12V Battery charger options

ld13

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(Mod Note: I posted this under the general Ekdsom/UPS etc. section, that happens to fall under Current Affairs - please feel free to move to Off Topic etc. as needed)

So I am starting to look at a 12V charger to charge up my SLA/AGM batteries. The first few results from Takealot kicked out these:
R157 - 2A Intelligent 12V Battery Charger
R355 - 6A Motoquip Battery Charger
R849 - 12A Motoquip Battery Charger

The cheapest one seems too cheap. The second one fits my budget, but bothers me as the 3rd one, also from Motoquip, has a review from someone stating:
This charger is just a transformer and a rectifier giving a fused supply through a meter. It's not a regulated supply and it has already destroyed a 7 a/h 12 volt battery.


This begs the question, firstly, why that is bad, secondly, if the 6A option is the same?
 

Neuk_

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Take a look at CTek or Optimate as an option, more expensive but widely used to maintain car, bike, truck, boat, batteries and are a lot more than just a charger.
 

ld13

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Optimate as an option, more expensive but widely used to maintain car, bike, truck, boat, batteries
I saw a random optimate one for R700 odd, but it was only 0.8A? That is going to take forever to charge a small battery, ain't it? But afaik they are the ones one can leave connected to a battery 24/7 without issues?
 

ld13

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I have two of the 3.8s and one 5A if I remember right.
But I got them on daily deals/specials etc, didn't pay that much.
See the 3.8 works out to ~R1300 and the 5A to ~R1500 on Amazon, with a UK plug.
 

Gordon_R

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Try some background reading:
An AGM battery is designed to be charged slow and low, and overcharging it can kill the battery itself. So, a normal battery charger can’t be used to charge an absorbent glass mat battery.

Most of the AGM battery chargers are equipped with microprocessors that collect information from the power cell to see its current charge status and to adjust the voltage and current accordingly.

However, there some battery chargers today designed to charge both lead-acid and AGM types of battery by having charging mode selection feature.

This feature allows a user to charge different types of battery by simply selecting the appropriate mode suitable for the type of battery they are going to charge.

Chargers like these can be very expensive but they can very useful if you have different types of batteries in your garage.
 

Gordon_R

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The OP doesn't state what sort of operation this is for, and the advice may differ depending on the application:
1. Fixed battery for backup power, permanently connected to charger.
2. Top-up battery charger for camping, etc.

For reference, our body corporate has a 33Ah SLA battery on permanent standby for the electronic gate system. The charger is a PSA008 Smart Battery Charger 8A, with 9 intelligent steps. This is widely used in the 4X4 community: https://www.4x4community.co.za/forum/showthread.php/230967-Discover-battery-and-PSA008-charger
 

ld13

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Try some background reading:
Extremely interesting. That would mean that a trickle charger or 0.8/2A charger at the correct voltage should be fine. But will investigate further.

The OP doesn't state what sort of operation this is for, and the advice may differ depending on the application:
1. Fixed battery for backup power, permanently connected to charger.
Alarm panel's battery went pop (it was old). The idea is to get two AGM/SLA batteries, one connected to the alarm and one on standby. With the longer load-shedding the alarm cannot charge the battery fast enough.

The backup battery does not need to be on the charger full time, but I guess that would be the better idea in the long run. I am also adding a voltage cutoff to the alarm system to protect the battery.

R1126.78 ain't too bad for their cheapest Smart 6 one. Worth a look.
 

PUP Backup

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The backup battery does not need to be on the charger full time, but I guess that would be the better idea in the long run.
Your backup battery (if it's not connected to anything) can stand on the shelf for a long time with no problem.
It will lose its charge slowly after a year or more but it can be recharged as and when.
I would not even keep a backup battery because it will die after 5 years (give or take) even if it isn't used!
That's the sad truth of lead acid batteries...
 

Paul_S

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Ctek ftw. I have 3 of them now
+1
CTek chargers rock.
You can leave them permanently connected to batteries and they will charge and maintain them without damaging them.

Much better than "semi intelligent" chargers which often kill batteries if left on trickle charge for long periods of time.
 

Sneeky

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CTek absolutely. Been using for years for my bikes.
For the bikes its really cool as it comes with an additional little lead and plug that you can connect directly to the battery and leave it there. Then whenever you need to charge its a simple process of just plugging in.
 

PUP Backup

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Not everyone agrees:
 

Neuk_

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I saw a random optimate one for R700 odd, but it was only 0.8A? That is going to take forever to charge a small battery, ain't it? But afaik they are the ones one can leave connected to a battery 24/7 without issues?
I use an Optimate 4 which if I remember correctly only supplied 0.8A but is perfectly fine for my MkI Golf which is connected 24/7 for long periods. As has been mentioned, it does a lot more than simply charging the battery.
 

PUP Backup

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With imported products like these I always worry about support.
The most you can expect is for the store to replace the unit if it's still has a warranty.
In my experience with these chargers you will not find informed technical support that local products have.
Remember that these are high power devices and the electronics works hard!
 

maumau

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With imported products like these I always worry about support.
The most you can expect is for the store to replace the unit if it's still has a warranty.
In my experience with these chargers you will not find informed technical support that local products have.
Remember that these are high power devices and the electronics works hard!
Support is definitely a concern with imported products.
 

Neuk_

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With imported products like these I always worry about support.
The most you can expect is for the store to replace the unit if it's still has a warranty.
In my experience with these chargers you will not find informed technical support that local products have.
Remember that these are high power devices and the electronics works hard!
I have had zero issues with my Optimate and have had it for years, probably 7 - 8 years. Despite this, I will get a Ctek when I need another or need to replace the Optimate, simply because the local importer of Ctek is a personal friend of mine.
 
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