Questions.

[ynot]

Please bear with questions from a first time BMS buyer.
Am planning on 5 leaf modules in series with 2 sets parallel for 40 V +/-. That is the best layout for the battery box.
Reason for 40 volts is that the motor and controller are nominal 36v from the days when every thing was L/A batts.
So have ordered a 48v daly bms thinking that it would be safer than a 36 volt being pushed. I intend to connect balancing jumpers to matching cells from each parallel set
The BMS's high voltage cutoff for the cells is 4.2, but have ordered a 40 volt power supply/charger, so am not likely to hit the high voltage cutoff.
BIG question for me is that there will be unused balancing leads, a wild thought is what if I double up the extra balancing leads say 5&6 together and 9&10 together, the BMS should just see them as individual inputs at identical voltages. or do I just leave the last ones un-connected or cut them off or tie them together.
Or is there a better BMS available, budget is a real concern as I blew my allowance for the year on the full leaf battery.
Hope am not being too stupid,
Ynot

 

[J_Mack58]

Please bear with questions from a first time BMS buyer.
Am planning on 5 leaf modules in series with 2 sets parallel for 40 V +/-. That is the best layout for the battery box.
Reason for 40 volts is that the motor and controller are nominal 36v from the days when every thing was L/A batts.
So have ordered a 48v daly bms thinking that it would be safer than a 36 volt being pushed. I intend to connect balancing jumpers to matching cells from each parallel set
The BMS's high voltage cutoff for the cells is 4.2, but have ordered a 40 volt power supply/charger, so am not likely to hit the high voltage cutoff.
BIG question for me is that there will be unused balancing leads, a wild thought is what if I double up the extra balancing leads say 5&6 together and 9&10 together, the BMS should just see them as individual inputs at identical voltages. or do I just leave the last ones un-connected or cut them off or tie them together.
Or is there a better BMS available, budget is a real concern as I blew my allowance for the year on the full leaf battery.
Hope am not being too stupid,
Ynot

I'll be waiting like you for some suggestions, I'm yet to put a BMS on my pack(s). Good question I think.

 

[floydR]

Many BMS's are voltage/series specific that is a 48v nominal 14s would probably not work as a 36v nominal 10s. There are exceptions Ant BMS's. can work with 7-16s, others can work with 8s-24s or more. tinybms 4-16s ,chargery bms 9-16s 16-24s Not all bms's list if they will work with lower series of cells some do and some dont.

later floyd

 

[OffGridInTheCity]

Please bear with questions from a first time BMS buyer.
Am planning on 5 leaf modules in series with 2 sets parallel for 40 V +/-. That is the best layout for the battery box.

A leaf module has 2 separate lithium-ion 'cells'. So 5 leaf modules in series implies 10s. And 2 of these in parallel (e.g. 10 leaf modules) would be 10s2p.

Reason for 40 volts is that the motor and controller are nominal 36v from the days when every thing was L/A batts.
So have ordered a 48v daly bms thinking that it would be safer than a 36 volt being pushed. I intend to connect balancing jumpers to matching cells from each parallel set

Its not (exactly) 48v vs 36v but rather you want a BMS that can handle 10s cells - e.g. will have 11 sense leads. 1 for bottom negative an then 1 for the positive of each cell in series. Notice the "10s" in the description of this DALY BMS listing https://www.amazon.com/DALY-Protection-Battery-Management-Current/dp/B087BYHJ92

And yes, you can hop-scotch each sense lead to each of the cells in the 2p groups if you need to. Its not clear to me (yet) if you have 1 battery of 10s2p or 2 batteries of 10s1p.

*Maybe you could post a pic or wiring diagram of how you plan to hook these in series and parallel - I sense some potential miscommunication here!!

The BMS's high voltage cutoff for the cells is 4.2, but have ordered a 40 volt power supply/charger, so am not likely to hit the high voltage cutoff.

