IXLR8

Well coming to an extremely well equipped lab at work everyday has its advantages. We test nearly everything electrical, mechanical, chemical, etc.


If the my other 3300 produces the same results, it can mean two things; 1) both chargers are duds and I think that is highly unlikley or 2) their claims are BS. I'm going to open my 3300 up to see what type of circuitry they use.

As for my charger (and maybe some or all of them) not entering pulse maintenance mode, no big deal. My CTEK 3300 charger cuts off and shuts down at 14.3V (or 14.65V in the Snowflake mode) and then restarts when it self drains (the battery by itself if on a bench or due to loads in the car) to 12.8V.

Actually, I prefer the on-off-on-off charging mode at reduced current (<10% of the Ah capacity of the battery) more. Quite a few think it is a better way to maintain a battery.

I'd test other brands, but I'm not about to go out and buy them to do so. The Xantrex Truecharge 2 that we tested did extremely well, but its more than a home charger at US$135 and up, depending on the charge rate of the model. Chargers in our price range can only be so capable.

What pi$$es me off with manufacturers is their false or misleading advertizing, be it leaking valve covers that only need seals, not billet aluminium valve covers, power chips with no before and after dyno runs, aftermarket junk that has poor fit, you name it.

Steen Jensen

This is what I use for my 8 batteries...

Cheap and effective.

http://www.harborfreight.com/automat...ger-42292.html

IXLR8

That it may be, but it is only a "float charger".

With a maximum output of 13.2V, it is quite useless if you wanted to charge a battery. It is intended to be used on fully charged batteries, so you will need a charger to bring it up to that state first.

See intended use and specifications.

Steen Jensen

Absolutely correct. It does what it is designed to do and I think what most guys here are looking for. Fantastic price.

I also have one of these...
http://batterytender.com/automotive/...emisphere.html
More expensive but the "Rolls Royce " of battery chargers.

IXLR8

As long as buyers knows its limitations.

In my case, I'll have the luggage compartment light on (hood isn't latched) while I am working on my car and would need a few amps of supply.

The other one is OK IF you fully charge the battery first and place it on the bench.


Thats debateable. Not until I test it. I have no faith in manufacturer's claims.

IXLR8

Yeah it looks like I have them shaking in their boots if they are calling me at work from Sweden.

By the way, I tested my other CTEK Multi US 3300 that I have (I bought two at different times) in my lab at work and it does not go into any form of "Pulse Maintenance Mode" either.

It simply shuts down when the charge current drops down to 0.4A with the battery at 14.3V; then restarts at 12.8V.

Once again, that is OK and another method of keeping a battery charged and maintained, but it does not do what they claim/advertize. Seems to be the norm with so many products...consumer beware.

acadian_dad

Hey Alex - wondering if when they show a pulsed maintenance mode do you think they mean it is a timed pulse or rather just a hysteretic charging / relaxation cycle based on measured voltage and a lower charging rate ?

I don't really know what a battery "wants" but I can sort of see a hysteretic mode looking like a pulsed maintenance.

Dave

IXLR8

Dave,

I connected a storage scope to the battery to see if it was being "pulsed". Nothing at all.

When the charger shuts off (when 14.3V is reached and current diminishes to 0.4A), the battery voltage steadily decreases back down to the 12.8V level at which point the charger switches back on. The fully charged battery icon stays on till that point.

CTEK's graph below shows what I should be seeing...


Note their comments for Pulse. Well of course the voltage falls; that happens if the charger no longer charges or if a charger goes into float/maintenance mode where it'll decrease to the set voltage somewhere in the mid 13s.

I now have the V and I curves on Excel after downloading them from the Graphtec data logger. I'll be posting them on my SmugMug site when I have time.

acadian_dad

Yeah I was just wondering if their transgression was really in the relative scale of the x-axis in the different modes. And calling what we refer to as "hysteretic regulation" in the power supply world as "pulsed mode".

As an aside - for some of the power supply chips that my company makes - when you design the power supply for a certain nominal loading, when you unload the supply enough it can be hard for the switcher to maintain output regulation - and in fact efficiency at light load can fall off dramatically. So we intentionally allow the supply to run into this type of hysteretic regulation with the output allowed to swing between two different levels bracketing the normal regulation level. It's commonly referred to as "burst mode" as there will be bursts of switching interleaved with quiet times. Same idea but on a significantly faster scale (usually). So I wonder if "pulsed" is a bit of a lost in translation version of "burst".

Eg. The hysteretic behavior you have measured looks like a "pulsed mode" when the time scale is big enough.

Misleading to call it pulsed I agree. But bottom line - isn't this an acceptable way to maintain charge on the battery - given that 12.8 V on a lightly loaded battery is pretty close to full ?

Mark Lue

Thanks Alex for the testing and info. I thought this charger was a real steal but after your findings I'm glad I bought it on sale as opposed to full price.

If someone has the one with the Porsche brand on it, it would be interesting to compare those results as well.

IXLR8

Yes it is and I prefer it over a constant float voltage that is current limited to some low value...say 500 mA max. I'd want it to switch at 12.6V though.

And in the end that is what I have done with a manual 800 mA charger for my motorcycle batteries in the past. I'd charge them to the upper 14s; they can gas as they are a FLA type and I can add distilled water. A short charge every now and then to the low 15s would equalize the cells. After charging, I'd let them sit till the OCV decreased to 12.6V and start over again. Those batteries always lasted 10 years which is reasonable for a small seasonal low-use battery.

I've never needed to maintenance charge any of my car batteries, even on the daily driver that has been parked for 6 weeks every summer, and it is in its 13th year.

IXLR8

For $50, its a good enough charger. What I really liked was the fact that I can switch it to a higher charge voltage (the Snowflake mode) during the winter when its cold in the garage. Battery charge voltages should be increased with a decrease in temperature and vice versa.

I'd like to return them both for what I paid. There is nothing wrong with them, but I'd like to go for the Xantrex Truecharge 2 - TC2012 (I thoroughly tested them and they are as good as a charger can get other than I'd like to make a very few minor changes to the program). They're about US$250, so not what the average owner would want to spend.


I'd bet they are the same circuit-wise.

I always drew a parallel when charger manufacturers state "charges all types of batteries"...a half truth. Sure it will, but how well? Sort of like an adjustable wrench will loosen that nut, but not as well as a 6 point socket will.

ronnie993tt

What's this about the snowflake mode in the cold? I've awlays left mine on car mode and the battery stays charged. I often see it topping up the battery - orange light for a few minutes then switches back to green at any temperature - when I go in to clear out the mickies.

IXLR8

Charged, but not fully charged.

Battery charge voltage is based on temperature, so if its near freezing or below where your battery is located, then you should be using the Snowflake setting.

Here is a chart for AGM batteries that East Penn has in their Technical Manual. Its close enough for regular FLA battery use.