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Going from 2S to 3S on a Traxxas Slash is the single biggest speed jump you can buy — roughly 50% more voltage, and on a brushless truck that is the difference between a 35 mph runner and something that will clear 50 mph on a long straight. It is also the upgrade most likely to end in smoke, because the pack is only half the decision.
Check your speed control first, before you check anything else. A Slash running the stock XL-5 brushed ESC is a 2S-only truck — 3S will cook it, and no battery on this page will save it. The VXL-3s brushless ESC is 3S-capable by design, which is exactly what the “3s” in its name means. If you are on a Slash 4×4 with the VXL-3s, you are good. If you are on a brushed truck, budget for a Velineon power system before you budget for a battery.
The second thing to check is the hole, not the pack. A Slash battery tray takes a 25 mm tall hardcase comfortably; most 3S 5000 mAh packs are close to 139 × 46 × 25 mm and drop straight in, but some high-C race packs run taller and a few shorty packs need foam to stop them sliding. Measure before you order. And set the low-voltage cutoff on the ESC to 3.2 V per cell — a LiPo that gets run flat once is a LiPo you throw away.
Below are ten packs that actually fit a Slash, from the plug-and-play Traxxas iD packs through to the budget cells that most bashers end up running.
| # | Product | Price | Where to buy |
|---|---|---|---|
| 1 | Traxxas 2872X Power Cell 5000 mAh 3S 25C | $80–$100 | Amazon · eBay |
| 2 | Traxxas 2849X Power Cell 4000 mAh 3S 25C | $70–$90 | Amazon · eBay |
| 3 | Spektrum Smart 5000 mAh 3S 30C Hardcase | $60–$75 | Amazon · eBay |
| 4 | Spektrum Smart 5000 mAh 3S 100C Hardcase | $85–$100 | Amazon · eBay |
| 5 | Gens Ace Bashing Series 5000 mAh 3S 60C | $50–$70 | Amazon · eBay |
| 6 | CNHL Racing Series 5000 mAh 3S 30C with TRX plug | $40–$60 | Amazon |
| 7 | Zeee 5200 mAh 3S 50C Hardcase | $35–$55 | Amazon · eBay |
| 8 | Ovonic 5000 mAh 3S 50C Hardcase | $45–$65 | Amazon · eBay |
| 9 | Venom DRIVE 5000 mAh 3S 50C with UNI 2.0 plug | $60–$80 | Amazon |
| 10 | SMC True Spec Premium 5000 mAh 3S | $85–$115 | Amazon |
The picks, in detail
Traxxas 2872X Power Cell 5000 mAh 3S 25C
The default answer, and the one to buy if you own a Traxxas charger. The iD connector means the EZ-Peak charger reads the pack’s cell count and capacity automatically — you plug it in and press one button, with no balance lead to fumble and no chance of charging a 3S pack on a 2S setting. You pay a premium for that convenience, and seasoned bashers will tell you the cells are ordinary, but nothing else removes as many ways to make an expensive mistake.
- 11.1 V, 5000 mAh, 25C continuous
- Traxxas iD high-current connector
- Hardcase, standard Slash tray dimensions
- 12 AWG silicone-jacketed wire
- One-button charging on any EZ-Peak charger
- Known-good fit in every Slash tray
- Warranty and dealer support are easy to reach
- Roughly double the price of an equivalent generic pack
- 25C is modest for a 3S brushless setup
- iD plug locks you into the Traxxas charging ecosystem
Traxxas 2849X Power Cell 4000 mAh 3S 25C
The short pack. Same iD system and same 25C rating, but shorter and lighter than the 5000, which matters more than it sounds — a Slash 2WD carries its battery high and behind the front bulkhead, and dropping 80 grams there noticeably calms the truck down on landings. You lose about 20% of the runtime for it. Buy this one if your tray is a tight fit or if you are racing short heats rather than bashing all afternoon.
- 11.1 V, 4000 mAh, 25C continuous
- Shorter hardcase than the 5000 mAh pack
- Traxxas iD connector
- Lighter, better weight balance on 2WD
- Fits trays the 5000 mAh pack fights with
- Less nose weight on jumps
- Same one-button iD charging
- Shorter runtime
- Still priced at the Traxxas premium
- Overkill cost for a basher who does not race
Spektrum Smart 5000 mAh 3S 30C Hardcase
Spektrum’s answer to iD, and arguably the better implementation. The Smart chip stores the pack’s spec and its own cycle history, so a Smart charger sets everything itself and you can read how many cycles the battery has actually done — genuinely useful when you own four packs and cannot remember which one is the tired one. IC5 connector, so budget for adapters unless you are already in the Spektrum ecosystem.
- 11.1 V, 5000 mAh, 30C continuous
- Smart chip logs cycles and stores charge limits
- IC5 connector
- Hardcase, Slash-compatible footprint
- Cycle-count telemetry no other pack here gives you
- Higher C rating than the Traxxas equivalent
- Wide Horizon Hobby dealer support
- IC5 plug needs an adapter for a Traxxas ESC
- Smart features only work on a Smart charger
- Priced above generic 30C packs
Spektrum Smart 5000 mAh 3S 100C Hardcase
The same Smart pack with race cells. A 100C rating is marketing more than physics, but the practical effect is real: lower internal resistance means less voltage sag when the Velineon system pulls 100-plus amps off the line, so the truck pulls harder at the top end and the pack runs cooler doing it. Worth the money if you have gearing for speed runs; wasted if you mostly drive around a park.
- 11.1 V, 5000 mAh, 100C rated
- Low internal resistance, minimal sag under load
- Smart chip telemetry
- IC5 connector
- Noticeably harder punch than 25–30C packs
- Runs cooler at high current
- Holds voltage on long speed runs
- Most expensive pack on this list
- The C rating is optimistic, as it is for everyone
- No benefit at all on modest gearing
Gens Ace Bashing Series 5000 mAh 3S 60C
The enthusiast default before you start paying for chips and telemetry. Gens Ace has been building these for a decade, the hardcases are consistently the right dimensions, and the 60C cells sit in the sweet spot for a VXL-3s — enough current headroom that the pack is not the limiting factor, without the price of race cells. Comes in EC5 or Deans depending on the SKU, so check the plug before you order.
- 11.1 V, 5000 mAh, 60C continuous
- Hardcase with standard 139 mm footprint
- EC5 or Deans plug options
- 12 AWG wire, welded tabs
- Best price-to-performance on this list
- Reliable dimensional consistency between batches
- Plenty of current headroom for a VXL-3s
- No smart charging — you balance-charge it yourself
- Plug type varies by SKU
- Warranty support is slower than the big brands
CNHL Racing Series 5000 mAh 3S 30C with TRX plug
ChinaHobbyLine sells this configuration specifically for Slash owners — it ships with the Traxxas-style high-current plug already fitted, so there is no soldering and no adapter dangling out of the tray. The cells are ordinary 30C stock, but at this price you can own three packs for the cost of one Traxxas iD, and three packs is what actually extends an afternoon.
- 11.1 V, 5000 mAh, 30C continuous
- Ships with TRX-compatible connector
- Hardcase
- Balance lead for standard chargers
- Plug-compatible with a stock Slash out of the box
- Cheap enough to buy multiples
- Consistent reports of honest capacity
- No iD chip — you set the charger yourself
- Shipping direct from the manufacturer can be slow
- 30C sags under a hard launch
Zeee 5200 mAh 3S 50C Hardcase
The budget pack that keeps showing up in basher recommendations, usually sold in two-packs. You are not buying premium cells and the labelled 50C should be read as maybe half that in practice, but the hardcases fit, the capacity measures honestly, and a pair of them costs less than one branded pack. The sensible use is as the batteries you are willing to abuse.
