Forums

SLB and charger question

Started by Andy K March 9, 2014
I would like to buy a NP 4-6 Yuasa 6 Volt 4 Amp Hour Battery.

Would this charger work and how do I determine how long to recharge a discharged battery ?

  Model: HB-0702-01
 Input: AC100-240V 50-60Hz 0.2A
 Output: DC7.2V 1.0A
 
 I would be powering some led lights that operate at 3.0 volts, so I would need to find out how to step down the voltage as well.
 
 Thanks.
On Sun, 09 Mar 2014 17:09:57 -0700, Andy K wrote:

> I would like to buy a NP 4-6 Yuasa 6 Volt 4 Amp Hour Battery.
That's nice.
> Would this charger work and how do I determine how long to recharge a > discharged battery ? > > Model: HB-0702-01 > Input: AC100-240V 50-60Hz 0.2A Output: DC7.2V 1.0A
First, this is an electronics design group, not a consumer devices review group. Second, you don't report on a brand, or what the charger purports itself to be. If it's labeled as being for sealed lead-acid batteries, then it may well work. If it's a name brand then the chances go up higher (but not, unfortunately, to 100%). The "Output:" rating looks more like something for a wall-wart, but could conceivably be for a battery charger. If it's a decent charger, it should tell you when the charge is done, or it should automatically go to float charge mode.
> I would be powering some led lights that operate at 3.0 volts, so I > would need to find out how to step down the voltage as well.
This deserves a whole separate thread. Isn't there anything in your "step down a 12V battery voltage" thread that's helpful? The whole kit and kaboodle belongs in sci.electronics.basics, for that matter. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
On Sun, 9 Mar 2014 17:09:57 -0700 (PDT), Andy K
<andrewkennedy775@gmail.com> wrote:

>I would like to buy a NP 4-6 Yuasa 6 Volt 4 Amp Hour Battery.
Like this? <http://www.ebay.com/itm/171258184100> URL's are always helpful:
> Model: HB-0702-01 > Input: AC100-240V 50-60Hz 0.2A > Output: DC7.2V 1.0A > > I would be powering some led lights that operate at 3.0 volts, so I would need to find out how to step down the voltage as well.
Good question. It's difficult to tell from the advertisements, which offer no useful numbers or information: <http://www.tmart.com/HB-0702-01-7.2V-1Ah-US-Standard-2-Flat-Pin-Plug-Charger-for-Lead-Acid-Batteries-Black_p226230.html> The problem is that it claims to charge "lead-acid" batteries, which in the common jargon for a flooded lead acid battery. Those have a different charging profile from an SLA (sealed lead acid) battery, such as your proposed Yuasa battery. <http://batteryuniversity.com/learn/article/lead_based_batteries>
>Would this charger work and how do I determine how long to recharge a discharged battery ?
You do not make that determination. Presumably, modern chargers have a way to detect EOC (end of charge) and either turn off or switch to a low level "float" charge. If you are counting on running a timer to determine the EOC, you will need to know the state of charge of the battery when you start charging, or you could easily overcharge and kill the battery. For the prices found, I doubt if the HP-0702-01 has any intelligence inside. I suggest you start with a 12V system as components are common and generally cheaper. Something like this for a charger: <http://www.ebay.com/itm/231064439281> According the above datasheet, it will charge any 12V gel cell from 2.5 to 10Amp-hr. The common 7Amp-hr gel battery should work. For driving your LED lights, it would be helpful if you provide some clues as to how many lights, what type, wattage, how they are wired, and what you plan to do with them. You can't just tie a mixed collection of random LED's in parallel, apply 3.0VDC, and expect them to light up equally. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Sunday, March 9, 2014 8:09:57 PM UTC-4, Andy K wrote:
> I would like to buy a NP 4-6 Yuasa 6 Volt 4 Amp Hour Battery. > > > > Would this charger work and how do I determine how long to recharge a discharged battery ? > > > > Model: HB-0702-01 > > Input: AC100-240V 50-60Hz 0.2A > > Output: DC7.2V 1.0A > > > > I would be powering some led lights that operate at 3.0 volts, so I would need to find out how to step down the voltage as well. > > > > Thanks.
Hello, In general, if a battery is rated at X Ampere Hour, the maximum charging current can be X/10 Ampere, in this case 0.4 A, or 400 milliAmpere. So, an appropriate current limiting resistor at the output of the 1.0 A power supply would work. The output voltage of the charger is fine, as it has to be slightly above the rated maximum voltage of the battery, in order to charge it. As for the LED lamp itself, what is the number LEDs to be used, and what is the average number of hours of use ? Note that as the battery voltage is just 6 V maximum, all the LEDs need to connected in parallel, each with a series dropping resistor of appropriate value. Hope that helps.