Thinking of a bit of a hack to provide some lighting during load shedding - using 12v led strip lighting. I would appreciate criticism/suggestions to improve my idea.

The Lights

A couple websites advertise 12v led strip lighting. There is a 'continuous' light option. These use 9w per metre and provide 1000 lumens per metre. These can be mounted in an 'A13' corner mounting profile which fits nicely along the ceiling in most houses. You can also get a RF remote to control the lights. In my view 2m is more than enough to light most rooms.

The Battery

I rate the BlueNova batteries very highly but they are expensive. However, Securi-prod make a 20ah lithium battery that can (supposedly) output 20a. I wouldn't want to push the battery that hard but 8m of led strip lighting (4 rooms) would only need about 6a. Which means that for 2.5 hours of load shedding - and all lights running - you would run a discharge of 75%. I think that should be ok. I don't know if there are other battery brands that anyone can recommend?

The Power Supply - Alarm Power Supply

Sherlotronics make a 6.5A alarm power supply. This power supply can fit a 20ah lithium battery. It provides 6 outputs of about 1a each. Now 2m of led strip light require 1.5a. So the solution is to group the output together to create a single supply of 6a which will supply the led strip lights. I might want to drop the 8m to 7m to include a little bit of margin here. The buzzer can be disabled. The built-in switchover circuitry is also nice.

My only concern is the low battery cut-off is too low for a lithium battery so I am relying on the BMS of the lithium battery. I would also prefer a power supply with a single output - and maybe a 10a rating.

The Power Supply - Solar Charge Controller

This appeals to me as many of them come with a USB charging port, have a programmable low battery cut-off, charging algorithms for lithium batteries and a higher current rating. I am thinking of using a 20a charge controller - to include some additional margin. I would need a DC power source but you can find those very easily. A 10a 12v dc power source should be sufficient - and wouldn't overload a 20a charge controller. The area of concern is that no manufacturer suggests using their device with a non-solar power source - but people are doing it. Are there charge controllers designed/advertised to work with other 12v sources?

Will need to add a fuse on the input in case something goes wrong. From what I understand the charge controller always charges the battery and the demand is always drawn from the battery but these circuits will only be used during load shedding so not too worried about a switch over circuit.

Wiring

Each set of lights would run of their own length of lighting. From my research, 1mm sq ripcord should comfortably handle the 1.5a each circuit will use. The concern would be the voltage drop but a 10m cable length will result in voltage drop of about 0.55v so that won't cause an issue. If I run 20m then a thicker cable would (perhaps) be needed. The voltage drop increases to 1.11v which will slightly impact the brightness of the strips. For safety I should probably add a fuse to each circuit in case there a short-cuit. 

Questions

I would appreciate suggestions/criticism of my idea. It is a bit of a hack to provide some lighting during load shedding. I have seem some circuits for charging, low voltage cut-off and switchover but using an already assembled device seems like an easier (safer) solution.

Thanks

28 minutes ago, CliveSA said:

Thinking of a bit of a hack to provide some lighting during load shedding - using 12v led strip lighting. I would appreciate criticism/suggestions to improve my idea.

The Lights

A couple websites advertise 12v led strip lighting. There is a 'continuous' light option. These use 9w per metre and provide 1000 lumens per metre. These can be mounted in an 'A13' corner mounting profile which fits nicely along the ceiling in most houses. You can also get a RF remote to control the lights. In my view 2m is more than enough to light most rooms.

The Battery

I rate the BlueNova batteries very highly but they are expensive. However, Securi-prod make a 20ah lithium battery that can (supposedly) output 20a. I wouldn't want to push the battery that hard but 8m of led strip lighting (4 rooms) would only need about 6a. Which means that for 2.5 hours of load shedding - and all lights running - you would run a discharge of 75%. I think that should be ok. I don't know if there are other battery brands that anyone can recommend?

The Power Supply - Alarm Power Supply

Sherlotronics make a 6.5A alarm power supply. This power supply can fit a 20ah lithium battery. It provides 6 outputs of about 1a each. Now 2m of led strip light require 1.5a. So the solution is to group the output together to create a single supply of 6a which will supply the led strip lights. I might want to drop the 8m to 7m to include a little bit of margin here. The buzzer can be disabled. The built-in switchover circuitry is also nice.

My only concern is the low battery cut-off is too low for a lithium battery so I am relying on the BMS of the lithium battery. I would also prefer a power supply with a single output - and maybe a 10a rating.

The Power Supply - Solar Charge Controller

This appeals to me as many of them come with a USB charging port, have a programmable low battery cut-off, charging algorithms for lithium batteries and a higher current rating. I am thinking of using a 20a charge controller - to include some additional margin. I would need a DC power source but you can find those very easily. A 10a 12v dc power source should be sufficient - and wouldn't overload a 20a charge controller. The area of concern is that no manufacturer suggests using their device with a non-solar power source - but people are doing it. Are there charge controllers designed/advertised to work with other 12v sources?

Will need to add a fuse on the input in case something goes wrong. From what I understand the charge controller always charges the battery and the demand is always drawn from the battery but these circuits will only be used during load shedding so not too worried about a switch over circuit.

Wiring

Each set of lights would run of their own length of lighting. From my research, 1mm sq ripcord should comfortably handle the 1.5a each circuit will use. The concern would be the voltage drop but a 10m cable length will result in voltage drop of about 0.55v so that won't cause an issue. If I run 20m then a thicker cable would (perhaps) be needed. The voltage drop increases to 1.11v which will slightly impact the brightness of the strips. For safety I should probably add a fuse to each circuit in case there a short-cuit. 

Questions

I would appreciate suggestions/criticism of my idea. It is a bit of a hack to provide some lighting during load shedding. I have seem some circuits for charging, low voltage cut-off and switchover but using an already assembled device seems like an easier (safer) solution.

Thanks

I rate the homework youve done here. Good on you. The bms/litthium combination looks after itself, it will cutoff regardlessly at specified low voltage. It will also protect against over discharge, and high chargevoltage. You must just make sure you stay within goid charge voltage limits. 

Fusing is totally important. 

9 minutes ago, BritishRacingGreen said:

I rate the homework youve done here. Good on you. The bms/litthium combination looks after itself, it will cutoff regardlessly at specified low voltage. It will also protect against over discharge, and high chargevoltage. You must just make sure you stay within goid charge voltage limits. 

Fusing is totally important. 

And dont be shy to also add a fuse as close the the battery positive terminal as you possibly can. Rate that fuse twice the size of the greatest of the maximum charge or discharge current. 

Dont wire this fuse in a disconnectable cartridge, hardwire it. 

Edited September 25, 20223 yr by BritishRacingGreen