"Large" parasitic loads - what affect on "smart" battery maintainers?

[rlaggren]

This train of thought began when I got impatient with the Pro-logix "resting" for hours as voltage dropped ever so slowly from 12.8 down through 12.778, 12.775, 12.771... I had been hoping to see it do an "exercise" cycle and decided to hurry things up a little by connecting an inverter on idle. I didn't take a thought and forgot about the inrush current for the caps - there was a nice sparkler affect. When I got that sorted I looked at the Pro-logix and based on the solid "charge" light, it had started a normal charge cycle. So it looks like it went from creeping down to an "exercise" cycle to cutting straight to the case and doing a regular "charge" cycle. Well and good, that sems like reasonable behavior. Probably the inverter inrush dropped the battery terminal voltage way down for a fraction of a second.

Now it seems to be cycling noticeably more slowly through the voltage steps of the charge cycle. Which probably makes sense with the idle current of the inverter and my volt meter eating part of its available charging amps. Unfortunately I don't have the instruments to check the charge current. At a gross guess the cheap 1800w inverter could idle at anywhere from 300-600 mA, maybe more. With the current to power the LED meter that's connected across the battery (500-600 mA for five 8-segment digits; at least from my quick research), good chance that's more than 1 amp - a big bite out of a 4amp max charging current.

Ok. It has been 3 hours or so and it looks like I'm not seeing an "exercise" period tonight. Has to get the batt charged and shut off before the voltage can draw down to trigger any exercise.

So with time to think (!), I then started wondering about what a parasitic draw of, say, 1.5amps would do to the maintainer programming after it had got the battery charged and stopped providing and amps during the "resting" phase. Maybe it will just slow life down a lot because the 4amp maintainer has now been effectively reduced to, maybe, a 2-1/2amp maintainer. But is it that simple?

I haven't come up with any obviously right ideas. The voltages I'm seeing across the battery (with the inverter connected and idling) seem very similar to what I observed on previous charging cycles with just the meter across the battery. They just seem to be taking longer. But I'm not sure about what this means to the low levels of current programmed for completion and resting phases. Will the maintainer increase output in those final stages to compensate for the larger draw and maintain the very low, tending to zero "resting" current? Will the charge cycle ever hit set point and end?

Not going to find out tonight. It seems to be settled around 12.35n volts, green lit, charge flashing, ticking the volts up one mV per 15-20min or so.

 

[rlaggren]

Checked it around 2am and Pro-logix was once again starting a full charge cycle. It looks like at some value of constant battery drain, maybe above 1amp, the smart charger/maintainer will never stop charging. It seems to fall back into "absorbtion" from "completion" instead of going on to "resting" phase.

It appears to me that the charger uses voltage points to determine it's behavior. Maybe it stops charging for a few seconds or minutes on a timed basis and checks the voltage w/out any charge current. I can see where removing the charge voltage could allow the current draw to lower the battery voltage to the point where the Pro-logix resets and starts the charge over. (?)

IAC, I may have to rethink my maintainer plans, depending on what actual constant draw my system will place on the battery. This is for a boat and there are some electronic water sensors and alarms that function always as well as pumps that may come on occasionally. The pumps probably don't present a problem because their activation should be rare and kicking the charger back into "absorbtion" once a week should be fine. Provided the maintainer can handle the full parasitic load and complete its cycles without falling into a constant high voltage loop.

I know some of this relates directly to battery size v. the load because the parasitic load would lower voltage on a large battery less than on a small one. This would make it more likely that the Pro-logix programming would operating as intended. I had hoped that the battery could be charged after some larger load (pump, inverter, whatever) reach "resting" and then (barring other large loads) kick down into "exercise" phase when needed. I would be ok with "exercise" once, maybe even more, a day. But I don't like the Pro-logix cycling between absorbtion at 14.6v and "completion" 13.4v constantly forever. Which is what it seems to want to do with a large parasitic draw.

I'm going to get serious about a new meter that includes amps - hopefully a clamp meter which will double as an accurate volt meter. Onward.

 

[rlaggren]

Ah, I just noticed I mislabeled the Pro-logix phases. When I said "absorbtion" it s/have been "fast charge" (called "bulk" in most references I've read). Where I said "completion" it s/have been "absorption". Too late to edit.

And "completion" in Pro-logix lingo would be "float" in most other parlance. But I guess they changed it cuz they shut off the amps completely (eventually) in this phase instead of doing a slow continuous trickle of "float". Oh well.

Long day still going.

