Battery Chargers - Garage Fun and Results

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I've gone a little OCD the past two months on chargers, since I had to replace my old motomaster charger that finally died. I dove into manuals, forums, and ultimately purchased several to observe their behaviors for myself.

Battery Chargers observed:
Noco Genius 3500
CTEK MUS 4.3
Erayak c9002
Schumacher SC3
Schumacher SC1
Battery Tender Junior

Out of all these chargers I've only returned one, the Noco. If you buy one I would highly recommend attaching a voltage meter to it for the first dozen cycles and watching carefully. I was surprised how inconsistent it was. The caution was raised when it was solid green on a wet cell, indicating the charging cycle was completed, and it was still pumping 14.88 volts. I left it for an hour hoping it would drop back to the previously observed 13.8 volts, it did not. The manual states when the solid green light is on the charger goes into maintenance mode, which should only monitor and charge when voltage drops below a certain threshold. My observations are that, in previous cycles in maintenance mode it was keeping a consistent 13.8 volts, indicating it was behaving similar to the CTEKs which hold a consistent 13.6 in stage 7 for up to 10 days before going into maintenance mode. The 'repair' mode also pushes a steady current of 15.8 volts for hours at a time. I could hear the boiling on the wet cells. Regardless of the 14.88v event, and the repair mode current, the observed behavior does not match the algorithm phases and status LEDs as explained in the manual.

That being said, the noco is a nice looking charger, with the parts/connectors and charger itself appearing to be very high quality. Maybe I got a bad one, or maybe the Noco was so wicked smart that it out smarted me and there is some explanation that reconciles the behavior of this charger.

I have spent hours watching and tracking the voltage patterns mapped against the documented algorithms for each charger. The most consistent, after dozens of charge cycles on multiple battery types, is the CTEK. The CTEK behaves exactly as the algorithm is explained in the manual. No deviation, ever.

The best value? The Schumacher chargers. $10 for a battery maintainer (SC1) and $20 for an 8 amp smart charger that both behave exactly as expected and get the job down well and safely. Both smart chargers, with simple 3/4 phase algorithms. The downside is they have fixed cables. So there is no option for interchangeable connectors. If you need ring terminals you will either need to splice in an SAE connector, or use another charger.

Of mention: the Battery Tender Junior algorithm was not what I was expecting. I was expecting it to behave just like the Schumacher SC1, which turns off all current immediately once it reaches 14.2 volts and only provides current again when voltage drops to 12.7 volts. You can clearly see the quick voltage drop from 14.2 when the SC1 turns off. The Tender Junior pumps a relatively steady current with the voltage bouncing between 14.2 and 14.6 initially and narrowing down to 14.5-14.6 volts for several minutes before it goes into maintenance mode. The voltage drop off was also noticeably slower indicating that it is potentially providing a small current to avoid back drain.

Anyway, it has been a fun learning experience for the reasonable price of approximately $200 (once the Noco was returned). I also now have a fleet of chargers, some of which I'll be lending to family/friends (hint: it won't be the CTEK), and hopefully this post will be helpful to others.

Happy Charging :p
 
Interesting information.

I am debating a tender for my bike.
I plan on riding regularly (never gets too cold for too long here), but may go a week or two without riding, so want to make sure it is topped up all the time.
Battery already had leads on the battery from previous owner, but no charger. I have an AGM battery so leaning toward the Battery Tender Plus (have read the Jr model is not quite up to par for AGM batteries).

I have had good luck with my Schumacher SE-1275A with many different batteries, and have hooked it up to the bike to make sure it is fully charged.
 
Thanks for doing that.

How would you compare the CTEK and the Schumacher? $20 is very good value for an 8 amp charger compared to the CTEK which is 4.3 amps.

I have the CTEK and am happy with it but ideally would have gotten a 20 amp charger since I have AGM batteries which I understand like the high amps.
 
