Battery Chargers Guide

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Our RC world is loaded with different battery chargers, this guide is intended to help you make a wise choice when shopping.

Battery chargers supplied with RTF models:

Many “Ready to Fly” (RTF) models come with rudimentary yet adequate balancing chargers. These will safely charge the batteries they were designed for.

Computerized battery chargers:

Computerized battery chargers, on the other hand, offer the most versatility and are available at affordable prices. These chargers have all the required safety components to avoid any charging issues & to allow your batteries to perform efficiently for many charge cycles.

These configurable battery chargers allow you to charge, balance charge, discharge & set your batteries up for proper storage by charging or discharging each cell to the configured storage voltage (3.7 to 3.85 Volts are recommended for storage). Most of them require a separate power source (separate power supply, 12 Volts car battery, some people even use old computer power supplies to power their chargers). Since they require a separate power source, most of them allow feature power source monitoring. This feature will stop and prevent the charging sequence to avoid draining your car battery at the field.

Which battery charger should I buy?

Like a radio transmitter, your charger should be able to keep up with your evolution in the RC hobby. You might have a small size RC vehicule at the moment using a 2200mAh 3S  battery. Deep down inside of you, you know that you will eventually step up into something using a 5000mAh 6S battery. Think ahead & if you can, purchase a bigger battery charger capable of handling your future batteries. This is a long term cost saver.

Purchasing this piece of equipment should not be price driven only. You will find a good number of very inexpensive chargers out there. Don’t trust any charger! A poor quality charger will destroy your batteries. Many of these poorly manufactured chargers under read the batteries cell and / or total voltage this makes the charger overcharge your battery & ruin cells. A good way of validating your choice is to select a unit that has a lot of good reviews. If a charger’s reviews mention that the cell and / or battery voltage is off by more than 0.1 Volts, stay away from it! Following is a trusted charger brand. It’s manufactured by a reputable company offering great customer service & support: www.progressiverc.com

How do I determine the charger size I need?

The battery charger must be capable of delivering a charge current (Amps) which is at least 1 X the capacity of the biggest battery you plan to charge, thus charging at a rate of 1C. In other words, if you plan on charging a 5000mAh, 6S battery you will need a charger capable of delivering at least a 5 Amp charge current. Once the required charge current is determined, add in a safety factor so that you’re not always maxing out your charger every time it’s charging your big batteries. So if you’re planning on charging 5000mAh batteries, a charger rated for at least 6Amps would be appropriate. Don’t forget to do the same with the power supply feeding your charger. It must be capable of supplying the proper power to charge your batteries plus the extra power required for the charger’s circuitry and a safety factor to keep it from overheating.

Battery chargers & power supplies sizes are usually rated in Watts which is equal to the number of cells of the battery to be charged multiplied by 3.7 Volts multiplied by it’s current capacity in mAh divided by 1000

For example, using our 5000mAh, 6S battery:

6 x 3.7 Volts = 22.2 Volts, 22.2 Volts x 5000 mAh / 1000 = 111 Watts.

In this case you may consider a 150 Watt charger, it will remain cool which will prolong it’s lifespan.

What’s the difference between charging & balance charging?

A LiPo battery’s performance is relative to the balance of all it’s cells. A balanced battery means that all of its cells voltage are closely matched (within 0.01 Volt). A balanced LiPo can be charged a few times (three or four to be safe) before it’s balance charged. A computer controlled charger usually supports both charge methods. A regular charge is quicker than a balanced charge because it monitors the batteries total voltage & assumes that each cell will take in their share equally. A balanced charge is a guarantee that your battery is in top shape. It monitors each cell & makes sure that they are closely matched. Combining regular & balanced charging allows for a few quicker charges a ensures that the battery remains in perfect working condition.

When & why should batteries be prepared for storage?

If you don’t plan on using a LiPo for a week or longer you need to prep it for storage. Once more, a computer controlled charger / discharger can come to the rescue. Sure, you can use a fully charged battery in your model & monitor it’s cells until they discharge until they’re at a proper storage voltage (somewhere between 3.7 to 3.85 Volts). However if you cannot use your model due to poor weather or whatever reason, your charger can easily make your batteries safe for long term storage. Storing a fully discharged battery might prevent it from ever being properly recharged and storing a fully charged battery might cause it to swell because of gases building up within the cells, which might damage them or render them hazardous. These are a few of the reasons explaining why they should be stored half charged.

Following are the main features to look for when selecting a battery charger:

Guaranteed precision (within 0.01 Volt) individual cell & total voltage reading & charging

Safety:

  • Maximum charge capacity configuration
  • Charge time limit
  • Some chargers also offer temperature monitoring

Convenience:

  •  Balanced Charging with individually displayed actual cell voltage
  •  Regular Charging
  •  Storage Charging

Power source monitoring:

Monitors the chargers supply battery to prevent you from draining your car battery at the field.

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