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Acumen Battery Charger Review

Yet Another Motorcycle Battery Charger

Review Summary

We last visited the topic of motorcycle battery chargers about one year ago with our review of the Battery Doc.

In that article, we mentioned that our three Battery Tenders had been in continuous use since 2000.

We’re now half-way through 2006 and the Battery Tenders are still going strong.

They’re pumping out those precious electrons 24 hours a day, 365 days a year.

We’ve had zero problems with them — that’s zero as in zip, nada, nichts.

You can’t ask for much more than that, especially for the 39 bucks each or so we paid for the things.

The Acumen Battery Chargers

But time marches on, and the Acumen Platinum motorcycle battery charger, popular in the UK, is now being distributed in the U.S.A. by Riderstation (aka ActionStations, see below).

We gave away the Battery Doc in a webBikeWorld contest last year, so I can’t compare it to the Acumen AcuMax 900 Platinum battery charger shown here.

But not to worry — we consider the Battery Tender Plus to be the “gold standard” for motorcycle battery charger comparisons, so let’s see how the Acumen compares.

As we mentioned in the Battery Doc article, every motorcycle in the webBikeWorld garage has its battery connected to a battery charger as soon whenever the bike is parked after each ride.

This means that other than for maintenance or repair, the motorcycles are never off the chargers when they’re parked.

A modern microprocessor-controlled charger is specifically designed for long-term motorcycle battery maintenance.

The manufacturers claim that using the charger whenever the bike is parked increases battery life and maintains the battery at peak performance.

We don’t have any actual data to prove this one way or the other, but I can say that in all the time we’ve been using full-time chargers, we’ve never experienced a battery failure, so the chargers must be doing something right.

All motorcycle battery maintenance chargers seem to be pretty much the same, more or less.

Acumen even admits this in their mis-spelled marketing collateral: “Our Platinum charger is just as clever as anyone elses [sic]”, they say.

So what does the Acumen have that distinguishes it from the rest?  For one thing, the entire charger is encased in an extruded aluminum housing measuring 6.75″ x 2.5″ x 2.125″.

Acumen even claims that the charger is splash proof, although why anyone would splash water on an electrically powered battery charger is beyond me. Please do not test Acumen’s claims at home!

Acumen Platinum Charger Cables


Microprocessors Do It

Water resistance notwithstanding, the Acumen’s “power brick” format is very nice. One thing that’s always bothered me about the Battery Tender is the open vent design.

After 6 years, the chargers are covered with dust, cobwebs and the like.

Although they haven’t failed us, I wonder if the dust will eventually short something out on the inside. Now that I think about it, next time I have the air compressor on I think I’ll give them a blast or two to clean them out…

If you’re guessing that Acumen can encase their charger in a near-solid block because modern microprocessor circuitry perhaps doesn’t heat up as much and doesn’t need the venting, well, I’m not so sure.

I noticed that the Acumen Platinum charger seemed to get fairly warm shortly after it’s plugged in, so I grabbed the Temp Gun infrared thermometer (review) to take some readings.

The air temperature was 83.5 degrees and the nearest Battery Tender measured 90.7.

The Acumen measured 104.1 degrees, which is doesn’t seem that warm, but feels hot when the aluminum is touched. The Acumen case does have some rudimentary fins which I assume can help dissipate the heat.

The Acumen Form Factor

In any case, the form factor is definitely one of the most important differentiators between the Acumen Platinum and other motorcycle battery chargers.

The Acumen is shipped in a nice (but thin) metal storage container, although I’m not sure how useful this is once the charger is mounted.

Acumen also includes a very nice wall mount and they even throw in four wall anchors and the screws. The wall mount is designed to allow the charger to protrude from the wall, allowing some air space for circulation.

The charger can be snapped in or out of the wall bracket if necessary.

The Acumen Platinum has a 45″ electrical lead that can be attached to one end of the charger and is removable. The other end of the charger has a short 17″ lead with the type of connector found on the Battery Tender.

However, the Acumen connector seems like it doesn’t quite have the quality of the Battery Tender version.

Here’s a photo showing the new Acumen on the left and the well-worn Battery Tender version on the right:

Acumen vs. Battery Tender Cable Connectors

In the Box

The Acumen Platinum charger also comes with a 100″ extension lead that is handy to attach to the bike over a sizable distance in the garage. We had to buy an extra 25′ extension for the Battery Tender.

By the way, Battery Tender has many accessories such as extension cords, extra fittings and connectors and more that can be ordered through most any motorcycle dealer.

Finally, the Acumen comes with two cable harness assemblies.

These include an alligator clip cable harness that allows a temporary attachment to a battery and a semi-permanent harness that has a positive and negative lead on one end which can be attached to the battery terminals.

The connector shown above then can be hung out the side of the bike and connected to the charger when necessary.

Careful of That Ground

Here’s something important that we learned about the Acumen connectors: apparently, the positive terminals on the Acumen connectors are the ones that are exposed, not covered.

The positive metal terminal in the Acumen lead is seen above; it’s the “naked” or unprotected terminal.

