Can a 'trickle charger' fully charge a 12V battery?

[Titan]

Is it possible for a solar 'trickle charger' to bring a 'deep cycle' battery (or battery bank) to full charge.

I know there are lots of different sized solar panel chargers, but I'm wondering about the simple 'dashboard-type' chargers.

 

[appraiser]

This is just my opinion, but every "trickle charger" I have ever used has been able to maintain the charge on a battery. I doubt they could charge a battery to full capacity.

If you look at the rated amp hour capacity of the battery, and divide that by the charger rating, that would be the the time it would take to charge it.

a 74 amp hour car battery and a trickle charger that does say 250 milli-amps would take 300 hours to charge.

A trickle charger will compensate for parasitic drain and that's about it.

 

[BenDover]

You can trickle charge (13.8V 1 AMP max typically) deep cycle batteries, but as stated it will take some time. In fact, the #1 cause of lead acid battery failure is allowing them to sit unused. The plates build up lead sulfate and the battery is toast. It is possible that a trickle charger will not be able to charge a battery that has been deeply discharged or one that has some sulfation. In such a case, you may need a higher current charge for a short time to remove the sulphation from the plates. If the battery has been sitting no amount of charging will remove these deposits...and its recycling time.

One other factor to be aware of is the self discharge current of the battery. All batteries will discharge just sitting there. Typically this rate is 3% of the amp hour rating per month but can vary. A small trickle charger is supplying this self discharge current in addition to charging the battery.

The last thing to be aware of is charge efficiency. Just because you put 1 amp hour into the battery does not mean you actually store 1 amp hour. Charge efficiencies can vary based on level of charge, charge rate, and a bunch of other things. They can be bad as 50%....so that 300 hour charge could be more like 600 hours.

 

[Titan]

Lots of great info....thanks guys.

 

[MichaelJR]

I use it on my jet ski battery....no issues

 

[cstockwell]

I use it on my jet ski battery....no issues

You use it to maintain your jetski battery between uses or in winter or charge a dead battery? There is a huge difference. Most trickle chargers are not designed for that function.

 

[garandman]

I've used a low output charger to charge a motorcycle battery overnight.

But now I use a 6 amp automatic to "top it off," then a Battery Tender to keep them fully charged. We use them on two motorcycle batteries, two marine batteries. They work great.

 

[goofycj7]

Depends on the size of the solar charger, time of year and how many batteries in your bank of batteries.

I can hook up my 5 watt solar charger and see how well it does on a generic car battery.... After all the snow melts and I can reach my jeep!

Seriously I will try to remember to give that a try in a couple months. Seem to remember that for batteries, up to a point at least, a slow charge is better then a fast charge.

 

[MichaelJR]

You use it to maintain your jetski battery between uses or in winter or charge a dead battery? There is a huge difference. Most trickle chargers are not designed for that function.

Woops fail, I didn't catch that he wrote 'solar'. hahaha

Disregard. I can't imagine a personal sized solar charger bringing any deep cycle anywhere near full charge.

 

[Titan]

Depends on the size of the solar charger, time of year and how many batteries in your bank of batteries.

I can hook up my 5 watt solar charger and see how well it does on a generic car battery.... After all the snow melts and I can reach my jeep!

Seriously I will try to remember to give that a try in a couple months. Seem to remember that for batteries, up to a point at least, a slow charge is better then a fast charge.

In my experience, I've used one of these small solar trickle chargers to charge an apparently dead battery to the point where I could start the truck.

I'm not sure if it had reached a full charge, or just enough to turn the thing over. The charger was on for one full sunny day.

 

[garandman]

Woops fail, I didn't catch that he wrote 'solar'. hahaha

Disregard. I can't imagine a personal sized solar charger bringing any deep cycle anywhere near full charge.

Routinely done on sail boats. Of course solar chargers range from something the size of a book to something the size of a bath towel.

A marine solar "battery maintainer" is 125mA Amps, 0.625Ah Amp Hours/Day, 1.8W Watts, 6.5"W x 18"H x 1.25"D
A "trickle charger" is 350mA Amps, 1.75Ah Amp Hours/Day, 5W Watts, 14"W x 13"H x 0.75"D
A "Battery Charger" is 1.0A Amps, 5.0Ah Amp Hours/Day, 15W Watts, 15.5"W x 41.5"H x 2.5"D

A buddy who is a C130 pilot has used a book-sized solar charger for his truck for years. He got it because his old truck had a dodgy battery. He used to put it on the dashboard and plug it into a cigarette lighter. Now he uses one with some suction cups at the top of the windshield so it isn't as likely to be snow covered all the time.

 

[MichaelJR]

Routinely done on sail boats. Of course solar chargers range from something the size of a book to something the size of a bath towel.

A marine solar "battery maintainer" is 125mA Amps, 0.625Ah Amp Hours/Day, 1.8W Watts, 6.5"W x 18"H x 1.25"D
A "trickle charger" is 350mA Amps, 1.75Ah Amp Hours/Day, 5W Watts, 14"W x 13"H x 0.75"D
A "Battery Charger" is 1.0A Amps, 5.0Ah Amp Hours/Day, 15W Watts, 15.5"W x 41.5"H x 2.5"D

A buddy who is a C130 pilot has used a book-sized solar charger for his truck for years. He got it because his old truck had a dodgy battery. He used to put it on the dashboard and plug it into a cigarette lighter. Now he uses one with some suction cups at the top of the windshield so it isn't as likely to be snow covered all the time.

No kidding....

Might be a hell of a lot easier to leave the machine in the water with one of those strapped to it while I'm not using it instead of pulling it out of the water...

 

[garandman]

No kidding....

Might be a hell of a lot easier to leave the machine in the water with one of those strapped to it while I'm not using it instead of pulling it out of the water...

They're awesome on boats, because nothing sucks more than getting a lot of rain, then getting on the boat and the engine won't start because the bilge pump has pulled down the batteries. Or worse yet, sinks.....

 

[ShadeWPI]

A deep cycle marine battery in "good condition" (one that was very recently discharged, but still has at least 10-15% capacity) has a self discharge current measured in single digit milliamps - even a very small maintance solar charger will slowly charge it back up to full (will take a VERY long time at 0.6Ah / day) but it will get there eventually.

Lead - Acid batteries like to be stored fully charged, hence the popularity of trickle chargers.

Lithium batteries however don't like being stored fully charged OR fully discharged (that's why new cell phones need to be charged before they're used) Lithium batteries like to be stored at a medium charge for long term storage. That's also why they recommend not recharging your cell-phone every night.

Ideal storage for lithium batteries: A slow trickle charger that charges the battery to 4V, then stops until the battery self-discharges to 3V and charges it again. Then store it in the refrigerator in a zip-lock bag with a few discant packs to keep the moisture out. Don't toss them in the freezer though.