12 volt Batteries in parallel

[Little Dutch]

Someone educate me on the proper way to connect batteries in parallel.

*most* images look like this:
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Where the positive is coming off of battery 1 and the negative is coming off of battery 2.


Some images show the positive and negative cables both attached to Battery 1:
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It's been a long time since I last took any sort of electrical engineering class but I thought the first method was correct. However, now I can't quite figure out why it matters.

Help me out here. Does it matter? Which way is correct?

[buffalobo]

Batteries connected in series stack their voltages in order to run machinery that requires higher voltage amounts. This can prove tricky when attempting to charge your battery, because it becomes necessary to account for the increased voltage levels. Because of the increased voltage, it is crucial to utilize a charger that satisfies the increased voltage output of a series configuration. Keep in mind that batteries connected in series have no effect on the amp-hour capacity of your configuration, thus, when charging a battery it is important to focus strictly on the increased voltage. For example, two 6 Volt batteries connected in series will deliver 12 Volts of output, but will carry the same amp hour capacity. Hence when charging these batteries, it is important to utilize a charger that satisfies the 12 Volt capacity that is necessary for both the 6 Volt batteries connected in series.


https://www.batterysystems.net/wp-content/uploads/2018/04/series-300x231.jpg

In contrast, batteries connected in a parallel configuration are able to increase the amp-hour capacity of your batteries, at the samehttps://www.batterysystems.net/wp-content/uploads/2018/04/parallel-300x198.jpg voltage. A parallel configuration is not meant to allow your batteries to power anything above its standard voltage output, but rather, it will increase the duration for which it could power an item at such a capacity. Thus, when charging batteries that are configured in a parallel combination, it is imperative to take into account the increased amp-hour capacity that will result from the new configuration. This is because when you are charging in parallel, you are not recharging the voltage of the system, but rather the amp-hour capacity.

Ultimately, it is important to know the different effects that both parallel and series configurations have on your battery’s performance. Whether it is the increase in voltage brought on by a series configuration or the rise in amp-hour capacity that arises from a parallel configuration; Understanding how these outcomes vary and how to adjust the manner in which you upkeep your batteries, is crucial in maximizing battery life and performance.

ETA - not my words, Battery Systems.net

In your pics either configuration should be fine.

[Little Dutch]

Hah! Nevermind. I found the answer. It makes sense now.

https://www.impactbattery.com/blog/tutorials/how-to-charge-marine-and-rv-batteries-in-parallel/

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[Gman]

Those diagrams are essentially the same The bottom one seems to be more of a logical diagram.

Does this website help? - https://www.mpptsolar.com/en/batteries-series-parallel.html

[Not_A_Llama]

The configurations are electrically identical, and it does not matter which of the shown configurations is used.

Resistance in a wire and (properly connected) junction is essentially nothing, compared to resistance within the cell.

The diagram from impactbattery is only true if the batteries have differing internal resistances. The article confirms that point, but the rest of the article makes no sense and should not be relied upon.

[Little Dutch]

The configurations are electrically identical, and it does not matter which of the shown configurations is used.

Resistance in a wire and (properly connected) junction is essentially nothing, compared to resistance within the cell.

The diagram from impactbattery is only true if the batteries have differing internal resistances. The article confirms that point, but the rest of the article makes no sense and should not be relied upon.

Good to know, thanks

[Little Dutch]

This would be the easiest route for me to take. It's a small two battery system.

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[thedave1164]

This would be the easiest route for me to take. It's a small two battery system.

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this would work, just be sure your cables are capable of carrying the total amp load of your batteries +25%

ie: each battery is 500CCA you would need to carry 1250 amps on the cables (500x2+25%) just to be safe and not create a fire situation :)

[Little Dutch]

I can do that. Thanks.