JHZR2
Staff member
That is strange. But if the battery was in moor enough condition for you to see 11V, you probably were seeing some attempt to desulfate and cause some plate motion. 11v is not normal to start.
Battery Charger Testing Results
- Thread starter JHZR2
- Start date
AutoMechanic
Site Donor 2024
Great idea to test all of these out. I’ll be excited to see which ones do best. I probably need to get a new one sometime I’ve been using my dads Diehard that he bought from Sears in 1983 it still works excellent and isn’t showing signs of quitting but I want to get a back up one too because like you I have tons of cars lol 8 to be exact. Usually only 3 or 4 get driven a whole lot.
JHZR2
Staff member
No guarantees that we will know which one is “best”. But we will know a bit more about how they operate and how their logic is set up.
AutoMechanic
Site Donor 2024
I’ll be glad to see the results of those then.
Kudos for your efforts. Very interesting.
The degree of parasitic draw the vehicle has with the hood open, or after unlatching the hood and opening closing the doors can affect how quickly the surface charge voltage falls, perhaps affect the charger's logic, and the data collected and conclusions reached. Might be better to remove these variables if not too inconvenient.
Is this a battery that you can pull the caps dip ahydrometer to check specific gravity, to see if it really is full when the charger says it is?
This was my big beef with smart chargers. Specific gravity does not easily mislead, as open circuit voltage can and does.
If going this far are you also going to do load tests, both carbon pile and impedence testers to see before and after results, and whether improvement has occurred, one charger vs another on same battery, or if improvement on a known sulfated battery occurs?
Spending your time is almost as fun as spending others money
Starting the charger on a battery from a known well depleted state, often has far different results than starting it on a battery at relatively high states of charge. The battery requirements are also quite different when deep or shallowly cycled.
Most SLI batteries never see deep cycle usage intentionally, but long times parked during a pandemic can be considered a deep cycle, depending on the vehicle and the durations it is parked.
Lots of influencing variables are one reason why i went the high amperage adjustable voltage power supply route, as I deep cycle intentionally and insist on a true full charge as often as possible, as soon as possible.
I'll set a timer as a reminder to prevent too much time at absorption voltage, and the ammeter tells me if the time chosen was accurate or not.
The degree of parasitic draw the vehicle has with the hood open, or after unlatching the hood and opening closing the doors can affect how quickly the surface charge voltage falls, perhaps affect the charger's logic, and the data collected and conclusions reached. Might be better to remove these variables if not too inconvenient.
Is this a battery that you can pull the caps dip ahydrometer to check specific gravity, to see if it really is full when the charger says it is?
This was my big beef with smart chargers. Specific gravity does not easily mislead, as open circuit voltage can and does.
If going this far are you also going to do load tests, both carbon pile and impedence testers to see before and after results, and whether improvement has occurred, one charger vs another on same battery, or if improvement on a known sulfated battery occurs?
Spending your time is almost as fun as spending others money
Starting the charger on a battery from a known well depleted state, often has far different results than starting it on a battery at relatively high states of charge. The battery requirements are also quite different when deep or shallowly cycled.
Most SLI batteries never see deep cycle usage intentionally, but long times parked during a pandemic can be considered a deep cycle, depending on the vehicle and the durations it is parked.
Lots of influencing variables are one reason why i went the high amperage adjustable voltage power supply route, as I deep cycle intentionally and insist on a true full charge as often as possible, as soon as possible.
I'll set a timer as a reminder to prevent too much time at absorption voltage, and the ammeter tells me if the time chosen was accurate or not.
I doubt this highly... their marketing department, for one, wouldn't tolerate this, it would be labelled as 20. Your data on the 2-amp model shows a max of 2 amps. Or are you thinking of a pulse width on the order of undetectable milliseconds?
JHZR2
Staff member
Update; Added Battery Minder 12248 on Group 29 battery test @ 8A.
JHZR2
Staff member
Undetectible milliseconds. The solid state devices arent that expensive, its the thermal management and integration for constant power.
I had a good article on battery charger design that talked about the use of PWM (which is a standard practice in power converters, at high switching frequencies). I need to dig it up.
JHZR2
Staff member
Getting fancier now.
JHZR2
Staff member
I’m moving the testing to a group 29 dc battery. Don’t have the time, energy or materials to do a hydrometer test at this time. Though at some point it’s probably a good idea if I can open the caps.Kudos for your efforts. Very interesting.
The degree of parasitic draw the vehicle has with the hood open, or after unlatching the hood and opening closing the doors can affect how quickly the surface charge voltage falls, perhaps affect the charger's logic, and the data collected and conclusions reached. Might be better to remove these variables if not too inconvenient.
