Mesh/Power - Revision history

Juul: /* Battery */

2016-08-09T23:19:51Z

Battery

← Older revision		Revision as of 16:19, 9 August 2016
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	Some USB battery packs don't allow charging and discharging at the same time. We ordered a selection of the cheaper units and tested them. Here are the results:		Some USB battery packs don't allow charging and discharging at the same time. We ordered a selection of the cheaper units and tested them. Here are the results:

	* [http://www.ebay.com/itm/321850110492 2600 mAh CoolGo pack] - $6.79 - Works!		* [http://www.ebay.com/itm/321850110492 2600 mAh CoolGo pack] - $6.79 - Works and verified at 2600 mAh!
	* [http://www.ebay.com/itm/301573240761 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!		* [http://www.ebay.com/itm/301573240761 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works but only ~1300 mAh capacity :(
	* [http://www.ebay.com/itm/181725452512 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works~~! (~~but max charge 500 mA)		* [http://www.ebay.com/itm/181725452512 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works but max charge rate 500 mA :(
	* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(		* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(
	* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.		* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.

Juul: /* Battery */

2016-08-09T04:46:35Z

Battery

← Older revision		Revision as of 21:46, 8 August 2016
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	* [http://www.ebay.com/itm/321850110492 2600 mAh CoolGo pack] - $6.79 - Works!		* [http://www.ebay.com/itm/321850110492 2600 mAh CoolGo pack] - $6.79 - Works!
	* [http://www.ebay.com/itm/301573240761 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!		* [http://www.ebay.com/itm/301573240761 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!
	* [http://www.ebay.com/itm/181725452512 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works!		* [http://www.ebay.com/itm/181725452512 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works! (but max charge 500 mA)
	* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(		* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(
	* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.		* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.

			Most of these are rated to charge and discharge at 1 A, except the cheaper "PowerBank" which is rated at 1 A discharge but only 500 mA for charging which would limit charging to 2.5 W.

	Assuming that these batteries actually have a capacity of 2600 mAh at 5v that's 13 Wh which is enough to power a 1 watt router like the NEXX WT2030F for 13 hours. That means that 2600 mAh is not enough to carry such a device through the night during winter in Oakland since the longest night is just under 14.5 hours long. It's probably a good idea to double the capacity since the capacity will drop over the lifetime of the battery.		Assuming that these batteries actually have a capacity of 2600 mAh at 5v that's 13 Wh which is enough to power a 1 watt router like the NEXX WT2030F for 13 hours. That means that 2600 mAh is not enough to carry such a device through the night during winter in Oakland since the longest night is just under 14.5 hours long. It's probably a good idea to double the capacity since the capacity will drop over the lifetime of the battery.

Juul: /* Low power nodes */

2016-08-09T04:42:12Z

Low power nodes

← Older revision		Revision as of 21:42, 8 August 2016
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	== Low power nodes ==		== Low power nodes ==

	The [[Mesh/~~hardware~~ experiments\|hardware experiments]] page lists some nodes that can be used with low power.		The [[Mesh/Hardware experiments\|hardware experiments]] page lists some nodes that can be used with low power.

	We can probably assume power usage of about 1 watt for most of the lower power stuff but probably not a lot less.		We can probably assume power usage of about 1 watt for most of the lower power stuff but probably not a lot less.

Juul: /* Low power nodes */

2016-08-09T03:25:04Z

Low power nodes

← Older revision		Revision as of 20:25, 8 August 2016
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	== Low power nodes ==		== Low power nodes ==

	The [[hardware experiments]] page lists some nodes that can be used with low power.		The [[Mesh/hardware experiments\|hardware experiments]] page lists some nodes that can be used with low power.

	We can probably assume power usage of about 1 watt for most of the lower power stuff but probably not a lot less.		We can probably assume power usage of about 1 watt for most of the lower power stuff but probably not a lot less.

Juul: /* Battery */

2016-08-09T03:24:25Z

Battery

← Older revision		Revision as of 20:24, 8 August 2016
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	* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(		* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(
	* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.		* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.

			Assuming that these batteries actually have a capacity of 2600 mAh at 5v that's 13 Wh which is enough to power a 1 watt router like the NEXX WT2030F for 13 hours. That means that 2600 mAh is not enough to carry such a device through the night during winter in Oakland since the longest night is just under 14.5 hours long. It's probably a good idea to double the capacity since the capacity will drop over the lifetime of the battery.

			Then the question remains if a 4 watt panel is enough to charge 14.5 hours worth of power in the ~9.5 hours of "sun" on the shortest day. We need 14.5 Wh generated in 9.5 hours. So we need a bit more than 1.5 watts of charge. Let's say 2 watts given conversion losses (how big are losses?). So if we have a solar panel that's theoretically generating 4 watts in full noon sun that's definitely not going to cut it on a cloudy winter day. We need some numbers on the efficiency degradation of standard solar panels on a cloudy day.

