Connecting 2 Batteries in a Parallel Connection While Considering Safety and Mismatching

The primary principle, when you are attaching 2 batteries in parallel is that you‘re including the amp hr ratings of both the batteries and maintaining the same voltage. For instance, if you link two 6 V 4.5 Ah batteries in a parallel connection, they can supply 6 V 9 Ah (4.5 Ah * 2) and if you connect four 1.2 V 2,000 mAh in a parallel link, they can offer 1.2 V 8,000 mAh (4 * 2,000 mAh). There is a huge no if you desire to attach two batteries of different voltages in parallel.

The battery having higher voltage will charge a battery having lower voltage for creating an equilibrium in the circuit. We do not suggest this process since the primary (disposable) batteries aren‘t created in a manner to handle the charge. Therefore, the battery with a lower voltage will certainly overheat and also as a result of this, it might bulge or leak. In extreme cases where voltages are dissimilar, the primary battery might explode as well as in the case of secondary (rechargeable) batteries, the battery having lower voltage can‘t charge above a specific limit. Therefore, overheating, bulging, or leaking might take place in the higher or lower voltage battery as it drains promptly. The bigger the voltage difference the more are the chances of a battery explosion.

In case you use batteries from different companies and of a similar voltage, you can have issues. As a result of the unlike production procedures, the voltages of batteries from different manufacturers might differ somewhat. It indicates a 1.5 V battery from a company can be 1.6 V, while a 1.5 V battery from another company could be 1.55 V. If these batteries are linked in a parallel setup, you can experience troubles aside from explosion since for primary batteries, the more powerful battery will anyway attempt to charge the weak one as well as reduce the lifetime of both the batteries. For secondary batteries, the stronger battery will certainly charge the weak one, drain itself as well as waste energy.

If you attach rechargeable batteries in a parallel connection and one of them discharges whilst the others are charged, then the charged ones will certainly try to charge the discharged battery. The charged batteries will certainly overheat as they quickly drain and the discharged system will overheat as it begins to charge over its design capacities.

In case you link batteries having different ages, then the batteries which are older will certainly have a lower voltage since all the batteries self-discharge as time passes and even rechargeable ones won‘t recharge to the same capacity as the new ones. To avoid the chances of issues, you must adhere to some safety rules while setting a connection. In the case of primary batteries, only make use of batteries of the exact same age and company. Dual check the battery voltages with the aid of a voltmeter. While using secondary batteries, use ones of a similar company as well as age, and before linking make certain all the devices are totally charged. In case you are unsure about this, link them individually with a charger or you can check the voltage using a voltmeter.

It is possible to link batteries with various amp hr capacities in a parallel connection and this will not create any significant issues, yet it is vital to think about some possible issues like inspecting your battery chemistries since Sealed Lead Acid (SLA) batteries have various charge limits. It means if you reenergize 2 batteries together, a few batteries will never charge completely. Consequently, there will be sulfation in those that don‘t charge completely, reducing their lifetime. Double-check voltages, in case you‘re linking batteries with different amp hr capacities since the voltages should be different (even if voltages on the labels are the same). Also, check with a voltmeter or you will experience problems.

Can we safely connect mismatched batteries in a parallel connection?

It‘s strongly not advised to attach batteries in parallel applications if these batteries are different in size, age, and type. Various firms of batteries can have different discharging and charging properties, like charging faster. It can also be feasible if these batteries are of the same size. Various batteries (flooded or AGM) additionally can have distinctive discharge/charge properties. In case you try to attach 2 or more batteries that don‘t discharge and charge at the same rate, a battery can end up being overcharged whilst the other one will wind up undercharged. That‘s why this procedure is not advised as you do not want to develop any trouble with your batteries, since it can reduce the lifetime of both batteries and might potentially produce a harmful situation, if one battery remains overcharged.

Wiring batteries in a parallel connection: Is it safe or not?

When 2 batteries are attached in a parallel connection, the voltage continues to be constant, however, the current is increased. This can be extremely useful in the case of some gadgets. However, if the batteries are delicate and also, they don‘t have any kind of circuit for security, after that it can be extremely dreadful for both the batteries.

Just how to attach 2 batteries in a parallel connection with an inverter?

You can link multiple batteries in a parallel connection with your solar hybrid inverter or power inverter for increasing the backup capacity. In case you possess a battery inverter, you can link more batteries in a parallel connection as the entire system‘s voltage will certainly remain constant while the capacity increases. For linking two batteries in a parallel connection with the inverter, you have to ensure that the power inverter can at the very same time charge several parallel connecting batteries. In case a charger isn‘t quick, you must not connect some larger batteries. Likewise, check the UPS or inverter specs to see if the charging current can be increased as it will aid the battery charging to increase and lower the time to completely charge batteries.


In case you are attaching batteries in a parallel connection, the extremely crucial thing to think about is that the batteries have a similar size, voltage, chemical construction, and capacity. The batteries linked in a parallel connection having all of these points the same, will supply power to the circuit swiftly as well as effectively. And also, if these variables are overlooked, specifically the same voltage and capacity of the batteries, it can be harmful to both the batteries.