IF YOU HAVE MAKE , TRY THIS .

[sisco]

Hi Great_Alex , maybe this for delay because minipuls delay fix

in 150us (Max told).

[J_Player]

Hi Max,
You say we are talking about Lead-acid batteries:

NiCd and NiMh are another topic. We were talking about gel-type lead-acid batteries....

But when I read Sisco's questions, he makes me think he is asking about NiCad, not lead-acid:

use 10 Ni-Cd battery 1.2V/700mA serial form: your total current is 700mA
and you must charge your batterys under 70mA current for 10 hour or 35mA for 20 hour.

parallel battery: use 4 Ni-Ca battery 1.2V/700mA parallel form : your total current is 2800mA and you must charge your batterys under 280mA current for 10 hour or 140mA for 20 hour.

be careful about battery because with little wrong damaged your battery for ever .(I do this for more 10 Ni-Ca battery)

When Sisco talks about NiCad batteries, I think he wants to know how to make a proper charging for NiCad, not lead-acid. Of course, lead acid batteries have different chemistry and require different charging, as well as lead gel cell charger should not be used for lead acid. But when I read Sisco's post, I think he does not talk about lead-acid batteries, he talks about NiCad.

Best Wishes,
J_P

[Max]

Hi Max,
You say we are talking about Lead-acid batteries: But when I read Sisco's questions, he makes me think he is asking about NiCad, not lead-acid:When Sisco talks about NiCad batteries, I think he wants to know how to make a proper charging for NiCad, not lead-acid. Of course, lead acid batteries have different chemistry and require different charging, as well as lead gel cell charger should not be used for lead acid. But when I read Sisco's post, I think he does not talk about lead-acid batteries, he talks about NiCad.

Best Wishes,
J_P

Hi JP,
no in the last post he wrote this:

"
Geo,my information about battery not good,but I think this is true because

write on my battery box, MODEL : 12V2.2Ah 20H

maybe mean charge 220mA for 20 hour.

can somebody help me for current battery charge ?
"

So it's a 12V1.2Ah, then a gel-type I think.

SISCO is gel-type lead-acid like in UPS or a package (serial) of NiCd or NiMh ???

Kind regards,
Max

[sisco]

Max , I use only this model battery (I think lead acid)

I don't use Ni-Ca and Ni-MH because it is very heavy and I have problem with

Ni-Ca and Ni-MH charge .(I damaged more than 10 Ni-Ca battery)

(I use Ni-MH only for my digital camera)

[Max]

Max , I use only this model battery (I think lead acid)

I don't use Ni-Ca and Ni-MH because it is very heavy and I have problem with

Ni-Ca and Ni-MH charge .(I damaged more than 10 Ni-Ca battery)

(I use Ni-MH only for my digital camera)

Hi Sisco,
ok, it's gel-type lead-acid battery, you can charge also in 10hours.
But don't use fast charge (1/4 current) cause is really dangerous... battery heats up.
It's very good for PI detectors. I have similar ones.

Best regards,
Max

[sisco]

Oh please , finally I must charge this battery for 10 hour under 1/10 current

or 12 hour under 1/10 current or 20 hour under 1/20 current or 24 hour

under 1/20 current or ..... what is better ???????????

or must do this : 1/10 current x .86 (your formula). for example 1.2 Ah = 120 x .86 = 103ma for 10 hour

(I must know because I have 4 battery like this, three 1.2Ah and one 2.2Ah)

[Max]

Oh please , finally I must charge this battery for 10 hour under 1/10 current

or 12 hour under 1/10 current or 20 hour under 1/20 current or 24 hour

under 1/20 current or ..... what is better ???????????

or must do this : 1/10 current x .86 (your formula). for example 1.2 Ah = 120 x .86 = 103ma for 10 hour

(I must know because I have 4 battery like this, three 1.2Ah and one 2.2Ah)

Hi Sisco,
you must provide charge for its capacity.
Example : if you have a 12V 1.2Ah you have to provide 1.2A but not in one hour.

Ideally you can charge at e.g. 1/10 of capacity 1.2A/10 = 120mA for 10hours. 1/10 is your ideal current limit.
Actually current will decrease, with charge progress , after some hours, under 120mA, it's ok.

You'll get 0.12A*10h = 1.2Ah , that's your battery capacity.

But you must consider always that process is not perfectly reversable (charge/discharge) so you must add some more current.
In my previous calculation I've indicated as 3% more current (often is 5%) you have to add to ideal charge current, so again for +3%:

120ma+0.03*120mA = 123.6mA

Round this to 125mA you get your right charge current limit.