Originally Posted By: webfors
The 'repair' mode also pushes a steady current of 15.8 volts for hours at a time. I could hear the boiling on the wet cells. Regardless of the 14.88v event, and the repair mode current, the observed behavior does not match the algorithm phases and status LEDs as explained in the manual.


Interesting write up, but current is measured in amps and voltage is in volts. Did you ever measure the current or just the voltage? If you just did the voltage, there's no way to be certain about the current and the amps it was pushing unless you also measured watts at the outlet, but then there'd be losses between the outlet and the other end of the charger.
 
Originally Posted By: CharlieBauer
Thanks for doing that.

How would you compare the CTEK and the Schumacher? $20 is very good value for an 8 amp charger compared to the CTEK which is 4.3 amps.

I have the CTEK and am happy with it but ideally would have gotten a 20 amp charger since I have AGM batteries which I understand like the high amps.


Two different chargers that I will use for different use cases. I'll use the Schumacher for my deep cycle RV batteries when I want a quick turn around. I will bring it with me on our adventures for when I have the pleasure of finding a 120v socket. I typically have two batteries with me when we're off grid. Also, since it has fixed cables I won't be using it as a long term maintainer, even though it is perfectly capable doing so.
 
Originally Posted By: Wolf359
Originally Posted By: webfors
The 'repair' mode also pushes a steady current of 15.8 volts for hours at a time. I could hear the boiling on the wet cells. Regardless of the 14.88v event, and the repair mode current, the observed behavior does not match the algorithm phases and status LEDs as explained in the manual.


Interesting write up, but current is measured in amps and voltage is in volts. Did you ever measure the current or just the voltage? If you just did the voltage, there's no way to be certain about the current and the amps it was pushing unless you also measured watts at the outlet, but then there'd be losses between the outlet and the other end of the charger.


Agreed, I should have used'for 15.8v'. The current is fixed on the Noco's repair mode at 1.5 amps.

I have an inline meter on the way and will be performing more observations when it comes in which will include all three variables. However, voltage tells 9/10ths of the story with "smart" chargers, since they are constantly changing current to hit and keep specific voltages. It will definitely be interesting to document the current is as exactly as spec'd. I'm looking forward to seeing the CTEK phase 4 current be modified. It keeps such a consistent voltage while decreasing current.
 
Originally Posted By: webfors
Out of all these chargers I've only returned one, the Noco. If you buy one I would highly recommend attaching a voltage meter to it for the first dozen cycles and watching carefully. I was surprised how inconsistent it was. The caution was raised when it was solid green on a wet cell, indicating the charging cycle was completed, and it was still pumping 14.88 volts. I left it for an hour hoping it would drop back to the previously observed 13.8 volts, it did not.

That does sound odd.

I have the G7200, and the few times that I monitored voltage, it was sitting around 13.6V towards the end of the charging cycle (100% LED still blinking), and then dropped to 13.0V once the 100% LED turned solid.

This was when using the "Norm" setting, not the "AGM/Cold". Ambient temp was around 70F.
 
Originally Posted By: Quattro Pete
Originally Posted By: webfors
Out of all these chargers I've only returned one, the Noco. If you buy one I would highly recommend attaching a voltage meter to it for the first dozen cycles and watching carefully. I was surprised how inconsistent it was. The caution was raised when it was solid green on a wet cell, indicating the charging cycle was completed, and it was still pumping 14.88 volts. I left it for an hour hoping it would drop back to the previously observed 13.8 volts, it did not.

That does sound odd.

I have the G7200, and the few times that I monitored voltage, it was sitting around 13.6V towards the end of the charging cycle (100% LED still blinking), and then dropped to 13.0V once the 100% LED turned solid.

This was when using the "Norm" setting, not the "AGM/Cold". Ambient temp was around 70F.




