Hi I just received my Maestro today and when I installed the batter there is no usb plug for charging the battery as shown in the manual.

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Samuel Strongin

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Posted 3 years ago

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Steve K9ZW, Elmer

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Official Response
Maestro were shipped without an internal micro-USB charging cable so the one USB A cable that you plug into  is to power the Maestro NOT Charge the battery.  You currently need to use an external USB Charger to Charge the Battery.  Flex will likely issue an official explanation.

and later from Tim:

 I'm wanting to be able to charge the battery while left in the Maestro case while plugged into 120v using the provided wall wart without opening the battery door to change cables.  Is that not possible?  

I am afraid not.

Let me provide some clarity.  We had fully intended for the battery installed in the battery bay to be recharged by Maestro when the unit was connected to an external DC power source (the coaxial DC power connector).  What we determined after extensive complete product testing, is that the battery charging feature was not working as intended and we decided to remove the feature.  As such, you must charge the battery using a charger or the recommended charging method provided by the battery manufacturer.

This business decision was made only after exhausting all reasonable options, meaning that engineering a solution that would work for most batteries would have significantly delayed the shipment of Maestro for a feature that is not mission critical to the operation of the unit.

As Howard indicated, the issue is very, very complicated. In summary, there isn't an industry standard by which these battery packs are engineered from a charging standpoint.  Worse yet, there is a significant amount of variation regarding how a battery behaves when being charged within the same battery model.  These variations in behavior resulted in adverse and anomalous Maestro operational behaviors, such as it would not boot from the battery when plugged into an Ethernet cable).

Battery management is discussed in the Maestro User Guide.  When the battery runs low, you will need to swap it out with a fully charged battery or connect it to an external power source.





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Gerald - K5SDR, Employee

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Official Response
Bottom Line:  

You charge the optional customer supplied power pack for Maestro exactly as you charge your smart phone or tablet.  You can even plug it into the same charger.

Maestro is designed to accommodate a customer provided cell phone LiPo power pack available through high volume consumer channels such as Amazon.  Charging and operation of the power pack for use in Maestro is accomplished in exactly the same manner you would for use with smart phones or tablets. Charging of the power pack is done by plugging its charging port into a standard 5V USB charger.  A charging cable typically provided in the package with the power pack.  To work properly in Maestro, the power pack must automatically turn on when it senses that a load is applied to its 2.1A output port.  This is easy to test by plugging it in and watching its LEDs come on to show it is supplying power.

Maestro is designed with a snap open battery compartment door (no tools required) that allows you to swap power packs in about 15 seconds.  The software will give you 2 minutes to change batteries when it detects that the power pack is dead.  A good 12000 mAhr power pack will give you 6-7 hours on a charge for around $20.  Buy two and you can run all day. 


We chose to incorporate off the shelf LiPo smart phone power packs because they offer very high power density at ultra low cost.  Their availability is driven by the high volume consumer products industry.

Our power control circuitry was developed and tested using Mogix and Sony batteries purchased last year.  In our internal testing they operated and charged flawlessly.  We demonstrated battery operation at many hamfests where we were able to charge the Mogix batteries inside Maestro.  As we expanded our beta testing over the last couple of months, more of our testers started to purchase Mogix batteries.  Suddenly we started getting reports from some but not all testers that they were having problems getting Maestro to boot on battery or to swap from DC to battery.  

At first we were not able to repeat the failure at FlexRadio because we were still testing with the original Mogix batteries.  Then we purchased a large number of Mogix batteries to use at hamfests for demo.  When we started testing the new batteries we found that some worked and some didn't.  For example the unit I use at home worked 100% of the time.  

A significant portion of recent delay in Maestro delivery can be attributed to trying to find the root cause of the problem.  We bought more batteries from different manufacturers and most seemed to exhibit similar problems.  Either they would not boot or they would not charge when placed in Maestro.  

We thought at first that we might have a software or hardware issue in Maestro.  We did extensive work to look at the power management software operation without success.  We looked carefully at the hardware power switching design and could find no fault there.  

Sometimes the root cause is the last thing you think of.  On April 28, I was personally testing every battery we have to look for some correlation that could be used for diagnosis.  I was showing Matt what I was doing and he asked, "What if you disconnect the charging port?"  I tried that and suddenly every single battery that was failing to boot Maestro now worked.  It seems that many but not all of the batteries we tested do not function properly with both their input and output ports simultaneously connected to Maestro.  Why?

That began a comprehensive digital scope analysis of the circuit along with a search for batteries that might function properly.  We tested a variety of software switching scenarios as well as potential circuit modifications.  None improved the reliability.

We actually found another pack that did work with both input and output connected but it charged very slowly and there is no assurance that the same brand will work the next time you buy it given our Mogix experience.  We came to the conclusion that there is no way for us to know if a given power pack purchased by a customer would allow both connections at the same time.  

We simply exhausted all of the practical near term hardware and software modifications to the design that we could make to assure reliable operation with the charging cable connected.  It turns out that the majority of these power packs are simply not designed to charge and discharge at the same time and thus their protection circuitry prevents such operation.  If they are, there is not assurance that the circuit will not change for cost or other reasons.  Therefore we made the difficult decision to remove the charging cable to prevent significant support issues due to customers plugging in both cables on batteries that won't work in that configuration.  That made no sense whatsoever.

So again, the bottom line is that you will charge the optional power pack exactly as it is designed and marketed - on a USB charger just like your cell phone.  In fact, I am using an old iPhone charger to charge mine.  Takes just 15 seconds to hook it up.  

If you are going to operating extended time on batteries you will want to have multiple charged batteries ready at all times.  The capability of swapping high density power packs in seconds allows you to carry a number of packs for extended operation that would not otherwise be possible.  You should be able to purchase 24 hours worth of batteries for under $100.  That's a bargain.