So must use with LM317 the formula:
1.25/R = current ---> R = 1.25/current ---> 1.25V/0.125A = 10ohm
You need a 10ohm 1/2W resistor or 10ohm 1W, and you'll be fine.

This is just a limit for maximum current charge... your power supply must give a regulated output of 13.8Volts (also 15 could be ok but not more, or you'll damage the battery, avoid this and use 13.8volts).

Also if battery is not fully discharged your current will drop to few mA after the partial charge required. I suggest you discarge it 80% or more before recharge, during first 2 or 3 charge cycles.

Best regards,
Max

[J_Player]

Hi Sisco,

The Volta Tech Vitalize battery is a sealed lead-acid battery. According to the manufacturer, it is an absorbed glass mat battery, not a gel cell. This battery uses special baffles to keep the electrolyte from spilling out rather than adding a gelling agent. Also, the Vitalize battery uses special lead/calcium alloy plates and catalysts that recombines the gases generated. This battery is advertised with very good specifications, but the charging requirements are not given. http://www.peesinc.com/battery.htm

The printed information on the battery (12V 1.2Ah, 20HR) means this battery will deliver 1.2A-hr when discharged over a period of 20 hours. This means this battery has a capacity to deliver 60ma for 20 hours before discharging the battery. If you run it at higher than 60 ma, then you will get less than 1.2 Ah from this battery. For example, 600 ma will not give 2 hours running, but lucky to get 1 hour.

You would be safe to charge this battery at C/10 for 10 hours or 12 hours. There is no advantage to charging at a lower rate for 20 hours. The optimum charging would be to charge at 25% or C/4 for about 80% of its capacity, then switch to a slower rate, or "float" for the final 20% of capacity, preferably C/10. This battery should not be charged at higher rates because fast charging causes them to heat up excessively, which causes the release of hydrogen and oxygen. This release causes the electrolyte to dry up. While the Vitalize battery claims to use special chemistry that recombines oxygen as it is produced, I would stay on the safe side and use C/4 or slower, like maybe C/10. One way you could determine if this battery is fully charged is to detect when the vent hole begins to discharge a small amount of gas. This indicates the battery is fully charged.

You can get longer service life from your Lead-acid or gel cell batteries if you do not allow them to discharge to low voltage. The worst damage is caused when a lead-acid battery is left in the discharged condition for a long time. The best practice is to recharge the battery when it is partly discharged, using a C/10 charge for the calculated amount of time needed to restore full charge. The Vitalize battery can probably be charged for a longer continuing C/10 for trickle charging as long as 18.8 volts is not exceeded.

If I owned this battery, then I would charge at C/10, and I would calculate how much charge time is needed depending on how much discharging power was consumed. Also I would look at Nimh replacement. I believe you can use NiMh for less weight and more power (10 Sanyo Nimh AA cells give 2.7Ah and total weight 300g).

Best wishes,
J_P

[Max]

Hi Sisco,

The Volta Tech Vitalize battery is a sealed lead-acid battery. According to the manufacturer, it is an absorbed glass mat battery, not a gel cell. This battery uses special baffles to keep the electrolyte from spilling out rather than adding a gelling agent. Also, the Vitalize battery uses special lead/calcium alloy plates and catalysts that recombines the gases generated. This battery is advertised with very good specifications, but the charging requirements are not given. http://www.peesinc.com/battery.htm

The printed information on the battery (12V 1.2Ah, 20HR) means this battery will deliver 1.2A-hr when discharged over a period of 20 hours. This means this battery has a capacity to deliver 60ma for 20 hours before discharging the battery. If you run it at higher than 60 ma, then you will get less than 1.2 Ah from this battery. For example, 600 ma will not give 2 hours running, but lucky to get 1 hour.

You would be safe to charge this battery at C/10 for 10 hours or 12 hours. There is no advantage to charging at a lower rate for 20 hours. The optimum charging would be to charge at 25% or C/4 for about 80% of its capacity, then switch to a slower rate, or "float" for the final 20% of capacity, preferably C/10. This battery should not be charged at higher rates because fast charging causes them to heat up excessively, which causes the release of hydrogen and oxygen. This release causes the electrolyte to dry up. While the Vitalize battery claims to use special chemistry that recombines oxygen as it is produced, I would stay on the safe side and use C/4 or slower, like maybe C/10. One way you could determine if this battery is fully charged is to detect when the vent hole begins to discharge a small amount of gas. This indicates the battery is fully charged.

