LiPo Balance Connector Types: How to Match Your Battery to Your Charger

You've got a new LiPo battery, but the balance plug doesn't fit your charger. Or maybe you ordered a charging harness online, only to find out it's the wrong connector type. The terminology doesn't help either. JST-XH, JST-EH, Polyquest, Thunder Power... they all sound like random letters until you know what you're looking at.

This guide aims to clear up the confusion. You'll learn how to identify your balance connector type, understand why batteries and chargers use different standards, and pick the right adapter or harness the first time. No more guessing at the hobby shop and no more wrong purchases sitting in a drawer.

What Is a LiPo Balance Connector?

You know that small plug with multiple thin wires coming out of your LiPo battery? That's the balance connector, and it lets your charger monitor each cell's voltage individually.

Here's why that matters. Most chargers these days have a built-in balancer that equalizes cell voltages during charging. Without this feature, cells can drift apart over time, and that's a problem. Charging a cell above 4.2V or letting it drop below 3.0V risks permanent damage, and in extreme cases, fire. The balance connector gives your charger direct access to each cell so it can keep them all in check.

You'll notice the wire count is always one more than the cell count. A 2S pack has 3 balance wires, a 3S pack has 4 wires, a 4S pack has 5 wires, and so on. Each wire taps into the junction between cells, giving the charger a complete picture of what's happening inside the pack.

For a deeper look at charging fundamentals, check out our guide on how to use and charge LiPo batteries.

The 4 Main Balance Connector Types

Now that you understand what balance connectors do, let's look at the specific types you'll run into. Most RC batteries use one of four standards, and while they look similar at first glance, the pin spacing differs enough that they're not interchangeable.

• JST-XH is by far the most common balance connector on RC LiPo batteries. It has a 2.5mm pitch (that's the distance between pin centers) and typically comes in a white plastic housing. If you buy a battery from most mainstream RC brands, chances are it uses JST-XH.
• JST-EH looks similar but uses a tighter 2.0mm pitch. It's less common than XH, though certain battery brands still use it. The housing shape is nearly identical to XH, which is why people mix them up, but the pins sit noticeably closer together.
• Polyquest/Hyperion (PQ/HP) is where things get interesting. While most batteries use JST-XH, most chargers have Polyquest balance ports. The connector has a different housing style with a more rectangular profile and different pin arrangement. This mismatch is exactly why balance boards and adapter harnesses exist (more about this later).
• Thunder Power (TP/FP) is an older standard that's been around for years. You'll still find it on some battery packs, particularly older stock or brands that never switched formats.

For more on connector types across RC applications, see our RC connectors explained guide.

How to Identify Your Balance Connector

So how do you figure out which connector type you're dealing with? It's actually pretty straightforward once you know what to look for.

Start with the pin spacing. If you have calipers, measure the distance between pin centers. JST-XH measures 2.5mm between pins, while JST-EH sits at 2.0mm. That half-millimeter difference is small, but it's enough to prevent cross-compatibility.

Once you've checked the spacing, count the wires to confirm your cell count. Three wires means 2S, 4 wires means 3S, 5 wires means 4S, 6 wires means 5S, and 7 wires means 6S. This won't tell you the connector type, but it helps verify you're looking at the right specs when shopping for adapters.

Another quick visual check is housing shape. JST-XH and JST-EH have similar rectangular housings with a locking tab on one side. Polyquest connectors look distinctly different with a wider, flatter profile. Thunder Power plugs have their own unique housing too.

If you're still not sure, check your battery's documentation or look up the brand's specs online. Our guide on LiPo battery markings and meanings can help you decode other labeling on your packs.

Balance Boards: The Universal Solution

So your battery's balance connector doesn't match your charger's port. What now? Whatever you do, don't force it. Jamming a JST-XH plug into a Polyquest port will bend or break the pins, and you'll end up with a damaged connector or incorrect cell readings during charging.

A multi-balance board is the clean solution. It accepts multiple connector types on one device, so you can charge JST-XH, JST-EH, Thunder Power, and Polyquest batteries all through the same charger port.

The setup is simple. The board connects to your charger's balance port via a lead that matches the charger's connector type (usually Polyquest). Your battery's balance lead then plugs into the appropriate row of pins on the board based on cell count. Most boards handle 2S through 6S packs, which covers virtually every RC car application.

You might be wondering whether you actually need one. Grab a balance board if your charger's balance port doesn't match your battery's connector type directly. Some chargers include a balance board in the box, so check what came with yours. If it didn't include one, or if you need a board that supports more connector types, you can find options in our balancer cables and boards category.

For help selecting a charger with the right features, see our guide on how to choose an RC charger.

Choosing the Right Balance Harness

While a balance board handles the connector mismatch, you still need a way to connect power to your battery during charging. That's where charging harnesses come in.

A harness connects your battery to your charger for both power delivery and balance monitoring, and the right one depends on your battery type.

Competition LiPo packs are a bit different from consumer batteries. They typically have internal 2mm tube-type balance ports rather than external JST plugs. These require a harness with a 2mm balance connector on the battery end and a Polyquest or XH connector for the charger's balance port. The power side usually uses 4mm or 5mm bullet connectors.

Sport LiPo packs, on the other hand, usually have external JST-XH or JST-EH balance plugs that stick right out of the battery. For these, you can plug the balance lead directly into a multi-balance board and use a separate power lead with Deans or XT60 connectors.

Traxxas iD batteries work differently altogether. They integrate balance monitoring into the main TRX power connector, so there's no separate balance plug. This works seamlessly with Traxxas chargers, but you'll need an adapter that breaks out the balance leads if you want to use other charging equipment.

Saddle packs (two battery sticks wired in series) have their own requirements too. They need a harness with an integrated jumper wire that connects both halves during charging.

One more thing to keep in mind: most pre-configured harnesses come with bullet or Deans power connectors. If your battery uses XT60 or another connector type, you may need a separate power adapter alongside your balance solution.

EuroRC stocks a wide range of balancer cables and boards covering most battery and charger combinations.

LiPo Balance Connector FAQs

My charger doesn't have a balance port. Can I still balance charge?

No. Balance charging requires a charger with balance capability and a dedicated balance port. Budget chargers often skip this feature to cut costs. If your charger lacks a balance port, you'll need to upgrade to a balance-capable unit for safer LiPo charging.

Can I use a balance extension cable if my leads are too short?

Yes. Balance extension cables are available for JST-XH and other connector types in various lengths. Just make sure the extension matches your connector type exactly. Using an extension won't affect charging performance as long as the connections are secure.

How often should I balance charge my LiPo batteries?

Balance charge every time, or at minimum every 3-5 charges. Cells naturally drift apart during use, and regular balance charging keeps them equalized. Skipping balance charges repeatedly can lead to cell imbalance, reduced capacity, and shortened battery life.

Can I convert my battery's balance connector to a different type?

Technically yes, but it's not recommended unless you're experienced with soldering small gauge wires. The pin order and spacing must be exact, and mistakes can cause incorrect cell readings or damage. A balance adapter board is a safer and easier solution.

Next Steps

Now that you understand balance connector types, here's what to do. First, grab your battery and identify the balance connector using the pin spacing method above. Second, check your charger's balance port type (look in the manual or check the manufacturer's website). Third, decide whether you need a multi-balance board, a complete charging harness, or both.

Once you know what you're working with, browse our balancer cables and boards to find the right adapter or harness for your setup. If you're unsure which product fits your battery and charger combination, drop us an email at info@eurorc.com with your equipment details. We'll help you get the right parts the first time.