Lithium ion battery jumper

[Dave Fritz]

I had to have my lawn tractor jumped and the guy used a small lithium ion unit with jumper cables attached. Anyone have experience with them and/or a recommendation?

[Jeff Monson]

I carry one in my truck all the time. They come in very useful. You can charge charge a cell battery or jump start a car. Now you cant get a ton of cranking amps out of those small cables but if you just need to boost a car that has a low battery that will work fine. You can find them at the local BORG's not sure on the quality. Mine came from my Mac tool dealer, had it for a couple years now.

[Dave Lehnert]

No personal experience but have had my eye on one.
This model at Harbor Freight gets good reviews.
https://www.harborfreight.com/lithium-ion-jump-starter-and-power-pack-62749.html

[Morey St. Denis]

Just keep in mind that impressive looking 12,000 mAh actually amounts to only 12 Ahrs; your average automotive starting battery should be in the range above 50 Ahrs. Lithium is very good rechargeable technology, relatively low impedance, longer lasting if treated well, considerably less "weighty" & more compact than NiCad, certainly other alkaline or Pb-acid formulations. The atomic weight of Lithium averages just; wait for it:..

Less than 7; while Nickel, Cadmium, Silver, Lead & Zinc are approximately: 59, 112, 108, 207 & 65 respectively. Lithium polymer cells have an inherent galvanic series potential of 3.6V, but do require substantially more advanced electronics; monitoring, balancing and regulating each individual cell during the re-charge. It is typical to find Lithium storage battery voltages available over quite a wide range, but largely by whole integer multiples of 3.6V.

[Grant Wilkinson]

Can those of you who have actually used these in the cold winter comment on their usefulness, please. I'm looking at them, but youtube videos (I know, I know) seem to indicate that in the cold, they don't do so well. Since I would only be using one in a Canadian winter, aversion to cold is not a good thing.

Since the more powerful models are quite pricey, and since I'm not too concerned about portability, I'm thinking a better bet may simply be to buy a regular battery. I'm only looking at any of these for use in boosting people's cars. My car batteries are in good shape, but I frequently find myself in a parking lot with some poor person whose battery is low/dead. I don't like hooking cables to my car battery, with all the electronics in it. So, I'm looking at carrying something separate.

[Morey St. Denis]

If you leave rechargeable Lithium battery packs in a vehicle or unheated jobsite overnight exposed to ambient temperatures, you will be disappointed by their cold waking performance. Most chemical reactions and energy storage solutions show a strong (even exponential!) relationship to thermal energy levels; typically doubling in rate with every 2 degrees Centigrade temperature increase. If you can manage to start your outdoor workday with charged batteries nearer room temperature and use them at least hourly, natural internal resistance or even a brief spell on the charger will produce just enough sustained warmth to likely deliver satisfactory performance throughout the day. Electrical energy storage options do not lose energy with prolonged cold exposure, they temporarily lose the ability to develop nominal electrical current flux. Cordless tool developers are well aware of these recurring concerns; more recent product generations do exhibit noticeably better cold performance than initial offerings, as they steadily tweak the Lithium formulation and electrolyte chemistry. Otherwise you may want to resort to a portable generator and corded power tools, or hand tools; with the notable exception of combustion powered framing and finish nailers. Whenever relying on lead-acid automotive batteries, many's the time we've had to briefly move car & truck batteries indoors to a sink of warm water to quickly restore electrical energy potential whenever temperatures dip double digits below zero.

BTW, when jumping car batteries don't connect directly to both posts of either battery, there can often also be problems with an inadequate battery ground connection. These potential faults can be safely & effectively bypassed by using a single, or even a remote jumper post when available, then finding a bare metal frame ground, often a threaded stud or unpainted bolt head on the nearby chassis, engine block or front suspension struts. Typically connect Positive before negative jumper leads, then break Negative before positive when removing jumper cables. Same preferential sequence goes whenever removing or installing automotive batteries. Ignore these basic guidelines at your peril; I once worked with a fellow who's face was unfortunately left severely scarred by sprayed sulfuric acid burns while attempting a good samaritan act in jumpstarting a stranded motorist. Ensure your jumper cables are thoroughly checked and maintained seasonally, if asked to use another's, always give those a quick inspection prior to use.

[Ronald Blue]

I don't know how well the lithium ion jump packs will work but I suspect that as has already been stated they are marginal at best. In my work we often use a jump pack on heavy equipment. Most of these are 24 volt machines. The jump packs we use are lead acid gel batteries. If it doesn't make the veins in your neck bulge when you pick it up it's not worth having. 8D batteries with 1400 CCA times 2. If they need a boost you need a jump pack that packs a punch. Obviously an auto or light truck doesn't need that sort of amperage but if you want it to have enough to make a difference on a weak run down battery it needs some reserve.

[Grant Wilkinson]

Tks much Morey and Ronald.

Morey: I do not connect the batteries directly one to another. In my previous life, at the age of about 17, I did that and the resulting "explosion" took out the complete side of a battery. Lesson learned.

Ronald: I figured as much. I used to have an old battery used for a trolling motor and the veins on my neck did bulge when hauling it into my car. That battery is done now, hence the question.

Tks again guys. Merry Christmas!