I own both, a noco and a ctek. And I’ve seen the videos too. The noco is better made by a good margin. my ctek is wall mounted, but i mounted it with a metal plate behind it because it really does get too hot when it’s at its full meager 4 amps. If only the noco (10 amp) would output real current. It doesn’t. It’s so conservative in its strategy - does not really fully charge the battery. The 2 amp noco is probably their sweet spot.
Battery Charger Testing Results
- Thread starter JHZR2
- Start date
Just had a read through this thread. How safe is it to be leaving battery chargers/maintainers that are using the pulse/reconditioning feature when the battery is still connected to the car? I've always made it a habit to fully disconnect the car from the battery if I'm running those repair modes as I figure the voltage spikes can't be good.
Noco mentions in the instructions that vehicle electronics could be damaged using the restore or repair mode.
f355spider
$50 Site Donor 2024
Depends on the manufacturer, check/read the instructions for use.
I have had no issues long term using either a Granite Digital Save a Battery, or Battery Minder. I leave them connected for weeks and months at a time. Both have some sort of continuous pulse desulfation mode and cannot be turned off. I have a bluetooth monitor on my Ferrari that graphically tracks the voltage and I can see the spikes...they are not very large...I would say a couple tenths of a volt at most.
I cannot speak for other brands, so you would need to look at their alogrithm or call the manufacturer directly.
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How safe do you think it is leaving a smart charger on overnight on a regular basis? My truck has a small occasional drain I think, it will usually drop down to 80% or so state of charge within a week and down to 34% or so if it sits a full weekend unused sometimes. It does this even if I remember to unplug the elm327 obd2 BT adaptor every night.
f355spider
$50 Site Donor 2024
That is a common problem on most cars made in the last 15 years or so due to the ECUs having considerable parasitic loss. I have been leaving them connected on various cars with all sorts of tenders for over 20 years. Often for weeks or months. I have never had a problem.
All of them are intended to be left connected for months. Trickle chargers or versions without microprocessor control are the ones that can overcharge. Those are hard find anymore as they are very uncommon today.
I've had no problem leaving one of my Noco chargers indefinitely connected to maintain a battery. I have an 11 year old Optima Red top in my 2002 Trailblazer that sits for sometimes weeks in charge-maintenance mode.
However, the "Repair" mode comes with a caution. That was the question that "nobb" asked in post 162.
Per Noco:
CAUTION. USE THIS MODE WITH CARE. THIS MODE IS FOR 12-VOLT LEAD-ACID BATTERIES ONLY. THIS MODE USES A HIGH CHARGING VOLTAGE AND MAY CAUSE SOME WATER LOSS IN WET (FLOODED) CELL BATTERIES. BE ADVISED, SOME BATTERIES AND ELECTRONICS MAY BE SENSITIVE TO HIGH CHARGING VOLTAGES. TO MINIMIZE RISKS TO ELECTRONICS, DISCONNECT THE BATTERY BEFORE USING THIS MODE.
However, the "Repair" mode comes with a caution. That was the question that "nobb" asked in post 162.
Per Noco:
CAUTION. USE THIS MODE WITH CARE. THIS MODE IS FOR 12-VOLT LEAD-ACID BATTERIES ONLY. THIS MODE USES A HIGH CHARGING VOLTAGE AND MAY CAUSE SOME WATER LOSS IN WET (FLOODED) CELL BATTERIES. BE ADVISED, SOME BATTERIES AND ELECTRONICS MAY BE SENSITIVE TO HIGH CHARGING VOLTAGES. TO MINIMIZE RISKS TO ELECTRONICS, DISCONNECT THE BATTERY BEFORE USING THIS MODE.
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Yeah I agree. My 40 year old Oldsmobile, I left the battery in it for almost a month since I last drove it before I pulled it for winter. Charger showed it at 87% state of charge.
I'm just trying to extend the life of my truck battery by keeping it topped up. But also worried I might be overdoing it.
The smart charging logic in my truck keeps on letting it drop down a bit before it starts charging as well. If I top it up it runs at like 12.6v until finally jumping back up to 14.7+ once it drains down a bit.
Mine has a desulf mode, but it does it if it decides the battery has a problem. Last time the battery seemed to be failing when this happened. I think the charger squeezed another few months out of it before I got it replaced under warranty. It never left me stranded, I only knew there was a problem because of the smart charger. A Schumacher SC1323.
f355spider
$50 Site Donor 2024
You really can't "over do it" with a smart charging battery tender, as the algorithm prevents damage from over or under charging and should keep it at a good float voltage. Some have an algorithm where it lets a battery discharge slightly before it starts charging it back up again...they claim this "exercises" the battery. I don't own one of those, but that shouldn't hurt anything to leave constantly connected either.
