Time for a battery upgrade? Wondering if the new battery will fit? Read on and we will discuss everything you need to know, from battery tray dimensions to choosing a new battery and charger.
Lets start with the basics to understand what is the biggest battery that will fit in the battery compartment.
What are the dimensions for the Traxxas Slash battery tray? Battery tray dimensions for all 1/10 scale Traxxas Slash models are 166mm long x 49.5 mm wide x 23/25 mm high. Height is adjustable from 23mm to 25mm by flipping the battery hold-down.(Size in inches: 6.54″ x 1.95″ x 0.98 “)
If you want to use a taller battery pack than 25 mm you will have to buy a battery extension kit(Discussed later). However there are more factors than just the dimensions of the battery to choosing a battery.
Battery Extension Kit
If you are not satisfied with the runtime or performance of the battery that fits in the standard battery tray you will have to get a battery extension kit. All that does is it raises the battery hold-down so there is space for a taller battery.
With the extension kit you will be able to use batteries that are up to 42 mm or 1.65″ tall. This allows to extend the capacity from around 7600 mAh to 10000 mAh. This will add a significant boost to and battery-life, yet the extra weight from the larger battery will affect performance and handling negatively.
Note: Slash 4×4 Ultimate & Platinum have a different battery extension kit.
Notes: mAh = Battery’s capacity. Essentially that determines the runtime.
For example if you had a 5000 mAh 7.4v 2s LiPO and that would allow for 25 minutes of racing then 10000 mAh 7.4v 2s LiPO would let you drive for about 50 minutes. That is just a rough estimate but that is essentially how it works.
Choosing The Right Battery
Your choice of battery will come down to the budget you have to work with and how comfortable you are with handling LiPO batteries. If you are willing to learn a little about LiPo safety and stretch your budget then my recommendation is to always to go with them. LiPo provides superior runtime and power compared to NiMH.
Since there are many different versions of Traxxas Slash I will list the battery options for all of them seperately. Beginning from the basic and most affordable model.
What is the Best Battery for a Traxxas Slash 2wd & 4wd?
Budget Battery
About $60
7.4V/5800mAh
The reason why I am recommending this instead of the $30 NiMH battery pack for a budget choice is that You probably already have a NiMH and are looking for a upgrade.
- Requires a Traxxas ID LiPo charger
- Check for ESC compatibility
Best Battery
About $75
7.4v/7600mAh
This will give optimal balance between weight/runtime and it will fit in the original battery compartment. It comes with Traxxas High-Current Connector.
- Requires a Traxxas ID LiPo charger
- Check for ESC compatibility
Extreme Runtime Battery
About $120
7.4v/10000mAh
I would only recommend this if you want to get the most runtime out of a single battery. For the same money you can buy two 5800 mAh batteries and get more total runtime for your money.
- Requires a Traxxas ID LiPo charger
- Weight will affect performance negatively
- Check for ESC compatibility
- Too high for stock battery holder. Requires a battery extension kit.
What is the Best Battery for a Traxxas Slash VXL,Ultimate & Platinum?
Budget Battery
About $60
7.4V/5800mAh
This is a good fit if you don’t care about the 60 MPH top speed that you will achieve with a 3S LiPo battery pack. Drive-train parts will last much longer if you use this.
- Top speed 40+ MPH
- Requires a Traxxas ID LiPo charger
- Check for ESC compatibility
Best Battery
About $70
11.1v/5000mAh
This will give optimal balance between weight/runtime and it will fit in the original battery compartment. It comes with Traxxas High-Current Connector. However be aware of extra drive-train wear.
- Top speed 60+ MPH
- Requires a Traxxas ID LiPo charger
- Check for ESC compatibility
- Keep an eye on ESC and Motor temp.
Extreme Runtime Battery
About $100
11.1v 6400mAh
- Requires a Traxxas ID LiPo charger
- Check for ESC compatibility
- Keep an eye on ESC and Motor temp.
- Too high for stock battery holder. Requires a battery extension kit.
- Different kit for Slash Ultimate and Platinum.
Charging a LiPo
Traxxas has made great progress in charging LiPo packs in recent years. Before their ID system you had to have much more knowledge about batteries to be able to use LiPo technology.
Because of this I will not go into more detail about how it actually works. They have made it as simple as charging a NiMH. However before charging please consult the chargers manual to be sure you are using the right battery/charger combination.
When picking a charger all you have to do is decide how many packs you want to charge at once and how fast you want it to be done.
Here is a comparison table between the Traxxas EZ-Peak Chargers.
| EZ-Peak Plus | EZ-Peak Live | EZ-Peak Dual | EZ-Peak Dual Live | |
|---|---|---|---|---|
| Price | $50 | $80 | $100 | $150 |
| How many Batteries you can charge simultaneously. | 1 | 1 | 2 | 2 |
| Approximate time to charge 2S 7600mAh battery. | 115 min | 40 min | 60 min | 30 min |
| LiPo Cell Count | 2S,3S | 2S,3S,4S | 2S,3S | 2S,3S,4S |
EZ-Peak Live is the clear winner out of those four chargers. Unless you have other larger scale RC-cars and need to charge very high capacity batteries fast, there is no need for the $150 EZ-Peak Dual Live Charger.
When charging a 7600mAh battery that is more than enough for the Slash you will save only 10 minutes by using the Dual Live compared to Ez-Peak Live. You can buy another battery with the money you save and get more continuous runtime.
Low Voltage Detection
The most important thing while using LiPo-s in your car is that you turn on Low Voltage Detection on the Speed control. This protects the battery pack from over discharging. I cannot stress this enough how important this is. Whenever you discharge a LiPo to a lower voltage per cell than 3.2v you risk damaging it.
| Cell count | Absolute minimum total pack voltage |
| 2S | 6.4v |
| 3S | 9.6v |
| 4S | 12.8v |
Usually over discharging happens when you use both NiMH and LiPo batteries. Since you have to switch the LVD off when you use NiMH it is easy to forget to turn it back on when you use a LiPo.
It is advisable to stick to using only LiPo-s or only NiMH unless you are willing to risk permanently damaging the battery.
Fortunately Traxxas has explained it in detail how to turn on Low Voltage Detection(LVD) on their website. You should have either XL-5 or VXL 3s speed control(ESC).
Check ESC Compatibility
Some older models of Traxxas Slash come with a speed control that do not support LiPo batteries. However it is worth noting that they work with LiPo-s, but lack Low Voltage Protection to protect the battery. In that case it is advisable to invest in a newer model ESC.
In the following table you can find out if your ESC has Low Voltage Detection and is compatible with LiPo-s.
| XL-5 | XL-5 | XL-5 | VXL-3S | |
|---|---|---|---|---|
| Housing color | Yellow | Blue | Blue | Any |
| background color behind the Traxxas logo | White | White | Black | Any |
| Supported | NO | NO | YES | YES |