Using Minty Boost as Load on Lipo / Solar Charger

Ideas and questions about MintyBoost kits

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theonedrewski
 
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Using Minty Boost as Load on Lipo / Solar Charger

Post by theonedrewski »

Hello,
I was hoping someone might be able to clear up some confusion. I have a 6600 mAhr battery plugged into my Lipo/Solar charger with the minty boost v3 in the load slot. I've check the connections on the pins and get 5v and 2v on the Minty Boost so as far as I can tell it should be working correctly. I'll post photos of the board later if needed.

My question is what max input current can the minty boost take? I have the Lipo charger set at 1A and not sure but I think I saw the Minty Boost only having a 500 mA output. It will charge from the Minty Boost USB when plugged into the mini USB port from the Lipo charger but the moment I remove the usb charger to run on the battery it stops (sometimes with some delay). I also noticed it gets hot if it is plugged into only the battery. I feel like my answer is to change my Lipo/solar to 500mAhr but wanted to make sure before I try to resolder another resistor.

Thanks guys!
Drew

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adafruit_support_bill
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by adafruit_support_bill »

I have the Lipo charger set at 1A and not sure but I think I saw the Minty Boost only having a 500 mA output.
The charge rate limitation on the solar charger is for the battery only. The load-sharing circuit can route current directly to the load while still regulating the charge current to the battery. The Minty may only put out 500mA at 5v, but in order to boost voltage, it needs to take in more current proportional to the boost. Combined with the fact that boost efficiency is not 100%, the Minty may draw 1A or more at 3v to produce 500mA at 5v.
It will charge from the Minty Boost USB when plugged into the mini USB port from the Lipo charger but the moment I remove the usb charger to run on the battery it stops (sometimes with some delay). I also noticed it gets hot if it is plugged into only the battery.
When plugged into the USB, the input to the Minty will be very close to 5v, so it won't be working very hard. When running from the battery, the input will be in the range of 3.3-4.2v, so it will need to work a bit to boost the voltage. When it is working hard, it will get warm.

What voltage do you measure at the battery terminals when running the Minty from battery only?
What voltage do you measure at the USB output terminals?
If you post photos of both the front & back of the board we can check for any assembly issues.

theonedrewski
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by theonedrewski »

Hey Bill and thanks for the reply!

I don't have a way to hook up just the battery quite yet, but I'll find one and post the voltages soon. I recall testing them and getting the correct 5V and 2V across the two different pins but I never tested it from inside the USB. When I plug it into USB power from computer it has no voltage across any of the pins. I've included a pic from my mintyboost. Thanks for the help and Ill post voltages in a bit. -Drew
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adafruit_support_bill
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by adafruit_support_bill »

When I plug it into USB power from computer it has no voltage across any of the pins.
What are you plugging into USB power? The charger?

Your Minty assembly looks fine.

theonedrewski
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by theonedrewski »

The USB from my computer is plugged into the solar Lipo circuit with a 3.7v battery attached and the minty boost as a load. I haven't tried using the solar panel yet, wanted to test the charging first. This is where I was unable to find any voltages across the pins of the USB output on the minty boost. I want to try with only a battery pack next (need to hit RadioShack) to eliminate either the minty or the solar Lipo charger as the problem. I also have another minty boost kit, so I figured I'd construct that too and try.

I noticed the capacitor on my solar Lipo charger was loose, which has me scared, and wonder if that might have caused something. That and when only the battery and the minty boost is plugged (with out USB input) I don't get a response from the leds on the solar Lipo (which I would believe is normal because it isn't charging something...but still I thought I should mention).

Another thought I had was maybe it requires more than an amp of current to make the 3.7 v to 5v increase?

Thanks again Bill! I'll post another reply as soon as I have more info on the testing the minty from battery or trying a fresh minty.

theonedrewski
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by theonedrewski »

Bill,
So I grabbed a two AA battery back and hooked up to the minty boost. Measured 3v across the battery pack terminals (with fresh batteries too). All pins (1 & 4, 2 & 4... Or pretty much any combo) all measured 0v. I changed the dip chip from my second minty boost kit and found the same response, 0v across all pins. I am going to try to build the second minty boost and then test again.
Respectfully,
Drew

theonedrewski
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by theonedrewski »

Bill,
I want to say thanks for all the help. I built the second minty boost and it appears to be working perfectly. Voltages came out correct and actually charges devices. I had a chance to re-read the minty boost info and I think I realized my mistake. I was originally planning to use 4 rechargeable lithium batteries I had, but was testing it with four fresh regular alkaline batteries on top of trying to charge a device that probably uses more than 500 mA on USB. I measured the voltage of the battery pack and it was over 6V. I think I fried something in my first test cause it was actually working for a brief moment. Live and Learn.

I do have one final question. Is there anyway to safely increase the output of the Minty Boost to say an 1 amp?

Thanks again!
Drew

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adafruit_support_bill
 
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Re: Using Minty Boost as Load on Lipo / Solar Charger

Post by adafruit_support_bill »

Is there anyway to safely increase the output of the Minty Boost to say an 1 amp?
Users have reported outputs significantly higher than 500mA for short periods. But to consistently and efficiently double the output would require a substantial redesign with higher rated parts and a larger coil.

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