Battery Charger Testing Results

[D1dad]

Are you saying that when the battery is discharged it is now taking half as long to run the full charge cycle to the point where it goes to float? That wouldn't be good, that would mean the battery is losing capacity so the same amount of current "charges" it faster.

If the battery has been on a charger or driven recently it is a good idea to turn on the headlights for a while (30s, 60s?) to bleed off the surface charge. Then wait around 5 minutes for it to recover. (This assumes a temperature like 25C, it probably needs much longer if the battery is cold.) Then once the battery voltage bears some relation to the actual SOC attach the charger. For instance, the BatteryTender Jr. will go straight to float on a battery if this isn't done, even if the actual SOC is way below 100%. The Harbor Freight 4A charger (it isn't really) had the same problem. I think that all chargers should do that themselves - if it sees a ~100% SOC voltage pull some current out, let the battery recover, then decide what to do. Many, perhaps most, don't.

No. What I’m saying is that when I 1st started using the agm charger after using the standard agm for months, the process took several hours. This could have been after a few hour drive or an all day trip. Now those same trips take just an hour or so to reach full charge. The battery tests 100% for state of health and over 100cca than advertised. I think after a few months of using it, there is a more complete charge on the battery.

 

[D1dad]

I just froze switching some battery charges around and took a reading on the 21012 agm. @ 2 degrees, the 2012 was maintaining @12.90. Temp comp in full effect. I had to string together 4, 25 foot cords to reach my son’s dump truck, but got the Pulsetech hooked up to his new Walmart max batteries that were testing @12.17 volts. All the other batteries, 9 in all, are fully charged and ready to go.

 

[pasadena_commut]

The battery tests 100% for state of health and over 100cca than advertised. I think after a few months of using it, there is a more complete charge on the battery.

Battery terminology (assuming AGM or similar chemistry):

1. capacity is in Ah, it is a measure of the amount of charge they can store.
2. CCA is in Amperes, a measure of peak current (under specific climate conditions) that the battery can provide
3. internal resistance is in Ohms, it is a measure of how hard it is for current to flow out of the battery.
4. lifetime is in some time unit, usually years, and represent the useful working life of the battery.
5. SOC (state of charge), is in percent, is a measure of how fully charged a battery is.
6. SOH (state of health), is in percent, in small testers it is typically a direct function of the internal resistance value, it can also be a function of starting and current capacity, but is only rarely calculated that way..

A batteryminder can improve 2,3,4 from some starting point worse than brand new by desulfating the battery and by keeping it from ever discharging very far. Always keeping the SOC high is a preventative meaure - deep discharge damages batteries, the less time they are in that state, the better. When 3 improves so generally does 6, because on most electronic testers they are not independent measurements. Any charger can increase 5, it just requires pushing charge into the battery, although some methods are faster or gentler than others. There is no solid evidence that I have seen to support the idea that any charger can improve 1. There are some extremely expensive testers that can actually measure capacity directly, but normally it is measured by doing a C/20 constant current discharge from 100% SOC to 0% SOC. This is a process which will probably damage most batteries due to the very deep discharge. A DTL150 tester that can do a true capacity test can be had for around $50. (Warning, they are fragile and easy to brick.) Some small electronic testers will show a capacity value (Harbor Freight sells one) but that value is wildly inaccurate.

Now then, there are three ways a 1A (for instance) charger can work "faster". The first is if the battery is being kept at a higher SOC, so when the charger starts it does so at say 80% rather than 70%. Since less charge needs to be pushed in, it takes less time to finish. The second is if the battery capacity is falling. If the capacity has fallen by 20%, then all else being equal, it would need 20% less total charge to reach 100% SOC, and again, this takes less time. The third is if the resistance decreases. At least hypthetically. If the resistance is lower less of the energy in charging is converted to heat in the battery and so more is available for charging. I suspect that this is not a very big effect unless the battery is at death's door.

For D1dad's battery my hope is that the first (and maybe third) of these is(are) happening. However, without a valid determination of battery capacity, the 2nd cannot be ruled out.

