Hi
Hi,
Max.
I have looked again and this AC/DC adaptor is actualy 300mA MAX OUTPUT!!!
So its look like I have to conect directly to lead-acid battery right?
And put in 12V?The only thing that bordars me is that when I measure the voltage from AC/DC adaptor when its in 12 V range the multimeter shows 15.60-15,70 sometimes 16 V.
What do you think?
I think that in AC/DC adaptor there is some kind of voltage regulator and I try to put another?
Please advice me.Should I try to charge 12V 1,4 Ah conected directly to AC/DC adaptor?If I put it in 12V for how long should I charge?
Thanks man I think that finaly will be ready soon!
I am not scared from snow,but what do you think If I clear from snow spot that I now that is good and try detect in frosen ground?Will there be many fals signals?Or I will be able to detect?
Thanks
p.s.AC/DC adaptor is LLA300D
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Hi,Originally posted by tiktak View Post
if the battery voltage isn't too low (so not too discharged) you can charge just using a stable voltage of 12.7Volts.
Current will drop very fast and battery will charge in few time... some hours...at 12.7V you can also leave battery connected to supply... but you need at least voltage regulation... and can't put something more than 13.7V there cause otherwise you'll damage it.
BUT THAT IS POSSIBLE WHEN BATTERY VOLTAGE IS MAX ABOUT -10% of full charged battery... so maximum untill 11.5V, and not under that.
If you try to charge a battery that have voltage of less you'll maybe damage it without a proper current limiter. Current rise will be too fast and higher and H2 bubbles will make pressure inside the container.
As security devices you could use a fuse (e.g. 500mA) in series with supply ; you could use a diode instead if use e.g. 13.5V regulated voltage... that way diode will open circuit when battery will reach about 12.8V during charge.
Be careful, check initial current with multimeter... it must be always under 0.5C from start (for 1.4Ah not more than 0.7A at start).
Best regards,
MaxLeave a comment:
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Hi
Hi,
Max.
Thanks for your adviceS!!
I conected this lead acid battery to TGS/just to see and compare how battery voltage drops.It were just like I bought it without charging.The voltage were 11.83./But I noticed that it drop very fast.Even faster than 700 ah NI-MH.Buy the way I were using aweys not nulled coil and noticed that when bad nulled machine consume around 45-even more mA!When nulled around 35-37mA.So maybe thats why they drop so fast?!!
And last time when I have charged one of the 700 ah batterie it drop almost good I have played 2 or 3 hours and the voltage droped a litlle bit faster but not as before/when reach 12,35v/.
When I charge this one I have measure the A from the first circuit that you give me/I just desolder afther the point where ADJ and Vout of LM317T connect afther 20ohm resistor afcourse and if my memory dont make me triks it were about 20 mA.Shouldn't it be 70 mA?Is this AC/DC adapter that make me crazy?Should I try to charge with only AC/DC adapter and for example 10 ohm resistor only?And for how long should I cherge with this configuration?
I will look for charger for 1,4 aH lead-acid battery,but my money have gone for now so I am in bad position.And seaching for simple solution!The charger that they try to sell me coast 45 euro!!!Isn't this too much?Can I charge with this AC/DC adapter and some resistor again?For how long should be charged this lead-acid type batteries?
THANKSLeave a comment:
-
Hi
Hi,
Max.
Thanks for your adviceS!!
I conected this lead acid battery to TGS/just to see and compare how battery voltage drops.It were just like I bought it without charging.The voltage were 11.83./But I noticed that it drop very fast.Even faster than 700 ah NI-MH.Buy the way I were using aweys not nulled coil and noticed that when bad nulled machine consume around 45-even more mA!When nulled around 35-37mA.So maybe thats why they drop so fast?!!
And last time when I have charged one of the 700 ah batterie it drop almost good I have played 2 or 3 hours and the voltage droped a litlle bit faster but not as before/when reach 12,35v/.
When I charge this one I have measure the A from the first circuit that you give me/I just desolder afther the point where ADJ and Vout of LM317T connect afther 20ohm resistor afcourse and if my memory dont make me triks it were about 20 mA.Shouldn't it be 70 mA?Is this AC/DC adapter that make me crazy?Should I try to charge with only AC/DC adapter and for example 10 ohm resistor only?And for how long should I cherge with this configuration?
I will look for charger for 1,4 aH lead-acid battery,but my money have gone for now so I am in bad position.And seaching for simple solution!The charger that they try to sell me coast 45 euro!!!Isn't this too much?Can I charge with this AC/DC adapter and some resistor again?For how long should be charged this lead-acid type batteries?
