Question about jumpacks

[dualhammers]

So I found this powerpack at the thrift store for $10. No manual. It came with a 9dcv / 900mah charger that plugs into the front.

I am curious if there is a way to deduce the max amperage the charging wire can take. Is it possible to rewire this to take a small, maybe 60watt, solar panel as input through a charge controller?


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[SternWake]

The battery within that unit is likely no good anymore.

the good news is that they are usually very easy to replace.

These are the two most likely batteries within that unit:

https://www.amazon.com/Sealed-Lead-Acid-Batteries-UB12120/dp/B004JHI8MM

https://www.amazon.com/s/ref=nb_sb_...earch-alias=automotive&field-keywords=Ub12180

You can hook solar up easily.

The plug in wall chargers that come with these jumperpacks are just single stage/ voltage wall warts which can barely, and only with enough time, get the battery within to a fully charged state when it is still newish and healthy. When older and degraded 13.8v applied for days will not really be able to return the battery to maximum energy density as a higher voltage is needed to force the last few % into it.

A solar controller will take much better care of the battery than will the 900Mah 13.8v wall wart provided with the unit.

Those AGM batteries above, when deeply discharged, Ideally should get close to 4 amps initially appled for the 12Ah battery and 6 amps for the 18Ah battery, until voltage gets to 14.5 to 14.9v, then held there until amps taper to a very low level(0.5% of the capacity), then drop to 13.6v float.

13.6/.8volts applied by the provided wall charger is a far cry from ideal for recharging these batteries. but is a OK safe set it and forget it charger when the battery is healthy and the time to recharge is not a factor.

Deep cycling and often cycled AGMS want a different recharge regimen, and that means higher amperage to a higher voltage applied promptly after a discharge. 100 solar watts is about 5 amps at noon.

You need not pursue ideal, these batteries are pretty inexpensive. Ideal just makes them last longer and perform better while they last.

 

[TucsonAZ]

Also, if you wanted to go on the cheap and are handy with some tools around, you could track down some old laptop batteries and pull the 18650s out of them, charge them and see which are still good and make a pack out of those. Not to be done if you don't know what you're doing though, plenty of info on youtube.

 

[DuneElliot]

If I ever run into anyone in Wyoming in the next couple of months who wants one of these, I have a like-new one (off-brand) they can have for free. It won't do much for my diesel truck but will handle a van or car jump-start just fine.

 

[dualhammers]

Also, if you wanted to go on the cheap and are handy with some tools around, you could track down some old laptop batteries and pull the 18650s out of them, charge them and see which are still good and make a pack out of those. Not to be done if you don't know what you're doing though, plenty of info on youtube.

That's a great idea. Thank you!

 

[SternWake]

AA size batteries are 14MM diameter, 50MM long and when lithium cells, are called 14500's


18650 are 18MM diameter, 65MM long

I would not be mixing and matching 18650 cells to make up a battery pack.

Tesla will be making something like a 21700 cell in their new gigafactory for whatever reasons and the 18650 cell will likely be less ubiquitous from here on out.

I have harvested 18650 cells from laptop battery packs.  they were all 2100Mah cells or therabouts when new.  The best ones I harvested, can deliver about 700Mah now, and it better not be A high amp load. n I used them individually powering a single cell portable USB power supply, or in my nitecore HC-50 head lamp

All my laptop battery harvested cells will soon be recycled at best buy, as their usable capacity is not worth the effort of exchanging them so often, and No way in heck would I hook these cells in series/parallel to make a 12vish battery.

If I wanted to do that I would use Identical new cells, and certainly not old capacity compromised ones.  Lithium fires are best avoided.  Soldering tabs to these cells for series parallel connections required one have the right tools, and skills.

While the AA and AAA alkaline batteries are not dangerous, the same cannot be said of the lithium cells, and those that use these cells should not treat them like Alkaline Nicad or Nimh cells, and no newbie shoud consider making up their own pack without knowing the risks and all that is involved in getting these cells to behave appropriately together.

 

[jonyjoe303]

Some of these jump packs can be charged from your car cigarette adapter to jump pack cigarette adapter, they even have a special male to male type wire for this purpose. So technically if you can connect a male adapter to your solar controller battery out, you can charge that way.

60 watt panels maxes out at 3 amps, well within the capabilities of the battery on the jumppack. I actually connected similar jump packs to my 240 watt panel through an mppt controller, capable of providing up to 15 amps. The small 18 amp hour agms can be charged at high rates, they can be used as a car cranking battery if thats all you got.

As far as using 18650 lithium batteries, it can be done. I actually fitted 60 of those batteries into an old jump pack. 60 batteries gave me a  3s 11.1 volt lithium 37 amp hour power pack. But its not easy to do. I build smaller lithium packs before I build the larger ones. If you can build a small battery pack with 9 cells, scaling up to larger sizes aint that much harder. 

The small agm batteries go bad because they arent charged regularly. They sit in a car for 9 months between charges. And then the small ac charger doesnt charge at the high amps the battery requires. All lead acid batteries are happiest when they get alot of amps regularly.