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Battery Chargers - Myths and Hype

globalrider

Alps Adventurer
Having worked with batteries and battery chargers during the last five years in the labs where I used to work, I thought I'd post some actual graphs of the charging process of some chargers that I own; the Optimate III and the CTEK MULTI US 3300.

I've read many reviews not so much for product information, but to see if the people reviewing the product actually had any background or technical ability to do so in the first place.

Answer: not really and most of them are laughable. For example, I contacted the people on WebBikeWorld about one of their reviews and they got downright upset that I would question them. Little wonder they got defensive since they knew SDA about electronics.

Then you have the average user who reports the battery charger they are using is great, and they are getting three years out of their batteries, the latter is nothing to write home about. Batteries should last about 10 years or more. Battery life does depend on a few factors though and while parked the important one is not letting them discharge which leads to sulphation if left discharged for any period of time. Sulphation is the number-one killer of batteries with heat and vibration being next. Of course, your vehicle's charging system has to be up to spec as well.

On the point of the much reported "it recovered my battery", I think the user should define what they meant by "recovered". I have yet to see a battery be recovered from a sulphated state to full spec of the battery. A battery that was drained due to leaving the lights on is not being "recovered" in my books, it is simply being recharged. And in most cases, unless fully discharged many times, that battery suffers little damage.


Here are the charging characteristics of the CTEK US Multi 3300.

This is what they claim. Note that they do not list any values. :scratch
CTEK%20MULTI%20US%203300%20Charging%20Algorithm.jpg


And this is what my data acquisition unit measured...
Charging%20Cycles.jpg


The charging cycles after the battery has reached full charge were recorded using a data logger over a two-week period. The above is a one-day snap shot.

Nothing special. Once 12.867V was reached, the battery was placed under charge by the CTEK till 14.34V was reached. This would take 5 minutes for the "already fully charged" YUASA 53030 battery (12V, 30 Ah) at which point the charger would turn off.

After approximately 2 hours and 15 minutes, battery voltage would reach 12.867V again and the charging process would commence again.

It does not go into any "float" or "maintenance" mode.


And this is the charge characteristics of an Optimate III charger...
Charging%20Cycles.jpg


Note, the battery being charged was discharged to the 1/2 charged state to start the test.

Again nothing special.

In fact, it bulk charges and when it reaches 14.3V, instead of going into absorption mode, a topping up of the battery at constant voltage as the current tappers to near zero, it goes right into a float mode and cycles between 13.4 and 13.7V.


Having tested many upper end chargers at work, some costing over a grand, I have to roll my eyes to some of the claims and advertizing found in the brochures and on packaging. I would be skeptical of any till I tested them. The only one I found to be near perfect are the Xantrex Truecharge 2, but those are meant for the RV, boating and car crowd.

Of course, any charger is better than letting the battery discharge and sulphate. The point being made after reading so many trumpet blowing threads about chargers is, the differences between chargers are minimal at the price points we are looking at.
 
So what happened to the " I saw it on the web, so it must be true" line. What you've posted applies to a heap of stuff, not just batteries.
 
Let's use Crest toothpaste as an example. For as long as I can recollect Crest has been advertising a new and improved formula for brighter and whiter teeth. Were that true users of Crest would have teeth that are too bright to behold. I wonder what, if any, significant changes have been made to the formula? Who checks that stuff?
 
Who checks that stuff?

Few, if anyone. But rest assured, there will be lots of forum talk praising the product based on...well, nothing.

There are these battery state monitors that supposedly give you information on how you battery or charging system is doing. Although I have seen threads discussing these, I haven't found one that is any good which is why I use a plain old digital voltmeter display that tells me exactly what is going on while riding and while parked.
 
Here is a good one. Rinty might remember this one.

On one of the car forums, one of the vendors (what are they doing on forums anyways?) introduced a battery charger that they called the "last battery charger you will ever buy". Haven't I heard that countless times. :laugh

The Save A Battery battery charger claims that it is an "All-In-One Battery Tool can quickly charge a weak battery, then test it using the built in load..."

That last part caught my attention. Wow, a built in load tester, great! That is pretty nifty in such a small package. So how does it load test a battery? After all, the load would have to be variable, like my large 500A carbon pile load tester.

So I asked the vendor on the forum. He didn't have a clue. I then asked the manufacturer but they didn't expect a tech question (how dare I question them).

Finally, I got an answer. It loads the battery a whole whopping 20W. Wow...less than 2 amps. Considering your starter easily draws 50 to 100A, how useless a test is that.

BTW, there is only one true test of a battery, a load test and a capacity test using a load tester and amp-hour tester, the latter which is time consuming. Those conductance testers that we see listed on many sites does not do a good job of that.

I just load tested my neighbor's battery across the street yesterday because the car would not start. Battery spec had CCA at 540 A, so I tested the battery at 270 A and watched the voltage quickly drop to about 6V in seconds. That battery was done.
 
I have heard that different types of batteries take different types of chargers, ie; AGM, gel, etc. Is there any truth to that?
 
I have heard that different types of batteries take different types of chargers, ie; AGM, gel, etc. Is there any truth to that?

Absolutely!

That is why I :rolleyes to battery charger manufacturer claims that it charges all types of batteries. Those chargers do, so what they do is lower the end charge voltage for the battery that takes the lowest voltage such as a GEL and the other types just get undercharged. They are not lying to you; they're just not telling you the truth. Sort of like an adjustable wrench can be used to tighten a nut, but a 6-point socket would do a better job.

A charger like the Xantrex lets you pick the battery type and actually changes the charge end voltage (absorption phase). This is what their panel looks like...
Xantrex%20TrueCharge2%20Panel-M.jpg
 
Absolutely!

That is why I :rolleyes to battery charger manufacturer claims that it charges all types of batteries. Those chargers do, so what they do is lower the end charge voltage for the battery that takes the lowest voltage such as a GEL and the other types just get undercharged. They are not lying to you; they're just not telling you the truth. Sort of like an adjustable wrench can be used to tighten a nut, but a 6-point socket would do a better job.

A charger like the Xantrex lets you pick the battery type and actually changes the charge end voltage (absorption phase). This is what their panel looks like...
Xantrex%20TrueCharge2%20Panel-M.jpg

Very good analysis approach. :bow I love reading posts that use facts and data! Boring for some, I know.
 
Last edited:
Very good analysis approach. :bow I love reading posts that use facts and data! Boring for some, I know.

By the way, we just didn't pick the Xantrex because of claimed specs. We actually ran tests on all aspects of that charger and it is near perfect.

Unfortunately, it is expensive and requires the remote panel to limit/control the charging rate. The 20A and larger units can do that; the 10A unit will not accept the remote panel and is too high a rate for our batteries.
 
Alex,

Have you looked at the Optimate 4? Just curious. My Optimate 3 went bad when I was on vacation for 6 weeks and I was using it to keep a BMW car battery up. It stopped doing much of anything when I disconnected it from the battery, but not before it boiled the battery almost dry (when an identical replacement battery weighs twice the weight of the one being replaced - it's gotta be a dry battery.) Optimate refused to do anything with the 3 - but lacking a Canbus trigger alternative (except the BMW charger) - I ordered the Optimate 4.

-------------------------------------------------------------------

My impressions of the 4 are - it claims to do a lot of things - different modes depending on battery condition, type, charger settings, etc - but it's also the worst documented device I've ever seen with an array of confusing LEDs blinking and flashing - often in patterns not described in the poorly written owners manual.

Just curious - I did have a battery almost completely discharge on my R1200R when I used the 4 in "CanBus" trigger mode to charge it through the accessory port. Turns out - it does turn on the accessory port and charges the bike, but simply disconnecting it doesn't turn OFF the accessory port, and the accessory port is wired in parallel with the GPS power/signal plug, and a Garmin Zumo 660 in it's cradle - even off - does draw enough to discharge the battery within about a week if the accessory port (and whatever else the ZFE turned on) isn't turned off.

