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Query about the recharging of a lead acid battery

amal152

Sep 9, 2023
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I have a sealed lead-acid battery of 4v and 1Ah.Its charge is almost empty and i need to recharge it,I have mobile charger of 5v , 2A.Is it safe to recharge this battery with this charger?And how much approximate time shall i keep it charging?Thank you for reading my question.
 

Bluejets

Oct 5, 2014
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Lead acid batteries are fairly robust devices.
There should be a max rate charge written on the case somewhere but if not, usual "trickle" charge would be around 100mA.( 1/10 of 1Ah)and time of 10 hours.
A boost charge with your supply for max 10 minutes should be within reason.

There are small modules that can handle the constant current/float charge ........cheap as.....add to your power supply.
The linked video is primarily about driving LEDs but the module itself could be used as a charge monitor.
 
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Alec_t

Jul 7, 2015
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Are you sure your 'charger' isn't merely a 5V power supply?
 

crutschow

May 7, 2021
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You could use the 5V supply but, at a minimum, you would need to add a small series resistor (likely about 10 ohms) to limit the charge current to 100mA and charge for about 10 hours.
Connect a multimeter in series to monitor the current.
 
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Delta Prime

Jul 29, 2020
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You have to babysit it for 10 hours because if you overcharge a sealed lead acid battery you will soon find out they are not hermetically sealed they are ported so when you overcharge the battery the excess heat generated will be vented through the port. And don't charge them upside down. Hehe.
 

ChosunOne

Jun 20, 2010
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What do you mean by "...its charge is almost empty"? If you mean its voltage reads at less than 2 Volts, then it might not charge back up again. Sealed lead-acid batteries don't do well when they're used to deep discharge. A circuit using a 12V SLA will typically have a cut-off feature that disconnects the battery when it reaches 10,5V or 11.5V, to keep it from going into deep discharge.
 

Delta Prime

Jul 29, 2020
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No...use a basic plug in timer or a 555 timer module on the output.
You're telling me no? You get one "No” a year and you just used it up.
This is how you do it.
A circuit using a 12V SLA will typically have a cut-off feature that disconnects the battery when it reaches 10,5V or 11.5V, to keep it from going into deep disch
You're a rookie and you may be the ChosunOne. But there can only be one! & that's me...
I have a sealed lead-acid battery of 4v and 1Ah
You like tomato juice? Ketchup!
:p
Oops sorry you've been here since 2010....yeah I like tomato juice.
 

Delta Prime

Jul 29, 2020
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It's called sobriety..
Court ordered!
By the way you think tomatoes can walk.
I guess a man of your stature is allowed.
:rolleyes:
It's always a pleasure running into you sensei.
Boy you really tore into the other guy a couple days back but he deserved it very impressive. :)
 
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Delta Prime

Jul 29, 2020
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Cannot say for certain, but from all previous and including today, I'd tend to think it's a permanent condition rather than one applied each time via the "whatever".
That's okay I have someone's other eye on you. (Hehe) you're all too very predictable ( low hanging fruit). :p
 

crutschow

May 7, 2021
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Cannot say for certain, but from all previous and including today, I'd tend to think it's a permanent condition rather than one applied each time via the "whatever".
You are probably correct. :eek:
 

Ylli

Jun 19, 2018
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I have a sealed lead-acid battery of 4v and 1Ah.Its charge is almost empty and i need to recharge it,I have mobile charger of 5v , 2A.Is it safe to recharge this battery with this charger?And how much approximate time shall i keep it charging?Thank you for reading my question.
If that is all I had, I'd just add a 10 ohm resistor in series with the charger output to limit the current, and connect it up. When the battery voltage stabilizes, give it a couple more hours and you should have at least 85% back in the battery.
 
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