 

[wrcsixeight]

Attempting to use a smart charger, as a constant voltage power supply, can be a time wasting lesson in frustration.

Most 30 amp 12vDc LED power supplies have an little voltage adjustment potentiometer with a range from ~11.5 to 15v.
just dont hook them to a healthy, well depleted Battery with voltage set high, as most will exceed their 30 amp rating, and release the magic smoke, in a few minutes.

Amazon.com

 

[f355spider]

Most battery maintainers when in the "maintenance" mode are keeping the battery at a steady voltage, its still charging, but usually at a milliamp rate. It can vary depending on the brand and algorithm. Some have temperature compensation to raise or lower this voltage (higher when cold, lower when warm ambient temperatures).

Pro Logix takes a different tactic and once it reaches its charge point, it will STOP CHARGING and allow the battery to self discharge to some programmed voltage, then start charging again. How often it charges would depend on the rate of self discharge of the battery itself, as well as the what parasitic draw the car, boat, whatever has as well.

So during the "resting" phase it is not charging...nor is it during the "excercise" phase.
Please look at the sales literature with a graph showing what it is doing during each phase:

https://cloreautomotive.com/wp-content/uploads/2022/01/4.0-Amp-612V-Intelligent-Battery-Charger-Maintainer-2.pdf

From my experience of reading the various literature of battery maintainer manufacturers, only a few stop charging completely like this and have a resting and/or exercising phase, then recharge. It is interesting and may be beneficial, but some users have concerns when they require immediate use, and the mainainter is near the end of this resting or exercise phase, the battery may not be in an ideal state of charge.

 

[J Dubbs]

I like the idea of a charger that shuts off, then comes back on at a predetermined lower voltage vs a constant current float charge strategy. I've never had a "float style" maintainer not eventually boil the water out of my sealed AGM batteries... and even my flooded ones with accessible caps, if I didn't stay on top of their water levels.

It was especially bad with smaller power sports AGM batteries, even using 1.5 amp and smaller maintainers. I now just monitor my batteries and charge when needed. I've extended my batteries lives and cut down on the water level checks that way... plus I can rest easier knowing I don't have to cross my fingers and "hope" the maintainers are actually doing their jobs, and not "going off the reservation" as Uncle Dave would say

I've had too many maintainers let me down over the years to blindly trust anymore ¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯

 

[rlaggren]

Thanks for all the thoughts.

I'm not really trying to use the maintainer as a 12vdc source. Up to this point I've used a DC supply while I'm onboard because I leave for 3-8 months at a time and that trashed the battery(s) early on. Until recently, that didn't matter, but now I'd like get back to a "live" system, hence the Pro-logix maintainer.

Also, I am now in the process of adding some, hopefully small, parasitic loads - 2-300mA? The LED volt meter is going to get a momentary contact switch so those little glowing digits don't draw 500mA+ all the time. But he exact load is TBD - maybe 2-300mA? Less? I think and hope that 2140 will deal with that easily, but TBH, I didn't think of it until the LED meter and the idling inverter started the Pro-logix looping between bulk and absorption constantly. The inverter will not be on unless in use and that rarely, but it started me on figuring out what parasitic loads might do to the charge cycle.

Also, I want to see my Pro-logix do each cycle (including "exercise") so I can be sure it's functioning as advertised.

JHZR2, bless him, has added immeasurably to our knowledge of smart chargers with his testing and recording. If I understand his graphs, the Pro-logix 2320 he tested did not do an "exercise" cycle until nearly 6 days after going into "resting". It looks like it kicked off the "exercise" when the batt had reached about 12.9vdc. My new Interstate batt has presently reached 12.84 with no "exercise" cycle and IIRC, on one of the earlier charge/discharge cycles I did, it reached 12.75vdc with no "exercise" (I got impatient and restarted it). Now that begs the Q whether my 2140 unit is defective or whether there is some kind of timer controlling the "exercise" instead of or in addition to the voltage level. Or something.

Next work week I'm going to try to reach a person at the manufacturer who can hopefully understand and answer this Q. Meanwhile, the batt with the LED meter drawing 500+mA and the maintainer on is dropping about .1vdc every 4 hours - so maybe time will tell.

 

[f355spider]

One advantage of the more expensive Pro Logix is they add a voltage meter

10/6/2 Amp 6/12V Intelligent Battery Charger / Maintainer - Clore Automotive

Combining fully automatic operation and the ability to properly charge multiple battery types, the PRO-LOGIX PL2310 is the perfect charger to meet the needs of today’s and tomorrow’s professional technician. Intelligent, beneficial, safe and versatile – one charger does it all, from fast...

cloreautomotive.com

One thing you could do, that would give you more information, is add an inexpensive bluetooth battery monitor.
I have one, and it allows me to monitor voltage out to 15 days as it records the data. It graphically displays voltage and the charging phases.

