What size jump starter do you need for a 6.4L V8 gas engine?
A 6.4L V8 gas engine (heavy-duty Ram pickups) needs roughly 391 cranking amps at freezing and about 547 at 0 F. Choose a jump starter its maker rates for at least 7.4L gas, typically a 2,000 peak amp class unit or larger.
4,000A peak / 8L gas / 6.5L diesel / 16,800mAh
Rated by its maker for 8L gas and 6.5L diesel, which covers a 6.4L gas engine with margin, the closest-sized match among the units that do, so you are not paying for capacity you will not use.
How many cranking amps does a 6.4L V8 gas need by temperature?
Estimated from displacement: 6.4L is about 391 cubic inches, and a gas engine draws roughly one amp per cubic inch at freezing. Cold raises the load because the oil thickens, while it also cuts what the battery and the pack can deliver.
| Outside temperature | Cranking amps needed |
|---|---|
| 80 F | 293 A |
| 32 F | 391 A |
| 0 F | 547 A |
| -20 F | 703 A |
Which jump starters are rated for a 6.4L gas engine?
27 units in our verified catalog state an engine rating of at least 7.4L gas. The table lists the ten whose ratings sit closest to this engine, with the ratings exactly as each maker states them.
| Model | Peak | Gas rating | Diesel rating | Price |
|---|---|---|---|---|
| TREKURE Portable Car Battery Jump Starter 4000A 16800mAh | 4,000A | 8L | 6.5L | $35.99 |
| S ZEVZO ET03 Car Jump Starter 4000A Jump Starter Battery | 4,000A | 8L | 7L | $53.99 |
| ELTPOWER 4000A Heavy Duty Jump Starter | 4,000A | 8L | 7L | $59.99 |
| WOLFBOX MV16A 3000A Jump Starter with Air Compressor | 3,000A | 8L | 6L | $159.99 |
| Scatach 3000A Car Battery Jump Starter | 3,000A | 9L | 7L | $39.90 |
| GOOLOO GP3000 Jump Starter | 3,000A | 9L | 7L | $59.96 |
| GOOLOO GP3000 Jump Starter | 3,000A | 9L | 7L | $59.99 |
| TREKURE Portable Car Jump Starter with Air Compressor | 7,000A | 9L | 8L | $69.99 |
| JOLTEKON Car Battery Jump Starter with Air Compressor 45 | 4,500A | 9L | 8L | $99.99 |
| TREKURE Car Battery Jumper Starter Portable 5000A | 5,000A | 10L | 8L | $49.99 |
What else matters besides amps?
- Clamp and cable quality. Thick cables and solid clamps deliver the current the pack is rated for; thin ones waste it as heat.
- Safety protections. Reverse-polarity and spark protection stop a wrong connection from doing damage.
- Cold performance. Lithium packs lose output when cold. Keep the pack in the cabin rather than the bed or trunk in winter.
- Extras. A built-in air compressor saves carrying a separate inflator, at the cost of weight.
More jump starters for a 6.4L gas engine
Ratings are as stated by each maker. Prices change often.
Scatach 3000A Car Battery Jump Starter,12V Jump Starter Battery Pack Portable (up to...3,000A peak / 9L gas / 7L diesel$39.90Check price on Amazon
S ZEVZO ET03 Car Jump Starter 4000A Jump Starter Battery Pack for Up to 8.0L Gas and...4,000A peak / 8L gas / 7L diesel$53.99Check price on Amazon
S ZEVZO A11 Jump Starter, Upgraded 5000A Car Battery Jumper Starter Portable (10.0L Gas...5,000A peak / 10L gas / 7L diesel$59.99Check price on Amazon
ELTPOWER 4000A Heavy Duty Jump Starter, 74Wh 12V Portable Truck Battery Booster Jump...4,000A peak / 8L gas / 7L diesel$59.99Check price on Amazon
TREKURE Portable Car Jump Starter with Air Compressor, 150PSI 7000A Car Battery Jump...7,000A peak / 9L gas / 8L diesel / 150 PSI / air compressor$69.99Check price on Amazon
TREKURE 16-in-1 8000A Car Battery Jump Starter with Air Compressor 160PSI, Jump Starter...8,000A peak / 12L diesel / 160 PSI / air compressor$89.99Check price on Amazon
Other engine sizes
Frequently asked questions
How many amps does it take to start a 6.4L V8 gas?
About 391 cranking amps at 32 F, rising to roughly 547 at 0 F and 703 at -20 F. The figure is an estimate from displacement; a worn starter or thick oil raises it. A jump pack needs margin over this because a flat battery absorbs some of its current.
Will a 2,000 amp jump starter start a 6.4L V8 gas?
Usually, if the maker rates that unit for at least 7.4L gas. Peak amp figures are not measured to one standard, so check the engine-size rating in the listing rather than the amp number. Every product on this page states a rating that covers a 6.4L gas engine with margin.
Can I use a jump starter rated for a smaller engine?
It may work on a warm day with a battery that is only slightly low, but it is likely to fail exactly when you need it: in the cold, or with a battery that is completely flat. Buy for your engine size with at least 15 percent margin, and more if you live somewhere with hard winters.