50 Cal Ammo Can Power supply

[NevetsG]

I built this last year, and been too lazy to post it, but here goes.

This is a very simple 48 18650 cell Li-Ion battery bank / power supply, but it isn't intended for high amp load, nor did I add an inverter. It is purely for 12V DC devices with a max of 20A draw. I didn't add any cooling, but if I want to draw more than 15 amps, I can pop the top to reduce the heat. It weighs about 10 + lbs.

I do not have a how to instructions on assembly, but I do have a parts list, wire diagram, and pictures.

Parts list:

48 - 18650 Li-Ion batteries
1 - VRUZEND battery kit V1.5 (https://vruzend.com/product/vruzend_basic_kit/ )
1/4" plywood for battery bottom and top (I designed and 3d printed special caps)
2 - Inline Holder 14AWG Wiring Harness ATC/ATO 30AMP Blade Automotive Fuse Holders
2 - 12V 20A Red Cover Rocker Toggle Switches (lighted). I designed and 3d printed the power supply label, but you can use a sharpie if needed.
1 - 300W DC Buck Converter Power Module Output Adjustable 20A Max DC-DC 6-40V Step Down to 1.2-36V (https://www.amazon.com/gp/product/B01NBR4NC0)
1 - 0-120V 0-30A Color LCD Display Digital Bi-directional Voltage Current Power Meter Ammeter Voltmeter Capacity Time Meter, Multimeter with Relay (DC 0-120V 0-30A) (https://www.amazon.com/gp/product/B0753CRMWB)

Any combination of these will work, but 4 sockets is about all you can fit into the can.
1 - SAE Socket, Front Panel Mount
2 - 12V sockets
1 - 12V USB socket

Assorted wire and connectors - make sure you don't under or oversize the wire, depending on the amp draw you will be looking for.

Last and most important item - Intelligent hobby grade battery charger, discharger, conditioner. I use this to charge a whole bunch of things, not only can you charge the power supply you can also use the power supply thru the charger to charge all kinds of things. Since you can control so many charging parameters, I can use it to slow charge my car battery. The one I use is a SKYRC B6 (https://www.skyrc.com/iMAX_B6AC_V2_Charger). Shop around, you might have a preference, but I went with the SKYRC B6 because it will fit in the can. Another huge plus in using this type of charger is that it can plug into your computer, and it is much safer to charge and balance a Lithium power supply. This allows me to eliminate a cheap charge and crappy balancers that fail giving you false readings that the battery has failed. An intelligent charger will help you figure you which cell bank has a bad battery, and you can pull it apart and replace the battery cheaply.

Stuffing all of this crap into the can is not easy, and good luck if you decide to build one.

 

[trae]

That’s a really clean build. Thanks for posting it. I’m working on something similar except with a 16p4s batttery. can I ask, why did you opt to go with 2 separate 4s rather then just a single 12s4p unit?


Sent from my iPhone using Tapatalk

 

[NevetsG]

That’s a really clean build. Thanks for posting it. I’m working on something similar except with a 16p4s batttery. can I ask, why did you opt to go with 2 separate 4s rather then just a single 12s4p unit?


Sent from my iPhone using Tapatalk

4 reasons...

1 - components - 44.4V would over power the compact low cost buck converters (20A max) I could find, and I wanted as much "pass thru" voltage/amperage as feasible, with the hope it would keep heat down as much as possible by reducing resistance in the conversion process, thus resulting in higher efficiency.

2 - charging - 4 p/cells gave me more options in selecting an intelligent compact hobby charger / balancer that will fit in the can, it also makes troubleshooting a bad cell a little bit easier, and the power to push juice into 12 cells during charging will generate more heat. Balancing cells with fewer batteries is quicker. Also (if really needed) I could use the 24V charging capacity of the my solar panels / charger.

3 - redundancy - If a cell goes bad in one of the batteries I can shut that battery down, and it will still operate, at a reduced capacity.

4 - flexibility - If I'm only using it to charge small electronics I don't have to use both batteries. I can drain each battery separately so I can maintain peak voltage for quick charges, longer.

 

[trae]

Doh, of course I meant a 12p4s unit, so that you'd have a 12 serial and 4 parallel groups. So the nominal voltage would be 14.8.

for 3/4, are you expecting a single cell to fail catastrophically? By distributing the load over 6s rather than a 12s group, are you not then increasing the load on individual cell?

What is the purpose of the SAE socket?

 

[NevetsG]

Doh, of course I meant a 12p4s unit, so that you'd have a 12 serial and 4 parallel groups. So the nominal voltage would be 14.8.

for 3/4, are you expecting a single cell to fail catastrophically? By distributing the load over 6s rather than a 12s group, are you not then increasing the load on individual cell?