Vgate Battery Tester Analyzer 12V BLE Car Battery Monitor Bluetooth 4.0 Device | eBay

Find many great new & used options and get the best deals for Vgate Battery Tester Analyzer 12V BLE Car Battery Monitor Bluetooth 4.0 Device at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[SubLGT]

Most battery maintainers when in the "maintenance" mode are keeping the battery at a steady voltage, its still charging, but usually at a milliamp rate. It can vary depending on the brand and algorithm. Some have temperature compensation to raise or lower this voltage (higher when cold, lower when warm ambient temperatures).

Pro Logix takes a different tactic and once it reaches its charge point, it will STOP CHARGING and allow the battery to self discharge to some programmed voltage, then start charging again. How often it charges would depend on the rate of self discharge of the battery itself, as well as the what parasitic draw the car, boat, whatever has as well.

So during the "resting" phase it is not charging...nor is it during the "excercise" phase.
Please look at the sales literature with a graph showing what it is doing during each phase:

https://cloreautomotive.com/wp-content/uploads/2022/01/4.0-Amp-612V-Intelligent-Battery-Charger-Maintainer-2.pdf

From my experience of reading the various literature of battery maintainer manufacturers, only a few stop charging completely like this and have a resting and/or exercising phase, then recharge. It is interesting and may be beneficial, but some users have concerns when they require immediate use, and the mainainter is near the end of this resting or exercise phase, the battery may not be in an ideal state of charge.

My OptiMate 6 Select charger float voltage is temperature compensated, and is 13.6V at 68F. The float duty cycle is 50%, with voltage applied for 30 minutes, then a rest period of 30 minutes. Float current is pulsed, up to 600mA.

 

[f355spider]

My OptiMate 6 Select charger float voltage is temperature compensated, and is 13.6V at 68F. The float duty cycle is 50%, with voltage applied for 30 minutes, then a rest period of 30 minutes. Float current is pulsed, up to 600mA.

That is probably a good compromise between the Pro Logix and the traditional constant milliamp charge of most maintainers.

 

[rlaggren]

> bluetooth batt monitor
Spider, that looks like a great idea. I'll begin the search, starting with your link.

I talked with Clore/Pro-logix this afternoon and was totally underwelmed. The lady I spoke with did not seem to know the the phases listed in the manual, could not find what triggered the "exercise" phase which she insisted was a "maintain" phase, and continued to refer to a "float" charge which the manual explicitly states is not what the Pro-logix does. She went off to talk with somebody and came back saying the charger wakes up when the voltage drops to 12.6... or maybe 12.5. This does not match with the tested result on page one where the re-up charge begins at about 12.7. There does not seem to be any understanding or knowledge on the phone at the corporate office. She also said the charger monitors the voltage constantly which again is not what the manual says. I _was_ happy to get a human w/in a couple minutes, but...

Very disappointing. I'll leave the charger on the batt which is discharging through the meter and hope to see the maintenance wake-up in a day or two when it gets down to 12.5. But that voltage seems low for keeping an AGM ready for service.

I'm looking around and here for your viewing pleasure is a very opinionated marine electrician shameless pushing Victron. Which is PROGRAMMABLE! He apparently got burned pretty good by Noco chargers and doesn't hold back about that. Look around the site and see if you think he's got smarts.

Choose Your Battery Chargers Carefully

The Victron IP-65, IP67 are the best values in marine chargers under 30A.

marinehowto.com

 

[JHZR2]

This train of thought began when I got impatient with the Pro-logix "resting" for hours as voltage dropped ever so slowly from 12.8 down through 12.778, 12.775, 12.771... I had been hoping to see it do an "exercise" cycle and decided to hurry things up a little by connecting an inverter on idle. I didn't take a thought and forgot about the inrush current for the caps - there was a nice sparkler affect. When I got that sorted I looked at the Pro-logix and based on the solid "charge" light, it had started a normal charge cycle. So it looks like it went from creeping down to an "exercise" cycle to cutting straight to the case and doing a regular "charge" cycle. Well and good, that sems like reasonable behavior. Probably the inverter inrush dropped the battery terminal voltage way down for a fraction of a second.

