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USB/DC/Solar battery charger & PowerBoost 1000 Basic
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USB/DC/Solar battery charger & PowerBoost 1000 Basic

by waterglass on Wed Sep 03, 2014 1:55 am

I'm using the USB/DC/Solar battery charger with the 6600mAh battery and the 6V 5.6W solar panel. One of the forum posting indicates that a PowerBoost 1000 could be used with this combination to power a Raspberry Pi using the USB input. I'd like to power and charge the battery and Raspberry from the solar panel which produces up to 6 V. In load sharing mode this voltage may appear on the load port of the USB/DC/Solar charger board. The datasheet for the TPS61030 on the PowerBooster 1000 indicates that the maximum input voltage is 5.5V. This makes the PowerBooster 1000 incompatible with the USB/DC/Solar battery charger using the 6V solar cell. Would you suggest an alternate "PowerBooster" for this application?

Excerpt from the USB/DC/Solar Lipoly Charger project
The smart load sharing means that the LOAD output can be as high as 6VDC if in direct sun because it will draw current directly from the 6V panel instead of from the battery. If using this with an electronic project, make sure it is OK for up to 6VDC input or use a low-dropout-regulator (LDO) to regulate the voltage down.

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Re: USB/DC/Solar battery charger & PowerBoost 1000 Basic

by adafruit_support_bill on Wed Sep 03, 2014 6:33 am

There are some suggestions for LDO regulators here: viewtopic.php?f=22&t=59259&p=299882&hilit=ldo#p299882

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Re: USB/DC/Solar battery charger & PowerBoost 1000 Basic

by adafruit2 on Wed Sep 03, 2014 11:56 am

What you can do is instead of grabbing from the LOAD JST output, connect the powerboost input to the B+ and GND pins, it will never be higher than 4.2V
its not as efficient as the LOAD shared output, but it'll work :)

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Re: USB/DC/Solar battery charger & PowerBoost 1000 Basic

by waterglass on Fri Sep 05, 2014 2:16 pm

Hi Adafruit2,
That is a good point and I had not considered using the battery charge output to drive the PowerBoost 1000 Basic. I was considering using a diode in series with the solar cell to give a ~0.7 V drop so that the voltage applied to the USB/DC/Solar battery charger would be around ~5.3 V and below the 5.5 V max input limit of the TPS61030. The diode reduces the solar panel output power by ~0.7W but this will be more efficient than using the battery charge voltage approach. Thank you for the link. After looking around a bit, there are several alternate choices available, but I'll give the series diode and the PowerBoost 1000 a try first.

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Please be positive and constructive with your questions and comments.