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Charger Li-ion / Li-pol

  • Author: Miloš Zajíc
  • Charging current: 0,35A : 0,75A : 1A
  • Charging voltage: 8,4 V ( 2 cells ) : 12,6 V ( 3 cells )
  • Supply voltage: 12V resp. 18V ( for 3 cells )

Each beginning modeller encounters in time a problem of charging the battery. While the kits for beginners typically include battery charger, for more advanced models or custom design one we have to buy a charger separately.

Charging Li-ion and Li-poly accumulators is very different from the less demanding Ni-MH battery and requires stringent compliance of charging parameters. The hazard of Li-poly accumulators is their relatively easy ignition and subsequent explosion. It is very important do not exceeding max. charging current and maximum allowed voltage per cell. Therefore it is important to monitor the charging voltage of each cell in the set separately. For this purpose an accumulator packs has service connector to connect to the monitoring device so called balancer. Charging without balancer is possible, but the risk of destroying the whole accu set is high.

High quality universal chargers are usually expensive. For novice modellers that investment means one or two models price. When I change accumulator on Fik model to Li-Poly one, price 3000, - CZK for charger were unrealistic. So I started looking for a cheaper alternative. And I found it! Charger about 100, - CZK balancer approximately 150-200 EUR for 3cels accu. It is not a competitive to hi-tech processor controlled chargers, but the accumulators are being charged well, so it is essential.

I made one charger and balancer and used it for some time. Over time, increased in number of aircrafts and accumulators to charge, I started to think about the make of other chargers, so I can charge multiple batteries simultaneously. Then the idea to a simple charging station was born. I will describe it in a separate article.

 

!!! WARNING !!! WARNING !!! WARNING !!! WARNING !!! WARNING !!!

If you are someone interested in building Your own charger, I must say this warning: the construction or involvement of the charger is not too complicated, but still building these things can be recommended only for experienced electricians. It is essential to accurately set the charging parameters, otherwise an explosion and fire can occur! If you do not have good quality voltmeter and enough experiences, rather let someone else to build it!

!!! WARNING !!! WARNING !!! WARNING !!! WARNING !!! WARNING !!!

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