Recharging 4 12V batteries in parallel

In summary: C (77F) to 13.5V to 13.8V.In summary, the conversation discusses the need to recharge 4 parallel lead-acid batteries, specifically Genesis NP7-12FR batteries rated at 12V, 7.0Ah. The individual is seeking advice on creating a circuit to charge the batteries using a 120VAC wall socket. A suggestion is made to use a 13.8V DC power supply with current limit, possibly from a ham radio store. The use of steering diodes and low value resistors for current monitoring is also mentioned. Additionally, the idea of constant charging is suggested, referencing the spec sheet for the Genesis batteries.
  • #1
uchacker11
1
0
I have 4 lead-acid batteries in parallel that I need to recharge. The batteries are Genesis NP7-12FR batteries rated at 12V, 7.0Ah. I need to create a circuit so that when I plug it into a 120VAC wall socket the batteries are charged. I was thinking of using a DC power supply but have no idea what size to use. Any help would be appreciated.
 
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  • #2
I would suggest a good 13.8 V (well stabilised) supply possibly with current limit. They would probably charge at something like 2 Amps (guessing really) each initially so that is 8 A x 13.8 V = 110 Watts. Ham radio stores will have lots of 13.8 Volt PSUs used for running radio transceivers. Steering diodes in series with low value resistors (for current monitoring - 0.1 - 0.25 Ohm...measure the voltage across them) in series with each battery would be a better arrangement but may not be very convenient if the batteries are connected as a parallel pack in normal use.. The diodes will drop 0.7 V so you will need 14.4 Volts. The resistors will act as current limiters.
 
  • #3
Welcome to PF uchacker11.

I'm guessing that you have a UPS. If so you might want to consider constant charging.
From the Genesis spec sheet (http://www.tnrbatteries.com/ennp72.html" ):
Standby use: Apply constant voltage charging at 2.275 volts per cell (or 2.25-2.3VPC)
 
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1. How do you recharge 4 12V batteries in parallel?

To recharge 4 12V batteries in parallel, you will need to connect all of the positive terminals together and all of the negative terminals together. This will create a parallel circuit, allowing the batteries to charge simultaneously.

2. Is it safe to recharge 4 12V batteries in parallel?

Yes, it is safe to recharge 4 12V batteries in parallel as long as they are all the same voltage and are in good condition. It is important to make sure the batteries are all connected correctly to avoid any potential hazards.

3. How long does it take to recharge 4 12V batteries in parallel?

The time it takes to recharge 4 12V batteries in parallel will depend on the charging rate and the capacity of the batteries. Typically, it can take anywhere from 4-8 hours to fully charge the batteries.

4. Can I use any charger to recharge 4 12V batteries in parallel?

No, it is important to use a charger that is specifically designed for parallel charging. This type of charger will evenly distribute the charging current among all of the batteries, ensuring they are charged correctly and safely.

5. What are the benefits of recharging 4 12V batteries in parallel?

Recharging 4 12V batteries in parallel allows for a higher overall capacity and longer run time compared to charging them individually. It also ensures that all of the batteries are charged equally, preventing imbalances and extending the lifespan of the batteries.

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