Agree it was strange. The algorithm, as I understood in the manual, was that a solid green LED indicates a fully charged battery and current is stopped until the voltage drops to a specific threshold. This was never observed in any cycle. It either pushed 13.8 consistently, or 14.88 as mentioned above (which threw the caution).

The NOCO manual is well written, with two obvious gaps. First the charging steps -> LED behavior mapping. I have no idea what charging step the charger is in when looking at the LEDs. Unlike the CTEK which identifies the steps directly via the LEDs on the top of the charger. This allows a direct one to one mapping of LED -> Step mapping and allows me to accurately confirm the algorithm behaves as documented. Second, while the max voltage for each mode is identified, it does not identify the thresholds that trigger a maintenance cycle. Since I did not observe the charger ever cutoff (as per the manual) I was not able to document what the bottom threshold is. Most likely between 12.6 and 12.8 volts like every other smart charger.

Looking at the modes/voltages explained in the manual, it's as if the charger was stuck in a 12v COLD/AGM (14.8 volts) active charging mode even though the LED stated it was completed and should have been in maintenance mode.
 
Originally Posted By: webfors
Agree it was strange. The algorithm, as I understood in the manual, was that a solid green LED indicates a fully charged battery and current is stopped until the voltage drops to a specific threshold.

Yeah, mine doesn't exactly do that either. When I check with my clamp meter, it looks like it's sending 1.5A pulses every 2 seconds or so. My clamp meter may not be quick enough to read it accurately, but there are definitely some current pulses going on.

Voltage is sitting at around 13.0-13.1V.

I agree, by looking at the lights, you don't know what it's doing... maintenance, or optimization, or something else.
 
Originally Posted By: Quattro Pete
Originally Posted By: maverickfhs
Thanks for all of this helpful information. Is CTEK, from HF(https://www.harborfreight.com/automatic-battery-float-charger-69955.html)?


Your link shows Centech.

This is the CTEK the OP was talking about:
http://a.co/dlAphkr



Makes sense, thanks for the clarification
smile.gif
 
Originally Posted By: webfors
Originally Posted By: Wolf359
Originally Posted By: webfors
The 'repair' mode also pushes a steady current of 15.8 volts for hours at a time. I could hear the boiling on the wet cells. Regardless of the 14.88v event, and the repair mode current, the observed behavior does not match the algorithm phases and status LEDs as explained in the manual.


Interesting write up, but current is measured in amps and voltage is in volts. Did you ever measure the current or just the voltage? If you just did the voltage, there's no way to be certain about the current and the amps it was pushing unless you also measured watts at the outlet, but then there'd be losses between the outlet and the other end of the charger.


Agreed, I should have used'for 15.8v'. The current is fixed on the Noco's repair mode at 1.5 amps.

I have an inline meter on the way and will be performing more observations when it comes in which will include all three variables. However, voltage tells 9/10ths of the story with "smart" chargers, since they are constantly changing current to hit and keep specific voltages. It will definitely be interesting to document the current is as exactly as spec'd. I'm looking forward to seeing the CTEK phase 4 current be modified. It keeps such a consistent voltage while decreasing current.


You mean you're also getting a watt meter so you can see the power draw of a particular device? Anyway thanks for the tip on the SC3, didn't know they even made that, the regular 8/10amp ones they make are always $30-$40. I have a cheap 2amp one now and don't really want to invest in another one as I think I've only used it twice in the last several years, but the next time I need one, I might just grab the SC3 at Walmart.
 
Originally Posted By: Wolf359
Originally Posted By: webfors
Originally Posted By: Wolf359
Originally Posted By: webfors
The 'repair' mode also pushes a steady current of 15.8 volts for hours at a time. I could hear the boiling on the wet cells. Regardless of the 14.88v event, and the repair mode current, the observed behavior does not match the algorithm phases and status LEDs as explained in the manual.


Interesting write up, but current is measured in amps and voltage is in volts. Did you ever measure the current or just the voltage? If you just did the voltage, there's no way to be certain about the current and the amps it was pushing unless you also measured watts at the outlet, but then there'd be losses between the outlet and the other end of the charger.