Is this a battery that you can pull the caps dip ahydrometer to check specific gravity, to see if it really is full when the charger says it is?
This was my big beef with smart chargers. Specific gravity does not easily mislead, as open circuit voltage can and does.
If going this far are you also going to do load tests, both carbon pile and impedence testers to see before and after results, and whether improvement has occurred, one charger vs another on same battery, or if improvement on a known sulfated battery occurs?
Spending your time is almost as fun as spending others money
Starting the charger on a battery from a known well depleted state, often has far different results than starting it on a battery at relatively high states of charge. The battery requirements are also quite different when deep or shallowly cycled.
Most SLI batteries never see deep cycle usage intentionally, but long times parked during a pandemic can be considered a deep cycle, depending on the vehicle and the durations it is parked.
Lots of influencing variables are one reason why i went the high amperage adjustable voltage power supply route, as I deep cycle intentionally and insist on a true full charge as often as possible, as soon as possible.
I'll set a timer as a reminder to prevent too much time at absorption voltage, and the ammeter tells me if the time chosen was accurate or not.
I don’t know that a load test will be very telling here, since esr is contingent upon temperature, SOC, etc. I am not controlling temperature.
Agree charging characteristics are different if deeply or shallowly charged. I’m pulling some charge out of the battery, but since I don’t have a well controlled cycled with fast DAQ, I’m not really in the business of super-scientific testing. This is about understanding what the charging profiles from different chargers look like, how they vary, etc. There absolutely are too many variables, and too many things that I don’t have the time, energy, materials, or inclination to do, which keeps this from being overly scientific. The fundamental interest here is if these chargers will charge a battery from a middling SOC, and how/what it looks like when they do.
Since my memory of how the Noco G7200 operates was rather flaky, I decided to pull it out and observe what it's doing. Granted, the battery was just about full already, so it went to 100% within just a few minutes. Once it got there, it started pulsing current, as can be seen in the video below. Voltage is still rising, but very slowly. I'll keep it plugged in for some time to see how far it'll climb. I'm assuming this current pulsing is normal and does not pose harm to the battery, even if done for extended periods of time?
Ambient temp about 50F.
Ambient temp about 50F.
JHZR2
Staff member
Take a look at my latest Battery Minder and CTEK MUS 4.3 testing, as it progressed and went to late stage/float. I even have zoomed in graphs. Lots of that up/down behavior. I suspect that it is another form of either PWM, limitation of the solid state switches (dont want to have another set in there to do the ultra low current), or some approach at desulfating.
Last edited:
Right. It looks like the amplitude of my current pulses is much higher than yours though. What is the frequency of your logging? Maybe that is masking actual current spikes? In my case, I'm guessing it pulses up to 2A, although my meter isn't fast enough to register it.
My CTEK 7002 behaves like your 4.3, with early termination of the constant current bulk phase, before the target voltage of 4.4V is reached.
Absorption phase is not constant voltage.
You mean like before it gets to 100%? Sorry I didn't capture that.
As far as float (or whatever stage it's currently in), I checked with another DMM (wired) and it shows pulses of 1.5A for about half a second, every 2 seconds, so that averages out to about 0.375A.
Regarding the stages, here is what the manual shows:
Because voltage continues to rise, my guess is it's in Optimization (7), and according to that little graph, that is the stage during which charging current is the lowest.
Last edited:
JHZR2
Staff member
Right. The graphic on the charger implies that it is, which is interesting too... though the manual graphic @Quattro Pete posted above seems to show that it is by design.
None of them seem to keep the CV at the high end. This is something that @wrcsixeight has talked about in various posts. The question is if it’s really an issue for an SLI battery in a car.
As I’ve mentioned before, I think there’s hesitance to keep voltage so high because of potential for gassing, and for the higher corrosion rates at elevated voltages. From a car integration perspective too, living at higher voltage results in higher stress on any capacitive element in the vehicle. So any constantlynhot electronics have marginally higher stresses.
Overall I’m not That concerned about the shift to a lower voltage. Especially if the maintenance setup ensures high enough voutage to prevent sulfation from being thermodynamically favorable..
FYI, I am now at 14.9V, and current pulsing continues. How high would you let it climb before pulling the plug?
It may be doing temperature compensation at 14.9V if its cold. I wouldn't worry about it unless I saw evidence of gassing.
The G7200 does not have automatic temp compensation function. It only has a manual "COLD" button/mode which the user needs to select if charging in cold weather. I did not select it because it's not all that cold in the garage right now.
I'm not too concerned about 14.9V with very little current going in. I was just asking how much higher would you let it climb? At what voltage level would you start getting concerned? 15.5V 16V? Higher?
