Best RC LiPo battery connector types: Choosing and Soldering

[PaPa Thorn]

My first truck had xt90's but everyone since has had ec5's. I ended up switching my first truck and all the batteries I had to ec5. Since most things I buy come with them it just made sense. No issues so far.

 

[FatCatRC]

Battery connectors are a common subject here and we get a lot of questions like"what battery connector is the best?" or "how to solder battery a connector?" and others. Hopefully this thread can serve as a central place to find answers to many of the questions we see when it comes to picking the best LiPo battery connector and how to use them.

Similar to what Recommend me a battery charger and What's your "budget" LiPo of choice? threads have done.

Popular LiPo Battery Connectors

There are dozen of different battery connectors one could use, but I'm only going to focus on the most popular and most recommended battery connectors that most people use in the R/C hobby on their car/truck Electronic Speed Controller (ESC), motors, and LiPo batteries.

Deans Ultra Plugs
View attachment 30292

Deans Ultra Plugs have been part of the RC hobby for years and Arrma used to use a Deans connector on many of their earlier models. Deans Ultra Plugs are designed so that it's impossible to plug them in the wrong way. The down side of Deans battery connectors is they can be a challenge to solder due to their flat ends. Due to their small size and tight fit they can also be harder to connect or disconnect.

These make great plugs for 3s or smaller LiPo batteries.

Amperage rating: 60 amps
Buy: Deans


XT-60 and XT-90
View attachment 30311

XT-60 and XT-90 connectors are very popular connectors across all areas of the RC hobby. These connectors where also found on Arrma RC models in the past. They are very similar to a bullet style plug but designed so they only connect one way. These connectors are also easier to solder thanks to how they cup the wire.

If you are running 4s or larger LiPo batteries, you would be best to use the XT-90 plug.

XT-60 Amp rating: 60 amps
XT-90 Amp rating: 120 amps
Buy: XT-60 / XT-90


EC3 and EC5
View attachment 30313

The EC3/5 connectors are popular connectors used a lot in the Losi and ECX brands. Now that Horizon has acquired Arrma RC, you will find any new Arrma RC models also ship with the EC plugs. These have been a personal favorite for a long while now. They are VERY easy to solder, thanks to them essentially being a bullet connector in a unique housing that prevents you from plugging them incorrectly. They also allow for a large amount of current to be passed through them.

EC3 Amp rating: 60 amps
EC5 Amp rating: 120 amps
Buy: EC3 / EC5


Bullet Connectors
View attachment 30314

These are common connectors typically used to connect ESC's to motors. These are NOT recommended to use for connecting batteries as there is no protection against plugging them in wrong. The advantage of bullet connectors is their ease to solder and ability to pass high current. They can also be found in a wide range of sizes: 2mm - 8mm!

3.5mm Amp rating: 35 amps
4.0mm Amp rating: 100 amps
5.0mm Amp rating: 120 Amps
5.5mm Amp rating: 130 Amps
6.0mm Amp rating: 140 Amps
6.5mm Amp rating: 150 Amps
7.0mm Amp rating: 160 Amps
7.5mm Amp rating: 175 Amps
8.0mm Amp rating: 200 Amps
Buy: Bullet connectors


Traxxas Battery Connectors
View attachment 30293

If you have a Traxxas RC then you're probably familiar with the Traxxas battery connectors as they have shipped with these connectors for several years now. The newer TRX connectors, which you can not buy, include a chip in them which communicates with the Traxxas charger to tell it exactly what kind of battery it is so that the Traxxas charger knows how to charge it.

The older TRX connector also have a flat surface similar to the Deans plug which can be tricky to solder. I've never been a big fan of these connectors as I never felt they offered anything new or a lot better than other connectors. It seems I'm not the only one either, Traxxas' Connector Crisis.

Traxxas does not sell their new TRX connectors to users. You must by a Traxxas branded or licensed battery.


Note: Even though the focus is on LiPo batteries, all of the connectors mentioned above will also work on NiMH packs as well.

Soldering RC Battery Connectors

Soldering is a just as important if not more important than the type of connector you use. Because if your soldering job is no good, than it doesn't matter if you're using an 8mm bullet plug, you won't be getting anywhere near its rated amperage usage. Instead you'll likely damage or burn something up.

How to Solder Correctly is a great resource that goes into great detail on how to and how NOT to solder. Below are several videos on the subject of soldering as well.


How to solder EC5 connectors:

How to solder to large wires together:

Recommended Soldering Tools

Soldering Iron Station or Soldering Iron - I use the Trakpower TK950 soldering station and am very happy with it's performance. The Hakko FX888D is another fine soldering station.

Solder - As already mentioned in the How to Solder Correctly article, good solder is very important. I follow what that article suggests and also use 63/37 solder:

• Kester Rosin Core Solder 63/37 1oz Dispense-Pak
• Kester Solder Roll, 63/37 Alloy, 0.031" Diameter
• BNTECHGO 3Pack Solder Wire Dia.1.0mm 63/37

Soldering Jig - This is an awesome little jig that will hold nearly any time of battery connector you might be soldering. From Deans, XT, EC, and bullet connectors.
View attachment 30316

You can get this soldering jig here. Another common solution is to make a jig from a scrape piece of wood or using a 3rd hand.


