When is the battery charged?

[Marine]

Hi guys. Just trying to work out when my battery is charged without having to disconnect it every time and wait about an hour before i test the voltage.
I have two 12v 4.5ah batteries I have built a bifilar single coil SSG the same way as The Daftman on youtube. Will the neon LED light up once the battery is charged? Is that what most people rely on to know when the battery is fully charged? The most i am getting one of the batteries to charge at is 12.44v. It had been running for 48 hours and when i tested the standing voltage of that battery, it was 12.34v. Is that fully charged? When i bought one of the batteries brand new last week, it was standing at something like 13.4v out the box. Yet i can't seem to get it back up to that level?
If anyone can shed some light that would be great.

(this is the circuit i coied. But i have since re-wired the neon to the other end of the diode as was told it was an error by Daftman. However it works both ways so i have found)

[Bung-ee]

I am not an expert here, though, I've read many times that you can NEVER test without waiting a battery to cool off at least 1 hour and yet better, a night
so you've got a nice experiment awaiting you when you go to bed !!

[Marine]

I am not an expert here, though, I've read many times that you can NEVER test without waiting a battery to cool off at least 1 hour and yet better, a night
so you've got a nice experiment awaiting you when you go to bed !!

Hello again bung. I do wait at least an hour when i check. Sometimes i check again after 2 hours and so on but it's always the same reading pretty much.
I know it's only a 4.5ah battery i'm using with a 800 turn bifilar coil, but surely it won't take days to charge it will it? I always thought that when no more charge can go into the battery, it will come back down into the circuit and be absorbed by the neon bulb?

[BobZilla]

General guideline for you...

While charging the battery should rise to 15 - 15.5v

Once you have terminated the charge and rested it an hour it will settle between 13.2 and 12.8 , this depends on the condition and construction of the battery. Most will rest at 12.8 after sitting awhile.

I always thought that when no more charge can go into the battery, it will come back down into the circuit and be absorbed by the neon bulb?

No it will not do that. What will happen is the battery will stay at it's top voltage (15.5 or so) and it will start gassing off it's electrolyte.

[axxelxavier]

How about alum batteries, which are the minimal recommended voltage for discharging, and maximal value for charging?

[Marine]

General guideline for you...

While charging the battery should rise to 15 - 15.5v

Once you have terminated the charge and rested it an hour it will settle between 13.2 and 12.8 , this depends on the condition and construction of the battery. Most will rest at 12.8 after sitting awhile.



No it will not do that. What will happen is the battery will stay at it's top voltage (15.5 or so) and it will start gassing off it's electrolyte.

Hi Bob.
I can't get anywhere near 15v! Will a bifilar coil moving a 22" bike wheel generate 15v? If so what am i doing wrong to only get 12.44 at the best of times?

[BobZilla]

@Marine
I couldn't say what you are doing wrong, possibilities are endless if you think about the question. But yes a bi-filer can produce enough, in fact it can and does produce at least 100V. I'm sure by now you have seen your neon light up before right,, well think about that,,,neons need between 75 and 90 volts to light.

@axxelxavier
Most of my experience with crystal batteries is with cells I constructed myself. Generally speaking converted batteries work like a regular battery but at a slightly lower voltage, almost as if one cell is bad. So a fully charged one may read like 11.8 to 12.2v. Discharge characteristics are far different from an acid battery. Mr. Bedini has made several video's that could explain far better than I could. Perhaps someone with more experience on conversions can chime in.

[aln]

axel,
Alum batteries are very durable. Discharge them to 7 volts if you want. I charge them up to 15 still and they come down to 12. If you discharge them that low, start charging again when done discharging soon and you will see it takes a while to fill them up. They hold a voltage well in the 7-10 volt range (meaning they don't give up like H2SO4 batteries). Aln

[Marine]

@Marine
I couldn't say what you are doing wrong, possibilities are endless if you think about the question. But yes a bi-filer can produce enough, in fact it can and does produce at least 100V. I'm sure by now you have seen your neon light up before right,, well think about that,,,neons need between 75 and 90 volts to light.

Yeah i see my neon bulb light up sometimes when i disconnect the charge battery briefly but that doesn't mean i get 100v going to my charge battery
I wish i could get more voltage to my charge battery but i have no idea how. I just assumed an 850 turn single bifilar can't push out that much. Most of the videos on youtube with 1 coilers pushing out 13-15v are using 8 filar coils. (?)

[Brodie Gwilliam]

neg to neg will help you get there, but ive found once a battery tops out and stops climbing you gotta put a small load on it for a couple hours (i used a 1amp bulb)and then put it back on the wheel and each charge cycle you should get a little higher in voltage

[BobZilla]

Yeah i see my neon bulb light up sometimes when i disconnect the charge battery briefly but that doesn't mean i get 100v going to my charge battery

Yea it does.
When your charge battery is connected it goes there, when disconnected the neon absorbs it to protect your transistor.

Brodie is right, just keep cycling your battery and see if it improves. Get the best charge on it you can and drain it off, repeat.

[Marine]

neg to neg will help you get there, but ive found once a battery tops out and stops climbing you gotta put a small load on it for a couple hours (i used a 1amp bulb)and then put it back on the wheel and each charge cycle you should get a little higher in voltage

Thanks for the tip about putting it on a load now and then.
What did you mean by "neg to neg" though?

[Brodie Gwilliam]

charging battery negative straight to primary battery negative(instead of positive), try to make sure your primary is at same or less voltage than your charging battery

[Marine]

charging battery negative straight to primary battery negative(instead of positive), try to make sure your primary is at same or less voltage than your charging battery

Tried that. Seems to make no difference at all....

[axxelxavier]

axel,
Alum batteries are very durable. Discharge them to 7 volts if you want. I charge them up to 15 still and they come down to 12. If you discharge them that low, start charging again when done discharging soon and you will see it takes a while to fill them up. They hold a voltage well in the 7-10 volt range (meaning they don't give up like H2SO4 batteries). Aln

thank you for responding. I usually charge alum batt to 15 volts, and I always wondered if it is not to much...