Trickle Charger vs Float Charger: Which One Should You Buy?
Trickle charger vs float charger: constant low-current charging against float-mode maintenance, with listing figures and guidance on which suits your garage.
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Schumacher Electric 15A Car Battery Charger & Maintainer9.8/10View on Amazon - 2
Battery Tender Plus 12V 1.25 AMP Car & Motorcycle Battery9.7/10View on Amazon - 3
Unocho 6V/12V Battery Charger Maintainer 1.5A Automatic9.5/10View on Amazon
Trickle charger vs float charger comes down to how each one treats a full battery. A trickle charger feeds a constant low current, such as the 800mA of the MOTOPOWER MP00205A or the 1A of the NOCO GENIUS1, whether the battery needs it or not, so a basic one can overcharge a battery left connected too long. A float charger brings the battery up, then holds it at a maintenance voltage, like the 13.6V the MOTOPOWER listings maintain indefinitely, and only replaces what the battery loses. Most modern smart chargers do both jobs in sequence, which is why the Battery Tender Junior calls itself smarter than a trickle charger.
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Below: what each type does, how the listings show the difference, and which one fits your garage.
Trickle charger vs float charger at a glance
| Factor | Trickle charger | Float charger |
|---|---|---|
| How it charges | Constant low current: 800mA (MOTOPOWER, Battery Tender Junior) or 1A (NOCO GENIUS1, FOVAL) | Bulk charge first, then hold at a maintenance voltage: 13.6V (MOTOPOWER) |
| Left connected | Can overcharge; the MOTOPOWER ends charging on a 24-hour timer above 14V | Built to stay connected; NOCO says indefinitely |
| Typical job | Topping a stored battery | Months of unattended maintenance |
| Stated protections | Reverse polarity, spark-free and overcharge protection vary by model | Same; check the listing: FOVAL, BLACK+DECKER and Battery Tender state theirs |
What a trickle charger does
A trickle charger pushes a small steady current into the battery the whole time it is connected. The listings here show 800mA on the MOTOPOWER MP00205A and the Battery Tender Junior, and 1A on the NOCO GENIUS1 and the FOVAL. That current never pauses on a basic unit, which is the catch: keep feeding a full battery and you cook it. The MOTOPOWER MP00205A answers that with a 24-hour timer that terminates the charge and enters maintaining mode once voltage rises above 14V. The FOVAL takes the modern route instead: it calls itself a trickle charger and a float charger, running a 4-step program of Initialization, Bulk Charge, Absorption Mode and Float Mode.
What a float charger does
A float charger finishes the charge, then drops back to a maintenance voltage that just offsets the battery’s natural self-discharge. The BLACK+DECKER BM3B describes it plainly: it stops charging automatically when the battery is fully charged or topped off, switching to float mode monitoring. The Battery Tender 3A goes into float mode to maintain proper voltage levels without overcharging. The MOTOPOWER MP00205A listing puts numbers on it: charge up to 14.4V, then maintain at 13.6V; the MP00205B listing maintains at 13.6V indefinitely. The battery takes only the small current that offsets its natural self-discharge, which is why float mode is the one you leave alone for the winter.
Smart chargers blur the line
Most of the listings refuse to pick a side. The NOCO GENIUS1 and GENIUS10 are sold as battery charger, battery maintainer, trickle charger and desulfator in one box, with an integrated thermal sensor that adjusts the charge for ambient temperature and monitoring that lets you leave the unit connected indefinitely. The Battery Tender Junior is a charger and maintainer that the maker calls smarter than a trickle charger, with an ISM microcontroller updating the charge sequence. The GENIUS2X2 does the same job for 2 banks at once. If you buy a smart charger, you are buying trickle and float in sequence, not one or the other.
Which one should you buy?
Pick a float charger or smart maintainer for a vehicle that sits: a classic car, a motorcycle or a mower that sleeps through the off-season. The NOCO’s leave-it-connected-indefinitely design and the Battery Tender’s float mode exist for exactly that job. Pick a basic trickle charger only for topping up a battery you will disconnect the same day, and mind the MOTOPOWER’s 24-hour timer as a reminder of why. For a dead battery, an 800mA trickle unit is not the tool: the NOCO GENIUS1 and GENIUS10 charge from as low as 1 volt and offer a Force Mode for completely dead batteries down to zero volts, which is the recovery job. Our battery charger vs battery maintainer guide goes deeper on the terminology.
Reverse polarity protection is the stated safety feature across these charger listings: MOTOPOWER, FOVAL, BLACK+DECKER and Battery Tender all name it, with spark-free or spark-proof connection stated on the MOTOPOWER and Battery Tender listings. Connect positive to positive and negative to negative first, and let the protection be the backup, not the plan.
Lead-acid batteries can release hydrogen while charging, so charge in a ventilated space away from sparks and flames, connect positive first and negative last, set the charger to the battery type (flooded, AGM, gel, lithium), and wear eye protection. Read our Safety Disclaimer.
Frequently Asked Questions
Can I leave a trickle charger on all the time?
Not a basic constant-current one: it keeps feeding current after the battery is full. The MOTOPOWER MP00205A handles that with a 24-hour timer that ends charging above 14V and enters maintaining mode. A smart maintainer with a float stage, like the NOCO units the maker says can stay connected indefinitely, is built for always-on use.
What voltage does a float charger hold?
The MP00205A listing states 13.6V for the maintenance stage, after charging up to 14.4V, and the MP00205B listing also holds the battery at 13.6V indefinitely. Other makers describe float mode without a number, so check the listing for the model you buy.
Is a battery maintainer the same as a float charger?
The listings use the words interchangeably. FOVAL calls its unit a battery maintainer, trickle charger and float charger; NOCO sells a trickle charger and maintainer in one box. A maintainer holds the battery at full charge, which is what float mode does.
Will a trickle charger charge a dead battery?
An 800mA trickle charger is built for maintenance and is a poor tool for recovery. The NOCO GENIUS1 and GENIUS10 charge batteries from as low as 1 volt and include a Force Mode for completely dead batteries down to zero volts, which is the recovery job.
Do I need a 6V or a 12V charger?
Match the charger to the battery. The NOCO GENIUS1 and GENIUS10, the BLACK+DECKER BM3B and the Battery Tender 3A all handle 6-volt and 12-volt batteries; the MOTOPOWER and FOVAL units here are 12V only.
Related: our battery charger vs battery maintainer explainer, the best battery maintainer for motorcycles and the best jump starter picks.