THANKSLeave a comment:
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Hi tiktak,Originally posted by tiktak View Post
Fred is right about constant voltage charge of that batteries without limiter...WHEN THEY ARE ABOUT ALREADY CHARGED.
The fact you need a bought charger or a circuit like the one I posted is related to situations where you have the battery discharged ... so when you connect supply to it you'll get a very high current due to the fact that reactions required for charging will provide a strong current flow inside the cells.
That would be the worse situation if you don't use a real commercial charger or a limiter: your current will be out of control... rising more that 0.25C and then producing H2 bubbles inside the battery case... till pressure will reach some bar and automatic valve will open and free H2 in the environment... but often the pressure rise is so violent that case can break and battery will be permanentely damaged.
That's why I strongly suggest you buy one good and cheap 12v charger for lead-acid (but good for gel-type or other small backup type batt.) or build a charger like in circuit that do some limitation of current.
Best regards,
MaxLeave a comment:
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Yes, that would be the right thing to do, but in that case if the battery is not too low, you could just charge it directly, as the voltage difference is not that big and all the 400ma will never go thru.NEVER let your battery go to a low voltage,if its gel it may never take charge again.
Fred.Leave a comment:
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Hi tiktak,Originally posted by tiktak View Post
The simple answer to your lead-acid cell charging problems is this:
A maximum charge rate (current) must not exceed 0.25 of the battery rated capacity. e.g. 4Ah battery max charge rate = 1A
Or - in your case, the 1.4Ah battery charge rate should not exceed 350mA.
The easiest solution is to buy a constant voltage sealed lead-acid battery charger. They're not very expensive.Leave a comment:
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Hi,
Hi,
Max please explain again:
I just bought this 12V 1,4Ah battery it's lead acid type!
I have this stupid ac/dc adapter that have scale for voltages.On back side its labeled that its giving 400 mA MAX.Is this mean that when the scale is set for max voltage its give 400 mA then.?
Can I try with this AC/DC adapter because I cant understand this scheme that you give me/I am Nob you now/.Again with some resistor?
The AC/DC adapter should be put in 12v range right?Or
Sorry again for the stupid questions but I wanna finish this finaly!
Thanks
p.s.If you give me some advices I will try to build this circuit but what are AC1;AC2;where should be batteries be conected?Leave a comment:
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HI,
Hi Max,
I have found some 12V battery 1,4Ah and I think it's lead-acid type.Its hevy but I am sick of this NI-MH experiments.So what do you think can I conect this dirctly to TGS?Or I have to add some other components too?
In the shop they dont have chargers for this one!I ask them what they think and they told me to conect to ac/dc adapter directly?I am afraid to listen to them anymore ,so I ask you!?Leave a comment:
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Hi,Originally posted by tiktak View Post
NiMh of 700mAh last for 15-20hours on TGS. That's why: you get something around 35mA of current when silent... then some double or more when it sounds with speaker (with headphones increase is very small).
So 700mAh/35mA = 20h but sometimes
it sound (target or battery checker at switchon) and so your current battery last is around 15-16hours with fully charged 700mAh batteries.
For me is more than enough to get it work very happy...even if some voltage drop occours in different way respect to gel-type.
The Gel-type lead-acid I mean is 12v 1.2Ah for a weight of 400-450gr (cause of lead and other stuff).
You need the second circuit to charge it well... circuit works pretty good as is...I suggest , if you wanna stay safe with battery life, you change the 2.2 ohm resistor to 4.7 ohm one. That will limit maximum current at about 125mA.
You can leave battery always connected to this charger without damage cause of the diode ... just have use a 16-18VAC adaptor and to set the trimpot for 13.8V output without load.
With lead-acid 1.2Ah your TGS will run at least 24hours before you need to recharge.
Best regards,
MaxLeave a comment:
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Hi
Hi,
Max.
I now that you are ususly right!
I were hoping that its better scenario.
But look when I charge with first charging circuit that you give me,batteies where not charged.They were droping instantly!Now when I try this they charge but dont last long and drop the same way when they reach 12 v.
His teory were that batteri need 14,1V when conected to pluged AC/DC adapter.
I cant aford no more games.
Can you tell me for those gell bateries?Are they easyer to handle?What type should I search for?
p.s.How long should last this NI MH battery?
ThanksLeave a comment:
Leave a comment: