What Battery Does the Proboat Blackjack 42 Use?
The Proboat Blackjack 42 is commonly described as an 8S RC boat, but that does not mean you normally install one large 8S battery. The standard configuration uses two matching 4S packs in series. With two 14.8V 4S LiPo batteries, the combined system is 29.6V nominal 8S while the capacity remains the same as one individual pack.
Pro Boat's published guidance allows a broad battery range, with two 4S packs in the 5000–9000mAh class and 100C or greater identified for optimal performance. That gives owners room to tune the Blackjack 42 around weight, runtime and water conditions rather than being locked into one battery capacity.
| RC Boat | Proboat Blackjack 42 8S Brushless Catamaran |
| Battery Configuration | 2 × matched 4S batteries in series |
| Standard LiPo Voltage | 14.8V per pack / 29.6V nominal combined |
| Manufacturer Capacity Guidance | 5000–9000mAh per 4S pack |
| Performance Discharge Guidance | 100C or greater for optimal performance |
| Power Connector | IC5 / EC5 power interface |
| Key Setup Variable | Battery weight and fore-aft position affect hull attitude |
Best CNHL Batteries for the Proboat Blackjack 42
There is no single best Blackjack 42 battery for every driver. A lighter 5000mAh pair stays close to the original setup philosophy, while 7000–8000mAh-class packs can add substantial capacity without necessarily becoming excessively heavy. A heavier hardcase battery can also play a different role when additional installed mass is desirable for the chosen hull setup.
| Recommendation | CNHL Battery | Key Specs | Best For |
|---|---|---|---|
| Best Stock-Style Choice | CNHL G+Plus 5000mAh 4S 100C EC5 |
14.8V / 4S LiPo 5000mAh 100C 146 × 48 × 36mm Approx. 560g |
Drivers who want to stay close to the factory-style 5000mAh battery setup with a 100C discharge rating and relatively low installed battery mass. |
| Best Overall / Flagship | CNHL Lightning LiHV 7800mAh 4S 120C EC5 |
15.2V / 4S LiHV 7800mAh 120C 149 × 51 × 40mm Approx. 598g |
The strongest capacity-to-weight choice for owners who want much more capacity without moving to a particularly heavy battery pair. |
| Best High-Capacity Hardcase | CNHL Racing LiHV 8200mAh 4S 120C Hardcase EC5 |
15.2V / 4S LiHV 8200mAh 120C 139 × 47 × 48mm Approx. 643g |
Drivers who want high capacity, a protective hardcase and slightly more installed mass as part of their battery and balance setup. |
Why the 7800mAh Lightning Is Our Best Overall Proboat Blackjack 42 Battery
For the Proboat Blackjack 42, battery capacity cannot be considered separately from installed weight. Moving from a 5000mAh battery to a much larger pack normally adds a noticeable amount of mass, which can change acceleration, hull attitude and how the boat reacts to changes in water and wind.
The Lightning 7800mAh is unusual because it provides substantially more capacity while weighing approximately 598g per pack. That is only about 38g heavier than the G+Plus 5000mAh 100C battery. In a dual-pack setup, that means a large capacity increase without the dramatic weight penalty normally associated with stepping from a 5000mAh battery toward the 8000mAh class.
This makes the 7800mAh Lightning especially attractive when the goal is longer usable running time while keeping the boat responsive. Drivers who intentionally want more physical battery mass may instead prefer the 8200mAh Racing hardcase.
5000mAh vs 7800mAh vs 8200mAh for the Proboat Blackjack 42
5000mAh: Stock-Like Weight and Setup
A 5000mAh pair is the logical starting point for owners who want the Proboat Blackjack 42 to stay close to the original battery configuration. The G+Plus 5000mAh 100C combines the manufacturer's familiar capacity class with a higher-performance discharge rating and manageable pack weight.
7800mAh: Maximum Capacity Efficiency
The 7800mAh Lightning is aimed at drivers who want a major increase in capacity without turning the battery itself into unnecessary ballast. Its approximately 598g weight is particularly attractive for a battery of this capacity.
8200mAh Hardcase: Capacity Plus More Installed Mass
The 8200mAh Racing LiHV pack follows a different philosophy. Its hardcase adds physical protection, while its approximately 643g weight gives the boat a little more battery mass than the 7800mAh Lightning. That can be useful when the owner deliberately wants a heavier battery setup while still remaining in a high-capacity 4S format.
Why Battery Position Matters on the Proboat Blackjack 42
The Blackjack 42 is sensitive to longitudinal weight distribution. Battery position should therefore be treated as part of the boat's setup rather than simply as a question of where the pack physically fits.
Moving both batteries forward generally adds bow weight and increases the stability margin. This is the more conservative starting direction when the boat feels too light at speed, when there is wind, or when the water surface is not ideal.
Moving the batteries rearward can allow the bow to ride higher and reduce wetted hull area. That may support higher speed in calm conditions, but it can also make the Proboat Blackjack 42 more flighty and increase the risk of a blowover. Change battery position gradually and evaluate the boat after each adjustment.
