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DIY 100Ah Battery, Version 2

Will Prowse

Will Prowse

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Youtube is being glitchy with my upload, so some may not have gotten a notification.

I used Al cased cells and they fit perfectly in the battery case! Also added some foam and a plastic box to mount the bms. Really solid little system now! I love it :D
 
One thing that we like to do is add those cheap $5.00 digital LED meters to the side of the lid .. that way ANYONE walking buy can see the current voltage and not have to have their phone checking ...YES i know that for 90% of the battery charge its going to read virtually the same voltage -- we are only concerned when we see it start to drop...
 
@Will Prowse do you think Alu cased cells need to be in compression when in use to stop bulging? You have always said that for the plastic cased prismatic but not for the more-likely to bulge Alu cased ones? I clocked you didn't bother in this build.

Only trying to get info on how important that is, so i can do it right on my cells (had shipping notification today).
 
Stupid Monkey said:
@Will Prowse do you think Alu cased cells need to be in compression when in use to stop bulging? You have always said that for the plastic cased prismatic but not for the more-likely to bulge Alu cased ones? I clocked you didn't bother in this build.

Only trying to get info on how important that is, so i can do it right on my cells (had shipping notification today).
Click to expand...
It is always wise to "block" cells together and constrain them. Not only to protect them from potential external harms but from expansion as well. The Aluminium "skin" is not that thick, they are meant to be contained. This applies to pouch cells even moreso.
 
Thinking out load, in an RV setting, whilst we would do everything possible to restrain the cells in place, vibrations will still 'get through'. With this in mind, would it be better to make all cell connections with cabling instead of busbars? Which would be better....busbars would help provide rigidity, however cabling would 'flex' ever so slightly with the vibrations. Would either system of connection be better in maintaining very tight connections???
I realise locking nuts, should do the job, but in an RV over 20 years???
Any opinions?
 
Stupid Monkey said:
@Will Prowse do you think Alu cased cells need to be in compression when in use to stop bulging? You have always said that for the plastic cased prismatic but not for the more-likely to bulge Alu cased ones? I clocked you didn't bother in this build.

Only trying to get info on how important that is, so i can do it right on my cells (had shipping notification today).
Click to expand...

NO - aluminium case cells do not need to be incased or compressed during use to prevent bulging ... we have NEVER had an aluminum case bulge regardless of the charge or discharge we gave it ... YES it will vent though if it starts getting to that point
 
In the video you mention the size of the terminals. Does anyone know the thread they use on them, so I can get appropriate hardware when mine arrive?
 
Solarfun4jim said:
Thinking out load, in an RV setting, whilst we would do everything possible to restrain the cells in place, vibrations will still 'get through'. With this in mind, would it be better to make all cell connections with cabling instead of busbars? Which would be better....busbars would help provide rigidity, however cabling would 'flex' ever so slightly with the vibrations. Would either system of connection be better in maintaining very tight connections???
I realise locking nuts, should do the job, but in an RV over 20 years???
Any opinions?
Click to expand...

On all of our work trailers we normally use aluminum case LiFePO4 200aH batteries connected via busbars ... and our trailers take a beating ... (think: being dragged down oil field roads in Texas and New Mexico) ... what you MUST do is build yourself a good battery system first .. First get yourself some good double sided (thick) tape and put them between the batteries -- that will allow for some heat/thermal dissipation ... then strap it all together with some good 2 inch wide electrical tape ... (you have to be careful using "hose clamps" on the aluminum batteries because you can crush the corners ... then BUILD yourself a wooden box to put them all in .. on the bottom of the box stop by Tractor Supply or Home Depot and get some of those compression mats that ppl use for standing all day -- the make a great FIRM yet vibration absorbing material ... THATS what you need to do ...

Making your own cabling is going to be just a pain and actually cause more stress on the connection tops if you don't get each one perfect ..
 
ghostwriter66 said:
On all of our work trailers we normally use aluminum case LiFePO4 200aH batteries connected via busbars ... and our trailers take a beating ... (think: being dragged down oil field roads in Texas and New Mexico) ... what you MUST do is build yourself a good battery system first .. First get yourself some good double sided (thick) tape and put them between the batteries -- that will allow for some heat/thermal dissipation ... then strap it all together with some good 2 inch wide electrical tape ... (you have to be careful using "hose clamps" on the aluminum batteries because you can crush the corners ... then BUILD yourself a wooden box to put them all in .. on the bottom of the box stop by Tractor Supply or Home Depot and get some of those compression mats that ppl use for standing all day -- the make a great FIRM yet vibration absorbing material ... THATS what you need to do ...

