12.63 volts fully charged?

[highdesertranger]

according to the manual for that model, bulk charging should be 14.4v. highdesertranger

 

[Rhianntp]

Doesn't bulk charging only occur when the battery is in a low state of charge? if its 12.6v would it be considered low state vs the 13.6 charging state?

 

[Spaceman Spiff]

Doesn't bulk charging only occur when the battery is in a low state of charge?  if its 12.6v would it be considered low state vs the 13.6 charging state?

Bulk charging occurs when a battery is below 70% to 80% capacity.  
Battery voltage is < 12.4V.
Charger voltage should rise until it reaches peak > 14V.

Absorption is when charging slows down.
Battery held at battery charger voltage >14V.
Current declines until < 2A per 100AH of battery

Float (or maintenance) charge is low amp (usually less than 1A) and 13.0V to 13.8V.
This is to maintain the battery at 100% (replace internal discharge).

A fully charged, healthy 12V battery should read ~ 12.7V
have a specific gravity > 1.265

All voltage measurements should be after a battery has sat idle (no load or charge) on it for more than 8 hours.  SG measurements have to be temperature adjusted.  For lead-acid 12V batteries.

 

[Rhianntp]

Thanks

 

[jacqueg]

All voltage measurements should be after a battery has sat idle (no load or charge) on it for more than 8 hours.  SG measurements have to be temperature adjusted.  For lead-acid 12V batteries.

I have a question about your statement that voltage measurements should be taken only after the battery has been idle for more than 8 hours. If you are using solar panels or otherwise charging your house batteries every day, how will you ever be able to get an accurate voltage measurement? 

And how much does it matter that you can't?

 

[Spaceman Spiff]

 . . . If you are using your house batteries every day, and using solar panels or otherwise charging your house batteries every day, how will you ever be able to get an accurate voltage measurement? 
And how much does it matter that you can't?

I know of three quick ways to check your battery:

Best is to use specific gravity, but it requires a good technique, must be temperature compensated, is messy, and can't be done with sealed or AGM batteries.  And batteries are usually in an awkward place to get at.

Very good is to watch charging amps; when your battery will only accept < 2A per 100AH the battery can be considered fully charged.
 - this is a problem with solar as you must be sure the solar panels are producing more current than the battery will accept.

A poor third is voltage.  Surface charge will give a false reading for 8 or more hours (battery dependent).  So a battery that reads 12.8V or more could actually be only 80% or 90% full.

If you can get your batteries to a known 100% a few times and read the voltage (with charging and loads disconnected), you can use that voltage reading to be close enough.
(You need to disconnect the charging; otherwise you will read the charger or charge controller voltage.  If something is drawing a load, the battery voltage will be lowered.)

Make sense?

 

[jacqueg]

How do I "watch" charging amps? Can I do it with a multimeter?

I have 2 6v 220ah AGMs. They are cabled together and sit on the floor of my van where they are easy to get at. I use alligator clips to charge them from an inverter generator (and hook up my fridge to them with alligator clips). I use the generator every day, and typically go from about 12.2v (read with no rest) to about 12.7 (read with about 30 min of rest)

What would be the minimum size solar panel I need to charge the batteries? I need to have a generator because I will be spending a good part of my time in the rainy PNW. But even though it's a quiet generator, I'd love to not have to run it so often.

Someday I will have all the controllers/gadgets, but for now, I am piecing it together as I go. And I don't mind doing readings myself, I figure it helps me understand how this all works.

 

[Tony's Dream]

I have been on this site for over a year and I know you guys are wicked smart....just from reading all of your posts!! People choose van life for the simplicity of it, and something I would love to do at some point. I am 2 years from retirement and still getting things together. Unfortunately my retirement life will see me pulling a small trailer because a van rebuild is just not in the budget.

I find the whole battery thing very confusing. I guess that is why so many people use solar power and generators. I want to be able to go off grid and stay in BLM areas for 10-14 days at a shot. So I am still trying to figure out what this will take. I would like to think that if use my power sparingly that two fully charged batteries (104 ah per battery) will be enough, but more than likely I will need to haul a generator along with me and recharge them as needed.

When I drink half of an 8 ounce glass of water, the glass would be half full at 4 ounces. Too bad the batteries are not as simple. One would think if I have a 12v battery it would be at half strength when I see the volt meter at 6v. At a reading of 6 my battery is dead. It is so interesting to think of a battery as fully charged at 12.8 and basically dead a 12.0.

 

[Rhianntp]

A lot of it is confusing and somewhat scary I am starting to feel somewhat comfortable with DC vs AC and all the stuff that goes along with each.

 

[Tony's Dream]

Other than weekend trips, I haven't tried a long term stay any where. I figure I will just go out some place close to home and see how things happen.....and learn as I go.