Agreed, I should have used'for 15.8v'. The current is fixed on the Noco's repair mode at 1.5 amps.

I have an inline meter on the way and will be performing more observations when it comes in which will include all three variables. However, voltage tells 9/10ths of the story with "smart" chargers, since they are constantly changing current to hit and keep specific voltages. It will definitely be interesting to document the current is as exactly as spec'd. I'm looking forward to seeing the CTEK phase 4 current be modified. It keeps such a consistent voltage while decreasing current.


You mean you're also getting a watt meter so you can see the power draw of a particular device? Anyway thanks for the tip on the SC3, didn't know they even made that, the regular 8/10amp ones they make are always $30-$40. I have a cheap 2amp one now and don't really want to invest in another one as I think I've only used it twice in the last several years, but the next time I need one, I might just grab the SC3 at Walmart.


Correct. I plan on installing an SAE connector on both inputs and outputs to simplify connections. Still thinking this through.

https://www.amazon.ca/Multimeter-DC6-5-100V-Amperage-Voltmeter-Measuring/dp/B01ESRBIJ2/ref=sr_1_1?s=hi&ie=UTF8&qid=1504892454&sr=1-1&keywords=dc%2Bamp%2Bmeter&th=1
 
There are a variety of different algorithms that get employed. Constant voltage, constant current, constant current to a voltage point then constant voltage until current drops to a certain level, etc., etc.

Sometimes the cell impedance determines how the battery is charged based upon the charger's rating. Some chargers do an equalization charge (higher voltage) depending upon how the battery took charge, or if the software is lousy, any time the battery is fully charged...

Too bad you didnt try any of the better chargers like battery minder, Solar prologix, Ampmatic, etc.
 
https://www.amazon.com/dp/B00C1BZSYO/ref=psdc_14244451_t2_B06Y5DDK6N

I have a few of these to employ on any charging source or most any load I have. I use Anderson 45 amp powerpoles as connectors and they are far superior to 12v SAE connectors, though the 45's are not so easy to crimp well without their special crimper.

I removed the 12awg leads from circuit board and instead used to 8awg to handle 40 amps continuous.

A lot of people put a lot of faith in an automatic charger, but these wattmeters or similar and a hydrometer on a flooded battery are really required to know what is really going on as most will revert to too low a voltage too soon, and some others like schumacher will blast a battery right past the mid 14s and have it gurgling and bubbling up a storm.

The green light only means the charger has stopped charging at absorption voltages, it does not indicate a truly fully charged battery.

Chargine a new depleted battery to full is way different than charging n abused capacity compromised battery to full, and if anyone believes their whizzbang ultra delux marketoscamo charger does what they want it to, well think again.

The last few % points are important for maintianing ultimate battery health, but 90% is certainly good enough to get the car started. Heck 50% could get the car started.

I've given up on automatic and use a 40 amp adjustable voltage power supply which I have modified with a better heatsinking and voltage adjustement. When my automatic chargers refse to complete the taskmy power supply and watt meters usually reveal I can stuff in 10 to 15% AH capacity into the battery.
 
Originally Posted By: JHZR2
There are a variety of different algorithms that get employed. Constant voltage, constant current, constant current to a voltage point then constant voltage until current drops to a certain level, etc., etc.

Sometimes the cell impedance determines how the battery is charged based upon the charger's rating. Some chargers do an equalization charge (higher voltage) depending upon how the battery took charge, or if the software is lousy, any time the battery is fully charged...

Too bad you didnt try any of the better chargers like battery minder, Solar prologix, Ampmatic, etc.


I looked at the BM 2012. I am considering buying one when I can find the right price. It isn't cheap. I found a vendor for the CTEK MUS4.3 on Amazon.com for $57. Any suggestions on a vendor for the BM?
 
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