Optima Battery Charger Maintainer Digital 400 Review

Optima Battery Charger FI
Battery Chargers
  • Feature Set
  • Power
  • Ease of Use
  • Value

Final Thoughts

The Optima Digital 400 battery charger is full of features, less than $100, and it’s small enough to fit in one hand. Great for a compact shop charger, or for someone on-the-go.

User Review
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Optima developed the first maintenance-free lead-acid batteries back in the 1970s, built for commercial and military use. Later, they introduced the first high‐performance AGM (Absorbent Glas Mat) automotive battery. You may know them as the red-top battery that looks like a six-pack. Now, they’re directing their groundbreaking focus on charging batteries with the Digital 400 Optima battery charger. This is the pint-sized version of their digital charger, hence Optima also produces the larger Digital 1200 battery charger as well.

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  • Battery charger, Maintainer, and Conditioner
  • Automatically determines the state of the battery, providing the correct charge
  • Recover old batteries as low as 1.25V
  • Works with Lead Acid and AGM batteries
  • Compact – 4″ x 8″
  • Less than $100



Optima Battery Charger Digital 400 Features

The first thing you’ll recognize with the Optima Digital 400 is how small and compact it is. At just 4-inches by 8-inches, you get a lot of features built into this small unit.

Huge plus for the cord management. In our tool review world, we tend to flip our lids a bit when we have corded tools, and the manufacturer never thought to make a place for the cords. Optima thought of this, so the needed cords and wires wrap neatly around the body of the Digital 400, and a velcro strap keeps them tight and tidy.

Optima 400 Digital Charger_7

Related Article: If you follow us here or on social media, you may have already seen the Optima battery charger Digital 400 in our Shop Tool Reviews Christmas Gift Guide 2018.

Digital 400 Charging Technology

Optima Digital 400 Battery Charger

Charging Selection

The included and automatic multi-stage charging in this Optima battery charger allows for not only charging batteries but also conditioning and maintaining as well. You may think of 12V batteries as being all the same, but just being the same voltage doesn’t necessarily mean they charge the same. Typical lead-acid batteries, like those that start your car, handle current differently than a deep-cycle or AGM battery. So, just hooking up the same ol’ charger you got from grandpa may not cut the mustard.

The Optima Digital 400 battery charger uses a microprocessor and software to determine certain battery conditions, therefore providing the correct amount of charge for the optimal performance. This not only allows for faster charging, but it also extends the life of batteries by not over-charging or charging too fast/too long.

6 Fully Automatic Modes

  • 1st Stage: Analyze your battery for the state of charge and quality of connections before charging.
  • 2nd Stage: Soft-Ramp Charging-controlled amperage for deeply discharged batteries – when necessary.
  • 3rd Stage: Fast-Charge Bulk Mode for batteries moderately discharged – also known as normal battery usage.
  • 4th Stage: Conditioning Mode for conditioning your battery with a finish/complete charge.
  • 5th Stage: Auto Maintain, float mode for keeping your battery fully charged.
  • 6th Stage: A 30-day storage Recondition Mode – while your vehicle or battery is in storage and is being maintained.

Optima Digital 400 LED LCD Screen

Do You Sulfate?

Pro Tip: Did you know that a battery that stays in a single state of charge, either charged or discharged, will begin to ‘sulfate’? This hampers the performance of the battery. The Optima battery charger has built-in technology that will condition the battery every 30 days, for up to 3 hours, then auto-maintain will kick back in. This ensures that your battery is at it’s best when you call on it.


Power Output

Max output for the Optima Digital 400 charger is only 4 Amps. This is where the compact size and portability count against the sheer performance output, but it’s something we expect. If you’re looking for something to jump-start vehicles, this is not that unit.

Still, this is a great charger for anyone needing to keep their boat or UTV charged or for someone on-the-go. This is even a great option for someone that doesn’t want to take up a lot of shop space for a larger charger since you can easily fit this in a small toolbox drawer.

Charge Times:

  • High-Performance AGM: 40-100Ah – 9-15 hours for 20-40% discharge
  • HP Deep Cycle AGM: 35-100Ah – 9-15 hours for 20-40% discharge
  • Auto/Marine Std Lead Acid or AGM: 40-130Ah – 9-18 hours for 20-40% discharge
  • Motorcycle: up to 40Ah – 3-9 hours for 20-40% discharge

Value and Ease of Use

Optima Digital 400 Charger ContentsIf the Optima Digital 400 lost points in the previous (Power) section, this is where it makes up plenty of ground. This charger is very easy to set up and use, and it comes at a great price for what it provides.

Value means much more to us than just price. It’s about what you get for the price you pay. It will be hard to find another charger at this size that includes this many features, including automation. Coming in at less than $100 makes the Optima Digital 400 an excellent value that’s easy to recommend.

Using the Optima Battery Charger

Without repeating the instructions verbatim, we’ll summarize how easy it is. The typical hookup sequence of the battery clamps should happen first (positive clamp to the positive terminal, then negative clamp to chassis ground).

Once the clamps are on, plug the power cord into any 120V outlet. Select the type of battery you’re charging: Performance AGM Battery (like an Optima battery), Deep Cycle AGM, Auto/Marine, or Motorcycle.

Once you make the selection, the Digital 400 kicks into gear and chooses the correct stage of charging. The LED lights provide an obvious indication of the amount of charge in the battery. The LCD screen provides a clear status of the current charging stage. Just let it go.

Optima Digital 400 Charger

Optima Battery Charger FIOnce the battery has a full charge, the Optima Digital 400 will automatically switch into conditioning mode, then into maintain if you leave it on.

If you want to use the Digital 400 as just a maintainer, then you can use the leads with the ring-terminals, especially with a marine battery or side terminals.

With the charging cable connector built in the wire leads, it’s very easy to switch from the ring terminals to the battery clamp leads.

Final Thoughts

This one is pretty cut and dry. If you’re looking for a compact battery charger with great features and a low cost, take a close look at this Digital 400 Optima battery charger.

You may want to check out the Digital 1200 from Optima for something more heavy-duty.

For less than $100 and a charger that you just set and forget, this one’s easy to recommend. We know there are cheaper chargers out there, but not that we’ve seen with this technology.

Click here for more information on the Optima Digital 400 battery charger.


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