# What is a full charge?



## budgetprepp-n (Apr 7, 2013)

My controller charges the batteries up to 14 volts and says there full. bounces 13.8 - 14.00 
I thought someone said 14.7 was the full mark?


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## pheniox17 (Dec 12, 2013)

age of batteries is the main factor, i aim for around 14v


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## paraquack (Mar 1, 2013)

What kind of battery, lead acid I assume, but don't know. If we're talking about flooded cell, lead acid, this is a pretty good chart I found. I believe these batteries are no longer on charge and the head voltage has dissipated. If your charge controller is sitting that high, I'd worry about overheating, water evaporation, etc. All things bad. What does your controllers paperwork say?
Here is a pretty good site that explains a lot. Solar Charge Controllers Information Center

State of Charge Specific Gravity Voltage
12V 6 V
100% 1.265 12.7 6.3
75% 1.225 12.4 6.2
50% 1.190 12.2 6.1
25% 1.155 12.0 6.0
Discharged	1.120 11.9 6.0


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## budgetprepp-n (Apr 7, 2013)

The batteries are not that old. There wally world deep cycle.
They have never been what you could call drained usually fully charged. I have never had to put water in any of them. 
When the charging system on a car is in good working order doesn't it charge like 13.7 -to- 14.3?
But I thought someone said 14.7


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## rickkyw1720pf (Nov 17, 2012)

I used to service industrial batteries and industrial charger. Mostly for the larger electric fork lifts. Paraquack is correct you need to test the specific gravity and the voltage needs to be check with out a load.


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## quinnbrian (Mar 6, 2014)

what type of inverter/charging system do you have? (brand name)


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## budgetprepp-n (Apr 7, 2013)

quinnbrian said:


> what type of inverter/charging system do you have? (brand name)


 I have a tracker I think 45 watts. And for batteries Wal Mart the [email protected] hrs deep cycle


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## PaulS (Mar 11, 2013)

The voltage to charge a lead/acid battery has to be about .2 - .5 volts per cell higher than the actual battery voltage.
A fully charged 12 volt battery is about 13.2 volts; add to the .5v x 6 cells and you have 16.2 volts to actually put anymore charge into the battery but you have to limit the amperage to about .5 amps at that voltage to keep the battery from cooking off the water. You should also remember that the voltage you measure should be measured with a load and that is why the voltage is a poor way to measure the state of charge. Checking the specific gravity (when the battery has been fully charged and the electrolyte level is properly filled) is the only way to determine its actual state of charge. 

The higher voltages are only used to equalize the cells and should not be done every time the battery is charged. 14.7 volts is for an average charge once the battery is discharged 80%. You should select your batteries so that they are discharging to 80% (20% charge) when they are in use. If they sit for long periods at low states of charge the plates become sulfated and will never recover - We call that battery memory - you lose the capacity that you don't use.

It's a no win situation - if you charge the battery after 50% discharge then you are using one of the 2000 cycles of its life and if you don't charge it then you lose some of its capacity. You should plan on replacing your batteries after 2000 cycles (discharge/charges) so if you are only discharging your batteries 20% when you replace them use lower amp-hour batteries to prevent the waste of the part of the battery that you don't use. With daily charges you can expect the batteries to last about 4.5 years. If you charge them every other day then you can expect to get 9 years of use but the last couple of years may be at a reduced capacity that may not keep up with the demand.

The above holds true for lead/acid and Edison cell batteries (including gel cell batteries) but not for Lithium Ion batteries. Lithium ion batteries have no "memory" so you can charge them after they are "completely" discharged without the length of time in a discharged state affecting the battery adversely.


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## bad (Feb 22, 2014)

What is your battery voltage once it is topped off and not being charged? Theoretically it should be 13.2 for a new battery and will go down somewhat as the battery ages, as mentioned. 

It takes voltage greater than 13.2 to get a battery to that range. 

Deep cycle batteries don't like to be charged as fast or discharged as fast as automotive batteries. 

So you are charging this battery with solar only? What are you powering with it? Just curious.
-Edit-
overlapped post with Paul


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## budgetprepp-n (Apr 7, 2013)

bad said:


> What is your battery voltage once it is topped off and not being charged? Theoretically it should be 13.2 for a new battery and will go down somewhat as the battery ages, as mentioned.
> 
> It takes voltage greater than 13.2 to get a battery to that range.
> 
> ...


I have a small solar set up ---300 watts -- with 5 lead acid batteries


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## dwight55 (Nov 9, 2012)

If you can analogize a trash bag being full of ping pong balls, . . . and you pouring them out on the floor slowly, . . . that is the electrons moving out of your battery and discharging the battery.