The trick there - when done charging it via the accessory port - cycle the ignition one time to turn off the port (and GPS connection.)

Oh - back on topic - that battery did seem to "recover" after an Accumate process (direct connected out of the bike), and I did have it load tested at a local mechanic's shop - it passed the load test fine. Dunno if that was due to the Accumate, or as you said - the battery was simply discharged.
 
Alex,

Have you looked at the Optimate 4? Just curious. My Optimate 3 went bad when I was on vacation for 6 weeks and I was using it to keep a BMW car battery up. It stopped doing much of anything when I disconnected it from the battery, but not before it boiled the battery almost dry (when an identical replacement battery weighs twice the weight of the one being replaced - it's gotta be a dry battery.)

I've only seen the Optimate 4 at motorcycle shows and dealerships, and with two Optimate 3 chargers and three CTEK MULTI US 3300 chargers, I think I have more chargers than I need.

The Optimate is a low current rate charger, 0.8A I believe. and a bit undersized to charge a car battery. Probably good enough to maintain a fully charged car battery which is what I take it you were doing.

A battery can boil/gas off below its per-cell max charge voltage if it is defective. You do need some ooomph from the charger and I would be surprised that the Optimate 3 could do that in a short time period. BTW, most of a battery's weight is in the lead.



My impressions of the 4 are - it claims to do a lot of things - different modes depending on battery condition, type, charger settings, etc.

You know my thoughts on "claims". When someone tries to troubleshoot a problem or evaluate something without testing/measuring, I always say...guess less and test and confirm more.


Oh - back on topic - that battery did seem to "recover" after an Accumate process (direct connected out of the bike), and I did have it load tested at a local mechanic's shop - it passed the load test fine. Dunno if that was due to the Accumate, or as you said - the battery was simply discharged.

Most likely it was simply discharged.

Its unfortunate I can't comment on other battery chargers other than the ones I have tested, most of which was done at the defense labs where I used to work (now retired so I can ride more...wink). Some of the big & well known names did poorly.

I ran those graphs above using a Madgetech data acquisition module that is the size of a small matchbox. If anyone has an on-board voltage issue, it can be used to monitor voltages (or anything else that can produce a voltage).

I wouldn't have an issue doing some testing for the ON, but I have so much on the go usually, I'd hate to make a promise I cannot keep. Plus I have the engine/transmission out of my 993 for some minor items.
 
Browsing the web, I came across this review on webBikeWorld...
CTEK US 800 vs. CTEK US 7002 Review

Introduction

Motorcycle battery chargers are among the most difficult products to review.


They are dead simple to review and test but I guess they are if you don't have the slightest clue what you are talking about.
TIP webBikeWorld..start with what a battery needs for a long life...then test the charger to see if it does that. Real simple!

That further confirms that the internet is the greatest source of unconfirmed information.

Why don't those guys seek out reviewers that actually know how to review subjectively. A simple lab might help.
 
Then, which charger

This thread has been really informative.

What I would like to know is, which charger(s) in a couple of different price ranges would you recommend?
 
What I would like to know is, which charger(s) in a couple of different price ranges would you recommend?

Unlike the countless comments found on forums and the web about what products are great that they haven't even tested, I can only comment on the CTEK 3300 and Optimate III chargers that I own and tested and the Xantrex Truecharge2 that we tested in our defence labs.

The CTEK 3300 and Optimate III I ran while charging my battery from a half discharged state and data logged the output vs time. They are OK but certainly nothing special and I would think the same applies to any charger in that price range. That said, we tested some well known brand name chargers that were very expensive and they were nothing special.

The Xantrex Truecharge2 20 amp model (XC1220) with remote panel (so that you can control charge rate) is really tops, but you are looking at about $300 for both.

BTW, these chargers are for FLA, AGM, GEL batteries.

Bottom line as mentioned in the first post: any charger (provided it does not overcharge) is better than no charger. Letting a battery discharge and sulphate is the #1 cause of short battery life.

Verify charge voltage using a digital multimeter.
 
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