Now it seems to be cycling noticeably more slowly through the voltage steps of the charge cycle. Which probably makes sense with the idle current of the inverter and my volt meter eating part of its available charging amps. Unfortunately I don't have the instruments to check the charge current. At a gross guess the cheap 1800w inverter could idle at anywhere from 300-600 mA, maybe more. With the current to power the LED meter that's connected across the battery (500-600 mA for five 8-segment digits; at least from my quick research), good chance that's more than 1 amp - a big bite out of a 4amp max charging current.

Ok. It has been 3 hours or so and it looks like I'm not seeing an "exercise" period tonight. Has to get the batt charged and shut off before the voltage can draw down to trigger any exercise.

So with time to think (!), I then started wondering about what a parasitic draw of, say, 1.5amps would do to the maintainer programming after it had got the battery charged and stopped providing and amps during the "resting" phase. Maybe it will just slow life down a lot because the 4amp maintainer has now been effectively reduced to, maybe, a 2-1/2amp maintainer. But is it that simple?

I haven't come up with any obviously right ideas. The voltages I'm seeing across the battery (with the inverter connected and idling) seem very similar to what I observed on previous charging cycles with just the meter across the battery. They just seem to be taking longer. But I'm not sure about what this means to the low levels of current programmed for completion and resting phases. Will the maintainer increase output in those final stages to compensate for the larger draw and maintain the very low, tending to zero "resting" current? Will the charge cycle ever hit set point and end?

Not going to find out tonight. It seems to be settled around 12.35n volts, green lit, charge flashing, ticking the volts up one mV per 15-20min or so.

Why don’t you read through the analysis and data gathering I’ve done on a number of chargers. I believe I did my pro logix and got it to get to a maintenance or exercise cycle.

I have some in the where my car was waking up for some reason, etc. They tend to keep trucking.

My 98 S-10 has a “parasitic” that I can’t find. I keep it on a maintenance charger permanently. Have for the last 15 years. No issues.

 

[JHZR2]

That is probably a good compromise between the Pro Logix and the traditional constant milliamp charge of most maintainers.

I’ve been underwhelmed by those. Get a real data logging multimeter if you want good data.

 

[rlaggren]

JHZR2
I read through your test (and thank you much) about a month ago and reread a few - in particular the Pro-logix. Your graph was part of what decided me on the brand. What I am doing is trying verify that the thing is operating as promised. My experience with electronics, any/all electronics, purchased over the last 10+ years, is a 5%+ problem rate. Ranging from DOA to software which does not perform according to spec (middle high ASUS router) to overheating at spec duty cycle to intermittent restarts, to... Thus I try to verify as possible before I put anything in service and "walk away". If the Pro-logix does the right thing before hitting 12.4v, I'll keep it and think about the voltage setpoints for a while. I have a full schedule here for at least a month so I'm hoping it will turn out workable. The real test is the battery when I return from the next 3-6 month trip to Chicago for house maintenance.

Your tests also sent me looking for a good DMM. I like the way you used the blue things, whatever they were, for the testing, and they have adequate reviews. But I didn't want to invest for, what was it, 10k data points; your kind of monitoring is going to be a work in progress. I did get a standard DMM clamp meter from a guy in Australia. A Brymen BM036 IIRC, which is on the way.

 

[f355spider]

> bluetooth batt monitor
Spider, that looks like a great idea. I'll begin the search, starting with your link.

I talked with Clore/Pro-logix this afternoon and was totally underwelmed. The lady I spoke with did not seem to know the the phases listed in the manual, could not find what triggered the "exercise" phase which she insisted was a "maintain" phase, and continued to refer to a "float" charge which the manual explicitly states is not what the Pro-logix does. She went off to talk with somebody and came back saying the charger wakes up when the voltage drops to 12.6... or maybe 12.5. This does not match with the tested result on page one where the re-up charge begins at about 12.7. There does not seem to be any understanding or knowledge on the phone at the corporate office. She also said the charger monitors the voltage constantly which again is not what the manual says. I _was_ happy to get a human w/in a couple minutes, but...

Very disappointing. I'll leave the charger on the batt which is discharging through the meter and hope to see the maintenance wake-up in a day or two when it gets down to 12.5. But that voltage seems low for keeping an AGM ready for service.

I'm looking around and here for your viewing pleasure is a very opinionated marine electrician shameless pushing Victron. Which is PROGRAMMABLE! He apparently got burned pretty good by Noco chargers and doesn't hold back about that. Look around the site and see if you think he's got smarts.

