Which battery charger to get?

[mpotapa]

I want to buy a new battery charger. I have a gift card to autozone and really don’t need anything. I’m not really sure what I need to charge my group 24 battery. Would this one do the job?

https://www.autozone.com/test-scan-a...ger/614273_0_0

[acadianbob]

Just make sure you get a "smart charger" that won't overcook your batteries if you leave it hooked up. It would also be a plus if it has anti-sulfation technology and the ability to "equalize" your battery.

[country ham]

I use a Harbor Freight float and maintainer charger, on sale 14.99 thru 3/10/18, I use it on lawn mower, 4 wheeler, camper

[cavie]

Originally Posted by mpotapa

I want to buy a new battery charger. I have a gift card to autozone and really don’t need anything. I’m not really sure what I need to charge my group 24 battery. Would this one do the job?

https://www.autozone.com/test-scan-a...ger/614273_0_0

Yes, this will work well for you. Here are the details of what you are looking at. It's all you need.

Microprocessor controlled ─ automatically adjusts the amperage rate to charge and maintain
Multi-stage charging for added precision, safety and battery life
Float mode monitoring ─ automatically maintains optimum battery charge •
Auto voltage detection ─ 6 or 12 Volt .

[mpotapa]

Originally Posted by cavie

Yes, this will work well for you. Here are the details of what you are looking at. It's all you need.



Microprocessor controlled ─ automatically adjusts the amperage rate to charge and maintain

Multi-stage charging for added precision, safety and battery life

Float mode monitoring ─ automatically maintains optimum battery charge •

Auto voltage detection ─ 6 or 12 Volt .

Ok thanks. I wasn’t sure if 8 Amps was enough.

[cavie]

Originally Posted by mpotapa

Ok thanks. I wasn’t sure if 8 Amps was enough.

Don't let your battery go 100% dead. It may not bring it back.

[mpotapa]

Originally Posted by cavie

Don't let your battery go 100% dead. It may not bring it back.

I actually have a battery charger but I can’t tell if it’s working correctly. On my old batteries a green light would come on when it was full and the meter would go to full and then lower. Not sure what it was exactly doing. With this new battery it doesn’t seem to do that. I do know it’s charging because my battery was reading at 12.37 and after I charged it a few hours it’s at 12.78. It’s also a 2amp slow charge or 10amp fast charge.

[cavie]

Originally Posted by mpotapa

I actually have a battery charger but I can’t tell if it’s working correctly. On my old batteries a green light would come on when it was full and the meter would go to full and then lower. Not sure what it was exactly doing. With this new battery it doesn’t seem to do that. I do know it’s charging because my battery was reading at 12.37 and after I charged it a few hours it’s at 12.78. It’s also a 2amp slow charge or 10amp fast charge.

the new charger has a "floater cycle" to keep the battery topped off automatically. Your present charger doesn't do that. I can't speak to your old chargers light sequence but a different battery won't change that.

[mpotapa]

Originally Posted by cavie

the new charger has a "floater cycle" to keep the battery topped off automatically. Your present charger doesn't do that. I can't speak to your old chargers light sequence but a different battery won't change that.

This is what I currently have.

[TitanMike]

Originally Posted by mpotapa

Ok thanks. I wasn’t sure if 8 Amps was enough.

8 amps over 24 or more hours is usually more than enough, In many ways these small chargers are safer than the larger ones that cause batteries to "boil".

Ideally you want to charge a battery only as fast as you can WITHOUT causing bubbles to rise in the electrolyte. If you open the caps and see bubbles rising, the energy you are putting into the battery is merely creating gas and not storing electricity.

FWIW, these small "Automatic" chargers are not always true multi-stage chargers. Some charge until a certain voltage is reached then shut off, waiting for voltage to drop again. Others will switch from max charge to a trickle rate of 1-2 amp. True "multi-stage" chargers will have three levels of charge voltage with the more premium ones having a fourth "equalization" or "desulfation" mode. The ones with four "modes" usually cost a lot more and are sold to the solar power/RV users, not just general automotive customers.


FWIW, If I had a gift certificate for AutoZone I'd use it to stock up on Oil and Oil/Air filters. Then use the money saved towards a charger designed specifically for long term use on deep cycle batteries.

[camaraderie]

Originally Posted by mpotapa

Ok thanks. I wasn’t sure if 8 Amps was enough.

10% of 20 hr. rating is the minimum to buy in a charger. Group 24 is generally around 75 amp hours so you are good to go with 8 amps.

[PenJoe]

This has gone up $12 on Amazon since we bought ours last year.
This is the one I chose:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Here is the reason we chose this one. It has both manual and automatic modes. That may not seem important, but I did a lot of research prior to making this choice.

