hello everyone, greetings for eveyrone in that forum

well, understanding the battery charger not really claer for me, and thats why im here seeking help understanding
we have lead acid batteries , SLA type

also diference between charging the battaries in series and in parallel connection

i know that the charging currenet should not be more than 20% of battery capacity ,

so if the charger is rated 10A , 12v
for example , if 5 batteries in parallel, for 12v and 7 AH, the one battery, the total will be 12v and 35 AH, and so charging currenet = 35*0.2 = 7A, now the charger is capable but how will apply the 7ah , automatically?, if so, what differenece between these two chargers?

https://shorturl.at/mzHbh

and this
https://shorturl.at/hFv6v

i see both are capable of charging the above configuraion, but what different in charging ampere?

regards

 

The charger will supply what it is able to, so using a 10A charger on a battery that has a lower maximum charge current (eg 7A) means it will be delivering excessive current.

Neither of the chargers you show seem very capable. Modern automatic chargers can provide the three-stage charging regime that best suits lead-acid cells. The chargers you show will charge but it seems will require manual supervision to guard against overcharging.

As for charging at 20% capacity, I have always used a limit of 10% to maximize battery life, but the maximum charge rate of your batteries should be in the datasheet - maybe 20% is ok. Do you have data for the battery you are using?

SLA batteries are not very tolerant of overcharging compared to flooded, so I would strongly recommend an automated three-stage charger.

 

hello everyone, greetings for eveyrone in that forum

well, understanding the battery charger not really claer for me, and thats why im here seeking help understanding
we have lead acid batteries , SLA type

also diference between charging the battaries in series and in parallel connection

i know that the charging currenet should not be more than 20% of battery capacity ,

so if the charger is rated 10A , 12v
for example , if 5 batteries in parallel, for 12v and 7 AH, the one battery, the total will be 12v and 35 AH, and so charging currenet = 35*0.2 = 7A, now the charger is capable but how will apply the 7ah , automatically?, if so, what differenece between these two chargers?

https://shorturl.at/mzHbh

and this
https://shorturl.at/hFv6v

i see both are capable of charging the above configuraion, but what different in charging ampere?

regards

It seems strange that the first charger is rated in terms of ampere hour, which seems very unusual. Usually, they are rated in amps.
The second one can charge at 10 amps which seems good but it's an older style. The modern ones can do more than one stage charging which is supposed to be better for the battery.

 

The chargers you show will charge but it seems will require manual supervision to guard against overcharging.

There will be manual supervision, but if the ampere will be excessive, that will not be good
I thought battery would take current as long as it needs and stop when full charge
I thought 7ah battery would take
0.7 ampere for charging from the charger, and that the 10A charger is capacity
Am I wrong?

 

5 batteries in parallel

I thought 7ah battery would take
0.7 ampere for charging from the charger, and that the 10A charger is capacity

It's not good practice to charge batteries in parallel, since one of the batteries with a slightly lower resistance could hog most of the current.
If you do, the charging current should be limited to what one battery can tolerate or about 10% of its Ah rating (here 0.7A).
If you wanted to push it, you could probably go to 20% or 1.4A.

 

It's not good practice to charge batteries in parallel, since one of the batteries with a slightly lower resistance could hog most of the current.
If you do, the charging current should be limited to what one battery can tolerate or about 10% of its Ah rating (here 0.7A).
If you wanted to push it, you could probably go to 20% or 1.4A.

Okay and if I use that 10A charger in post 1, it will provide the battaries ampere?, or will be too much?

the charging current should be limited to what one battery can tolerate or about 10% of its Ah rating (here 0.7A).

The charging current will be 10% of total capacity of battaries in parallel, so if 10 battary of 7ah in parallel, capacity will be 70 ah and so charging current is 7A not 0.7 A

 

The charging current will be 10% of total capacity of battaries in parallel, so if 10 battary of 7ah in parallel, capacity will be 70 ah and so charging current is 7A not 0.7 A

Did you not understand what I said about one battery possibly hogging the current, and thus getting too much current?

 

Did you not understand what I said about one battery possibly hogging the current, and thus getting too much current?

Yes the current, it will take more current than other battaries

 

I thought 7ah battery would take
0.7 ampere for charging from the charger, and that the 10A charger is capacity
Am I wrong?

You are wrong. The limit on charge current is provided by the charger, not the battery.

This is OPPOSITE to normal circuit behaviour, where a load will take needed current from a supply of whatever size. A charger connected to a battery doesn't behave like that.

 

I thought battery would take current as long as it needs and stop when full charge

Also wrong. A simple charger will provide current to a battery past full charge, which will cause the electrolyte to gas until the battery is dry (and wrecked, in the case of SLAs)

 

Yes the current, it will take more current than other battaries

And that's not desirable.

 

Yes the current, it will take more current than other battaries

Yes, and you have to be very careful with this. If one battery gets too hot it could actually explode.
Normally a charge balancing circuit is used. That makes sure each battery only gets so much current and not any more.
Lead acid batteries can explode as well as Li-ion cells. It's not a pretty sight and very dangerous to say the least.
Eye protection is mandatory to start with.

 

A small resistor in series with each battery (say 0.5 ohm) will help balance the charge current for each.

 

Lead acid batteries can explode as well as Li-ion cells. It's not a pretty sight and very dangerous to say the least.
Eye protection is mandatory to start with.

There is limit in the charger circuit at which the battery can not take more current