My BMW M550iX and my Ferrari rarely get driven in winter, maybe once a month or less. Then they go right back on the battery tender.
My BMW 540 is daily driven and lately I connect it up almost every day when I return home. I only started doing this in the past 6 months...but the AGM battery is around 5 years old...but still tests at over its 900 CCA rating. It really can't hurt anything. I can't say for sure it is really helping either though. But I have a bunch of tenders and its super easy to connect up as the cig lighter is always active on it, and I have a cig lighter adapter on my battery tender. The door seals close around the cord no problem when connected.
Is it best to recondition the battery before or after charging?
f355spider
$50 Site Donor 2024
I doubt it matters, but you should consult with the user manual/IFU of the manufacturer.
The usual steps is to recondition after charging, as first you have to charge the battery and test it to confirm it needs the reconditioning process.
You have more trust in battery chargers than I do. Like all electronic devices they can fail, and they can damage your vehicles ECU and BCU. I will admit that this scenario seems to rarely occur in real life, based on the low number of hits I get with Google when searching this topic of vehicle damage from chargers. In the cold half of the year I charge my battery once a month, and always disconnect the battery from the vehicle. When I reconnect the battery, there is a very simple 20-sec reset procedure on my old Subaru. I have charged the battery a few times with it still connected to the vehicle, but it always makes me feel uneasy.
f355spider
$50 Site Donor 2024
Yup, I have no major concerns...been using them for over 20 years without incident. My Ferrari and BMW M550iX are continously connected also, so is my motorcycle with lithium battery. My Ferrari has a battery tender connection from the factory, it came with a Ctek, though I use a Battery Minder instead. My BMW M550iX calls out where to connect a battery tender in the owners manual, so they are aware customers use them. One cannot assume, but there may infact be protection from voltage spikes if manufacturers know and even provide battery tenders with the cars.
One thing I have seen is the battery tenders fail electronically and melt/smoke...seen a couple examples online and a post on a Ferrari forum. For that reason, I have mine wall mounted, not on the car floor. My garage has a smoke alarm and two fire extinguishers, one is Halon.
In the universe of possibilities, any number of things can and will fail. Everyone has to figure out their risk level. I've had friends have car batteries explode, engines catch fire, etc...stuff happens. Make sure you are prepared and insured.
I remember working at the GM dealer, a truck came into the drive thru where myself and 2 other service advisors worked out podiums. This guy drove his truck in and when it went to start up to drive out...the battery blew up with a bang! It was still under warranty and the other service advisor and I were arguing with the shop foreman because he didn't want to warranty it "because the guy had to have tried to boost it while frozen, they don't just blow up". We told him we literally heard it blow up and it had driven in fine.
I tried figuring out the smart charging in my 08 Silverado back when I had it. I think it measures how much the battery dips while cranking. If it dips a lot, it figures it needs a healthy charge. I've seen 15.4 volts in the winter.
So if one were to top off their battery independently, the truck thinks everything's fine, and gives a half hearted charge attempt.
I think it may also taken ambient temp into account but I notice that even if I charged it to 100% if it's fairly cold out it will at least charge 14v for a little while. I don't know this for sure though.
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@JHZR2
For the noco chargers, do you have an idea of how long it might have taken to go from the optimize phase (flashing green) to the full soc (solid green)? Would it also be unwise to leave the charger on the battery to achieve the full soc, or unplug once it has finished bulk charging (75% soc)
I am considering getting a genius 1 amp for off vehicle charging on 12volt batteries
For the noco chargers, do you have an idea of how long it might have taken to go from the optimize phase (flashing green) to the full soc (solid green)? Would it also be unwise to leave the charger on the battery to achieve the full soc, or unplug once it has finished bulk charging (75% soc)
I am considering getting a genius 1 amp for off vehicle charging on 12volt batteries
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It varies on the battery condition, I believe.
My abused plow truck’s battery takes about eight hours to go from “breathing” green to solid; my daily driver about 40 minutes. This is using the Genius 5 charger.
That would be unwise. Lead acid batteries should be maintained at 100% SOC to prevent irreversible sulfation of the "active material", which leads to capacity loss and shortened service life.