What is the purpose of the SAE socket?

OMG, I just realized my battery diagram is WRONG... It is 4 serial 6 parallel... Face palm... That way I was only converting the voltage down to 14.1 for the max voltage in a 12V system.

The split into 2 primary batteries started with flexibility (like multi-battery systems in RVs), and it is a test bed for a larger unit I want to build into the RV. Another concept I was considering would be to build "dumb" batteries using ammo cans, build a control system (compatible with my solar panels), then install them into the RV as modules.

SAE socket is for 20A max draw for high flow air compressor, and a better connection for the battery charger (output) to charge my toys (drones, RC rock crawlers).

When I get home tonight I will fix the battery diagram showing what I built, although it would work the way I drew it.

 

[john61ct]

Swap SAE for 45A Andersons

 

[NevetsG]

Swap SAE for 45A Andersons

Been using Deans plugs for many years for hobbies. SAE is automotive, and I can get a panel mounted plugs. My air pump, solar panels (back feed), and LED camp lights are all using SAE. If needed, I can use it to charge my trailer battery via the solar panel controller.

 

[Fullkontact]

I built this last year, and been too lazy to post it, but here goes.

This is a very simple 48 18650 cell Li-Ion battery bank / power supply, but it isn't intended for high amp load, nor did I add an inverter. It is purely for 12V DC devices with a max of 20A draw. I didn't add any cooling, but if I want to draw more than 15 amps, I can pop the top to reduce the heat. It weighs about 10 + lbs.

I do not have a how to instructions on assembly, but I do have a parts list, wire diagram, and pictures.

Parts list:

48 - 18650 Li-Ion batteries
1 - VRUZEND battery kit V1.5 (https://vruzend.com/product/vruzend_basic_kit/ )
1/4" plywood for battery bottom and top (I designed and 3d printed special caps)
2 - Inline Holder 14AWG Wiring Harness ATC/ATO 30AMP Blade Automotive Fuse Holders
2 - 12V 20A Red Cover Rocker Toggle Switches (lighted). I designed and 3d printed the power supply label, but you can use a sharpie if needed.
1 - 300W DC Buck Converter Power Module Output Adjustable 20A Max DC-DC 6-40V Step Down to 1.2-36V (https://www.amazon.com/gp/product/B01NBR4NC0)
1 - 0-120V 0-30A Color LCD Display Digital Bi-directional Voltage Current Power Meter Ammeter Voltmeter Capacity Time Meter, Multimeter with Relay (DC 0-120V 0-30A) (https://www.amazon.com/gp/product/B0753CRMWB)

Any combination of these will work, but 4 sockets is about all you can fit into the can.
1 - SAE Socket, Front Panel Mount
2 - 12V sockets
1 - 12V USB socket

Assorted wire and connectors - make sure you don't under or oversize the wire, depending on the amp draw you will be looking for.

Last and most important item - Intelligent hobby grade battery charger, discharger, conditioner. I use this to charge a whole bunch of things, not only can you charge the power supply you can also use the power supply thru the charger to charge all kinds of things. Since you can control so many charging parameters, I can use it to slow charge my car battery. The one I use is a SKYRC B6 (https://www.skyrc.com/iMAX_B6AC_V2_Charger). Shop around, you might have a preference, but I went with the SKYRC B6 because it will fit in the can. Another huge plus in using this type of charger is that it can plug into your computer, and it is much safer to charge and balance a Lithium power supply. This allows me to eliminate a cheap charge and crappy balancers that fail giving you false readings that the battery has failed. An intelligent charger will help you figure you which cell bank has a bad battery, and you can pull it apart and replace the battery cheaply.

Stuffing all of this crap into the can is not easy, and good luck if you decide to build one.

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What are you going to be powering with it?

 

[NevetsG]

What are you going to be powering with it?

Any number of things, it is a proof of concept to for a modular set of batteries and controllers I want to build for my trailer, storms, and traveling. I have it set up to run campsite lights on my Jeep (going to set up lights on the Taco to do the same), also can charge devices (including laptops), fans, micro projector, etc.

 

[Fullkontact]

Any number of things, it is a proof of concept to for a modular set of batteries and controllers I want to build for my trailer, storms, and traveling. I have it set up to run campsite lights on my Jeep (going to set up lights on the Taco to do the same), also can charge devices (including laptops), fans, micro projector, etc.

That’s pretty genius for sure. You really can’t beat an ammo can either. I use a few for storing things that I need to keep water proof as well and are easily packed!