I have been using the USB / DC / Solar Lithium Ion/Polymer charger - v2 for several weeks now. I usually use a solar panel (Adafruit) or a 5V 1A DC power supply to power the charger. Everything has been working as advertised up until today. I plugged in the 5V supply, and disconnected the load (Arduino nano + XBee S1) because I wanted to charge the battery (Adafruit Lipo) up. A few hours later the battery appeared to be fully charged but the charger was dead. The charging light still lit up as usual when any supported power source was applied, but no power was delivered to the load output. It appears the charger is dead.
How did this happen? I have been using the charger and other components as specified with no problems up until now. Suddenly, poof! Is there anything I can do? Any way to diagnose and repair? This was a prototype project but the plan was to buy dozens, if not hundreds for production. However, with a random failure like this I am unsure if this product is suitable for our needs.
Suggestions?
Thx.
USB / DC / Solar Lithium Ion/Polymer charger - v2 - Failure
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- djmauro
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USB / DC / Solar Lithium Ion/Polymer charger - v2 - Failure
Last edited by djmauro on Tue Mar 20, 2018 10:48 am, edited 1 time in total.
- adafruit_support_mike
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Re: USB / DC / Solar Lithium Ion/Polymer charger - v2 - Fail
What voltage, if any, do you see on the LOAD pins?
- djmauro
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Re: USB / DC / Solar Lithium Ion/Polymer charger - v2 - Fail
I see 0 volts on the LOAD pins. It is zero regardless of the voltage source - USB, barrel jack or DC IN. And the battery is not hooked up.
Thx.
Thx.
- adafruit_support_mike
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Re: USB / DC / Solar Lithium Ion/Polymer charger - v2 - Fail
The battery needs to be connected at all times. The Solar Charger is built around a LiPo charger (the MCP73871) and that part doesn't work without a battery.
To verify, did you have any load connected when you disconnected the LiPo?
To verify, did you have any load connected when you disconnected the LiPo?
- djmauro
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Re: USB / DC / Solar Lithium Ion/Polymer charger - v2 - Fail
To sum up the usage of the charging system:
Providing charging power to the system from
- the 5V barrel using either the solar panel or a 5V DC charger
- USB port running from my computer.
In all cases, the battery was usually connected. Sometimes a load (Arduino nano + XBee) was connected, at other times not.
The amber Charging LED and the red Power LED were always lit up.
So, basically all combinations of source voltage, battery connection and load connection were tried and everything worked perfectly.
The last time I used the system was to get a good charge into the battery because I wanted to run a test to see how long the system would operate without and solar charging (to simulate nighttime and poor weather conditions). In this case there was no load connected.
After a few hours I removed the battery to check the charge. I noticed that the red power LED was no longer lit, though the Charging LED was still lit. Now, with or without the battery connected and with or without a load, the charging LED still lights, but the power LED does not. And there is no voltage at the Load pins under any conditions.
Thx.
Providing charging power to the system from
- the 5V barrel using either the solar panel or a 5V DC charger
- USB port running from my computer.
In all cases, the battery was usually connected. Sometimes a load (Arduino nano + XBee) was connected, at other times not.
The amber Charging LED and the red Power LED were always lit up.
So, basically all combinations of source voltage, battery connection and load connection were tried and everything worked perfectly.
The last time I used the system was to get a good charge into the battery because I wanted to run a test to see how long the system would operate without and solar charging (to simulate nighttime and poor weather conditions). In this case there was no load connected.
After a few hours I removed the battery to check the charge. I noticed that the red power LED was no longer lit, though the Charging LED was still lit. Now, with or without the battery connected and with or without a load, the charging LED still lights, but the power LED does not. And there is no voltage at the Load pins under any conditions.
Thx.
- adafruit_support_mike
- Posts: 67485
- Joined: Thu Feb 11, 2010 2:51 pm
Re: USB / DC / Solar Lithium Ion/Polymer charger - v2 - Fail
The Solar Charger is built around an MCP73871 LiPo charger, which has an automatic load-sharing feature.
When an external power source is connected, the MCP73871 routes power from that source to the load first, then uses any excess power to charge the LiPo. When the external power source is disconnected, the MCP73871 automatically switches over to using the LiPo to power the load.
The MCP73871's load-sharing switch is known to be weak when no LiPo is connected. The chip's reason for existing is to charge a LiPo, so running without a LiPo is outside its design spec. The failure you experienced is consistent with either a spike of input power the MCP73871 couldn't route to a LiPo, or a spike in load current that overloaded the switch from the external power source.
When an external power source is connected, the MCP73871 routes power from that source to the load first, then uses any excess power to charge the LiPo. When the external power source is disconnected, the MCP73871 automatically switches over to using the LiPo to power the load.
The MCP73871's load-sharing switch is known to be weak when no LiPo is connected. The chip's reason for existing is to charge a LiPo, so running without a LiPo is outside its design spec. The failure you experienced is consistent with either a spike of input power the MCP73871 couldn't route to a LiPo, or a spike in load current that overloaded the switch from the external power source.
Please be positive and constructive with your questions and comments.