Pilot InstaBoost: Battery Capacity

The cardboard package liner claims the lithium-ion battery inside our Larval Engineer’s shiny new InstaBoost jump starter is good for 10.8 A·h and and the minuscule inscription on the case truncates it to 10 A·h. Given what I’ve seen for other batteries, either value would be true when measured under the most favorable conditions, but these curves still came as a bit of a surprise (clicky for more dots):

Pilot Instaboost
Pilot Instaboost

The three short, abruptly dropping curves come from the main terminals, with the battery clamps attached to similar clamps (with a glitch when they shifted position) plugged into my CBA II/IV battery tester, showing that the InstaBoost shuts off after a few minutes, regardless of load. That makes good sense: don’t connect a lithium battery to a lead-acid battery for more than a few minutes!

The two longer curves come from the 12 V jack on the side and show that it will run until the battery goes flat. Evidently, the internal battery protection circuit cuts out at less than the 10 V minimum I used for these tests.

I didn’t bother testing the USB charging outlet, as I assume it would produce 5 V at 1 A for slightly less than twice as long.

Under the most favorable conditions I could come up with, the actual battery capacity of 3.5 A·h is a third of what it should be. I’d expect that from the usual eBay supplier, not Lowe’s.

Given the cheapnified clamps, perhaps Pilot deliberately gutted the battery capacity to save a few bucks. After all, the customers will never notice. Will they?


Another customer took his apart and found three 3.6 A·h “high output” (whatever that means) lithium cells in series. In that configuration, the individual cell capacity does not add and the pack should produce about 3.6 A·h. Those curves show it produces slightly less than that when discharged to 10 V, which means the thing works exactly like you’d expect. Indeed, it’s better than a typical second-tier product and much better than typical eBay crap.

The most charitable explanation would be that somebody screwed up, multiplied the number of cells by their individual capacity, put that number in the specs, and everyone downstream ran with it. If the cells were in parallel, then the total capacity in ampere·hours would equal the sum of the cell capacity.

If you change the specs to match the as-built hardware, then, apart from those cheapnified clamps, it’s working just fine…

13 thoughts on “Pilot InstaBoost: Battery Capacity

  1. Here’s your chance to become the lead plaintiff in a class action lawsuit over the specs of the unit. While most people in the class action lawsuit don’t get much, the lead plaintiff(s) do usually get a reasonable chunk of money. You’ve done the detective work – go for it! Lowe’s has deep pockets!

    1. That would certainly take my mind off all my other problems for quite a while…

  2. Ah, battery issues. My UPS decided to drop the “uninterruptable” part of the function in honor of the latest power glitch. Haven’t opened it up yet, but I assume the 4 year old gel-batteries have packed it in. Radio Shack (local one is still open) is out of stock, and the farm supply doesn’t sell fence-charger batteries in that configuration. Memo to self–check the function monthly.

    Belkin did one “oops”. It’s very easy to short 24V to ground when installing the case. I need to add a piece of anti-shorting cardboard so I don’t have to rewire the ground trace–again. It’s also old enough that I need to look at the capacitors…

    1. Someone, somewhere, does an annual run-time test on all their UPSes to verify that the batteries have enough capacity. That wouldn’t be me…

      There are at least five UPS boxes around here: it could be science! [sigh]

        1. Looks like a dedicated tool for a specific test, but wow it’s the right hammer for that job: much better than the many hours required for a discharge test!

          Or I used to.

          I rest my case. [grin]

  3. For a while I was doing inventory and battery swapout on about 90 APC UPSes at a total of 9 convalescent hospitals (the company that I worked for part time had the IT contract.

    The small UPSes used on the phone systems used one 7AH 12v unit, the small computer UPSes used two. The server UPSes used two of the 18AH units.

    When USA made batteries were available locally we could count on 4.5 to 5 years from each battery or set of batteries. When we were forced to go to Power Sonic (made in China) the live dropped to 2.5-3 years.

    One bit of info on locating batteries – there is a company named ADI that has retail stores in almost all the states, plus they will drop ship anywhere. They mainly sell alarm, network and phone systems stuff – which included some sizes of gell-cells. It might be useful to check this web page to see if they have a supply house near you: but batteries are heavy, watch the shipping charge. we had a clerk that lived near their local store, we had her pick up orders on the way into work to shave shipping charges when we bought batteries – and there were times that we’d buy from two to twelve batteries at once.

    Some localities have different rules – here in Calif. they will not sell alarm panels to people that do not have an alarm installers license, but they will sell wire products and batteries to anyone.

    1. As of the last time I needed SLA batteries, MAT Electronics (at the obvious http://www.matelectronics.com) had good prices and reasonable shipping.

      The shipping definitely gets ya: batteries with “free shipping” cost much more than the rest…

      1. Mike, thanks for the info on battery life. I guess I did OK. (The UPS worked properly last summer, so the Radio Shack generic batteries lasted over 3.5 years.) ADI is too far away, but Batteries Plus is near the regional Costco if I wait til March. RS batteries cost about the same as for B+ with shipping, so I’ll check in town every few weeks.

  4. PS – I have no connection to ADI except as a part-time employee of a occasional customer.

  5. Ed said “As of the last time I needed SLA batteries, had good prices and reasonable shipping.”

    I think there was a noun dropped there. Who was the vendor?
    I’m always interested in recommendations from knowledgeable people that have been there and done that.

    1. Worse than that: the whole URL went missing.

      Lemme see if I can fix that…

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