This comparison between Lithium and AGM batteries is based on comparing equal Amp Hour Capacity. For this exercise we are looking at a Capacity of 200 Amp Hours. Because AGM batteries are limited to 50% discharge, only half the 200 amps can be used, therefore two 200 amp hour batteries are needed to match the Victron which can use all of its 200 amp hours.
# Batteries to produce 200 amp hours
# of Batteries needed over lifetime
Cost over Lifetime
64% of AGM
Note Charge Cycles; Charge Cycles is the indicator of Battery life. The Victron Lithium battery has a lifetime expectancy of 5,000 cycles at 50% discharge while the AGM only has 1,000 cycles.
Note # of batteries needed over lifetime; Since we need two AGM's for one Lithium and the Lithium lasts 5 times longer, then ten AGM's will equal the 200 amp hours capacity over its lifetime.
Note cost; The AGM batteries need to be replaced 5 times to equal the lifetime of the Lithium Battery. As there are two AGM for equivalent amps there will be ten AGM batteries to equal the lifetime of one Lithium. The cost of the Victron lithium when this comparison was made on Oct 3rd 2017 is $2730. Each AGM costs around $527 so total cost of the AGM batteries comes to $5270.