May 23, 2016

DEEP CYCLE BATTERY BASICS

DEEP CYCLE BATTERIES BASIC CONFIGURATION

There are many ways to wire batteries to attain the kind of bank that you need to suit your needs. For instance commonly road vehicles and Marine applications run off a 12v DC type of system. In order to build up your battery capacity you will probably need more than one battery in order to attain the storage that you need. Also you may run into space or cost issues with the larger 12v batteries. Often people will use two 6 Volt batteries wired in series to get to the 12 volts that they need.

Good battery interconnect cables are an essential part of putting your battery bank together. Choosing the proper gauge wire is critical and the correct wire length determines the efficiency of your system. Cables that are too long will result in power loss and unnecessary resistance

An amp hour (AH) is a rating usually found on deep cycle batteries. The standard rating is an Amp rating taken for 20 Hours. What this means, say for a 100 AH rated battery is this: Draw from the battery for 20 hours and it will provide a total of 100 amp-hours. That translates to about 5 amps an hour. 5 x 20 = 100. However, it’s very important to know that the total time of discharge and load applied is not a linear relationship. As your load increases, your realized capacity decreases. This means if you discharged that same 100 AH battery by a 100 amp load, it will not give you one hour of runtime. On the contrary, the perceived capacity of the battery will be that of 64 Amp Hours.

The nameplate rating on a battery is the fully developed capacity; therefore, testing a battery immediately after it is purchased is misleading since it may take up to 100+ cycles for it to reach its full capacity. Beware of a battery that promises full capacity at the time of purchase or one that reaches full capacity after only a few cycles. Batteries with a 100+ cycle warm-up will always outlast a battery touting a high initial capacity.

Batteries can be connected in a serial connection and a parallel connection. Let’s look at this more closely

Serial Connection

When you wire batteries together in series you will increase the voltage while keeping the amp hour capacity the same. For instance the two 6V 105Ah batteries pictured here, if wired in series will give you a total of 24V at 105Ah:

 

serial

 

Parallel Connection

Wiring batteries together in parallel has the effect of doubling the capacity while keeping the voltage the same. The setup pictured here, of four 6V 105Ah batteries connected in parallel will allow you to four times the capacity, producing 6V with 420Ah out the end:

 

Paralel

 

Wiring in both Series and Parallel

Batteries can be wired both in series and parallel, this increases both the amperage and voltage available. In this example here two “Strings” of batteries are wired up in Series to essentially make 2 x 12V Banks, these are then wired together in series (doubling the 105Ah) to eventually provide 24 Volts at 310Ah:

 

both

 

We truly hope this section has given you all the information you needed on Deep Cycle Batteries.