As you pick them up and put them back into the bag, . . . it is similar to re-charging the battery.

But if you lose a few of the balls, . . . the whole final package will not weigh as much with those missing. This is analagous to your battery not achieving "absolute FULL charge".

The chemical reaction of the sponge lead and the sulfuric acid exchanging electron will eventually (really, . . . it starts very quickly) become somewhat less. Lead falls off the plates and lands in the bottom cavity of the battery, . . . giving less effective surface to charge / discharge. This is why the top voltage tends to go down over time.

Just one of those things. 

What you want to do is do a test discharge, . . . charge em up fully, . . . then put them on a known & predictable load, . . . and time it to where the voltage goes seriously down. I don't remember where we stopped, . . . but we used to do that in the Navy. It was one way of checking out a battery.

Doing one today, . . . then one in 6 mos, . . . 1 year, . . . etc. will tell you how fast they are truly diminishing.

May God bless,
Dwight


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## Smokin04 (Jan 29, 2014)

budgetprepp-n said:


> The batteries are not that old. There wally world deep cycle.
> They have never been what you could call drained usually fully charged. I have never had to put water in any of them.
> When the charging system on a car is in good working order doesn't it charge like 13.7 -to- 14.3?
> But I thought someone said 14.7


No. 14.7 is the stoich value of air to fuel ratio in automobiles.

Anything over 13.5V can be considred functioning fully. A way to test...turn on your car with a volt gauge and watch. If your alternator is fairly new, you'll pump out 13.7-14.5...as your alternator and battery age, they dwindle to more like 13.3-14.0. Don't worry too much if you're seeing anything close to 14...you're in great shape if you do. If it drops below 13V, you are dealing with aged components or extreme power draw.

I'm VERY experienced with this bro...cars/automotive sciences have been my passion for the past 12 years. Actually was in the biz as a side gig for the past 10. If you have specific questions...PM me...


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## paraquack (Mar 1, 2013)

My RV's 2- 6 volt golf cart batteries are over 12 years old and still do a reasonable job. Proper care and feeding and sulfation prevention can save a lot of money over the life of a system.


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## quinnbrian (Mar 6, 2014)

Are you just charging off the solar panels? Or are you doing an equalizing charge , with a generator very 30 day. If you are just using solar, even if the charger says full charge and you have more then one battery ,sometime the charger will give a false "full charge" reading. The first battery in line might be fully charged and maybe a couple more, the others will not be. With a equalizing charge (high amps for a extend period of time) it will shake all the electros of the lead sheet (inside the batteries) evening out the charge state inside the batteries. Something a solar panel system will not do. I would have to find my chart for 12volt , I run on 48volt and my full charge is 54-55 volts.
Hope this helps
Brian

Note: One induction of the batteries not evenly being fully charges is if you are not getting the same amount of time as usual . They say "full charge" but last half the time as normal. An equalizing charge maybe in order.


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## budgetprepp-n (Apr 7, 2013)

quinnbrian said:


> Are you just charging off the solar panels? Or are you doing an equalizing charge , with a generator very 30 day. If you are just using solar, even if the charger says full charge and you have more then one battery ,sometime the charger will give a false "full charge" reading. The first battery in line might be fully charged and maybe a couple more, the others will not be. With a equalizing charge (high amps for a extend period of time) it will shake all the electros of the lead sheet (inside the batteries) evening out the charge state inside the batteries. Something a solar panel system will not do. I would have to find my chart for 12volt , I run on 48volt and my full charge is 54-55 volts.
> Hope this helps
> Brian
> 
> Note: One induction of the batteries not evenly being fully charges is if you are not getting the same amount of time as usual . They say "full charge" but last half the time as normal. An equalizing charge maybe in order.


 Ok I'm sure how to put this in words but I'll give it a shot.
I'm only using solar to charge my batteries as my batteries set in line I have positive charge wire going in on one end and 
the negative hook up to a different battery on the other end. So the charge has got to sort of got to go through all the batteries.
I have never used a charger on them. And when I got the reading of 13.8- to -14.00 the batteries were not being charged
by the solar panels. And there was no power draw on them. 
They do a nice job running the lights and small stuff computer,TV


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## Montana Rancher (Mar 4, 2013)

budgetprepp-n said:


> My controller charges the batteries up to 14 volts and says there full. bounces 13.8 - 14.00
> I thought someone said 14.7 was the full mark?