	= Power usage =		= Power usage =

Juul: /* Battery */

2016-08-09T03:10:27Z

Battery

← Older revision		Revision as of 20:10, 8 August 2016
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	Some USB battery packs don't allow charging and discharging at the same time. We ordered a selection of the cheaper units and tested them. Here are the results:		Some USB battery packs don't allow charging and discharging at the same time. We ordered a selection of the cheaper units and tested them. Here are the results:

	* [http://www.ebay.com/itm/321850110492 - 2600 mAh CoolGo pack] - $6.79 - Works!		* [http://www.ebay.com/itm/321850110492 2600 mAh CoolGo pack] - $6.79 - Works!
	* [http://www.ebay.com/itm/301573240761 - 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!		* [http://www.ebay.com/itm/301573240761 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!
	* [http://www.ebay.com/itm/181725452512 - 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works!		* [http://www.ebay.com/itm/181725452512 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works!
	* [http://www.ebay.com/itm/252224862952 - 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(		* [http://www.ebay.com/itm/252224862952 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(
	* [http://www.ebay.com/itm/221974269792 - Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.		* [http://www.ebay.com/itm/221974269792 Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.

	= Power usage =		= Power usage =

Juul: /* Battery */

2016-08-09T03:10:09Z

Battery

← Older revision		Revision as of 20:10, 8 August 2016
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	* [http://www.ebay.com/itm/301573240761 - 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!		* [http://www.ebay.com/itm/301573240761 - 2600 mAh No-name "extruded aluminum square" with button] - $6 - Works!
	* [http://www.ebay.com/itm/181725452512 - 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works!		* [http://www.ebay.com/itm/181725452512 - 2600 mAh PowerBank "extruded plastic square" without button] - $3.75 - Works!
	* [http://www.ebay.com/itm/252224862952 - 2000 mAh Motorola flat pack with integrated micro-usb cable - $6 - No discharge while charging :(		* [http://www.ebay.com/itm/252224862952 - 2000 mAh Motorola flat pack with integrated micro-usb cable] - $6 - No discharge while charging :(
	* [http://www.ebay.com/itm/221974269792 - Cylindrical unit without included 18650 battery - $1.25 - Waiting for it to arrive.		* [http://www.ebay.com/itm/221974269792 - Cylindrical unit without included 18650 battery] - $1.25 - Waiting for it to arrive.


	= Power usage =		= Power usage =

Juul at 03:07, 9 August 2016

2016-08-09T03:07:13Z

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 = Power usage =
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 On top of that some electronics are needed for battery charge control. I'm not sure what the price for that is, but probably around $20. And then there's the battery.
 == Battery ==

Juul: /* Power usage */

2016-04-07T05:35:37Z

Power usage

← Older revision		Revision as of 22:35, 6 April 2016
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	= Power usage =		= Power usage =

	Ubiquiti routers all use 8 watts (actually maybe only 6.5 watts for current gen gear). That comes to 5856 watt-hours per month. As of May 2013, the average price for electricity in the bay area was 22.8 cents per kilowatt-hours. $0.228 * 5.856 kilowatt-hours ~= $1.335. So less than $1.5 per month.		Ubiquiti routers all use 8 watts (actually maybe only 6.5 watts for current gen gear, and we should test that). That comes to 5856 watt-hours per month. As of May 2013, the average price for electricity in the bay area was 22.8 cents per kilowatt-hours. $0.228 * 5.856 kilowatt-hours ~= $1.335. So less than $1.5 per month.

	== Voltage ==		== Voltage ==

	The Ubiquiti gear takes between 10.5 volts and 25 volts. I believe most of their official numbers state something like 12 to 24 volts, but one of their engineers posted a spreadsheet on their forum which listed the actual limits.		The Ubiquiti gear takes between 10.5 volts and 25 volts. I believe most of their official numbers state something like 12 to 24 volts, but one of their engineers posted a spreadsheet on their forum which listed the actual limits.

			TP-Link N750 routers use a [http://www.monolithicpower.com/desktopmodules/documentmanage/api/document/getdocument?id=428 MP1482] voltage regulator which takes between 4.75v and 18v input.

			Western Digital N600 routers use a [http://www.richtek.com/assets/product_file/RT8293B/DS8293B-03.pdf RT8293B] voltage regulator which takes 4.5v to 23v input.

	= Solar =		= Solar =

Juul at 21:20, 10 February 2016

2016-02-10T21:20:43Z

← Older revision		Revision as of 14:20, 10 February 2016
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	Either way we shouldn't discharge car batteries below 11 volts. How do we prevent that? What is the simples/cheapest low voltage cut-off circuit?		Either way we shouldn't discharge car batteries below 11 volts. How do we prevent that? What is the simples/cheapest low voltage cut-off circuit?

			Twisted_Haywire has some ideas for super simple circuits. Another option is to use a voltage comparator + divider + mosfet. You can get cheap comparators for $1 or less on ebay/aliexpress.

			== PCB ==

			If we end up wanting low voltage cut-off then if makes sense to put it on a PCB. [http://dirtypcbs.com/ Dirty PCBs] charge $14 for ten 5x5 cm PCBs, so $1.4 extra per unit, and it drops to $75 for 100 units.

	== Higher voltage extended version ==		== Higher voltage extended version ==