The Bioenno Power LiFePO4 batteries seem to be very popular. They are lighter, per amp hour, then the sealed lead acid batteries. They also have a slightly higher voltage then a SLA battery. But, they are more expensive than SLA's LiPo batteries, as used in model aircraft, are also good choices but the amp hour capacity is very limited. They are very small in physical size, great for backpackers and perfect for QRP radios.
When it comes to cost per amp hour, I found the LiFePO4 battery to be the best alternative:
The above battery is an LifePO4 (Lithium Iron Phosphate Battery) that is rated at 20 amp hours. This battery has a built in BMS (Battery Maintenance System) to protect the battery from over charging, draining the battery to a voltage lower then 10 volts and temperature control. The actual weight of the battery is less than 4 pounds. That's at least half the weight of a SLA battery of the same capacity.
When I received my battery, the first thing I did was to fully charge it and then load test it. I put a 2 amp load on it and it came out to 19.76 amp hours. That's close enough for me. I like it so much I ordered a second battery. I now have a 40 amp hour total capacity for setting up portable and being able to run 40 watts out for an extended period of time.
These batteries are 60% cheaper then the Bioenno Power batteries. You can get them on Amazon. When I purchased mine, the cost was $81.99.
Maybe a 20 amp hour is a tad too small for your needs? If so, they also make a nice size 36 amp hour battery. Weighing in at only 9.5 lbs, it sure is a lot lighter than an SLA battery. At the time I created this web page, the selling price on Amazon, was $129.99.
Another good choice would be a 24 ah LiFePO4. This battery also included a nice battery charger. Amazon Now selling for only $86.99
If a 20 amp hour battery is overkill for your needs, maybe a 10 amp hour battery would be a better choice. I purchased one of these to be used with my QRP only radios. The battery shown below is a 12.8v 10ah LiFePO4 . Again, Amazon sells them for $37.99.
A word about charging these batteries. First off you need a charger that is designed to charge LiFePO4 batteries. The voltage of these batteries is slightly higher then SLA batteries. You can use an SLA type charger on these batteries but they won't charge the LiFePO4 batteries to their full capacity. It's best to use a charger designed for these batteries.
The charging rate can be anywhere for 10% to 30% of the batteries rated capacity.
Example: To charge a 20ah LiFePO4 battery, the charging rate can be between 2 and 6 amps. 2 amps is 10% of the battery's capacity and 6 amps is 30% of the battery's rated capacity.
Pictured above right is a good little dual purpose charger. It has a mode change button so it can be use on SLA as well as LiFePO4 batteries. Amazon Charger
I use mine to not only charge the above batteries, but I also put it in the SLA mode and trickle charge my motorcycle battery and garden tractor battery while in winter storage.
A word on life span:
Most SLA batteries last anywhere from 4 years up to 10 years. Depending on where they are used, you may not notice the actual capacity decreasing.
When it comes to LiFePO4 batteries, if not abused, they can easily last up to 20 years.
Bottom line, LiFePO4 batteries may cost two to three times the cost of SLA batteries, but in the long run you are saving money. You are really getting a big bang for the buck !
A word of caution:
The above batteries are not designed to be use for starting engines. DO NOT replace or try to jump start your garden tractor with any of these batteries. They do make packages using LiFePO4 batteries for motorcycles, cars and garden tractors, but the above are not them.
TalentCell Batteries
The above pictured TalentCell YB1206000 battery is rated for 12 volts at 6000 mah. It uses three paralleled paired of 18650 batteries wired in series. The DC coaxial jack is limited to 3 amps of current drain. That is more than enough to power almost any modern day QRP radio like the Icom IC705 and the Elecraft KX series radios. The power jack is 5.5 mm x 2.1 mm. The battery also comes with a charger as well as a set of cables that has two male and one female coaxial connector. I like the idea that this battery has an on/off switch. The battery's dimensions are: 5.7" x 3.35" x 1.1"
At the time I posted this, the battery sold for $40 off of Amazon. You can get this same battery, minus the USB jack for $34 off of Amazon.
At 5 watts out of my Elecraft KX3, the current drain on the battery is less than 1-1/2 amps. With the use of the 6000 mah TalentCell battery I should be able to operate an entire day when setting up for a parks on the air activation.
If you want an even larger capacity battery, TalentCell makes an 11000 mah battery. You can draw up to 6 amps of current off this model. At the time of this posting, this battery sold for $65.
If you operate at a power level of less than 5 watts, or maybe operate short term whereas you use a very low current consumption, maybe the TalentCell YB1203000 would fill your needs. This battery pack is smaller in size than either of the above two batteries and is limited to only 3000 mah. This battery sells for $28 and has a USB port.
All of the above batteries have 5 LED indicators to show the capacity level. All five LED's will light when the battery is fully charged. You can charge the battery off of the supplied 115 volt wall wart or charge the battery from your car's power outlet with the optional car charger purchased from TalentCell.
I like the idea of these batteries including a USB power outlet. I always use my cell as a hotspot when setting up portable so the cell phone is always on. From time to time I may use my AT-10 auto tuner. The ATU has its own internal battery, but if I get in the field and possibly forgot to charge the ATU's battery, I can use a USB cable and charge the ATU's battery from the TalentCell. For those that use the Mat-tuner ATU, it can be also charged the same way, via USB cable. The NanoVNA as well as the TinySA (Ultra) can also be charged via the USB port.
For many years, when I operated portable, I would used RC vehicle LiPo batteries to power my radios. I would cut off the connector that was attached to the battery and add Anderson Power Poles. They worked just fine. The TalentCell battery pack is a much cleaner package and I like the idea that they have an on/off switch and a USB port.