Batteries Parallel vs. Series

You may find yourself saying (I know one of those doubles the voltage and one doubles amp hours) while working on an electrical task either going “Off the Grid” or simply trying to make a battery pack. As for the rest of you , it may be more of a question of; what is this guy talking about? We’ll discuss both what they do and what you need to know. Before you go and slap together a few batteries it’s recommended that you continue reading this article.

First we’ll discuss AH (Amp Hour) rating.
Amp Hour rating is the way we rate the power available by a battery when used evenly over a 20 hour period. Not saying that a battery with a 7ah rating will give 7amps for 7 hours, remember that the rating system is based on a 20 hour scale. In order to get the actual amount of time you will get 7amps you must divide 7 by 20 so it would come out looking something like this ( 7AH / 20 = .35hrs or 21 minutes). For those 21 minutes the battery would be able to supply 7 amps continuously. Obviously if you are attempting to go Off Grid you wouldn’t use a 7ah battery, this is only to gain an understanding of how the rating system works and what to expect from a given battery.

Voltage is a rating for a given output of a battery but NOT to be confused with AMPS. Voltage can in laymen terms as a garden hose, now if you have a garden hose that is as wide as a bowling ball you can transfer power pretty quickly but in the same sense the length of time you can transfer power decreases because of the increase in flow. So the higher the volts the less ah you will get out of a battery or battery pack, and consequentially the more batteries that must be put in parallel to make up for the reduced ah.

Series & Parallel
The Differences between the two are rather simple. One increases the time in which you may use a battery (increasing Amp Hours) while the other increases Voltage without affecting AH and vice versa.
First we’ll cover Parallel. Parallel keeps the same volts but Adds the AH’s. So if you took two batteries both 12V and 20AH and wired them in Parallel you would have 12V and 40ah.

When wiring parallel you MUST have the same type of batteries weather they are lead acid or lithium ion, you should not mix battery types as they could explode. To wire parallel you line the battery’s up and connect the positive terminals together as well as the negative terminals.
Series is close to parallel but differs in the respect of what it does to the battery output. Series increases the output voltage of the battery’s that are being tethered together instead of the battery capacity. Now having said what series does I should mention that you may want 24v 36v or any other voltage with increased AH’s as well. This is possible and you would wire batteries in series and behind them you would wire a “bank” of batteries in parallel to gain the amount of capacity that you require.