Li-ion to jump start a car?

[IT_Architect]

Somewhat tangential to the discussion: a hybrid LiFEP04 + supercap concept is in the works to replace your car battery. If not this particular manufacturer, then another is apt to produce something like this.;

I know that standard group size LiFE-Po batteries are around because someone posted a link to them I ran across last week on another forum. They do not use the capacitors. However, they are EXPENSIVE, which is why I lost interest and didn't save the link. They are easy to find for motorcycles, but they are still in the $359 range. They have electronics in them that not only protect the cells from over-discharging, but also balance the cells during charging to prevent over-charging the individual cells. They claim 8 years, but I'll believe it when I see it. I get 7 out of OEM lead acids. Watch out for the words, equivalent. Compare to the PCA and CCA to the OEM lead acid, and you will likely find out they aren't equivalent, and never equivalent on AH. So even if you do pay a fortune to get the same PCA and CCA, if the AH is way off you won't be able to have the accessories on long.

Lead-acids are tough to beat. They've had competitors before, such as flooded NiCADs like they use in aircraft. It's always something like safety, maintenance, reliability, longevity, cost, etc. Even small aircraft use lead-acids.

 

[idleprocess]

I know that standard group size LiFE-Po batteries are around because someone posted a link to them I ran across last week on another forum. They do not use the capacitors. However, they are EXPENSIVE, which is why I lost interest and didn't save the link. They are easy to find for motorcycles, but they are still in the $359 range. They have electronics in them that not only protect the cells from over-discharging, but also balance the cells during charging to prevent over-charging the individual cells. They claim 8 years, but I'll believe it when I see it. I get 7 out of OEM lead acids. Watch out for the words, equivalent. Compare to the PCA and CCA to the OEM lead acid, and you will likely find out they aren't equivalent, and never equivalent on AH. So even if you do pay a fortune to get the same PCA and CCA, if the AH is way off you won't be able to have the accessories on long.

Lead-acids are tough to beat. They've had competitors before, such as flooded NiCADs like they use in aircraft. It's always something like safety, maintenance, reliability, longevity, cost, etc. Even small aircraft use lead-acids.

We may have to agree to disagree.

I live in Texas where heat routinely kills batteries in 3-4 years - I'm amazed that the battery manufacturers offer warranties here. Conversely, it drops below freezing perhaps 20 days of the year; block heaters are a concept the natives don't understand.

My daily driver is a well-maintained compact car that uses a group 35 battery - 550 CCA is in line with what average batteries in that category. Starting the car is its primary function in life - accessories are quite rarely run for more than a few minutes with the engine off; the small reserve is of little concern to me. I suspect there are quite a few people out there with median use cases like mine that would be interested in a battery such as this just so they don't have to futz around with batteries that fail at the worst possible time - warrantied or not.

Provided the concept can reliably meet its claims, I think it will have a place in the market. Like I said earlier - it won't be everything to everyone.

Your "it's been tried before and failed" retort would be valid were this a rehash of something that's been tried before, but to the best of my knowledge this is the first commercial attempt at a hybrid battery. But the concept doesn't seem to have any inherently fatal flaws, so I'm going to wait and see; I'm hardly at the shut up and take my money phase. One suspects that should Ohm succeed, others will enter the market and the category will see marked improvements in both price and performance.

 

[ElectronGuru]

Re: The new lithium-ion jumpstarters

From an over-readiness standpoint, I love the idea of a pocket sized jumper. But as has been said, you can't leave it in the glove box for a year and you won't be carrying it in your pocket. So it needs to be a USb source first and a jumper second, in which case you may not have it when you need it for the car.

I'd rather spend the extra cash on a good AGM battery. It can handle abuse better, it should last longer in most applications, and it will always be in the car.

 

[IT_Architect]

Your "it's been tried before and failed" retort would be valid were this a rehash of something that's been tried before, but to the best of my knowledge this is the first commercial attempt at a hybrid battery.

I was referring to a LiFE-Po Group 86 battery, which if memory serves, would set me back $1700. Moreover, the advertised 12% increased life expectancy claimed, may be far from what is possible under real-world automotive conditions.

I've seen many flash-in-the-pan ideas come and go, more than a few of my own, and own a patent. It taught me respect for the thought that went into, and being honest about the merits of established technology, when evaluating the veracity of a new idea.

