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Jump starter for a boat
Updated
A portable jump starter can start many boats with a 12 volt lead acid starting battery. NOCO lists boats on its Boost support pages, and the GOOLOO GP4000 listing names yachts. Size it the same way as a car: the engine size in liters, gas or diesel, plus headroom.
Size it by the engine
Take the engine size from your engine manual, not the boat length. For a 4.3 liter gas inboard, our rule of thumb gives these targets:
- Mild weather5.4 L
- Cold weather6.5 L
| Engine | Climate | Rating to look for | Our picks that cover it |
|---|---|---|---|
| 4.3L gas | Mild | 5.4L gas | NOCO Boost GB40, NOCO Boost GBX75, GOOLOO A3 with air compressor, GOOLOO GP4000 |
| 4.3L gas | Cold | 6.5L gas | NOCO Boost GBX75, GOOLOO A3 with air compressor, GOOLOO GP4000 |
| 3.0L diesel | Cold | 4.5L diesel | NOCO Boost GBX75, GOOLOO A3 with air compressor, GOOLOO GP4000 |
Small outboards need far less. Any pick on our list covers a small gas engine. Use the size picker for your exact engine.
What is different on a boat
- More than one battery. Many boats have a starting battery and a separate house battery. Jump the one that starts the engine. Your boat manual shows the wiring.
- Water. The NOCO GB20 and GB40 listings give an IP65 rating. That is protection from dust and splashing water, not from being dropped in the lake. Keep the pack dry and in a bag.
- Fumes. A gas engine space can hold fuel vapor. Follow your boat's ventilation steps before any spark source goes near it.
- Heat and sun. A boat deck in summer is a hot place to store lithium. NOCO's support FAQ says not to store its Boost packs above 122°F. See can you leave a jump starter in a hot car.
Picks that fit a boat
- NOCO Boost GB40 for a small or midsize gas engine in mild weather. It is small and IP65 rated per the listing. Caveat: its diesel rating stops at 3.0 liters.
- NOCO Boost GBX75 for a bigger gas engine or a midsize diesel. Caveat: NOCO's own support FAQ lists its diesel rating as 6 liters while the Amazon listing says 6.5.
- GOOLOO GP4000 for a large diesel. Caveat: owner reports on holding a charge are mixed, which matters for a pack that sits all winter.
Safety: check the battery for cracks, bulging or a rotten egg smell before you connect anything, as AAA advises. Wear eye protection. Follow the boat and engine manuals, and ask a marine mechanic if your wiring is unclear.