kipper
New Member
OK so here’s a project that ran away with itself!
I thought I'd show my completed battery as I struggled to find much in the way of DIY metal cases so with any luck this might help others.
So, another workshop lead acid battery bit the dust on my small scale solar / wind storage unit that charges my Ebike, powers the lawn mowers / garden equipment and workshop lighting.
As I’m in the process of building a 14KW LifePO4 system for the house I decided on a similar smaller scale battery for the workshop, kind of a quarter scale version.
I chose 4 x 280Ah LiFePO4 cells and a 150Ah JBD controller. Initially I built them into a plywood crate, although this worked it was somewhat Heath Robinson and the gubbins were a bit exposed, a wet Ebike dripping onto the BMS was a disaster waiting to happen, so I cadded up something a bit more robust. After a bit off beating and wrestling sheet aluminium into shape this is what I ended up with. I’m quite pleased with the result, it works like a charm, it means my Ebike is once again charging from 100% solar (and a bit of wind) and should outlast several lead acid batteries. I haven’t weighed it yet but boy is this thing heavy! That being said the handles make it a doddle to carry, two people can easily carry it between them over a distance using one handle each.
I chose to use 10mm cork tiles for thermal insulation, not massively fire proof but easily available in small amounts, the workshop should never drop below about 5 degrees so doesn’t need anything more and won’t need built in heaters as per the house battery. The end plates of the enclosure provide a decent amount of clamping force to the cells, each cell is electrically separated by 1mm acetate sheet.
I designed my own UART to RS485 converter board, they are available cheaply but I needed a built in 3.3V regulator. and some LED's always are always a welcome aid to fault finding and commissioning a system.
The total cost of around £473 / $614 breaks down as follows;
4 x 280Ah cells £260 $337
150A JBD BMS £75 $97
Aluminium sheet £60 $78
RS485 converter pcb £15 $19
Cable crimps £12 $15
120A sockets £21 $27
Cork insulation £30 $39
I did the fabrication and painting inhouse, the front panel artwork is temporary as I need to get it professionally printed. The artwork on top is purely for cosmetic effect, I did this with a vinyl cutter at minimal cost.
The complete system comprises of;
1 x 215W Sanyo HIT panel
1 x Outback Solar Flexmax80 charger
1 x Victron compact 12V 1200W sinewave inverter
Maximum discharge is around 160A surge and then settles to around 55A with the lawn mower running, maximum charge has been around 17 - 18A, which is pretty good for a 17 year old 215W PV panel, I can only put this down to the shallow angle of the panel, the sun being directly overhead, midsummer and a pathetic UK summer temperature of about 15 degrees thus making the panel a tad more efficient. The real test will come in the Autumn, traditionally the shorter days only give enough juice to charge the Ebike once a week (I’m at 53.4 Degrees north, kind of similar to Newfoundland). In the depths of winter this setup powers the house Christmas lights.
If I was to build these in quantity I would definitely get the parts laser cut and powder coated, obviously this would bump up the price significantly.
Finished and working battery, it looks almost professional.
Fabrication almost complete.
Parts spray pained with 2K paint over epoxy primer.
Closeup of front panel, this contains the RS485 interface board, battery sockets, enable switch and circuit breaker for the aux / HMI 12V feed.
Batteries fitted with cork insulation
Complete system in the corner of the workshop.
HMI, work in progress but taking shape.
Internal shot showing the BMS and busbar connections.
I thought I'd show my completed battery as I struggled to find much in the way of DIY metal cases so with any luck this might help others.
So, another workshop lead acid battery bit the dust on my small scale solar / wind storage unit that charges my Ebike, powers the lawn mowers / garden equipment and workshop lighting.
As I’m in the process of building a 14KW LifePO4 system for the house I decided on a similar smaller scale battery for the workshop, kind of a quarter scale version.
I chose 4 x 280Ah LiFePO4 cells and a 150Ah JBD controller. Initially I built them into a plywood crate, although this worked it was somewhat Heath Robinson and the gubbins were a bit exposed, a wet Ebike dripping onto the BMS was a disaster waiting to happen, so I cadded up something a bit more robust. After a bit off beating and wrestling sheet aluminium into shape this is what I ended up with. I’m quite pleased with the result, it works like a charm, it means my Ebike is once again charging from 100% solar (and a bit of wind) and should outlast several lead acid batteries. I haven’t weighed it yet but boy is this thing heavy! That being said the handles make it a doddle to carry, two people can easily carry it between them over a distance using one handle each.
I chose to use 10mm cork tiles for thermal insulation, not massively fire proof but easily available in small amounts, the workshop should never drop below about 5 degrees so doesn’t need anything more and won’t need built in heaters as per the house battery. The end plates of the enclosure provide a decent amount of clamping force to the cells, each cell is electrically separated by 1mm acetate sheet.
I designed my own UART to RS485 converter board, they are available cheaply but I needed a built in 3.3V regulator. and some LED's always are always a welcome aid to fault finding and commissioning a system.
The total cost of around £473 / $614 breaks down as follows;
4 x 280Ah cells £260 $337
150A JBD BMS £75 $97
Aluminium sheet £60 $78
RS485 converter pcb £15 $19
Cable crimps £12 $15
120A sockets £21 $27
Cork insulation £30 $39
I did the fabrication and painting inhouse, the front panel artwork is temporary as I need to get it professionally printed. The artwork on top is purely for cosmetic effect, I did this with a vinyl cutter at minimal cost.
The complete system comprises of;
1 x 215W Sanyo HIT panel
1 x Outback Solar Flexmax80 charger
1 x Victron compact 12V 1200W sinewave inverter
Maximum discharge is around 160A surge and then settles to around 55A with the lawn mower running, maximum charge has been around 17 - 18A, which is pretty good for a 17 year old 215W PV panel, I can only put this down to the shallow angle of the panel, the sun being directly overhead, midsummer and a pathetic UK summer temperature of about 15 degrees thus making the panel a tad more efficient. The real test will come in the Autumn, traditionally the shorter days only give enough juice to charge the Ebike once a week (I’m at 53.4 Degrees north, kind of similar to Newfoundland). In the depths of winter this setup powers the house Christmas lights.
If I was to build these in quantity I would definitely get the parts laser cut and powder coated, obviously this would bump up the price significantly.
Finished and working battery, it looks almost professional.
Fabrication almost complete.
Parts spray pained with 2K paint over epoxy primer.
Closeup of front panel, this contains the RS485 interface board, battery sockets, enable switch and circuit breaker for the aux / HMI 12V feed.
Batteries fitted with cork insulation
Complete system in the corner of the workshop.
HMI, work in progress but taking shape.
Internal shot showing the BMS and busbar connections.
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