How do you know when a battery is near fully charged without checking the specific gravity of the fluid?
I have a sealed lead acid 4 volt, 4 amp battery that I bought as a replacement for a solar powered electric fence charger.
Your supposed to leave the charger out in the sun for a few days before using it...at least that's what the users manual said to do when it was new.
Well I can't wait that long (PIA horse issues), so I have it plugged into a 4.7 volt power supply.
When I plugged it in about 1.5 hours ago it was pulling 2.3 amps.
Now it is down to .6 amps. The battery is not getting warm.
I assume the amps will continue to go down as it charges up. Not knowing how much charge it had to begin with...when should I unplug it?
I don't have a volt meter available at the moment.
Any hobby guys have a suggestion?
I think if you search for discussion on: charging sealed lead acid battery you will find lots of information. You may find most of it relates to nominal 12 volt batteries and need to scale their voltage numbers down by a factor of 3 for yours.
I assume you mean 4 amp-hours and not 4 amps. Most of them come from the store with a partial charge, so if you put around 2 amps into it for an hour before current started dropping, you've added half of its capacity (ignoring an efficiency factor) on top of the original partial charge and are getting close.
Certainly a drop-off in current means it is getting close to full, and I expect you could put it into service now if there is a solar trickle charge on it. If it starts heating up you've gone too far.
Bill, yes I meant 4 amp hour.
Everything on the internet that is easily found has to do with larger batteries.
I read somewhere the current draw should 2% of the 20 hour amp hour rating.
In this case (if that is a 20 hour rating) it would be around .1 amps.
It's been 3.5 hours and its pulling .25 amps and not getting warm.
I think I will just pull it off the charger and put it in service like you suggested.
Once the horse remembers what electric fences do, I will be able to shut it off and just let the sun charge it the rest of the way up.
imaudigger, post: 361708, member: 7286 wrote: Once the horse remembers what electric fences do, I will be able to shut it off and just let the sun charge it the rest of the way up.
Too bad you don't keep elephants -- they never forget.
Can't answer question, but your comment on horses reminds me when at a place with horses and electric fences.
There was a paddock that once was cut in 2 by a now removed electric fence.
The horses would gallop around until coming to an abrupt halt at the very place where the fence once was.
Interesting to watch.
The only thing keeping the horse from walking down the driveway and getting loose was two strands of electric fence. For the last 1.5 years it has not even been charged. There was some respect for the fence.
However, she figured out how to break the electric fence to get in the yard. I put her in a pen for a couple days and thought I had the fence fixed. Turned her out and the next morning the fence was broke in the same location. Back to the pen for a couple days.
Last night I replaced the battery on the fence charger, installed another grounding rod, and verified with my hands that the fence was actually energized. It's just a 2 mile energizer made for small animals and most of the time it only gives a mild shock. However if you are providing a good ground, it will turn your elbow inside out. I turned her out last night and this morning the fence is still up.
I'm keeping the driveway gate closed just in case.
Horses are actually very intelligent, curious, and emotionally sensitive animals. I recently shaved some of my beard off. This morning she came over to the fence and stared at my face for a minute or so. Then she had to feel my new beard with her snout. First the shaved part, then the beard. Lastly she wanted to grab ahold and give a tug on my beard with her lips. I gently told her no and she turned around and walked off and ate grass with her back to me.
I would describe her personality to be somewhere between a dog and a cat. Sometimes more like a dog and other times exactly like a cat.