We travel for extended periods and have several 12 volt batteries that we charge when we get back. Occasionally, an automatic battery charger can not detect and extremely low battery, so it will not start to charge. A battery test at a local automotive supply would tell you the battery is bad because of lack of voltage.

However, in manual mode, the charger is not trying to detect a battery, but merely applies a charge between terminals. The manual charge , in effect, wakes up a battery that may otherwise have been deemed a discard. Once the battery has a small charge, the charger can be put on automatic.

We also have the charger you have noted. It's an okay charger, but is pretty basic. It is more difficult to adjust for the 3 elements of charging. There is also no gauge to determine the rate of charge.

[mpotapa]

Originally Posted by PenJoe

This has gone up $12 on Amazon since we bought ours last year.
This is the one I chose:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Here is the reason we chose this one. It has both manual and automatic modes. That may not seem important, but I did a lot of research prior to making this choice.

We travel for extended periods and have several 12 volt batteries that we charge when we get back. Occasionally, an automatic battery charger can not detect and extremely low battery, so it will not start to charge. A battery test at a local automotive supply would tell you the battery is bad because of lack of voltage.

However, in manual mode, the charger is not trying to detect a battery, but merely applies a charge between terminals. The manual charge , in effect, wakes up a battery that may otherwise have been deemed a discard. Once the battery has a small charge, the charger can be put on automatic.

We also have the charger you have noted. It's an okay charger, but is pretty basic. It is more difficult to adjust for the 3 elements of charging. There is also no gauge to determine the rate of charge.

The diehard I posted pictures of or the one I originally linked from autozone? I ask because the diehard one I own appears to be similar to the one you currently have.

[Mountainmanbob]

Originally Posted by mpotapa

Ok thanks. I wasn’t sure if 8 Amps was enough.

I would buyer higher Amps model.

A little bigger would be better.

M-Bob

[25snakeman02]

I know nothing about battery chargers. Does the brand name Battery Minder fall into the good category?

[TitanMike]

Originally Posted by 25snakeman02

I know nothing about battery chargers. Does the brand name Battery Minder fall into the good category?

It's highly rated among those who've purchased. It's pretty much what it's name implies, a Battery Minder or maintenance charger.

Low current for the most part so not what you'd want for quick charging depleted batteries but great for maintaining multiple batteries while in storage.

Uses High Frequency voltage to desulfate rather than just high voltage/current.


If I had a bunch of batteries I had in storage for any length of time I'd use one of these.

For my TT, I just upgraded to a Progressive Dynamic's 9260 which does it all without me having to do a lot of switching back and forth. Just check water regularly and start generator when boondocking.

[Murbella7]

Originally Posted by mpotapa

This is what I currently have.

Attachment 162739

Be aware that a typical home garage battery charger is usually NOT a multi-stage battery management device. If it is a low current device then you can be certain it is not. For RV use, you really do need a multi-stage charger capable of output voltages of up to 16v. Your batteries are expensive and difficult to move if they have to be replaced.

A charger needs to have enough guts (current output capacity) to kick a half-dead battery back into life, hence the high current output requirement. It also needs the ability to then gradually reduce the charge current until the battery is topped up so that the battery doesn't cook and potentially explode. Finally the charger needs to be able to 'float' the battery on minimal charge. Typically nowadays these are 7 stage devices but even a 3 stage charger is better than a simple 8 amp car battery device.

[TitanMike]

Originally Posted by Murbella7

Be aware that a typical home garage battery charger is usually NOT a multi-stage battery management device. If it is a low current device then you can be certain it is not. For RV use, you really do need a multi-stage charger capable of output voltages of up to 16v. Your batteries are expensive and difficult to move if they have to be replaced.

A charger needs to have enough guts (current output capacity) to kick a half-dead battery back into life, hence the high current output requirement. It also needs the ability to then gradually reduce the charge current until the battery is topped up so that the battery doesn't cook and potentially explode. Finally the charger needs to be able to 'float' the battery on minimal charge. Typically nowadays these are 7 stage devices but even a 3 stage charger is better than a simple 8 amp car battery device.

All of what you said plus:

You need to make sure that the charger is large enough to charge the SIZE of your battery bank. If you are charging a 50-100 amp hour capacity battery a small 8 amp charger may be OK. If 250-400 amp hour battery bank, that 8 amp charger is nothing more than a small trickle charger.

Lastly, if the charger doesn't have enough "juice" to warm up a cold battery and the electrolyte doesn't reach the optimum temperature for electricity to be stored charging will take forever.

FWIW, coach and trailer manufacturers could be a lot more helpful by installing better quality converter/chargers in their units or at least offer them as options rather than going with the cheapest available.