting stays the same. The actual usable capacity will differ. Andy at offgridgarage youtube channel covers this fairly well. The manual may also help.

Seplos 48v 200A 8S-16S BMS - Please read this manual carefully before operating and retain it for - Studocu

Share free summaries, lecture notes, exam prep and more!!

www.studocu.com

 

[Rossman]

Can you highlight / point out specifically where in the manual it says this? Feel like I've read it many times and not come to that conclusion.

 

[Sanwizard]

Can you highlight / point out specifically where in the manual it says this? Feel like I've read it many times and not come to that conclusion.

Section 2.3 to 2.6. You need the PC software to change parameters.

 

[toluxa1]

busbars.
i dont daisy chain, too much current , so i have each battery connected to a common busbar ( like the eg4 racks), where the positive and negative connection to the inverters arebon opposite side

as for interconnecting the comms, just a plain utp cable

If I am doing this for 4 battery packs, do you think a bus bar of 400A is okay?

 

[Sanwizard]

If I am doing this for 4 battery packs, do you think a bus bar of 400A is okay?

You will end up expanding, and this is a critical junction point for your system. The connections need to be well made. I bought the Blue Sea Systems 1000amp busbar to be sure. Its tinned copper, so the connections will have less resistance from possible corrosion.

Should be available on Amazon or Alt-e store

 

[Ron-ski]

@Sanwizard If its anything like the Victron 1000 amp busbars, it won't actually be a 1000 amp rating by physical size. I can't see what size the Blue Sea one is, but it looks 38mm wide, and therefore would need to be 20mm thick according to the below calculator.

You can check what current a busbar can handle here https://www.electrical4u.net/calculator/busbar-current-calculator-online/

@toluxa1 I used 40 x 8 (384A) for my battery busbar, with the main inverter feed take off in the middle, and the four batteries connected at the ends. See this post

 

[toluxa1]

@toluxa1 I used 40 x 8 (384A) for my battery busbar, with the main inverter feed take off in the middle, and the four batteries connected at the ends. See this post

That's Great. In order words you believe the 400A is sufficient enough.
The Bluesea ones are way on the high side for me, plus hard to get in west Africa where I live.

I'll go with the 400A.

 

[Danke]

You can check what current a busbar can handle here https://www.electrical4u.net/calculator/busbar-current-calculator-online/

That chart seems very conservative.

Electrical: Busbar - DC Copper Busbar Ampacities

The following tables have been provided by the Alliance for Telecommunications Industry Solutions (ATIS), T1 Committee, and represent ampacities for busbar sizes and arrangements typically found in the telecommunications industry.

www.copper.org

Electrical: Bus Bar - Table 1: Ampacities

Ampacities in the table below are for bus bars having an emissivity of 0.4.

www.copper.org

 

[Ron-ski]

That's Great. In order words you believe the 400A is sufficient enough.
The Bluesea ones are way on the high side for me, plus hard to get in west Africa where I live.

I'll go with the 400A.

In my case yes, my inverter can pull about 160A continuous, recommended fuse is 400A, so I considered 40 x 8 to be sufficient.

@Danke Yes that chart does make the 384A rather conservative for 40 x 8, but it also makes the 30 x 8 that Victron claim is good for a 1000A rather optimistic, although I didn't do a direct comparison as it's in old world inches

 

[Sanwizard]

@Sanwizard If its anything like the Victron 1000 amp busbars, it won't actually be a 1000 amp rating by physical size. I can't see what size the Blue Sea one is, but it looks 38mm wide, and therefore would need to be 20mm thick according to the below calculator.

You can check what current a busbar can handle here https://www.electrical4u.net/calculator/busbar-current-calculator-online/

@toluxa1 I used 40 x 8 (384A) for my battery busbar, with the main inverter feed take off in the middle, and the four batteries connected at the ends. See this post

Here are some example of the Blue Sea Systems product. Pretty substantial. I trust blue sea systems specs also. All that said, just make sure your busbar does not get hot under load, and you should be fine. I doubt your loads will be pulling over 100 amps most of the time.

 

[Ron-ski]

@Sanwizard But what are the dimensions of the actual copper busbar?

I'm not the only one to question the Victron Lynx busbar 1000A claim.

This thread makes interesting reading https://community.victronenergy.com/questions/109894/lynx-power-in-really-1000a.html

As you say though, at the end of the day as long as the busbars not getting hot under heavy load, it will likely be fine, but I do prefer to air on the side of caution and design my system for peak power.

 

[Sanwizard]

@Sanwizard But what are the dimensions of the actual copper busbar?

I'm not the only one to question the Victron Lynx busbar 1000A claim.

This thread makes interesting reading https://community.victronenergy.com/questions/109894/lynx-power-in-really-1000a.html

As you say though, at the end of the day as long as the busbars not getting hot under heavy load, it will likely be fine, but I do prefer to air on the side of caution and design my system for peak power.