For cars which have conventional starters the CCA number is the best indicator of the health of the battery, and that is something that the little electronic testers can measure adequately. My view on AGM batteries is skewed because the one I have is in a Prius, and this works the same for most other Hybrids. CCA is irrelevant, the car just needs to pull ~40A for a second or so to start the hybrid part of the system, and after that the 12V battery doesn't do a thing except recharge slowly. The battery can have almost no capacity and the small electronic testers will still measure a CCA that is high, or present a bogus capacity number which does not correspond to the actual state of the battery. So unless the resistance happens to have gone high, the testers don't reveal that the battery is almost gone. Conversely, the chargers do give information, because the battery will charge from something like 50% SOC to 100% SOC very very quickly on a low current.

 

[04GTO]

My favorite charger currently is my Battery Minder 12248. It does nearly everything I need a charger to do, with two exceptions. It does not do higher than 8 amps for deep discharges, nor does it have the ability to set a specific absorb time and/or tail current on deep discharges for proper 100% charging.

Enter the Victron BlueSmart IP67 12/25. I won't go into all of the details here, but it fixes these two shortcomings and adds a lot of other very useful settings, including Bluetooth monitoring through the Victron Connect App. Through the advanced and expert mode settings in the app, the IP67 can be set to exactly replicate the Odyssey battery recommended charging algo and temperature compensation settings.

The IP67 arrived yesterday (got it second hand for under $100). Since this charger is more or less designed to be semi permanently installed, I am going to customize it a little. I want to make it more practical like a shop charger. I ordered a couple Anderson connectors and a set of nice alligator clamps pre-wired with a Anderson connector. I also ordered some rubber feet that can be added to the existing mounting bolt holes, so that it won't have to sit directly on the ground or floor and get scraped up. This will make it a lot more flexible and useful for me.

BateryMinder and Victron have two very divergent philosophies when it comes to battery restoration. BatteryMinder, of course, leans into the pulse desulfation. Victron, on the other hand, basically considers pulse desulfation to be snake oil. Victron holds firm that low current and constant high voltage is the way to go. I have had a five year old Duralast Gold 24F FLA battery on the battery minder for the last month+. Internal resistance has gone down from 6.4 mΩ to 5.3. While cca went from 615 to 695. Before that it was maintained for 3 years with a Diehard 3A smart charger without the BatteryMinder constant desulfation. So I feel like the desulfation is working. This week, I am gonna draw that 24F down to 11.8v under load and then hit it with the IP67 restoration mode and see if it can get the 24F even closer to the factory cca of 750. I will report back here.

 

[f355spider]

BateryMinder and Victron have two very divergent philosophies when it comes to battery restoration. BatteryMinder, of course, leans into the pulse desulfation. Victron, on the other hand, basically considers pulse desulfation to be snake oil. Victron holds firm that low current and constant high voltage is the way to go. I have had a five year old Duralast Gold 24F FLA battery on the battery minder for the last month+. Internal resistance has gone down from 6.4 mΩ to 5.3. While cca went from 615 to 695. Before that it was maintained for 3 years with a Diehard 3A smart charger without the BatteryMinder constant desulfation. So I feel like the desulfation is working. This week, I am gonna draw that 24F down to 11.8v under load and then hit it with the IP67 restoration mode and see if it can get the 24F even closer to the factory cca of 750. I will report back here.

Great info, keep us posted.
I have found the Battery Minder will keep improving a sulfated battery out to about 2 months. At that point, it has done what it can.

Someone posted about the IP65 variant a couple years ago with a link to their website or Amazon listing. It was a 5 amp or 7 amp variant. Similar features (bluetooth and automatic temperature compensation), but being a lower amperage, it came with quick disconnects to use ring mounts, cigarette lighter adapter or battery clamps.

 

[04GTO]

Great info, keep us posted.
I have found the Battery Minder will keep improving a sulfated battery out to about 2 months. At that point, it has done what it can.

Someone posted about the IP65 variant a couple years ago with a link to their website or Amazon listing. It was a 5 amp or 7 amp variant. Similar features (bluetooth and automatic temperature compensation), but being a lower amperage, it came with quick disconnects to use ring mounts, cigarette lighter adapter or battery clamps.

The IP65 was actually the first one that caught my attention. But the IP65 12/25 version is hard to come by and only seems to sell for at or near the MSRP. Where as the IP67 12/25 that I have transacts for quite a bit less. Settings wise they are identical, the only real differences in addition to the obvious ingress protection, the IP67 has a potted aluminum casing (vs plastic), no included clips or quick connects etc. Also, not sure why exactly, but likely due to the IP67 rating, and the associated step up in build quality, the IP67 seems to have a far better reputation for durability. Which is always welcome.