40v max charging will give you 4.0v hi per cell. That's safe but you won't have the option to charge a 10s battery all the way up. They do make 10s lithium-ion chargers - https://www.amazon.com/Adapter-Charger-Lithium-5-5x2-5mm-5-5x2-1mm/dp/B088PDJ6FL

BIG question for me is that there will be unused balancing leads, a wild thought is what if I double up the extra balancing leads say 5&6 together and 9&10 together, the BMS should just see them as individual inputs at identical voltages. or do I just leave the last ones un-connected or cut them off or tie them together.

Not sure what you mean when you say 5 & 6 or 9 & 10. Not sure what this means. See my comment about about pic and/or wire-up diagram to help clarify your design.

Or is there a better BMS available, budget is a real concern as I blew my allowance for the year on the full leaf battery.
Hope am not being too stupid,

No problem. This is a information sharing site - no judgements on beginning questions

Ynot

 

[ynot]

Maybe you could post a pic or wiring diagram of how you plan to hook these in series and parallel - I sense some potential miscommunication here!!

Thanks for the reply
two batteries five modules in series in each. 10s connected + to + - to neg, for each battery, standard connection for cells in series will use some the bus bars out of the original pack. Tough for me to do graphics.

40v max charging will give you 4.0v hi per cell. That's safe but you won't have the option to charge a 10s battery all the way up.

The power supply will go to 50 volts if needed, plan to set it at 40 volts /4.0 per cell to be easy on the battery.

Not sure what you mean when you say 5 & 6 or 9 & 10. Not sure what this means.

If a balance lead number 5 goes to the center tap on the nth cell, would it work/help/be smart/or dumb, to stack number 6 lead on the same center tap on the same cell, to use up any excess leads that way. My thinking is that the BMS would see the voltage as being the same on sequential cells, with no harm done. Or should I just leave them open or connected to each other but not to a cell.
I cannot tell you how much help this is being. A little background, in the 80's built about 600, 200 watt 12 volt wind turbines for sailboats, & have wired and installed all manner of tools and appliances in houses, RV's and yachts, so fairly familiar with some stuff but these solid stat batts and controls are black boxes.
Ynot

 

[floydR]

What bms are you getting? Is it a smart BMS?
As I said before some are designed for multiple voltages/chemistries some maynot work at other voltages than they were designed for. Most of the ones designed for multiple voltages will state that in the sales ad.

Later floyd

 

[ynot]

What bms are you getting? Is it a smart BMS?
As I said before some are designed for multiple voltages/chemistries some maynot work at other voltages than they were designed for. Most of the ones designed for multiple voltages will state that in the sales ad.

Later floyd

Getting this one DALY BMS 13S 48V 60A Li-ion PCB Protection Board with Balance Leads Wires Smart Programmable Configurable BMS for 18650 Battery Pack 48V with UART RS485

Am a bit worried that I may have jumped the gun, but if so it is returnable.

Thanks, Tony.

 

[floydR]

As far as I can tell this bms is for 13s only Might be more configurable than it seems (no screen shots,or list of what can be changed) understand about jumping the gun I have several BMS's with no home ( read I bought them before checking the specs then waited too long to return them. The BMS may be able to be used for a 10s setup. I have learnt if not stated in the amazon/ebay link as being able to do Xyz it probably won't do Xyz.
Later floyd

 

[ynot]

Floyd, from what I am beginning to learn from you and others here that the 10s is more important than the nominal voltage. This old (78) dog is struggling a bit, and the 44C 113F temps are not helping.
But the tractor is now up & running, which will help with the house building, just gotta get the BMS, feed the forklift winch 12 volts, and the series winding switched on the motor, all while siding the house and putting a roof over the deck we just built,
St Peter don't you call me, wife is not done with me yet <grin>..