So these are the more common and most suggested LiPo battery connectors. I've also touched on how to solder and some very useful tools to make your soldering projects that much easier.

Now lets hear from you, what tools do you use and like? Any tips or tricks? What's your favorite battery connector?

Used to use xt60 but now xt90 all the way.

 

[Overpowerrc]

I use qs8s

 

[TpPartsRcXtreme]

Xt90 and xt150

 

[jkflow]

Didn't generate this list but forget where I got it from. I believe from Castle directly here on the forum, good reference.
Connector rating:
Tamiya plug - 6.5 amps
Deans - 45 amps
EC3 - 60 amps
XT60 - 60 amps
Castle 4.0mm Polarized - 75 amps
XT90 - 90 amps
IC5/EC5 - 120 amps
Castle 5.5mm bullets - 150 amps
XT150 - 150 amps
Castle 6.5mm Polarized - 200 amps
Castle 8.0mm bullets - 300 amps

 

[jondilly1974]

I’ve now swapped all of my cars and packs to XT150.

 

[Yas]

Switched all of my connectors to EC5 since HH acquired Arrma and have found them perfect for all of my 3-6s RCs

Word of advice - if planning on switching connectors out across batteries/ESC/charge leads, it's best to get multiple packs of the same brand. Some brands fit too tight or too loose with another brand of the same connector

I used a few connectors up learning to solder them anyway so it's best to get spares and keep them reserved

 

[Kiwi]

G

No mention of the Castle connectors??

Great connections and they are made for the thick gauge wire. They are my 8s battery connections for both outcast and kraton.

 

[Sandracer_NL]

XT90.

 

[bkhlouf]

I switched from the XT90 to XT150 that are away easier to solder than the XT90. Some issues with XT150: sparks, difficult to clip the cover and very hard to remove the cover afterward. Hence, I decided to move toward the AS150 that offers almost the same performances as the XT150 with anti-spark design, 7mm, easy to fit insulation cap with thread and based on some YouTube tutorial the soldering seems to be easy.

any experience with those AS150 from other users ?

 

[olds97_lss]

I run XT90's on everything now. eJato, stampede 4x4, outcast, erbev2 and savage flux. I put an XT90S on one pack out of each pair I have as well. Except for some recent ones I bought that came with xt90's on them.

 

[GMballistic]

Castle 8mm bullets on all my vehicles even on my 3S Serpent 1/12th scale as they're speed runners.

Also use OSE8 on my Limitless because they're "anti-spark" connectors and my Limitless is running 8S so big "pop" on connecting otherwise.

 

[BashingBrian]

Also use OSE8 on my Limitless because they're "anti-spark" connectors and my Limitless is running 8S so big "pop" on connecting otherwise.

I just love that scary spark pop as you plug in 8mm bullets..????
I've got 8mm bullets on a few cars, also run EC5's and XT90's I'm not too fussed as I just make up another charger adaptor if I need it..?
If you can solder it really isn't too much of an issue to swap connectors, everyone who can't solder should learn..!!

 

[rotauq]

Regular XT90 at my limitless atm. But they spark so hard on my 8S XLX setup that the connectors are already covered with black layer. I've ordered some XT90S and EC8. I've not decided which i will use though.

Trick for using bulletplugs on batteries (which i do on my boats) is to put male plugs on - and female on +, then they are easy to connect in serial and cannot be connected wrong.

 

[Resu]

Changed everything to use the XT90 since a while and stuck with that. Even when the IC5 are easier to handle, I don't want to change everything again

 

[jondilly1974]

I just love that scary spark pop as you plug in 8mm bullets..????
I've got 8mm bullets on a few cars, also run EC5's and XT90's I'm not too fussed as I just make up another charger adaptor if I need it..?
If you can solder it really isn't too much of an issue to swap connectors, everyone who can't solder should learn..!!

Can’t imagine not being able to solder. Would limit the hobby so much. What I need to learn is welding and CNC machining. Then I could take it to another level like the legends here. ???

 

[GMballistic]

Can’t imagine not being able to solder. Would limit the hobby so much. What I need to learn is welding and CNC machining. Then I could take it to another level like the legends here. ???

Knowledge is power,


....oh and money & quality equipment too.

 

[Uplift-RC]

I prefer the XT90 connectors on all of my arrma rigs except for my Proboat sonicwake 36 speed boat!! I am using a Seaking 180 ESC and a Leopard 4074 / 1650kv motor, so I will be using Castle Creations 6.5mm bullet connectors for this set up.

 

[Primarrma]

I've recently swapped everything over to XT150, couldn't be happier with the connection options, they are great if you want to run a couple of packs in series without the need for a Y lead. The only concern I have is if you have someone that doesn't know how they work, they could accidentally connect the positive and negative of the battery to each other, they aren't fail safe in that sense.

 

[jondilly1974]

I've recently swapped everything over to XT150, couldn't be happier with the connection options, they are great if you want to run a couple of packs in series without the need for a Y lead. The only concern I have is if you have someone that doesn't know how they work, they could accidentally connect the positive and negative of the battery to each other, they aren't fail safe in that sense.

I’ve never considered that possibility ?