Battery Chargers for 4, 12v 35ah batteries

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1

What is the best charger for charging a 4 bank of 12v 35ah batteries? Thanks for your help?

2

Hello @dpc !

Welcome to the forum. I’m guessing you got all 4 batteries in parallel, you can check this one.

You can read the specs to check if that is what you need. In addition to, I strongly recommend you to check your battery’s type and validate if they are compatible each other.

Hope this could help you,

Regards.
Carlos.

3

Thanks Carlos, actually they are all 12v 35Ah SLA in a series of 2 arrays. Does that change your suggestion?

4

Hello @dpc ,

Yes, of course, when connecting in series, all batteries voltages are added, and the quantity of batteries in your system is usually limited for your charger voltage capacity, in most cases 24V, that means 2 batteries of 12V connected in series with the same capacity (Amps) . If you got all 4 batteries connected, you will need a charger with at least 48V. Having said that, the one I advise you before won’t work. The solution I could give you is to change to a 24V charger and take two of them charging by time.

In the case of the conventional chargers the amount of batteries in series that we can put is limited by the maximum tension of the charger, in our case 24V and therefore like maximum we will be able to put 2 batteries of 12V in series.

Steps to follow:

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  1. To make sure that all the batteries are of the same capacity and to associate them in series by means of clamps.

  2. We turn off the shipper.

  3. We make sure that the corresponding cable is in the correct tension, that will be the sum of those of the batteries.

  4. We connect the red clamp to the positive terminal that has remained free in the association and the black one to the negative free.

  5.  We divide the capacity by 10 to obtain the charging intensity (In your case 3.5A).

  6. Select the minimum charge intensity 1 - MIN - CHARGE.

  7. We turn on the charger and check the charging intensity, if it is lower than the calculated one, we increase it by means of the combination of switches until we get closer.

  8. We periodically check the battery temperature.

  9. After the estimated time of charge we check the tension in battery terminals and we write down value and time. The battery is charged if the terminal voltage remains unchanged for one hour.

  10. The charger is then switched off.

  11. Disconnect the terminals and batteries taking care not to short-circuit.

I couldn’t find a charger for you, sorry. But to keep in mind, at least 24V and more than 3.5A should work for you.

Sorry I couldn’t help more.

Carlos

1 Like
5

When a fully discharged battery is connected, the current can reach 2 - 3 amperes, i.e. to limit the power supply + 5VSB. This is about the same as starting charging a car battery 60 A * H with a current of 200 A. It is unlikely that the battery will like it. And the voltage of 5 V is too big for this battery, even for the charge-discharge mode, not to mention the buffer one. In addition, when the battery is connected to USB, a voltage drop may occur with the failure of other USB devices. So without a limiting resistor can not do.

6

Sorry, what you said makes no sense to me. Please provide a Battery charger recommendation if you have one.