Edited to add, just cancelled the 12s I hope & ordered this one
DALY BMS 10S 36V 120A Li-ion PCB Protection Board Common Port with Balance Leads Wires Battery Protection Module BMS for 18650 Battery Pack 36V

 

[floydR]

Yuk high temps are brutal especially when building. I shut down when temps are nearing 40c. Only way i can function in the outdoors once the temps hits 38c is working for 15 minutes, then water break maybe a cool wet towel around my neck. I have worked in 45-48 c (114-118f) weather but that was years ago. and I am 18 years younger than you. The heat in British Columbia , Washington State, Oregon, extreme northern California, Nevada, Idaho has been brutal this month.

I thought the forklift would have been hydraulic. But electric works. A separate 12v battery or a tap after 2 leaf modules?I suspect that the 12v motor in industrial equipment can* handle 16v. But check before using the forklift motor at higher than 12v lead acid battery voltages.

Later Floyd

 

[OffGridInTheCity]

My thinking is that the BMS would see the voltage as being the same on sequential cells, with no harm done. Or should I just leave them open or connected to each other but not to a cell

OK I get the idea but have not heard of anyone doing this... it would lead to an incorrect 'overall battery voltage' and you'd loose over-charge protection (for example).

Typically you just skip (don't hook up) the extra leads IF the BMS will allow it - some do and some don't. For example - you might have a 14s BMS that let's you use 1st 10s sense leads and leave the 'extra' 4 unused.

 

[ynot]

I thought the forklift would have been hydraulic. But electric works. A separate 12v battery or a tap after

Floyd, gonna use a buck converter to a 12v LA battery so the battery stays charged but the winch does not lack for amps.
Picked up the forklift in Quartzite for $35 USD, it had a hand winch and wheels intended for order picking in a warehouse. Cut the feet off it & put a Harbor fright $50 winch on it about ten years ago. With me in the seat and 4 golf cart batteries behind the rear axle, it has picked the back wheels up trying to lift heavy weight. Chain the snow blade or the dirt blade to the forks for ploughing and grading.
We about 70K East of Osoyoos, sounds like you might be in the same country.

 

[floydR]

Beautiful country up there but no I am in California but have family in Oregon and Idaho also chat with a lady just south of Spokane, Washington so I have been hearing how hot it has been. I try Not to be "the stuck up American" some Americans seem to be.

With me in the seat and 4 golf cart batteries behind the rear axle, it has picked the back wheels up trying to lift heavy weight

I suspect the rear end of the tractor will be even lighter with leaf modules. Two or more 80lb bags of cement with gravel might be needed to off set the weight difference.
I hadn't thought of getting a old manual forklift for my electric lawn tractor project. will be on the lookout for one.
Fortunately I don't need the snow plow. I hated shoveling snow when I was a kid.

Later floyd

 

[ynot]

I suspect the rear end of the tractor will be even lighter with leaf modules. Two or more 80lb bags of cement with gravel might be needed to off set the weight difference.

I could fill the battery box with about 20 modules if I wanted, but think the heavy lifting is pretty much done, if I need more traction for the hill I borrow the wife who sits on the battery box, gotta put new wire on the winch soon. The battery box tells me it wants 2 stacks of modules on the flat, the terminal ends face each other about 5 inches apart. I could go 10 high for a 10s 4p, or stand them on end, but that way there is not much clearance on top for making the connections. Would kinda like to do a 3p but cannot think of a nice way to connect 2 modules in one stack to 3 in the other across the 5 inch gap
last year was our first full winter in the North for about 20 yrs. Before we moved into the house we came through Ca on our way to central Mx.
Americans aren't all that bad, my favorite wife is one & our daughter who is a dually married one.
Just shut down for the afternoon, will stay inside till the sun goes behind the hill.
Cheers, Tony.

 

[Iris]

Your 16S Daly BMS works perfectly for your 10S (40V) Leaf pack—no need to buy a new one.
Do NOT double up unused balance leads (e.g., tie 5&6 or 9&10 together). That will short adjacent sense inputs and damage the BMS.