Substituting Li-Ion in place of the standard AGM battery will cost over $2000 extra per kW and we recommend a minimum of 3 kW. (But expected battery life is four times greater.) Now brace yourself, you'll also want 2-8 more solar panels to make going lithium worthwhile (i.e. additional $4000+).
Li-Ion Weight Difference
An AGM battery weighs about 80 lbs per kW; Li-Ion batteries weigh about 20 lbs per kW. A 3kW SUNLION will weigh about 160 lbs and can be the linking power module of a solar electric power system or the primary unit of any offered inverter-model type.
The SUNLION unit looks similar to any other SUNRNR on the outside, but the inside (lithium ion in place of AGM battery) makes the input/output characteristics quite different:
3 kW of Li-Ion storage capacity will fit in place of the 2+kW AGM battery in any of the primary units. Because a power module does not have an inverter, there is room for 6 kW in a SUNPWR!
Lithium Ion batteries can charge at a faster rate (50+%) than the 10% of battery capacity an AGM battery is limited to. Each kW of Li-Ion can accept the charge of at least two 140W solar panels. That means a minimal 3kW SUNLION can fly over 800W of solar panels and as we always say, the power is in the panels.
However, an AGM battery is better than a Li-Ion at providing the hard start-up power for certain loads. Having a little of both makes for the perfect system.
SUNRNR models are defined by their inverters (or lack thereof with respect to the non-invertered SUNPWR Power Module). Any model can have either AGM or Li-Ion battery storage (and in special cases, both). An excellent solar electric powersystem would be mix and match - having one primary unit be one type of battery and another unit (either power module or another primary unit w/different inverter) be of the other battery type. Stored battery power may be shared by use of the Link Cable shown below.