 

[04GTO]

My favorite charger currently is my Battery Minder 12248. It does nearly everything I need a charger to do, with two exceptions. It does not do higher than 8 amps for deep discharges, nor does it have the ability to set a specific absorb time and/or tail current on deep discharges for proper 100% charging.

Enter the Victron BlueSmart IP67 12/25. I won't go into all of the details here, but it fixes these two shortcomings and adds a lot of other very useful settings, including Bluetooth monitoring through the Victron Connect App. Through the advanced and expert mode settings in the app, the IP67 can be set to exactly replicate the Odyssey battery recommended charging algo and temperature compensation settings.

The IP67 arrived yesterday (got it second hand for under $100). Since this charger is more or less designed to be semi permanently installed, I am going to customize it a little. I want to make it more practical like a shop charger. I ordered a couple Anderson connectors and a set of nice alligator clamps pre-wired with a Anderson connector. I also ordered some rubber feet that can be added to the existing mounting bolt holes, so that it won't have to sit directly on the ground or floor and get scraped up. This will make it a lot more flexible and useful for me.

BateryMinder and Victron have two very divergent philosophies when it comes to battery restoration. BatteryMinder, of course, leans into the pulse desulfation. Victron, on the other hand, basically considers pulse desulfation to be snake oil. Victron holds firm that low current and constant high voltage is the way to go. I have had a five year old Duralast Gold 24F FLA battery on the battery minder for the last month+. Internal resistance has gone down from 6.4 mΩ to 5.3. While cca went from 615 to 695. Before that it was maintained for 3 years with a Diehard 3A smart charger without the BatteryMinder constant desulfation. So I feel like the desulfation is working. This week, I am gonna draw that 24F down to 11.8v under load and then hit it with the IP67 restoration mode and see if it can get the 24F even closer to the factory cca of 750. I will report back here.

Finished up the mild customization:

Here is the second Anderson quick connect I have set up with some quick release battery terminal connectors. This battery is the old battery out of my wife's car that has been experimented on a bit.

 

[04GTO]

Finished up the mild customization:
View attachment 337794
Here is the second Anderson quick connect I have set up with some quick release battery terminal connectors. This battery is the old battery out of my wife's car that has been experimented on a bit.
View attachment 337795

Today I completed my test, using the ip67 set on normal/recovery mode and attached to the Duralast Gold DLG-24F battery. Prior to this test the battery had been off the maintainer for 24 hours, though still attached to the Landcruiser. This battery had been connected to the BatteryMINDer 12248 nearly 24/7 for 7 weeks. Here are the test results on the Ancel tester:

Note from my original post above- This battery was maintained for about three years on a Diehard 3amp smart charger. About 2 months ago the battery had 6.4 mΩ internal resistance and 615 cca. Now with 7 weeks through this weekend it was on the 12248, which brought it to 4.23 mΩ internal resistance and 692 cca. Pretty good results for the "snake oil" pulse desulfation. Now after the ip67 recovery mode, and 24 hours of rest, while connected to the Landcruiser, we have this:

4.08 mΩ internal resistance and 718 cca! Also, I always get better results from the tester when the battery is fully disconnected from the vehicle, all tests herein were with the battery still in the vehicle and fully installed. I find this to be a remarkable combined result, from the ip67 and 12248. Why? Because this battery is 5 years old. From every decent 24F battery I could find, specs when new range from 3.0 mΩ to 4.20 mΩ internal resistance and 600-750 cca. This battery being 5 years old and still falling within a very good spec range for a new battery is quite impressive. That says a lot about the quality of the battery itself. This particular battery was manufactured by Clarios (formerly Johnson Controls Power Solutions). It also says a lot about how great each of these chargers are in their own way, with their very divergent tech and philosophies.

Is anyone else impressed by this?

 

[f355spider]

I have three Varta (Clarios) AGMs that are between 7 and 8 years old. All are still passing as good...they are on a Battery Minder at least a couple nights a week for the past three years or so .

 

[JHZR2]

If something puts you at 12.51v after 24 hours, something is wrong, IMO. Land Cruiser may have a high parasitic draw but that’s a low voltage for my taste.

If you maintain the battery, the impedance should stay low. It will fail from other things unfortunately. But it looks like you’re doing the best one could ask for!

