The basic concept is that when connecting in parallel, you add the amp hour ratings of the batteries together, but the voltage remains the same. For example: 1. two 6 volt 4.5 Ah batteries wired in parallel are capable of providing 6 volt 9 amp hours (4.5 Ah + 4.5 Ah). 2. four 1.2 volt 2,000 mAh wired in parallel can provide 1.2. This is the big “no go area”. The battery with the higher voltage will attempt to charge the battery with the lower voltage to create a balance in the circuit. 1. primary (disposable). This is possible and won't cause any major issues, but it is important to note some potential issues: 1. Check your battery chemistries – Sealed Lead Acid batteries for example.