Choose Your Battery Chargers Carefully

The Victron IP-65, IP67 are the best values in marine chargers under 30A.

marinehowto.com

This is very interesting, thank you for sharing. I see they are sold through a number of online outlets as well. ($90 for the IP65 on Amazon)
Here is a link to the sales brochure: https://www.victronenergy.com/upload/documents/Folder-A5-Blue-Smart-IP65-Charger-120V_EN_web.pdf

Operators manual with good details of the entire charging cycle algorithm: https://www.victronenergy.com/upload/documents/Manual-Blue-Smart-IP65-Charger-120V-EN-FR-ES.pdf

 

[rlaggren]

Happy to report that the Pro-logix PL2140 kicked into action after the batt drifted down to 12.71-12.72. I missed the wake-up, so I can't say how it began; I noticed the voltage at 13.31 and rising (slowly). Amber LED flashing, Green LED solid = "completion" according to their graph and chart. Now I let it run to see what voltage it will consider done and good, post that here in a few hours. Call it "good enough" and install the thing with the new batt and proper breakers etc. Bit longer road than expected, but seem to have arrived.

 

[J Dubbs]

Happy to report that the Pro-logix PL2140 kicked into action after the batt drifted down to 12.71-12.72. I missed the wake-up, so I can't say how it began; I noticed the voltage at 13.31 and rising (slowly). Amber LED flashing, Green LED solid = "completion" according to their graph and chart. Now I let it run to see what voltage it will consider done and good, post that here in a few hours. Call it "good enough" and install the thing with the new batt and proper breakers etc. Bit longer road than expected, but seem to have arrived.

That's how my Noco works as well... I like that method way better than a constant float voltage that may or may not be good for my batteries. I haven't had good experiences with charger/maintainers that "floated" my batteries for extended periods of time, they either undercharged them and they sulphated, or (mostly) overcharged them and boiled the water out... so I stopped using them.

I've actually had the best results by just checking my batteries regularly with a mm and charging when needed. That's how I've got the longest life

It says on Noco's website, and I believe Pro-Logix says it as well, that they purposely don't float charge because they found it to be bad for the batteries, the same thing I've found out lol.

But if I was going to leave a charger on a battery it would be a Noco or Pro-Logix

 

[f355spider]

That's how my Noco works as well... I like that method way better than a constant float voltage that may or may not be good for my batteries. I haven't had good experiences with charger/maintainers that "floated" my batteries for extended periods of time, they either undercharged them and they sulphated, or (mostly) overcharged them and boiled the water out... so I stopped using them.

I've actually had the best results by just checking my batteries regularly with a mm and charging when needed. That's how I've got the longest life

It says on Noco's website, and I believe Pro-Logix says it as well, that they purposely don't float charge because they found it to be bad for the batteries, the same thing I've found out lol.

But if I was going to leave a charger on a battery it would be a Noco or Pro-Logix

Interesting. I posted in another thread that my Battery Minders are supposed to float at 13.6vt and temperature compensate higher or lower based on ambient temperature. I noted it was lower than this and called their technical support and they admitted they changed the algorithm a year or two ago (and never updated the manuals and infact still publish on their website the 13.6vt). They claim the new algorithm floats at 13.2vt and then is temperature compensated up/down based on ambient temp. My testing confirms that figure of 13.2vt. They said the change was necessitated by complaints from customers of boiling electrolyte and resulting fluid loss in flooded batteries. But that doesn't explain why they did this for their AGM versions too.

I've always heard that 13.6vt was the ideal target float voltage for flooded and AGM batteries....is that not the case, or not for long term storage?

 

[SubLGT]

I've always heard that 13.6vt was the ideal target float voltage for flooded and AGM batteries....is that not the case, or not for long term storage?

I haven't heard that. Charger manufacturers have their own ideas about float charging. Battery Tender says 13.3-13.5V is ideal. Other manufacturers disagree.

Float/Maintenance Charging: Is it really necessary?

www.batterytender.com

Mainstream automotive battery manufacturers like East Penn, Clarios, etc don't provide detailed charging instructions. Odyssey provides good information about charging their AGM batteries. They recommend 13.6V at 77F for float charging, with temperature compensation.

Some industrial battery manufacturers, such as Rolls, provide a wealth of information on charging and maintenance of flooded and AGM batteries.

Battery Charging

support.rollsbattery.com

Trojan Battery | Battery Maintenance

The key to achieving optimum performance and long battery life is to follow a regular care and maintenance program. Read our tips for high performance battery maintenance.

www.trojanbattery.com