Battery Charger Testing Results

[pasadena_commut]

Hmm... I used a DC amp clamp on my HF 4 amp charger to see how it's algorithm worked. On mine, I regularly saw it put out a nominal 4 amps on regular sized car batteries (groups 65, 34, 24, etc.). It would do the "probe mode" thing you mentioned and then did a series of constant current charges. It would put out 4 amps and hold it steady until the voltage climbed to about ~14.4v to 14.6v, then it would start over with a probe and then charge at 2 amps until the voltage climbed back to fourteen and a half volts. It would repeat the process with 1 amp and finish with .5 amps. With regular flooded batteries, the float charge would bounce around between 13.2v and 13.4v.

Mine would do constant current charging only briefly and then would go into a pulse mode. The technical description of how this device works is mostly lacking, and there is no mode indicator, but it could be that it was improperly entering the desulfating mode, which pulses. The thing is, it did that on every battery, including ones which were practically brand new. So perhaps it was defective from the get go, trying to desulfate batteries that didn't need that. Or maybe that was normal operating procedure for some models.

I wonder how many different variations of this charger HF has sold. They all look the same from the outside, but they may not be the same inside. Mine is at least 4 years old, is yours recent? There are no date codes or production numbers on the outside of the device.

 

[f355spider]

I did a before and after test with the battery "reconditioning" setting of my Black and Decker 15 amp charger. I used it for 6 days on a weak 5 year old battery that would still marginally work to start a vehicle. After 6 days, the internal resistance on that battery increased as measured by an Ancel BA101 tester, so it made it worse.

Not surprising. It is clear some desulfation modes simply do not work in all cases. My Granite Digital "save a battery" battery tender claims its pulse desulfation during float mode would both prevent and remove sulfation, but was clearly not the case for my two batteries. It was in regular use on the batteries several times overnight per week . Later use with Battery Minder restored them, using the same overnight use several nights a week.

 

[repairman54]

My barometer for how well a desulfation mode in a maintainer works is how long the useful life of the battery has been extended.
10 + year old batteries, a mix of wet and AGM ones, on temp. compensated Battery Minders that are still in service tells me the BM works. At least in my toys that are always on one when parked.
I've brought back a MC battery with the BM on continually for couple months straight for a friend, battery was so low BM would not activate, took a old school charger, non auto, to get it up to 6v for the BM to activate. Battery was in an '11 Spyder which the battery was a major PITA to remove. Key was left on for a couple weeks so that battery was flat. That was last winter, battery still hanging in there this summer.
My snowmobile club has Noco's on our equipment. I'm not impressed at all with them. 5-6 year old batteries going bad that always have them plugged in when parked vs my twice as old batteries on the BM.

 

[D1dad]

Noco is a joke compared to BM and Pulsetech. Proprietary cables, undercharges constantly and supposedly can charge my battery to full in just an hour or so. The last time I used it, I put the battery Noco claimed was charged on the Pulsetech and it charged for almost 3 hrs. It has a feature like an old school buzz box which is why I still have it. Although I haven’t needed it.

 

[pasadena_commut]

The testing will be done using two Owon B35T+ Bluetooth Datalogging multimeters. These are cheap and available on Amazon. I am not looking for low mA accuracy, so will take current readings through the 20A sensing port. Data is taken at a pre-defined interval, and the CSVs that are pulled from the meters will be processed in Excel.

I am curious how this is actually wired together. That is, which type of electrical connectors are used where. I can see an alligator clip in the picture but it is all a bit of rat's nest and the cables from the multimeters exit the picture.

Also these use bluetooth. Do you have a spare phone you leave in the car?

Edit: the current measure is through the multimeter, not via a clamp. Any idea what the input resistance or burden voltage is in the ammeter mode used? The internal resistance of the last battery I tested was 9.3 mOhms, and this Fluke data sheet

https://www.grainger.com/ec/pdf/Fluke-Digital-Multimeters-Detailed-Specifications-Sheet.pdf

gives a burden voltage of 0.03 V/A in the 6A range. Which I think is equivalent to a series resistance of 30 mOhms. And that's a very good multimeter. Makes me wonder if the chargers might think the battery isn't so healthy since it would look like it had an internal resistance of ~40 mOhms.

 

[JHZR2]

I am curious how this is actually wired together. That is, which type of electrical connectors are used where. I can see an alligator clip in the picture but it is all a bit of rat's nest and the cables from the multimeters exit the picture.

Also these use bluetooth. Do you have a spare phone you leave in the car?

Edit: the current measure is through the multimeter, not via a clamp. Any idea what the input resistance or burden voltage is in the ammeter mode used? The internal resistance of the last battery I tested was 9.3 mOhms, and this Fluke data sheet

https://www.grainger.com/ec/pdf/Fluke-Digital-Multimeters-Detailed-Specifications-Sheet.pdf

gives a burden voltage of 0.03 V/A in the 6A range. Which I think is equivalent to a series resistance of 30 mOhms. And that's a very good multimeter. Makes me wonder if the chargers might think the battery isn't so healthy since it would look like it had an internal resistance of ~40 mOhms.

This was generally done with a spare loose battery in my garage for general interest.

I have folks that do the most advanced battery testing you can imagine, with millions of dollars of equipment. This was shade tree analysis. Those cheap Owon meters didn’t job, but no idea their specs. I guess it may be published or available from the vendor.

Your point is good - there could be a big resistance increase over a direct connect to the battery. But my primary interest was in the voltage traces to look at the charging profiles. There is a lot to be learned just from the profile and how soon it cuts it off or how high it goes before making mode changes, etc.

 

[pasadena_commut]

Your point is good - there could be a big resistance increase over a direct connect to the battery. But my primary interest was in the voltage traces to look at the charging profiles. There is a lot to be learned just from the profile and how soon it cuts it off or how high it goes before making mode changes, etc.

Not disagreeing with that. Wondering if some of the devices change their charging profile in response to observed high resistance.

There could be a similar problem when charging a battery still electrically attached to the rest of the car. Most vehicles these days pull 25 mA or so out of the 12V even if they are "off", and it can be 300 mA or more if a door is open. They can also have current draw spikes when some computer or other decides to wake up. If the charger is nearly done, and is pushing in a small amount of current, then suddenly the battery voltage starts falling, one would have to assume it might get a little confused.

I'm still curious about how the pieces went together physically. Multimeter connections tend to be on the rickety/finicky side, whereas in this application at least the lines carrying current should be rock solid.