You can get longer service life from your Lead-acid or gel cell batteries if you do not allow them to discharge to low voltage. The worst damage is caused when a lead-acid battery is left in the discharged condition for a long time. The best practice is to recharge the battery when it is partly discharged, using a C/10 charge for the calculated amount of time needed to restore full charge. The Vitalize battery can probably be charged for a longer continuing C/10 for trickle charging as long as 18.8 volts is not exceeded.

If I owned this battery, then I would charge at C/10, and I would calculate how much charge time is needed depending on how much discharging power was consumed. Also I would look at Nimh replacement. I believe you can use NiMh for less weight and more power (10 Sanyo Nimh AA cells give 2.7Ah and total weight 300g).

Best wishes,
J_P

Hi JP,
http://www.peesinc.com/battery.htm is not the website of manifacturer.


Website is: www.voltatech.co.kr
Is a korean manifacturer that made gel-type also. I'm not sure that the VT12012 is lead-calcium. I think could be also gel-type, sealed battery.
Even if it has the "Vitalize" stamped over.

Anyway, this is not big difference... cause both have the security valve system for the excess pressure (10psi) due to H2 release... so lead-calcium plates are not so safe if one charge e.g. at 1/4 or more of capacity.

Battery manifacturer is based in Korea, but factories are located actually in China.

VT12012 data are:

voltage 12V
nominal capacity 1.2Ah (20H)
capacity 20H 1.2Ah (60mA)
capacity 10H 1.1Ah (120mA)
lenght (mm/inch) 99/3.90
width (mm/inch) 43/1.69
height (mm/inch) 52/2.05
total height (mm/inch) 58/2.28
weight (kg/lb) 0.60/1.32

Charge is the same for both types, as explained.
Constant voltage (13.8V) + current limiter.
1/10 current limit is good.

Best regards,
Max

[Great_Alex]

this is 2 good battery chargers for lead acid battery like your battery SISCO

[Max]

another charger

Hi,
I have another good and simple schematic too:

Just set the trimpot to read 13.8V at the output leads.

- NOTE : the 2.2 ohm resistance fix the current limit

that is 1.25/2.2 = 0.568 Ampere that is big

It's good e.g. for bigger batteries... e.g. 4Ah or more

But for smaller ones I suggest use always the 1/10 limit so putting a right value.

It's very important do so cause a big peak current in initial charge phase could seriously damage the battery (could also explode etc).

So use 1/10 ... find value as always 1.25/Ampere-limit

example:
1.2Ah -> 1/10 * 1.2Ah -> 120mA
+3% and round -> 125mA
1.25/0.125 -> R = 10 ohm

Best regards,
Max

PS: you could leave the battery attached as you want with this type... keep battery always in charge as voltage at its leads drops.

[diggerbarns]

Diagrams

Dear Alex and max, these diagrams above are very nice and not to big. I think more people would post stuff if they knew how the diagrams are drawn. ( what software you use ).

[Qiaozhi]

Dear Alex and max, these diagrams above are very nice and not to big. I think more people would post stuff if they knew how the diagrams are drawn. ( what software you use ).

Hi diggerbarns,

One of them is on the internet here: http://www.uoguelph.ca/~antoon/circ/bcgla.htm
The other one looks like a scanned picture.

Personally I use Eagle to put a schematic together quickly. It's free, easy to use, and is available here: http://www.cadsoftusa.com/

[J_Player]

Hi Great_alex,

Those are nice circuits for charging batteries. I presume the 500 ma 12 vac transformer is provides 12 volts when connected in the circuit under load, and has a higher voltage at no load.

The two circuits you show are for SLA and for Gelled lead acid, which require two different charging voltages. We should note that the Vitalize battery, according to the manufacturer is an absorbed glass mat type sealed lead acid battery, not a gel cell. So this battery would use the first circuit shown at the top of your post. The Gelled electrolyte batteries require a slightly different voltage to prevent damaging them.

Best wishes,
J_P

[Max]

current mistake...

Hi,
I've made a mistake in previous post about current calculation.

LIMIT IS

0.6/R ---> 0.6/2.2 = 272mA that is always hi for e.g. 1.2Ah battery

Good value for 1.2Ah battery is 4.8 ohm (limit at 125mA).

Sorry for that...was in a hurry.

Circuit works perfect with both gel-type or adsorbed-glass-mat.
Just rotate the trimmer to get 13.8 V at output.
Use an AC 18+V transformer with it.

Kind regards,
Max