Always move the left and right packs together. Do not intentionally use unequal battery positions or mismatched packs to correct hull balance.
How Much Runtime Can You Expect?
Runtime on a Proboat Blackjack 42 varies too much to promise one fixed number. Throttle use, propeller load, water conditions, battery condition, pack capacity and overall setup all matter.
A stock-style 5000mAh setup naturally provides less stored energy than a 7800mAh or 8200mAh pair. Moving to a larger-capacity pack can increase available running time, but runtime does not increase in a perfectly linear way because the heavier battery changes the load carried by the boat and driver throttle use often changes as well.
For that reason, choose capacity based on the overall setup rather than buying the largest number available purely for runtime.
Do Two 4S Batteries Become an 8S Battery?
Yes in voltage, but not in capacity. When two matching 4S batteries are connected in series, their voltages add while the amp-hour capacity remains unchanged.
| Battery Pair | Resulting S Count | Resulting Capacity |
|---|---|---|
| 2 × 4S 5000mAh | 8S | 5000mAh |
| 2 × 4S 7800mAh | 8S | 7800mAh |
| 2 × 4S 8200mAh | 8S | 8200mAh |
Why the Two 4S Batteries Should Be Matched
Two batteries used in series should be treated as a matched pair. The same current flows through both packs, so a weaker or lower-capacity battery can reach its discharge limit before the other one.
For the Proboat Blackjack 42, use two batteries with the same:
- Brand and battery model
- Cell count and chemistry
- Capacity
- Discharge rating
- Approximate age and cycle condition
- State of charge before installation
If one pack begins to age noticeably faster than the other, replacing the pair together is generally the safer approach for a high-load series setup.
EC5 Batteries with the Pro Boat Blackjack 42 IC5 System
The CNHL batteries in this collection use EC5 main connectors. EC5 and IC5 share the compatible main positive and negative power interface, which is why EC5 battery packs are a practical power option for the Blackjack 42 when polarity, connector condition and wire clearance are correct.
CNHL EC5 batteries are not Spektrum Smart batteries. They provide the main power connection but do not include the additional Smart data connection used by compatible Spektrum batteries.
That means a suitable CNHL EC5 pack can power the Proboat Blackjack 42, but you should not expect the same Smart battery identification or remaining-capacity information that a compatible Spektrum Smart battery can provide through the radio system.
50C vs 100C vs 120C Batteries for the Proboat Blackjack 42
The Blackjack 42 has been sold with 50C-class battery guidance in some product information, while the Pro Boat manual also lists 100C or greater for optimal performance. These two numbers should not be interpreted as meaning the boat cannot operate on a suitable 50C battery. Instead, they show the difference between a basic operating specification and a more performance-oriented battery recommendation.
A 100C or 120C pack gives additional discharge headroom for a large 8S boat that sees repeated full-throttle acceleration. Higher discharge capability can also help reduce battery-side voltage sag when the cells and complete pack are capable of delivering the advertised performance.
A higher C rating does not force extra current into the motor and does not automatically increase top speed. Current draw is determined by the complete power system, especially motor load, propeller, ESC settings, drivetrain condition and running conditions.
Bigger Props, Higher Load and Battery Capability
A powerful battery cannot protect an overloaded drivetrain. Increasing propeller diameter or pitch can increase motor current, ESC load, battery load and heat throughout the system.
This is important on the Proboat Blackjack 42 because the boat already uses a large 8S brushless system. A higher-capacity or higher-discharge battery should be viewed as electrical headroom for a properly configured power system, not as permission to increase propeller load without monitoring temperatures and drivetrain condition.
After changes to the propeller, battery setup or other power-system components, monitor battery, motor and ESC temperatures and check for unusual vibration before continuing repeated high-speed runs.
Important LiHV Note for the 7800mAh, 8200mAh and Other LiHV Packs
Several batteries in this collection are 4S LiHV packs rated at 15.2V nominal rather than standard 14.8V LiPo. LiHV chemistry can be charged to a higher maximum cell voltage than standard LiPo, but this should only be done when the complete power system is confirmed to support the resulting voltage.
Do not assume that an ESC marked simply as “8S” automatically supports two fully charged 4S LiHV batteries at 4.35V per cell. Unless the maximum input voltage of the specific Blackjack 42 ESC has been confirmed for full-charge LiHV use, charge these LiHV batteries only to the standard LiPo limit of 4.20V per cell.
Always use a proper balance charger, select the correct charging mode, inspect the packs before and after running, and never exceed the voltage limit appropriate for the confirmed system configuration.
Battery Retention Matters on a 42-Inch 8S Catamaran
A pair of large 4S batteries represents a significant amount of moving mass. Hard acceleration, rapid deceleration, tight turns and a rollover can place substantial force on the battery straps and tray.
Before every run, confirm that both packs are firmly retained and cannot slide forward, rearward or upward. This becomes even more important with 7800mAh, 8200mAh, 8500mAh and other high-capacity batteries because additional pack mass creates more inertia if a battery comes loose.
Battery weight can be useful as a tuning variable only when the packs remain exactly where you intended them to be.
What About 6200mAh, 7200mAh, 8500mAh and 9500mAh Batteries?
The three featured batteries are not the only options in this Proboat Blackjack 42 collection. Other CNHL packs can make sense depending on the balance you want between battery weight, capacity, chemistry and price.
6200mAh is a practical middle-capacity choice for users who want more runtime than 5000mAh without moving into the larger 7500–8000mAh class. 7200mAh also sits in a useful middle-high capacity range, while 8500mAh is aimed more directly at drivers prioritizing maximum capacity within the manufacturer's published 5000–9000mAh range.
A 9500mAh pack goes beyond the 5000–9000mAh range quoted in the Pro Boat guidance. It may still be physically usable when dimensions, retention and desired hull balance have been confirmed, but it is not one of our three primary recommendations for a stock-style Blackjack 42 setup.
What to Check Before Buying a Proboat Blackjack 42 Battery
- Buy two matching 4S packs for normal 8S operation.
- Confirm battery dimensions and wire clearance inside your particular boat.
- Confirm both packs can be secured firmly by the retention system.
- Use the same battery model, capacity, chemistry and discharge rating on both sides.
- Keep the two packs at a similar age, condition and state of charge.
- Check EC5 / IC5 connector condition and polarity before connecting power.
- Do not expect Spektrum Smart battery data from a standard CNHL EC5 pack.
- Start with a conservative battery position and adjust fore-aft placement gradually.
- Recheck hull attitude after changing to a significantly heavier or lighter battery.
- Monitor battery, ESC, motor and drivetrain temperatures after setup changes.
- For LiHV packs, confirm ESC maximum voltage before using full LiHV charging voltage.
FAQ: Proboat Blackjack 42 Battery Setup
Does the Proboat Blackjack 42 use one 8S battery?
The normal setup uses two matched 4S batteries connected in series to create an 8S power system.
What is the best battery capacity for the Proboat Blackjack 42?
5000mAh is the closest stock-style choice. Around 6000–7000mAh offers a middle-ground setup, while 7500–8200mAh is attractive for drivers who want more capacity and are prepared to account for the change in battery weight and hull balance.
Why do you recommend the CNHL 7800mAh Lightning?
Its main advantage is capacity-to-weight ratio. At approximately 598g, it provides 7800mAh capacity while remaining relatively light for a battery in this capacity class.
Is the 8200mAh hardcase better than the 7800mAh Lightning?
Not necessarily. They serve different priorities. The 7800mAh Lightning emphasizes capacity with lower weight, while the 8200mAh Racing hardcase adds capacity, a rigid case and somewhat more installed battery mass.
Should I move the Blackjack 42 batteries forward?
Forward placement is the more conservative starting direction because it adds bow weight and can calm the boat. Rearward placement can free the hull for speed but may reduce the stability margin. Adjust gradually rather than making a large position change at once.
Can I mix a 5000mAh battery with a 7800mAh battery?
No. Use a matched pair of batteries with the same capacity, chemistry, model and discharge rating for the series-powered 8S setup.
Can I use EC5 batteries in a Pro Boat Blackjack 42 with IC5 connectors?
EC5 and IC5 share the compatible main power interface. A suitable EC5-equipped CNHL battery can therefore supply power when physical fit, polarity and wire routing are correct. CNHL EC5 packs do not provide Spektrum Smart battery communication.
Will a 120C battery make the Proboat Blackjack 42 faster than a 100C battery?
Not automatically. A higher-discharge pack provides more current headroom, but actual speed depends on voltage under load, motor, ESC, propeller, drivetrain efficiency, hull setup and water conditions.
Can I fully charge the LiHV batteries to 4.35V per cell?
Only after confirming that the specific ESC and complete power system support the resulting maximum voltage. If full-charge LiHV compatibility has not been confirmed, charge the LiHV packs only to the standard LiPo limit of 4.20V per cell.
Will a heavier battery stop the Blackjack 42 from blowing over?
No single battery can guarantee that. Battery weight and placement affect hull attitude, but high-speed stability also depends on wind, water conditions, propeller, strut setup, trim setup and driving technique.
Explore More RC Boat and 4S Battery Options
For batteries across other electric boats, hull sizes and power systems, browse our RC boat battery collection. It brings together CNHL battery options for performance boats, catamarans, deep-V hulls and other electric marine applications.
If you want to compare additional capacities, discharge ratings and connector configurations in the same voltage class, explore the CNHL 4S LiPo battery collection.
For the Proboat Blackjack 42, the safest starting strategy is simple: use two matched 4S batteries, secure both packs firmly, begin with a conservative forward battery position, monitor temperatures and hull attitude, and change only one setup variable at a time.