Making your own cabling is going to be just a pain and actually cause more stress on the connection tops if you don't get each one perfect ..
Click to expand...
Many thanks, thats exactly the type of feedback i was looking for. Much appreciated. ;-)
 
Agi said:
In the video you mention the size of the terminals. Does anyone know the thread they use on them, so I can get appropriate hardware when mine arrive?
Click to expand...

M6 threads

https://www.aliexpress.com/item/4000412185571.html

Copper BusBars Cell-to-Cell Interconnect For lithium Batteries

Copper BusBars Cell-to-Cell Interconnect For lithium 3.7V 3.2V lifepo4 battery for 100AH 120AH 150AH 180AH 200AH 280AH 300AH BUSBAR For lithium 3.7V 3.2V lifepo4 battery Connector anti-oxidation for12V 24V 36V 48V 72V 96V 120V 80AH 100AH 200AH 300AH 400AH 500AH 600AH 700AH 800AH 900AH 1000AH
Features: Connector for 80-600Ah LiFePO4 Battery Pack. Weight: 28.5g
Dimensions: 78x 20 x 2.4mm Hole-to-Hole (center) Dimension: 53±0.5mm Diameter ：10mm
Adapter screw：M6
 
natefxx said:
M6 threads

https://www.aliexpress.com/item/4000412185571.html

Copper BusBars Cell-to-Cell Interconnect For lithium Batteries

Copper BusBars Cell-to-Cell Interconnect For lithium 3.7V 3.2V lifepo4 battery for 100AH 120AH 150AH 180AH 200AH 280AH 300AH BUSBAR For lithium 3.7V 3.2V lifepo4 battery Connector anti-oxidation for12V 24V 36V 48V 72V 96V 120V 80AH 100AH 200AH 300AH 400AH 500AH 600AH 700AH 800AH 900AH 1000AH
Features: Connector for 80-600Ah LiFePO4 Battery Pack. Weight: 28.5g
Dimensions: 78x 20 x 2.4mm Hole-to-Hole (center) Dimension: 53±0.5mm Diameter ：10mm
Adapter screw：M6
Click to expand...
Holy cow those are pricey. Sure is hard to beat the cost and performance of a hammer smashed and drilled $6 copper pipe. Wow.
 
Steve_S said:
It is always wise to "block" cells together and constrain them. Not only to protect them from potential external harms but from expansion as well. The Aluminium "skin" is not that thick, they are meant to be contained. This applies to pouch cells even moreso.
Click to expand...
I disagree with strapping the aluminum cells. Mine came with separators. The cells at about 3/8" apart . You do not want the cells to connected. Due to the possibility of internally shorting to the case. Also the ability release heat during high C charge/discharge.
 
grizzzman said:
I disagree with strapping the aluminum cells. Mine came with separators. The cells at about 3/8" apart . You do not want the cells to connected. Due to the possibility of internally shorting to the case. Also the ability release heat during high C charge/discharge.
Click to expand...
This is a source of debate all over the place you know. I agree that we disagree but I'm not about to reshash the topic which is like beating a dead horse LOL....
 
ghostwriter66 said:
On all of our work trailers we normally use aluminum case LiFePO4 200aH batteries connected via busbars ... and our trailers take a beating ... (think: being dragged down oil field roads in Texas and New Mexico) ... what you MUST do is build yourself a good battery system first .. First get yourself some good double sided (thick) tape and put them between the batteries -- that will allow for some heat/thermal dissipation ... then strap it all together with some good 2 inch wide electrical tape ... (you have to be careful using "hose clamps" on the aluminum batteries because you can crush the corners ... then BUILD yourself a wooden box to put them all in .. on the bottom of the box stop by Tractor Supply or Home Depot and get some of those compression mats that ppl use for standing all day -- the make a great FIRM yet vibration absorbing material ... THATS what you need to do ...

Making your own cabling is going to be just a pain and actually cause more stress on the connection tops if you don't get each one perfect ..
Click to expand...
@ghostwriter66
Hi ghostwriter, what is the maximum capacity cells you have used on work trailers? Is it limited to around the 200Ah maximum (due to the internal strength of the plates etc) or do you go higher than that? I read an article that suggested sticking with 100Ah cells, but 200Ah at an absolute maximum, for vehicles ....just wondered if your 'on the ground' experience was different from that article?
Thanks for any opinion offered.
 
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