Provided the concept can reliably meet its claims

Exactly! As the saying goes, "Figures don't lie, but liars DO figure." The only thing a business needs to be successful is paying customers. It's not unusual for companies to advertise possible future capabilities in the present tense, and specs that are not achievable under real-world conditions.

As to the topic of the thread, these devices are being marketed as jumper cable replacements. It has not escaped my notice that the people who are happy with them, use them almost every day. The people that say they are junk, threw them in their trunk, and when they needed them, they didn't work. We already know that running down below the critical voltage, whether through load or self-discharge, is a far more significant event in the life of Li-Ion-based batteries than other technologies.

This is hardly to forum for me to get practical on, and I have some Li-Ion flashlights of my own, that if I were to be honest, are better at impressing people than providing me with real-life benefit. As much as I would like to buy one of these boxes, I think I'm going be honest with myself for a change, and buy some 100% copper, 4 gauge, made-in-USA, short, jumper cables.

 

[Lynx_Arc]

I think I'm going be honest with myself for a change, and buy some 100% copper, 4 gauge, made-in-USA, short, jumper cables.

I have a set of 4 gauge jumper cables that are 20 feet long and they are perfect for most uses as too much shorter and you would have problems with them reaching when a car is dead in a parking lot with other cars near them. I've had 16 foot cables and they are ok but a few times the extra few feet could have been handy. If I were starting cars often I would get a set of 00 gauge 25 foot cables they can handle 3 times the current as 4 gauge and 25 feet long can have you parking behind a full size extended cab truck and able to reach its battery.

 

[IT_Architect]

You're right of course, and 20 footers and a plastic case were my first reaction. Then I started thinking short as possible, 12', because they take up less space, and I don't have a truck or a car with a trunk, I have a Saturn Vue, and with my IT supplies behind the rear seat. 12' would be a little less voltage drop too, which might make a small difference. 4 gauge copper conducts like 2 gauge aluminum, very flexible, and has ends that don't give wire-to-clamp connection problems. I'll think about the length one more time though before I buy. I only use them once every year or two.

 

[idleprocess]

I was referring to a LiFE-Po Group 86 battery, which if memory serves, would set me back $1700. Moreover, the advertised 12% increased life expectancy claimed, may be far from what is possible under real-world automotive conditions.

Yes, that would be a marginal value proposition in all but a handful of niche situations... routinely utilizing most of the reserve being about the only one that comes to mind. A BEV module for the do-it-yourself electric vehicle modder also comes to mind since you can use lead-acid's simpler charge management systems.

I've seen many flash-in-the-pan ideas come and go, more than a few of my own, and own a patent. It taught me respect for the thought that went into, and being honest about the merits of established technology, when evaluating the veracity of a new idea.

Similar to why I'm not buying stock in the hybrid concept. I want to see how well it holds up after a year or two while the early adapters chase down the bugs. Seen far too many kickstarter campaigns and the like go over like software projects - 300% over budget, 16 months late on a 12-month timeline, and barely meet 65% of the original scope... some of which was due to bad project management, some due to unrealistic promises.



I once had a lead-acid jump starer - I got it in one of woot.com's "bag o crap" offerings (for $3 plus $5 shipping you get an assortment of random stuff they have in the warehouse in addition to "a bag" of some sort). It revived the dead vehicle - barely - the one time I used it before the cheap integrated charger killed the SLA. I recall that it had screw-post terminals rather than the clip-on variety more common with ~7.2A-H alarm batteries, suggesting that it was at a high-rate battery.

For the Li- chemistry jump starter to be successful for the average person, they need something that can either sit idle at a useful state of charge for a long time or something that can be maintained via the vehicle's electrical system but not discharge into whatever load kills the main starter battery.

 

[IT_Architect]

For the Li- chemistry jump starter to be successful for the average person...

We are on exactly the same page. I asked the manufacturers if they had anything that beeps like a smoke alarm battery going bad so people would charge them. None did. They said you can see from the indicator. That wouldn't happen until you needed it.

 

[Gauss163]

Some people say you can make your own with RC batteries. I'm familiar with the RC world and I design solid state circuits as part of my profession. This is my take:
- There is a big difference between Li-Po RC batteries and and Life-Po (LiFePO4​) batteries. The ones that I've checked out seem to use the LiFE-Po batteries, which are quite different than RC Li-Po.

I'm not aware of any jump starters that use LiFePO. Beware exaggerated marketing claims. Many claim to use safer LiFePO cells but actually use LiPo, e.g. see teardowns here and elsewhere.

