An inexpensive battery option superior to lead batteries is the SB 12 volt 100Ah LFP

12 volt 100Ah Lithium deep cycle batteries can cost $1000 or more. The SB-12V-100Ah is a robust 12v LFP 100Ah (1280Wh) currently priced at $750 plus tax and with old battery exchange (lead acid)
Designed to be the least expensive and high quality lithium iron phosphate for installation in RV and trailers. MFG in USA

 

What is the Least Expensive LFP Battery?

LFP refers to lithium iron phosphate chemistry and 100Ah to battery capacity for deep cycling.
The small size of the SB 12V-100Ah is convenient as a  direct replacement of common RV & trailer 12v group 24 lead acid batteries. Both batteries are categorized as group 24 size and measure 10 1/8 " L x 6 5/8" thick and 9" tall.
Lead acid group 24 batteries start at $100 ea and last a few seasons. Group 24 lead acid AGM batteries can last longer but even the very best, still have a max cycle life of 1200 cycles to 50% depth of discharge and start at $200 ea.
The least expensive 12 volt lithium deep cycle battery, mfg in USA, currently would be the SB 12V-100Ah priced at $750 ea plus tax and with old battery exchange (lead acid) and a life of use anywhere between 2 and 5 thousand cycles, depending on the temperature, how fast the battery is charged and discharge, and charger quality (amps)

Electrical Specifications
Nominal Voltage	12.8 Volts
Nominal Capacity	100 Ah
Capacity @20 Amp	300 Min
Energy	1280Wh
Resistance	≤30m Ω @ 50% SOC
Efficiency	99%
Self-Discharge	<3.5% per Month
Maximum Batteries in Series	2
Discharge Specifications
Maximum Continues Discharge Current	100 Amp
Peak Discharge Current	260 Amp (≤5 s)
BMS Discharge Current Cut-Off	300A±50A(2.2±1ms)
Recommended Low Voltage Disconnect	11 Volts
BMS Discharge Voltage Cut-Off	8.8 V(2.2±0.08vpc)
Reconnect Voltage	10 V (2.5±0.1vpc)
Short Circuit Protection	200-400 ms
Temperature Specifications
Discharge Temperature	-4 to 140°F (-20 to 60°C)
Charge Temperature	32 to 113°F (0 to 45°C)
Storage Temperature	23 to 95°F (-5 to 35°C)
BMS High Temperature Cut-Off (Discharge)	167°F (75°C)
BMS Reconnect Temperature	122°F (50°C)
Low Temperature Cut-Off (Charge)	32°F (0°C)
High Temperature Cut -Off (Charge)	129.2°F (54°C)
Mechanical Specifications
Dimensions (L x W x H)	10⅛" x 6⅝ x 9
Weight	26 Lbs.
Terminal Thread	5/16"
Case Material	ABS
Enclosure Protection	IP56
Cell Type	Prismatic
Chemistry	LiFePO4
Configuration	4S1P
Charge Specification
Recommended Charge Current	50 Amp
Maximum Charge Current	100 Amp
Recommended Charge Voltage	14.6 Volts
BMS Charge Voltage Cut-Off	15V (3.75±0.1V)
BMS Reconnect Voltage	14.2 Volts
Balancing Voltage	14.0V(3.5±0.025vpc)
Balancing Current	30±5,mA

 SB 12V-100Ah

$750 ea plus tax and with old battery exchange (lead acid)

How Long Will the Lithium Battery Power My Devices?

From the typical RV battery set up above, the following devices will have operating time in hours:

Cell Phone 10 watts - 240 hours

30 watt Light Bulb - 85 hours

Refrigerator 150 watt - 16 hours

Fan 20 watt - 128 hours

TV 50 watt - 48 hours

FAQ for the Least Expensive lithium battery for sale

Q:  What is estimated lifespan?
A:  The battery will have a life of use anywhere between 2 and 5 thousand cycles, depending on the temperature, how fast the battery is charged and discharge, and charger quality (amps).

Q  What are the applications?

A:  The battery is designed as an energy storage source and easily stores energy from solar, wind, or an AC charger. It can also be used to start small engines (marine, up to 90 HP), ATVs, or used to run trolling motors.

Q:  Will the SB 12V-100Ah fit with an Airstream Trailer?
A:  Yes, SB 12V-100Ah has a group 24 foot print.