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    • I'm not a fan of the lead acid backup batteries for mobile applications, because it's *primary* duty is readiness--keeping a mobile, always-there bank of juice for weeks and months, at-the-ready, and lead acid tech kind of sucks at that.

      In fact, the readiness functionality of one of these backup power banks runs counter to the very nature of lead acid batteries. They self-discharge pretty significantly over the course of months. More dramatically in the winter months too. And that leads to deep discharge, which shortens their life. And then people think "what a piece of crap" 9 months later when they actually need it to perform its 2nd duty (actively delivering the stored juice). They find that only a fraction of juice still remains, and whats worse, the oxidation of the lead plates means that it can't be fully charged anymore. They get frustrated, and they chuck out what could have been a useful piece of gear, if it was deployed in a better manner.

      In fact, the one exception I have to my distaste for mobile lead battery banks is when it's deployed the smart way--like...for the manner in which all lead acid batteries are incorporated into cars & RVs.

      Paired with a means of recharging, and a charge controller, lead acid batteries can give you good bang for the buck, and if you have a vehicle to carry its weight, who cares that it weighs a ton. Then you don't just have a battery bank, you have a whole system thought out. But aside from RVs, police cars, and tow trucks, I rarely see anyone implementing such an ambitous mod. You never see packs likt that Cat Jump starter sorted out with its own charge controller, & plugged into an onboard alternator for frequent automatic top-ups. But open the hood of tow truck and RVs and sometimes you'll notice that they're equipped with a 2nd battery and even a 2nd alternator (all optional OEM equipment, by the way) under the hood doing exactly that. Those are good mobile 2ndary power sources.

      If you do get the jump starter, I recommend you get in the habit of putting a reminder on your calendar maybe every other that sucker up on a fairly frequent routine.

    • Thanks for the input.....I was reading some reviews and it guess this cannot be, I was thinking just keep it plugged in stored in my garage and then when I head out on a single multi-day adventure, throw it in the back.

    • Ya, that'd be a great way to use it.

      I don't have many lead acid battery-powered gizmos, but one that I've had for years is an el-cheapo LED spotlight. It has a relatively beefy SLA battery housed in it. It's charge controller sucks (always on), so I have it on a 4 times a year charge routine. Every changing of the seasons...I pull that thing out and charge it up. If you pair it up with the maintenance routine it'll do its job.

      I even took it apart to see what the battery spec was, and made myself a little reminder (the manufacturer actually publishes great specs for their batteries). Manufactured in 2008. I've been religious about topping it up. Still serves me well.

    • For anyone who doesn't actually plan on multiple days away from a power outlet or super heavy loads, there's cheaper simpler options, once you let go of the idea of solar charging.

      If you're always going to juice up from a 120v power outlet, and the max load you really care about is, say, a laptop--getting your hands on a laptop-oriented power bank might be all you need. Maybe less flexible...but within its limited scope...great bang for the buck. And sometimes...dirt cheap.

      The distinct value of going w/ something that charges itself off of a dedicated power cord is simple... 30 W wall chargers gives you *fast* recharge time. 6-8 hrs over solar panels? Psshhh... AC baby...

    • One benefit of lead acid is it can be used for jumpstarting a car. Do we know if lithium ion batteries can jump-start a car without destroying/damaging the battery?

      I'd like to also have a portable power solution that I can use to start the car if its battery is dead. It would be awesome if there's something that would fullfill all my needs.

    • For backpacking you of course wouldn't want anything like this, though I do sometimes carry a small USB power pack if I want to keep a phone charged.

      I also camp in an a-frame camper, often off the grid. The camper has an on-board battery, but I'm usually also powering a laptop and astronomy equipment.

      One of the pictured units would probably work for me, but for a cheaper solution I use a deep cycle battery. It's in a plastic battery box (like you would have on a camper for for a trolling motor), where I've added fused 12V power ports (power poles and auto DC sockets) and a volt meter. It's heavy, but lasts a long time.

      I recharge both the camper and battery box using a 100W solar panel and charge controller. I just hook it up to whatever needs charging for the day and leave it out.

    • I bought one of these from Costco for $79 for one of our cars and it turned out to be so handy, we bought one for every car. Works great. I dunno how many jumps we get per charge, but I'm guessing 6.

      We have old cars and if the kids leave a door ajar or something, we need to jump.

    • Actually these days I don't do as much... I was doing astrophotography, so I needed to power an equatorial mount and laptop, and dew heaters if needed.

      These days though I'm doing more visual astronomy. My thinking is that I shouldn't spend time outside staring at a computer screen when I could be looking up!

    • There are a few tricks you may want to try to see if it's up to the task. If your battery is really dead, often I find that it takes more than a minute for enough energy to transfer to the dead battery to crank the engine. Also making sure the clamps have sufficient surface contact to support a decent amount of current. The more surface contact you can make with the clamps, the less patience you'll need. But regardless you will need *some patience* . Only after you've waited a while would I try the ignition switch.