Multistar 10000 blowing chargers

We've just flown with a multistar 10,000 and it flew very well. Gave us all 10,000 mA at 6S at 5 amps. 1hour and 15 in the air.

When we went to charge it at 5 amps, we killed two I charger 208Bs and then blew up the power supply.

Something's not right. Battery was not hot. Cells are all balanced. Charger was not hot.

Can't work it out. Is there a trick to charging big batteries?

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  • Developer

    HK products have great prices, but ZERO quality assurance. It's the price you pay for such low prices.

    If there is a bad production batch, it is always discovered after the fact when users start complaining. So my guess is that you bought the chargers/power in one order, meaning they originate from the same batch and hence suffer from the same fault either in charger or power.

    • Thank you all so much for your input.

      I've just ordered the biggest iCharger I could and we are going to use a 24V truck battery (trickle charged) to supply the charger with a 20 amp fuse.

      I'll keep all informed. Given that we appear to be the only one with issues, I agree that it might just be a bad batch.

      Thanks again.

      • Just an update - HK have suggested that there is indeed a problem with the chargers and will replace them.

  • I wonder, could it be that the PSU voltage sagged under load. This means that the stepper inside the charger had to work extra hard which then puts the caps under extra load. It is simply the voltage difference between the supply (Can't see that you mention what it is?) and the required voltage for a 6S pack.

    There are two common things - the battery and the supply.

    At the risk of blowing a charger, buy a cheaper one, charge the suspected 6S at 2A from your car battery. Does it blow? No.

    As has been said already, a LIPO going short on a cell and not actually letting you know is most odd and unlikely.

    If this test does not blow the charger then it's now a case of looking at the PSU. The PSU might have a larger-than-needed ripple on the output. This would then make the charger's switcher work even harder. Do you have access to a volt meter? A 'scope would be much better.

    If you want to find out what it is then you need to start testing - we can all sit here for 3 weeks arguing and farting in the wind - it's pointless.

    Remember, these chargers and PSUs are made cheap because we want them cheap. They are not made with mil-spec components. There is not much headroom in spec on a lot of the components. I have a Turnigy 400W charger - the output caps are rated at 30V. A full 6S is 25.2V.

  • I over discharged a battery and the I-Charger warned of a week cell, then refused to charge it.

    Also, there are power supplies and there are power supplies. The stated and actual rating can be two very different animals. A "gold" rating is for a good reason. At least that's been my experience with PC's.

  • There is no failure mode of a battery that will kill a charger...  This is a fact.

    You asked the question in the first post but have all ready come to your own

    conclusion, so whats the point if you will not listen.

    if you want help.. listen close..

    There is no failure mode of a battery that can kill a charger. period.

    • Eddie, YOU listen. I had a problem, I asked the community, they generously offered advice, I drew a conclusion after listening to that advice.  Tell me where my logic is flawed. 

      We managed to fully charge the battery yesterday with a $30 Turnigy charger (in a fibreglass bag with a fire extinguisher right next to it).  All cells perfectly balanced.

       At least we can fly. 

      Michael, we had the power supplies set to 15 Volts. Your argument is good. Combined with the ripple current it may be the culprit. We will change the voltage on the remaining supply to 25V.

      Still no news from HK.

      • Ok.. I am listening.  I just read that you charged the battery and everything is fine...  Interesting

  • This doesn't make sense to me either.  To charge at 5 amps the charger adjusts the voltage to the battery to achieve the proper current to the battery.  As the battery charges it keeps upping the voltage until it gets close to full.

    So it should not matter what size battery except that the higher the S could the higher the input voltage that it needs to generate to get to 5 amps.

    The manual states good to 8S.  It also says there's a log function that can show how it was charging.

    That's one of the features I like about my charger.  It displays a graph of the charge.  Input Voltage, Output Voltage, Current and total mah along with time.

    To charge a 6S it would need to generate 4.2Volts X 6 = 25.2 volts. If the input power is at say 15 Volts it would need to convert Amps from the power supply into Volts.  That could cause a problem for the Power supply.

    This could cause a problem for the ICharge and maybe take both out.  Manual doesn't state it has input voltage protection just reverse polarity.

     

    • Developer
      LiPo chargers are more complex at charging that. They are constant current (variable voltage) when below 4.2V per cell, and when at 4.2V they are constant voltage (variable current) until the current going in drops below a cut-off.

      If you just connect a fixed voltage to a drained lipo, the current in would be too high and something would blow.
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