Low-self discharge 9v NiMH batteries have become available in the last few years. The “low-self discharge” label means these batteries will hold their charge for a year, unlike previous NiMH batteries. This makes these 9V battery much more compelling, because 9V batteries are often used in applications like fire alarms, where the battery must sit for year or more.
Accupower has released a 300 mAh 9 Volt Rechargeable NiMH Battery — this currently the highest capacity rechargeable 9V.
The second highest capacity 9V is the Ansmann low-discharge 250 mAh 9v.
Centura 9V NiMH Battery by Tenergy
Imedion 9V NiMH Battery by Maha
The 250 mAh 9V Imedion by Maha is available on Amazon for $20.95 for a pack of 2 batteries. These batteries are more expensive, but they have a higher capacity of charge (250 mAH compared to Tenergy’s 200 mAh), and Maha’s batteries have a better reputation in terms of quality.
You can also get 9V rechargeables from Energizer, but their quality is poor.
9v Lithium Ion Rechargeables
You can also get Lithium Polymer 9v rechargeable batteries, that use a new gel-type electrolyte. This gel has an energy density that is 20% more than typical lithium ion batteries (550 mAh in capacity). They also last 2 to 3 times longer than rechargeable 9V NiMH batteries, and they hold their charge longer. They are available on Amazon, for about $13 each. You can get the charger and battery pack here.
See also our review of this year’s best rechargeable NiHM batteries and chargers.