I own this boot device now for almost 2 years. I bought it (tempered light and what there so everything is still possible) to me for my hybrid, because if once the 12V battery should be discharged for any reason. But I have not been required because my Prius or the 12V battery in the vehicle has not yet left me at this time in the lurch. I use the Gyspack therefore primarily in the summer, to feed my electric cooler for the time of my purchases with electricity, because, unfortunately, the built-in vehicle outlets only work on the "Ignition" and not just supplies the box in the shopping time with current becomes. This is undesirable because the interior but very heats in strong sunlight. This works without any problems and it is with this battery pack a supply time of the icebox of 3 hours guaranteed. Then I have announced a voltage of 10,9V is available and it is charging. Only the charging time is quite long with something puny charger. I own but as a high-frequency charger, so that the internal battery is then charged much more quickly and with a corresponding charging curve. For that I clip the charging cable directly to the terminals of the battery pack. The manufacturer, or the German distributor for the Gyspack I can not give any good reviews. In various technical questions before buying, I have never received a reply as to whether this is connected with the Franco-German friendship, I can not say. I bought it anyway because there is no reasonable alternative in the market (either compressor but it inefficient or with displays and various voltage outputs that none required). But what I find is good that this battery pack without reloading (about every two months to instructions) by holding many months without losing large voltage (eg over the winter months and housed in a cold car). The shows, which must be quite well the built-in battery apparently. Let's see how long it makes me well before the battery needs to be replaced.
