Trickle charger

elevensies

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Resistivity (measure in ohms) is directly linked to current and voltage, hence ohm's law V=IR. A smart charger (such as the ctek) can alter the current flow into the battery, as well as the voltage.

I can see that a damaged battery will be MORE damaged by a charger, but can't see a healthy one being 'killed' by a smart charger.
i agree, yet i have to wonder....batteries today, are not made like they used to be im convinced, im double convinced, so is a modern trickle charger really helping??

i still have 3 of the things, the ctec one is used for the mustang, the others are for bikes, but they rarely get used.
 

Pond

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Spaldingski, Lincs
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yet i have to wonder....batteries today, are not made like they used to be im convinced, im double convinced, so is a modern trickle charger really helping??
No they are not made like they used to be.....
They are far, far, better.
They don't leak and rot your car in a week like they used to
They hold massively more electricity than they used to
They have to do much, much more work than they used to
AGM (and other) technology mean they have huge cranking amperage and can start a high compression engine in milliseconds unlike they used to
They generally last a lot longer than they used to (most cars were on the scrap heap before a modern battery needs replacing)

And Li-ion and new technologies make them even better. Look at the advances recently in EVs.
 

Nodzed

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Zephyr

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Reviving this thread.
one of my cars has an AGM battery and I am wondering if I need a special AGM charger for that.
I do have one that has an AGM button, but is a very big one and would prefer to use my good old CTek in hibernation mode as it seats neatly under the bonnet (hood) and I can keep it shut when the car is parked.

Also, the instrucrions on how to charge that make zero sense to me.
Why do all that and not just use the designated spots (positive on battery and negative on the strut tower)?

How to charge an AGM battery
Before anything, take off any jewelry, put on safety glasses and go to a well-ventilated area or outdoors.

  1. Plug in your AGM-compatible battery charger. Follow any other instructions for your specific charger.
  2. Connect a backup power supply to the onboard diagnostics OBD-II Port.
  3. Disconnect the car’s negative terminal and wrap it with a glove, rag or anything to prevent it from touching any metal. The negative cable is usually black, but you can also look for a minus (-) symbol on the cable as well.
  4. IMPORTANT: Select AGM or Absorbed for the battery type on your charger. A smart charger may detect the voltage and battery type when you connect it, but don’t leave it to chance. Select 12 volts to match the voltage of your AGM battery.
  5. Connect the charger to your car battery posts. Again, check the indicator lights and make sure they’re set to AGM or Absorbed.
  6. Start the charger and wait two to eight hours to fully charge your AGM battery.
  7. Disconnect the charger from the battery when it’s done. Your charger’s indicator light will signal when it’s done charging the battery. Again, avoid letting the charger’s clamps touch the battery’s loose negative clamp.
  8. Reconnect the car’s negative terminal to the battery. Disconnect the backup battery. Now you’re ready to hit the road with a fresh start.
All this seems quite confusing and pretty "black magic" stuff. Up to today, it was, pop the bonnet, connect, forget.
Why do this ritual and why can't I use a simple charger for AGM?
 

B21

Zorg Legend
British Zeds
Joined
Oct 1, 2023
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Scottish Borders
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E89 35is
Reviving this thread.
one of my cars has an AGM battery and I am wondering if I need a special AGM charger for that.
I do have one that has an AGM button, but is a very big one and would prefer to use my good old CTek in hibernation mode as it seats neatly under the bonnet (hood) and I can keep it shut when the car is parked.

Also, the instrucrions on how to charge that make zero sense to me.
Why do all that and not just use the designated spots (positive on battery and negative on the strut tower)?

How to charge an AGM battery
Before anything, take off any jewelry, put on safety glasses and go to a well-ventilated area or outdoors.

