When charging LiPo and LiFe batteries you need to make sure to balance charge them once in a while or even at every charge to make sure all cells in a pack have the same voltage level as too low or too high voltage values can lead to dangerous battery conditions.
Most of today's LiPo and LiFe-compatible charger feature an internal balancer, a unit and software feature that equals the voltage of the cells, making sure they are at the same level. To use this feature a balancer harness is needed that allows the charger to "read" every cell in a battery pack.
When searching for the correct balancer harness for your battery and charger you need to keep attention to several points as are the type of your battery's power connector, the balancer connector type as well as the respective connector types on your charger.
The most common battery connect types are the 4mm and 5mm bullet-type connectors, the so called T-plug (also known as Deans connector) as well as the Tamiya-style Molex plug and a few other such as the Traxxas TRX and iD connectors.
On the balancer side of things the most common types are the very common JST-XH and not-so-common JST-EH plugs while the respective connector for chargers is called Polyquest or PQ, although there are also devices that use JST-XH connectors. As you can see this can already cause some confusion as at time the terms are mixed up.
Now, when you are looking for the perfect balancer wire for you, first check the balance connector on your charger. Refer to the supplied manual or information given on the manufacturers website to see what connector type you are after. Say your charger uses the Polyquest connectors you then look after the respective balancer port on your battery pack. When using competition-type batteries, you will likely find an internal 2mm tube-type connector port while many "sports" batteries are equipped with external XH or EH balancer ports. Finally you only have to detect the type of battery connector your battery has.
With the given information you can now look after your perfect balancer and charging harness. EuroRC offers a wide range of pre-wired balance harnesses and even adapter wires if you did not find a pre-configured one.
Charging industry-standard 2S LiPo packs requires most likely a harness such as Vampire Racing's 2S charging wire with EH/PQ balancer port, stepped 5mm/4mm bullet-type connectors and 2mm balance connector.
Traxxas battery packs use their own TRX iD connectors with integrated balancer connection and saddle pack battery packs require a harness with integrated jumper wire. Most of the wires come with XH or PQ balancer connectors for the charge side, meaning you can either use them directly with the charger or with the addition of – most likely included – balancer boards/adapters. When using "sport" battery packs with external balancer connector, you can plug those directly into the balance board/adapter. If your charger comes without a balanced board, you can get a multi-balance board for EH, XH, TP/FP and HP/PQ balancer connectors here. It is usable with 2S to 6S battery packs and thus should meet virtually every RC car related need.
As for the battery connector, competition packs will likely use 4mm or the newer 5mm bullet-type "tube" connectors while sport packs will use T-type "Deans" or XT60 connectors. Most pre-configured balancer wires come with either bullet- or T-plug connectors while XT60 and other "less usual" plugs require respective adapters.
If you are unsure what harnesses or adapters to use with your battery, feel free to contact us!