LiDiVi Waterproof Dual USB Charger Socket Power Outlet 2.1A & 2.1A with Digital Voltmeter Blue LED Light for iPad iPhone Car Boat Marine Mobile
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【WORRY-FREE WARRANTY】With 12month manufacturer 100% money back guarantee. You are welcome to contact us if you have any questions or concerns. Our reliable customer service will reply within 24 hours, always. 【WIDE COMPATIBILITY】 Fits for almost input DC 12V-24V car, Boat, Marine, ATV, RV etc. The advanced full nylon body with a scratch resistance technology, keeps it sturdy and protects it against drops and scratches. High quality nylon material let your car charger always looking like new.
Some comments about this we saw on the web:
* /u/Burning_blanks on /r/BurningMan I use a 40 watt solar panel that does pretty well. https://www.amazon.com/gp/product/B00U8KY6FM/ref=oh_aui_detailpage_o03_s03?ie=UTF8&psc=1I would also recommend one of these as you can charge two devices at the same time and it will also give you a voltage indicator on your battery.: https://www.amazon.com/gp/product/B01M0GR0FQ/ref=oh_aui_detailpage_o09_s01?ie=UTF8&psc=1
——* /u/Burning_blanks on /r/BurningMan I would say you need to be careful with that as well. It depends on what voltage the batteries are that are being charged. For example my battery pack is charging to 58.5 volts.
300 watts solar is quite a bit of power and probably could theoretically push as much as 15 amps at 12 volts.(probably more realistically push 10 amps). You should make sure you get a decent solar controller and not some cheap knock off. Get it placed into some type of enclosure that will protect it against dust.
Second a more standard DC to AC inverter may be helpful. Make sure that it rated appropriately for the total continuous watts you plan on pulling. Keep in mind that for every 1 amp 110volt AC (120watts) you plan on pulling translates into 10 times the amount of 12 volt amps. so 2 amps of AC current will pull 20 amps of DC current out of your battery. Depending on the capacity of your battery, you can drain it very quickly. The inverter will most likely have a fan. Keeping it as dust free as possible will be important.
if you just need to charge off of USB power, take a look at these: https://www.amazon.com/gp/product/B01M0GR0FQ/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1
They will give you two 2.1amp USB ports off of a 12 volt battery. Be aware that large capacity USB batteries could take a long time to fully charge off of these.