Mega +PURE SINE WAVE commercial UPS series.
It can handle up to 2000 watts of active load, it requires exactly two 12v batteries connected in series (or a single 24v lithium unit), fully compatible with tubular, SMF, Gel and lithium (lifePo4) batteries. It also features a rapid 20A-25A variable charging current that can effectively juice up batteries even when nepa/grid voltage drops as low as 70v-90v. A 2.5kva system is ideal for a standard flat or small office