  1. Plug in your AGM-compatible battery charger. Follow any other instructions for your specific charger.
  2. Connect a backup power supply to the onboard diagnostics OBD-II Port.
  3. Disconnect the car’s negative terminal and wrap it with a glove, rag or anything to prevent it from touching any metal. The negative cable is usually black, but you can also look for a minus (-) symbol on the cable as well.
  4. IMPORTANT: Select AGM or Absorbed for the battery type on your charger. A smart charger may detect the voltage and battery type when you connect it, but don’t leave it to chance. Select 12 volts to match the voltage of your AGM battery.
  5. Connect the charger to your car battery posts. Again, check the indicator lights and make sure they’re set to AGM or Absorbed.
  6. Start the charger and wait two to eight hours to fully charge your AGM battery.
  7. Disconnect the charger from the battery when it’s done. Your charger’s indicator light will signal when it’s done charging the battery. Again, avoid letting the charger’s clamps touch the battery’s loose negative clamp.
  8. Reconnect the car’s negative terminal to the battery. Disconnect the backup battery. Now you’re ready to hit the road with a fresh start.
All this seems quite confusing and pretty "black magic" stuff. Up to today, it was, pop the bonnet, connect, forget.
Why do this ritual and why can't I use a simple charger for AGM?
AGM has a different physical structure..resulting in different float voltage requirements..so if you use a normal non AGM charger it will either under or over cook it..can’t remember without looking it up..simples..
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project and E89 Z4
Reviving this thread.
one of my cars has an AGM battery and I am wondering if I need a special AGM charger for that.
I do have one that has an AGM button, but is a very big one and would prefer to use my good old CTek in hibernation mode as it seats neatly under the bonnet (hood) and I can keep it shut when the car is parked.

Also, the instrucrions on how to charge that make zero sense to me.
Why do all that and not just use the designated spots (positive on battery and negative on the strut tower)?

How to charge an AGM battery
Before anything, take off any jewelry, put on safety glasses and go to a well-ventilated area or outdoors.

  1. Plug in your AGM-compatible battery charger. Follow any other instructions for your specific charger.
  2. Connect a backup power supply to the onboard diagnostics OBD-II Port.
  3. Disconnect the car’s negative terminal and wrap it with a glove, rag or anything to prevent it from touching any metal. The negative cable is usually black, but you can also look for a minus (-) symbol on the cable as well.
  4. IMPORTANT: Select AGM or Absorbed for the battery type on your charger. A smart charger may detect the voltage and battery type when you connect it, but don’t leave it to chance. Select 12 volts to match the voltage of your AGM battery.
  5. Connect the charger to your car battery posts. Again, check the indicator lights and make sure they’re set to AGM or Absorbed.
  6. Start the charger and wait two to eight hours to fully charge your AGM battery.
  7. Disconnect the charger from the battery when it’s done. Your charger’s indicator light will signal when it’s done charging the battery. Again, avoid letting the charger’s clamps touch the battery’s loose negative clamp.
  8. Reconnect the car’s negative terminal to the battery. Disconnect the backup battery. Now you’re ready to hit the road with a fresh start.
All this seems quite confusing and pretty "black magic" stuff. Up to today, it was, pop the bonnet, connect, forget.
Why do this ritual and why can't I use a simple charger for AGM?
Ignore all that rubbish.
An AGM battery is the same as a normal lead acid battery (it is still lead acid) so can be treated exactly the same.
AGM stands for Absorbent Glass Mat. That essentially means an AGM can store more electrickery than a standard battery for a given physical size, as it has a glass mat inside. They also 'recover' their power quicker after a large current drain (like starting the engine), so are used for 'stop-start' cars. That is all the differences. Nothing special really.
On a Ctek charger, the AGM 'function' just charges to a slightly higher voltage (14.7v instead of 14.4v) as the battery has a higher tolerance.
So a non-AGM mode charger may just charge the battery to 98% instead of 100% of it's capacity. Big deal.

I have both AGM batteries and non-AGM and I often forget to change the 'setting' on my Ctek when charging either. Nothing bad has happened to any of them.
I also have a really cheap 'smart' charger without an 'AGM' mode. This trickle charged an AGM battery perfectly for 2 years without incident.
 
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