 

[04GTO]

If something puts you at 12.51v after 24 hours, something is wrong, IMO. Land Cruiser may have a high parasitic draw but that’s a low voltage for my taste.

If you maintain the battery, the impedance should stay low. It will fail from other things unfortunately. But it looks like you’re doing the best one could ask for!

The Landcruiser actually has low parasitic draw, lower parasitic draw than any of my newer vehicles for sure. Which are all in the normal range. All these measurements are with the battery connected to the vehicle. Disconnected always reads about .2v higher, sometimes more with this tester. Same with my other more expensive testers, due to additional resistance/impedance added by all the other wiring etc. Adding in the estimated .2v drop puts this firmly in the healthy battery range of 12.71v +/-
As stated previously, prior to the "before" result the battery was connected to the vehicle as normal along with the Diehard battery maintainer. Then the charger was disconnected for 24 hours. Then the battery was charged with the ip67. The charger was then disconnected (though as above, still installed in the vehicle) from the battery for 24 hours. The battery was then tested 24 hours later for the "after" result. Testing the battery now after 48+ hours, this time, disconnected with just my multimeter, I got 12.79v.

 

[JHZR2]

The Landcruiser actually has low parasitic draw, lower parasitic draw than any of my newer vehicles for sure. Which are all in the normal range. All these measurements are with the battery connected to the vehicle. Disconnected always reads about .2v higher, sometimes more with this tester. Same with my other more expensive testers, due to additional resistance/impedance added by all the other wiring etc. Adding in the estimated .2v drop puts this firmly in the healthy battery range of 12.71v +/-
As stated previously, prior to the "before" result the battery was connected to the vehicle as normal along with the Diehard battery maintainer. Then the charger was disconnected for 24 hours. Then the battery was charged with the ip67. The charger was then disconnected (though as above, still installed in the vehicle) from the battery for 24 hours. The battery was then tested 24 hours later for the "after" result. Testing the battery now after 48+ hours, this time, disconnected with just my multimeter, I got 12.79v.

Unfortunately what you’re saying doesn’t make sense in terms of the battery. It doesn’t read 0.2v lower unless there is a load on the battery, or, your cables are fouled and giving faulty readings.

Voltage at the terminals is the electrochemical voltage (open circuit) plus or minus the current times resistance.

Vt=Voc +/- I*R

If you cleaned the on battery connecti9ns to Lenny bright, it wouldn’t matter whether the battery was connected or not, assuming that the vehicle indeed doesn’t have a big draw.

 

[04GTO]

Unfortunately what you’re saying doesn’t make sense in terms of the battery. It doesn’t read 0.2v lower unless there is a load on the battery, or, your cables are fouled and giving faulty readings.

Voltage at the terminals is the electrochemical voltage (open circuit) plus or minus the current times resistance.

Vt=Voc +/- I*R

If you cleaned the on battery connecti9ns to Lenny bright, it wouldn’t matter whether the battery was connected or not, assuming that the vehicle indeed doesn’t have a big draw.

On each of my very well maintained cars, the reading with a battery tester is always lower when connected to the car vs disconnected. No fouled cables, no dirty terminals et al.

 

[JHZR2]

On each of my very well maintained cars, the reading with a battery tester is always lower when connected to the car vs disconnected. No fouled cables, no dirty terminals et al.

So what magic or revision to the laws of physics lets it show a lower voltage when connected, without a parasitic draw?

 

[04GTO]

So what magic or revision to the laws of physics lets it show a lower voltage when connected, without a parasitic draw?

Just what sorcery then also causes my multimeter to read differently at the jump posts then it reads directly at the battery posts? Hint for the slow people in the back: Current flowing out of the battery must overcome the battery's internal resistance and the resistance of the wires of any wires connected to it. This results in a voltage drop according to Ohm's Law (\(V = I \times R\)), meaning the measured terminal voltage will be lower than the resting OCV.

 

[JHZR2]

Just what sorcery then also causes my multimeter to read differently at the jump posts then it reads directly at the battery posts? Hint for the slow people in the back: Current flowing out of the battery must overcome the battery's internal resistance and the resistance of the wires of any wires connected to it. This results in a voltage drop according to Ohm's Law (\(V = I \times R\)), meaning the measured terminal voltage will be lower than the resting OCV.