Note that the Consumer Reports blurb claims that the best capacity unit (Antigravity XP-10) had 3x the capacity of the others, so almost surely it is not LiFePO, which has much poorer energy density than LiPo cells (universally used in the cheap Chinese units).

Said CR blurb is completely lacking in technical details, which does not lend much confidence to its credibility.

What units did you check out that had LiFePO cells?

 

[Crimson]

Re: The new lithium-ion jumpstarters

It may seem awkward to use that voltage, but I've measured the voltage of a fews cars while starting them when I had batteries going dead. Under start load I've measure in the low 10V range. As long as the charger can maintain at least 3.4ish volts under load it should be able to start the car. Question is how many starts it can handle in the long-run before the battery starts to degrade and can't hold voltage under load.

Maintaining 3.4 volts won't help you when starting a car, you still need the full 12.7 volts required by the vehicle's electrical system. You can't connect a 3.4 volt battery to the now-10 volt car battery to get the required voltage. Just as important, however, are how many Cranking Amps it can provide. You can have 12.7 volts provided all day long, but without enough Cranking Amps you aren't going to get any result either.

I bought one of these jump starters to play around with and I was surprised to find out it works well. I wouldn't bet on getting more than a couple starts out of it before needing to charge it though. I will say that the brand I bought (not pictured here) has been blowing fuses like crazy and it's not cheap to replace the cable with built in fuse. Luckily mine has been fine so far.

 

[IT_Architect]

I'm not aware of any jump starters that use LiFePO. Beware exaggerated marketing claims...(Antigravity XP-10) had 3x the capacity of the others, so almost surely it is not LiFePO...What units did you check out that had LiFePO cellsI'm not saying you're not right as I haven't cotact?

I'm not saying you're not right as I haven't contacted AntiGravity https://www.pegasusautoracing.com/productdetails.asp?RecID=12594 http://www.amazon.com/gp/product/B00KQSEOPI/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687702&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B00HE00OYG&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=04RYFV2W0YKY75HKNZ06

 

[Gauss163]

That reminds me that in an earlier thread someone posted what might be a Tenergy jump pack containing LiFePO cells. But until someone does a teardown I am a bit skeptical, since some Chinese "manufacturers" are known to go to great lengths to create Frankenbattery fakes, e.g. below are excerpts from a Youtube video teardown of a fake Sony NP-F970 videocam battery. What a piece of work, eh? I shudder to think what may be inside some of these jump packs, esp. now that competition is heating up and some are selling for less than $30 on eBay. Caveat emptor!

 

[Gauss163]

Beware the scammers

Beware that some scammers have recently started listing these LiPo car jump starters at too-good-to-be-true prices on eBay, e.g. here and here. If you see them listed for < $30 by a seller who previously sold only very cheap items then it is probably a scam.

 

[Gauss163]

Re: Beware the fires too!

Beware also that some of these jump starters have recently been reported to catch on fire while charging.

 

[Overclocker]

Re: The new lithium-ion jumpstarters

what's the starting current for something like a corolla/civic? i just built this 48V pack from Samsung 25R cells (rated 20A per cell)

 

[Gauss163]

Hopefully you are charging that beast more intelligently than the "surefire" chargers linked in my prior message. I shudder to think about the fire that would produce.

 

[Overclocker]

haha of course. iCharger 106B+ it's a 250W charger. that's just a small pack.

this samsung 26F pack has 96 cells:

i'm also planning to build 200+ samsung 29E

 

[fluke]

Old thread I know.

Is 140 degrees the max these jump starters can take ?

Pointless really as even in the UK summer temps in car get way higher.

 

[TinderBox (UK)]

Well these are supercaps but it is still interesting.

https://www.youtube.com/watch?v=z3x_kYq3mHM

John.

 

[farmerpete]

Hello Clever boffins
My 98 mercedes benz has a very long ( ie 2 m ) positive cable running to the starter.Battery is under the back seat
There is a +ve pole under the bonnet for emergency jumpstarts.
I have a new battery.
I have checked all connections and seem good. Electric wiring appears original and in good order
Problem.. car has a slow start crank. Diesels don't like slow crank starting especially in Winter.
If I use the emergency +ve pole with jumper leads the starter cranks fast like a gem.
My thought....permanently mount one of these mini jumpstart batteries on the +ve pole under the bonnet ?
Thoughts ????
Cheers from Australia