In the U.S.A., the positive or power terminal is always the protected terminal in these types of connectors. This helps prevent a short or spark if the unprotected terminal touches a ground (earth).

I double- and triple-checked this, and the exposed terminal on the Acumen harness is positive.

The only thing I can think of is that the harness that we attached to the battery was mislabeled at the Acumen factory, with the red, or positive, indicator on the wrong lead.

The only reason I found out about this is because I used the Battery Tender’s 25 ft. lead to reach to the parked Triumph Tiger. When I plugged in the Acumen charger, it started beeping and the Reverse Polarity LED started blinking, which, by the way, is a nice feature.

However, it makes you wonder — if they have a built-in warning for reverse polarity, perhaps they realize that some countries use the protected terminal as positive?

Acumen Charger Showing LED Indicator Lights

LED Indicators

Speaking of LEDs, the Acumen Platinum also has a “Power On” LED that remains illuminated while the charger is powered up.

Besides the Reverse Polarity LED and beeper, the unit includes a green “Good Battery” LED that glows when the battery is fully charged.

A “Charging” LED glows while the battery is being tested and charged. Charging is at a constant 0.8 Amps until the Voltage stabilizes at 14.2 to 14.9 Volts. If the battery has less than 2.3 Volts, the charging cycle will not commence.

A “Weak Battery” LED glows if the charger can’t get the battery charged to more than 12.2 Volts. And a “Recovering” LED glows when the battery Voltage is between 2.3 and 12.2 Volts.

The charger will attempt to revive the battery and then will automatically convert to the Charging mode to finish the job. But a conscientious motorcycle owner would never let a battery get that low to begin with, right?

Warning Light Problem

We discovered another problem: there is no warning if the Acumen Platinum is plugged in to an outlet but not to the motorcycle’s battery!

The green “Power On” light will glow virtually forever but you’ll never know that the bike is not being charged because there’s no indicator.

The first time I used the charger, I forgot to connect one end of the 25 ft. Battery Tender extension to the lead coming out of the bike. When I saw the green light on the charger, I figured everything was ready to go.

But the next day when I came out to check on things I found that the charger had never been connected.

This is a major and, I think, crucial difference between the Acumen Platinum and the Battery Tender Plus. And it’s a very serious flaw.

The Battery Tender Plus has a bright red light that flashes on and off whenever the charger is plugged in to the outlet but not connected to the battery, a positive sign that something isn’t right.

So apparently the Acumen connectors can come loose and you’d never know it, which is not a good thing.

There is no indication in the Acumen instructions that the Acumen Platinum charger has a light that indicates that the charger is powered on but not attached to a battery.

We’re not sure if our Acumen Platinum may have been one of the first designed, labeled and sold for the U.S.A. market or not. It has a curious “Approved By” label on the bottom that looks to be a checklist for the factory to determine when a prototype is ready to go.

We purchased the charger directly and anonymously (as always) through the U.S. vendor, so we’re not sure about the purpose of this label. I hope ours is not a prototype that somehow got into the regular production run?

That’s not uncommon and has happened to use before. Here’s a photo of the strange label, seen on the right-hand side:

Acumen Platinum Motorcycle Battery Charger - Rear View


Owner Instructions

The charger comes with a very basic instruction sheet that has directions for mounting the hanger but does not include directions for attaching the harness to the motorcycle.

No problem, just be sure to visit the wBW article on installing a maintenance-free battery for more info.

UPDATE: Speaking of labeling, we also noticed no UL (Underwriters Laboratories) mark on the Acumen charger, nor is there any reference to UL approval in the instructions or on the box.

Many electrical products in the U.S. are submitted to UL for a “seal of approval” on a voluntary basis.

However, we couldn’t find a UL approval seal on any of the Battery Tenders either. Although UL approval is voluntary, many municipalities require it for various types of electrical devices.

We’re not sure if battery chargers are included. We will attempt to contact the U.S. distributor to learn more and will report back.


There’s not much more to report; the Acumen Platinum motorcycle battery charger seems to do a good job as long as it’s connected.

The LED lights are useful; the wall hanger is very nice and including the extension cord is a nice touch.

We think Acumen should definitely add a blinking light or some type of warning though if the charger is powered on but not connected to a battery.

The Acumen Platinum carries a 3 year warranty. UK owners can check the Acumen (UK) website for bargains; occasionally a box gets dented and Acumen sells the charger at discount rather than going through the trouble of repackaging the unit.

Acumen UK also sells accessories for the charger, like cables and connectors.

wBW Motorcycle Battery & Charger Reviews  |  Maintenance & Repair Articles

wBW Review: Acumen Platinum Motorcycle Battery Charger
Manufacturer: Acumen (UK) List Price (2006): $59.99
Review Date: July 2006 Made In: Unknown
Note: For informational use only. All material and photographs are Copyright © webWorld International, LLC since 2000. All rights reserved. See the webBikeWorld® Site Info page. Product specifications, features and details may change or differ from our descriptions. Always check before purchasing. Read the Terms and Conditions!


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