Current flowing from the battery. You’ve made my point.

But low parasitic draw on a 4 mOhm battery doesn’t create 0.2V drop.

0.004 Ohm battery resistance requires a 50A load to drop 0.2V. You don’t have a 50A parasitic.

I have indeed seen different (lower) voltage readings at different points in the circuit, like, say, at the cigarette lighter port vs the battery. That’s due to losses in the connections (since a high impedance multimeter effectively flows no current, so the drop cannot be current related).

But at the battery terminals it has to be something else. Or fouled terminals.

And to be clear, I was commenting on the 12.5v photo, not the 12.68v one, which I’d agree is just fine and “full”.

 

[04GTO]

Current flowing from the battery. You’ve made my point.

But low parasitic draw on a 4 mOhm battery doesn’t create 0.2V drop.

0.004 Ohm battery resistance requires a 50A load to drop 0.2V. You don’t have a 50A parasitic.

I have indeed seen different (lower) voltage readings at different points in the circuit, like, say, at the cigarette lighter port vs the battery. That’s due to losses in the connections (since a high impedance multimeter effectively flows no current, so the drop cannot be current related).

But at the battery terminals it has to be something else. Or fouled terminals.

Nope.

 

[JHZR2]

Nope.

Huh? Even a 0.02v drop (note my edit above, my initial comments were really concerned about the 12.5v value), is a 5A parasitic. Properly functioning you should have less than 50mA.

5 x 0.004 =0.02

Open circuit voltage is also temperature dependent.

So you have pristine connections, an absolutely 100% soc battery, and magic or luck is causing a voltage drop, not connections or parasitics… right.

The leads themselves will have some resistance too of course. But the multimeter has a resistance in its circuit on the order of Megohms, so effectively no current flows in the measurement, thus no IR loss.

 

[repairman54]

Just woke up my Harley from it's winter slumber. 2017 Odyssey on a BM 1500 since installed when parked still reading great. Sub zero winter temps also.
Can't beat a BM maintainer / conditioner IMO.

 

[pasadena_commut]

Is anyone else impressed by this?

I'm going to be that guy. There are significant method issues you are not taking into account.

1. temperature
2. tester technology
3. parasitic load from vehicle

Considering these one at a time.

Lead acid batteries are temperature dependent devices, and so are their measured electrical properties. For two tests of the same battery to be comparable they must be made at the same temperature, ideally in a temperature controlled chamber, but more practically, at "close" to some target temperature. Like 25C +- 1C. Minimally, note and report the temperatures during the test.

The small electronic testers don't actually measure the R and CCA, they do some tests and use a formula to derive them. They are OK for detecting a really bad battery with terrible R, but not so good for comparing the same battery in slightly different states of charge. A more accurate, but vastly more time consuming approach, is to use a device like a DTL150 to discharge the battery at C/20 and plot I and V over time (as in many of the posts in this thread). Ideally this would be down to a full discharge, but that is bad for the battery. An alternative is to do all comparisons by discharging for a known time (2 hours) or to a target voltage (like 12.4V, maybe 12.0V, not lower). Do all your tests the same way and you can compare them. Except... this is problematic because these tests take hours and the temperature will change during the test. Without having a temperature controlled place to do this the battery is changing its properties during the test.

Trying to measure a battery that is attached to a car is a mistake. It is fine to see if it is "Good" or "Bad", but it isn't OK for making precise measurements of battery properties. Merely walking near the vehicle with a key fob in your pocket can cause the car to change the amount of current it is drawing from the battery. On our Prius "testing the battery" from the front jump point gives different values than testing on the posts with the battery detached from the car. That is an AGM battery, and it would fail the former and pass the latter. (And it was a nearly worthless test because the little testers are not at all precise when used on AGM batteries.)

We live in a hot environment, and water loss is the primary killer of batteries here. Many batteries these days cannot be serviced. Is a battery drying out? Electrical tests will hint at that, weighing the battery will answer the question. So I also suggest weighing a battery periodically. Each time use the same accurate digital scale and put the scale in the same place (on a spot of the floor, position on a table,) because tilt could be an issue if the scale is in a different place. Weigh it when it is brand new, and then once a year or so, pull it out, clean it off thoroughly, dry the outside, and weigh it again. The difference will be the amount of water lost from the battery (mostly, maybe a little acid will also have escaped).