I Dont have my micrometer handy, but the weight should help. The Blue Sea 400amp fuse holder weighs over 1lb. The 1000amp busbar is over 4lb. The copper is bar is the width of a finger.

If you compare that to the Seplos JASSN busbar, which is engineered to handle 750amps (6 x 125amp breakers), you can see how over engineered the Blue Sea Systems components are.

The JASSN keeps the overall system looking professional, since it has the same look as the batteries. It has 12 holes on the bottom for 6 neg and 6 pos cables from the batteries, and 6 holes on top for up to 3 Inverters.

I put the Blue Sea on top of the JASSN so you can compare the thickness of the bar itself. Even the 400 amp fuse holders are massively more robust. Difference of made in USA vs made in China I guess.

 

[Ron-ski]

@Sanwizard I'm not disputing their quality, just their 1000A claim.

In the picture below on the left is a 40 x 8mm tinned copper bar, on the right a Bussmann JJN-400 T class fuse for comparison, the bolt in the lug is 8mm (5/16").

That bar is two finger widths, which is twice the width of yours presuming we have the same size finger 40 x 8 in imperial measurements is 1 and 9/16" x 5/16". Imperial measurements are just so messy.

Going by the link that @Danke posted earlier, my 40 x 8 copper bar is rated at 721A. 40 x 8mm (320mm2 )is near enough the same cross sectional area as a 1/4 x 2" bar (25.4/4)*(2*25.4) = 322.58mm2. But I notice in that link they have the cross sectional area as 636.6cm2 which is most odd.

 

[Sanwizard]

@Sanwizard I'm not disputing their quality, just their 1000A claim.

In the picture below on the left is a 40 x 8mm tinned copper bar, on the right a Bussmann JJN-400 T class fuse for comparison, the bolt in the lug is 8mm (5/16").

That bar is two finger widths, which is twice the width of yours presuming we have the same size finger 40 x 8 in imperial measurements is 1 and 9/16" x 5/16". Imperial measurements are just so messy.

Going by the link that @Danke posted earlier, my 40 x 8 copper bar is rated at 721A. 40 x 8mm (320mm2 )is near enough the same cross sectional area as a 1/4 x 2" bar (25.4/4)*(2*25.4) = 322.58mm2. But I notice in that link they have the cross sectional area as 636.6cm2 which is most odd.

View attachment 134073

I should have said finger thick instead of width. It looks similar to your copper bar in thickness. Yours looks like it should handle any load you throw at it and still stay cool. In any case, yours is an elegant solution at a much lower cost.

 

[Danke]

@Sanwizard I'm not disputing their quality, just their 1000A claim.

In the picture below on the left is a 40 x 8mm tinned copper bar, on the right a Bussmann JJN-400 T class fuse for comparison, the bolt in the lug is 8mm (5/16").

That bar is two finger widths, which is twice the width of yours presuming we have the same size finger 40 x 8 in imperial measurements is 1 and 9/16" x 5/16". Imperial measurements are just so messy.

Going by the link that @Danke posted earlier, my 40 x 8 copper bar is rated at 721A. 40 x 8mm (320mm2 )is near enough the same cross sectional area as a 1/4 x 2" bar (25.4/4)*(2*25.4) = 322.58mm2. But I notice in that link they have the cross sectional area as 636.6cm2 which is most odd.

View attachment 134073

The circular mil is a unit of area used especially when denoting the cross-sectional size of a wire or cable.

A circular mil is the equivalent area of a circle whose diameter is 0.001 (10-3) inch, or approximately 0.7854 millionths of a square inch.

4/0 cable cross section is 158.9mm2, Ampacity 440 from chart for battery cable.


So with that bar 1/4” x 2” I calculate it being 322.58mm2 also (but their chart is 410.7mm2?), I can see 731/721 ampacity.

Electrical: Bus Bar - Table 1: Ampacities

Ampacities in the table below are for bus bars having an emissivity of 0.4.

www.copper.org

 

[GummiSolar]

Can you direct me to where I can find that settings?

Go to Load Parameters and you will see battery Capacity #58. Change it to 304Ah.

 

[danmc]

Can anyone advise?

Background: I'm using LF280K EVE cells with the new double terminals, and as the EVE busbars or the ones provided with the mason aren't long enough to bridge the gap between the two rows I bought nickel plated copper bar from China planning to make my own.

The busbars provided by EVE seem to be 20mm x 2mm so I ordered the same in nickel plated copper bar, unfortunately what arrived does not appear to be 2mm thick. And even if it is it isn't as thick as the EVE busbars. Would it still be OK to use? Or do I need a plan B? How many amps would it need to be able to safetly carry?