Well this may not be realavent but if you are in an artillery battery "full charge" means charge 5 green bag or charge 7 white bag.

Just saying

If you know what this means then like me!

Haha


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## paraquack (Mar 1, 2013)

What brand and model charge controller do you have. I'd like to look it up on the internet and read its specs. Something just doesn't sound right. It may just be a diode bank to prevent drain from the batteries back into the panel at night?????


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## budgetprepp-n (Apr 7, 2013)

paraquack said:


> What brand and model charge controller do you have. I'd like to look it up on the internet and read its specs. Something just doesn't sound right. It may just be a diode bank to prevent drain from the batteries back into the panel at night?????


 It's called a tracker there is a picture of it on the first page. 
I don't have any problems with my set up at all. As a matter of fact I'm pleased with the performance for being
a budget set up it dose good. I can run my lights all night if I use the led lights. 
Or with the flip of a few switches I can power the regular household lights and small appliances but if I run the regular 
lights and stuff I need a sunny day every other day. I have a 1500 watt inverter.
this not a big "Powerhouse" system. It's more for just lights, TV, computer and stuff like that.
Beats the pants off of candles or oil lamps when the electric goes out.
I was just questioning what the voltage should be at full charge when the system is full and just sort of idling. 
For well under $1500 I'm happy. It has been trouble free from day one.

It will not run the refrigerator, washer dryer, or water pump in my well but still, It's better than nothing


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## quinnbrian (Mar 6, 2014)

budgetprepp-n said:


> Ok I'm sure how to put this in words but I'll give it a shot.
> I'm only using solar to charge my batteries as my batteries set in line I have positive charge wire going in on one end and
> the negative hook up to a different battery on the other end. So the charge has got to sort of got to go through all the batteries.
> I have never used a charger on them. And when I got the reading of 13.8- to -14.00 the batteries were not being charged
> ...


Ok so , just for shits and giggles. Take all the batteries apart, and test every battery with a volt meter and you will see a different voltage on each battery. That's all I'm saying , if they are doing the job, that's great , but in 6 month or a year when there not doing the job ( not lasting as long as usual)You'll know why. Open voltage totally charged , with out a charge be put into the batteries is 12.6 volts (fully charged). Your charging system (built into your solar charger) is or should be limited at around 14.7 volts max input, that way it doesn't fry your batteries or boil them over. In your case the charging system is limiting itself to 14 volt. Some charging system have a multi stage charging system , a high amp charge at first, followed by medium amp charge ...etc. And some (like mine )have a built in heat sensor and will stop charging ,if the batteries start to get too hot. This way the water doesn't get boiled out of the batteries. Check the water once a week or month...or ,if the water ( distilled water with no mineral , minerals will stick to the lead plate and shorten the life of the batteries) get below the lead plates inside the batteries, you will shorten the life or destroy them.
Going "off grid" or just having a back system, just in case the lights go out, is probably one of the coolest thing anyone can have!! Anytime you can take any of the big player out of your day to day life, and still do everything , you always do every day.....well there got to be something to be said about that!! 
Have fun and ask questions
Cheers
Brian


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## Montana Rancher (Mar 4, 2013)

If you are over 14 volts you are good, don't sweat the small stuff,

Keep in mind on a normal 12 volt camper battery the expected life is 3 years

I would suggest if you intend to upgrade getting true long term batteries which normally come in 6 volts here is my fav

MK 8L16-DEKA 6V 370Ah Wet Battery

Don't fall over backwards on the price as I purchased some within the last year for $209 each and that included core charge.

You will not have to do much research to figure in the long run the batteries I listed are better than what you have, and better in the long run even though they are expensive.


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## ralper (Mar 30, 2014)

budgetprepp-n said:


> My controller charges the batteries up to 14 volts and says there full. bounces 13.8 - 14.00
> I thought someone said 14.7 was the full mark?


*For solar that really works go to the "Handy Bob Solar" blog.
*
To answer the question: The voltage must be brought up to 14.8 volts and held there for at least 2 hours. This is per Trojan battery specs.

To know what the batteries are doing you need a quality battery monitor, Aprox. $ 200.00. Without a precise instrument you have no idea what is going on in the batteries. Poor charging and under charging are the reason batteries do not last as they should. With proper charging 8 to 12 years is not an unreasonable battery lifetime.

Rule of thumb: One battery per each 100 watts of solar panels for optimal performance of the system.

LARGE WIRES: My RV system is 400 watts and it needs a minimum of #4 wire and I used #2 for less than a 1.5% voltage loss.


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