PowerBoost 1000 Charger + Wireless receiver

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baleph
 
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PowerBoost 1000 Charger + Wireless receiver

Post by baleph »

Hey I'm looking at this PowerBoost 1000 Charger (https://www.adafruit.com/products/2465) so that I can power my raspberry pi with a lipo battery (https://www.adafruit.com/products/328). Instead of the recommended 5V 2A DC power supply I was wondering if I could connect a qi wireless receiver (https://www.adafruit.com/products/1901) to the charging port and use a charging station like this: http://www.adafruit.com/products/2162/.

It looks like the qi wireless receiver and most of them out there charge at a rate of 500mA, while the PowerBoost 1000 can handle a max of 1000mA, and recommends a 2A DC supply with thick wires because "lower quality ones will not act well due to the voltage drop on the wires or droop on the power supply." So I'm wondering if I will have a problem using the weaker wireless receiver. Or is that warning only there if you intend to draw the max 1000mA, which the qi charger cannot do?

Thanks!

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adafruit_support_mike
 
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Re: PowerBoost 1000 Charger + Wireless receiver

Post by adafruit_support_mike »

You could use the Qi to recharge the LiPo while the RasPi isn't running, but the Qi can't supply enough current to run the RasPi through the PowerBoost.

IMO, any combination of a Qi and a PowerBoost would be dubious. The power transfer of a Qi is only about 40% efficient, and the PowerBoost is about 80% efficient. Together, you're looking at an efficiency of about 32%, meaning about 2/3 of the power you pull from the wall gets wasted.

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baleph
 
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Re: PowerBoost 1000 Charger + Wireless receiver

Post by baleph »

The current drawn by the RPi would be from the LiPo battery rather than the Qi wouldn't it? I was under the impression that the power from the Qi charger would only go toward the battery. Although it does still sound like charging would be extremely inefficient. Do you know of any other similar device that will allow me to charge and supply power from a LiPo on the same board?

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baleph
 
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Re: PowerBoost 1000 Charger + Wireless receiver

Post by baleph »

Hoping for clarification on this. A 2500mah or 6600 li-ion battery should have no problem powering the raspberry pi and a couple motors, even through the powerboost, right?

Also, does anyone know if the qi charging pads and receivers marketed for phones will be finicky if I use them to charge things other than phones? In my case, the Li-ion battery through powerboost.

Thanks!

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adafruit_support_mike
 
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Re: PowerBoost 1000 Charger + Wireless receiver

Post by adafruit_support_mike »

The PowerBoost 1000C uses an MCP73871 LiPo charger, which performs load balancing between the input power and the battery. Input power goes to the load first, and any current the load doesn't use goes to charging the LiPo.


A 2500mAh LiPo can feed the PowerBoost enough current to run a RasPi, but only for an hour or two. An A+ will give you the longest battery life because it uses the least current.

Motors tend to use a lot of current, which will deplete the battery faster.

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