- 11.1 V, 5200 mAh, 50C rated
- Hardcase with Deans (T-plug) connector
- Frequently sold as a two-pack
- Standard balance lead
- Lowest cost per pack here
- Honest measured capacity for the price
- Two-packs make an afternoon session realistic
- C rating is generously stated
- Cell matching varies between units
- Effectively no support if one puffs
Ovonic 5000 mAh 3S 50C Hardcase
A half-step up from the cheapest packs. Ovonic’s quality control has been more consistent than most in this price band, and the 50C cells hold voltage better than the 30C generics when the Velineon motor pulls hard out of a corner. Deans plug as standard. A good compromise for someone who wants three or four packs without buying the very cheapest thing on the shelf.
- 11.1 V, 5000 mAh, 50C rated
- Hardcase, Slash tray footprint
- Deans T-plug
- 12 AWG silicone wire
- Better voltage hold than the 30C budget packs
- More consistent batch quality than the cheapest brands
- Still well under branded pricing
- Deans plug needs an adapter on a stock Slash
- No smart charging support
- Puff rate is higher than premium cells if run hot
Venom DRIVE 5000 mAh 3S 50C with UNI 2.0 plug
Venom’s trick is the UNI 2.0 connector system: the pack ships with a universal plug and a set of adapters, so the same battery works on a Traxxas truck today and whatever you buy next year without a soldering iron. That is worth real money if you own more than one brand of vehicle. The cells themselves are solid mid-tier 50C stock.
- 11.1 V, 5000 mAh, 50C rated
- UNI 2.0 plug with Traxxas, Deans and EC5 adapters included
- Hardcase
- US-based warranty support
- Adapters included, so no soldering for any vehicle
- Real warranty you can actually claim
- Mid-tier cells that hold up to bashing
- Adapter stack adds bulk in a tight tray
- Costs more than an equivalent generic pack
- Adapters are another connection to go resistive
SMC True Spec Premium 5000 mAh 3S
The pack the fast crowd buys. SMC sorts and matches cells rather than just labelling them, and the difference shows on a data logger as less sag and a flatter discharge curve rather than as a bigger number on the wrapper. If your Slash is geared for a speed run and you are chasing a GPS number, this is where the remaining tenths live. If you are jumping it off a kerb, it is money you do not need to spend.
- 11.1 V, 5000 mAh, race-matched cells
- Very low internal resistance
- Hardcase
- Sold with a choice of connectors
- Flattest voltage curve of anything here
- Genuinely matched cells, not just an optimistic C number
- Long service life when charged properly
- Premium price for a marginal gain on a basher
- Limited dealer network compared with Traxxas or Spektrum
- Wasted unless your gearing and motor can use it
Buying tips
- Confirm your ESC before anything else. The stock XL-5 brushed speed control is 2S only. The VXL-3s brushless unit is 3S-rated — that is what the “3s” in the name means. Putting 3S through an XL-5 is the most common way Slash owners destroy an ESC.
- Set the low-voltage cutoff to 3.2 V per cell (9.6 V on a 3S pack). A LiPo taken below roughly 3.0 V per cell is permanently damaged even if it still charges afterwards.
- Measure your tray, not the spec sheet. Most 3S 5000 mAh hardcases run about 139 × 46 × 25 mm, but a few race packs are taller and will not sit under the retainer.
- Store packs at storage charge, around 3.8 V per cell, not fully charged. A LiPo left at 4.2 V for a month loses capacity permanently; every decent charger has a storage mode for this.
- 3S makes the drivetrain the weak link. Expect to upgrade the stock spur gear, slipper pads and eventually the differential — the motor is no longer the thing that gives up first.
- Charge in a fireproof bag, on a hard surface, and never unattended. This is not a formality; a punctured or over-charged pack burns hot enough to set a carpet alight.
- Buy at least two packs. A single 5000 mAh 3S gives roughly 12–18 minutes of hard driving, and the charger takes longer than that to put it back.
As an Amazon Associate and eBay Partner, toptenpick.com earns from qualifying purchases. Prices and availability are subject to change.