Aldi 4WD Capacitor Batteryless Jump Starter

dorian · Guru

Aldi 4WD Capacitor Batteryless Jump Starter

rgren2 · Guru

Dont know about the capacitor ones. I have one of these and it'll start my 6.5 litre diesel.

https://no.co/gb70

RustyD · Guru

Tim-The-Toolman size! I was impressed when the RACV started my Spyder with this type of small starter. Not sure what it was but the mechanic said it was a the expensive end of the type as he needs to start big stuff. Is the price on the website US$? Even converted toAU$ it's a lot cheaper than a battery jumpstarter for a diesel.

RustyD · Guru

Dorian.

I think the cranking current is the limit here. My diesel Ranger has a battery with a CCA of 750A and my wife's 2.0L turbo petrol has a CCA of 800A (CCA - Cold Cranking Amps and appears to be one measure of battery).
Not sure if the 450Amp cranking current on the Aldi box means it won't start big engines.
I'm interested to see someone else's evaluation here as I want one that will start all of my vehicles.

dorian · Guru

I have no idea whether the device will do what it claims, but ISTM that the capacitors are being operated at the absolute limit of their spec. In the absence of any information to the contrary, I would avoid it for that reason alone.

As for the "up to 450A" cranking current, this spec is much too vague. If the price of ultracaps continues to fall, then perhaps one day there will be some genuine jump starters with realistic specs, but I don't have much faith in the current crop.

dorian · Guru

ISTM that these jump starters would be useless. I say this because their Amp-hour capacity would be a fraction of that available from other gimmicky jump starters such as those which use 4000mAh lithium polymer cells.

See thegreynomads.activeboard.com/t61144684/portable-power-jump-starters/

Five series connected 500F capacitors would have a combined capacitance of 100F. Assuming they are charged to their rated voltage of 2.7V, then the total voltage would be 13.5V. If we further assume that cranking stops when the voltage falls to 6V, then the maximum energy delivered to the starter motor would be ...

E = (energy at 13.5V) - (energy at 6V)

The energy stored by a capacitor is given by ...

1/2 x C x V^2

So ...

E = (1/2) x (100 farads) x (((13.5 x 13.5) - (6 x 6)) x (volts^2)) = 2.03 watt hours

At 11V, a bank of three 3.7V 4000mAh Lithium cells would store 44 watt hours. That's 22 times more energy.

Warren-Pat_01 · Guru

They might work - if the capacity of the capacitors is 500F. In all my working life as a radio/communications technician, I have never seen a 1F capacitor! I saw some big micro Farad caps but never a 1F cap. It would take up an enormous amount of room & 5 x 500F capacitors would be larger than a house! And like all capacitors, they discharge very quickly so it would be an instant hit & a big one!
My guess is that the capacitors are 500 micro-Farads - you'd need an enormous number of them to kick a car over!

What are your thoughts, PeterD?

Is the date April the 1st?

Warren

JeffRae · Guru

I read the instruction manual, definitely won't be buying one.
Would spend my money on the unit rgren2 has

Mike Harding · Guru

Warren: they are 500F caps. - they are called "SuperCaps" and hit the market around 20 years ago iirc.

Dorian: (Ah, poor Oscar, a sad loss) - the caps may not be in series as that would be a poor way to design such a device.

Indeed, given that they state it can be charged from a depleted battery I suspect it has a semi intelligent switch-mode which distributes the charge energy at 2V5 or similar to the five caps and that when an engine start is required a second switch-mode boosts the 2V5 to 12V(ish) and the caps are, effectively, in parallel.

I am quite sure it will work if for no other reason than Australian consumer law would send them broke if they were so stupid as to put a non working product on the market.

Just take a look at the case - a fair bit of design and manufacture has gone into that product and that equals a fair bit of money, additionally Aldi are not fools and would not support an unusable product.

dorian · Guru

@Mike, I think if you examine the photo at the URL that I provided, you will come to the conclusion that the caps are most likely in series, and that there is only a single, step-up DC-DC converter.

@Warren, please refer to the datasheet at the URL I provided.

Mike Harding · Guru

Do you mean this one?:

This photo of the innards shows 6 ultracapacitors.
https://c1.iggcdn.com/indiegogo-media-prod-cld/image/upload/c_limit,w_620/v1472460286/mgblivf9ex5p0pvj5fwp.jpg

It's a different product isn't it?

dorian · Guru

True, it's a different product, but I can't believe that Aldi's product doesn't follow the same design philosophy. In any case what you are proposing doesn't make any sense to me.

Firstly, charging the capacitors in parallel as opposed to charging them in series doesn't make any difference -- the caps will still be charged to 2.7V, and they will still store the same amount of energy.

Secondly, using a second switchmode regulator to step up a 2.7V supply to 12V begs the question, what kind of capacitor(s) would be filtering the 12V supply? An additional 12V ultracap?

If you are not filtering the 12V output, then what kind of pulsed voltage will the starting system see? Moreover, if the output (cranking) current is 200A, then the current on the 2.7V side of the converter would be around 1000A.

Mike Harding · Guru

They could be using these 3V0 devices:

http://www.farnell.com/datasheets/2211736.pdf

And, keep in mind, the working and AbsMax spec is across the full operational temperature range.

In any event if, as you suggest, they are rubbish I'm sure the internet forums will be letting us know early next week.

dorian · Guru

As per my first post ...

"Capacitors: 2.7V 500F x 5 Pieces"

dorian · Guru

Those Vina Tech supercaps have a shelf life of 2 years. IME automotive batteries typically last 4 years. This makes me wonder what I can expect from one of these jump starters when I need to use it.

Also, the Farnell datasheet makes no mention of absolute maximum ratings.

dorian · Guru

Here is a Jaycar product with some confusing (and potentially misleading?) claims.

Capacitor Based 12V 300A Jump Starter (cat MB3765):
http://www.jaycar.com.au/capacitor-based-12v-300a-jump-starter/p/MB3765

Description

Battery free means Maintenance free! Just a 60 second charge is all that is required to charge the internal super capacitors! No need for a top-up during storage and super lightweight for easy handling. It features 300A cranking current, GLOW mode to cold start a diesel engine, and bypass mode to start an engine without any battery mounted. It can generally start a warm 4.0L or cold 3.0L petrol engine, or 2.0L diesel engine. There is a built-in voltage meter to read the vehicle's battery voltage, and it can also operate in freezing temperatures. Charge using the supplied 12V lead, from a 12V car battery or from a USB power source (15 min charge).

- 300A cranking current
- 60 seconds quick charge
- 10 Year shelf life
- Voltage Indicator
- Includes a 5V 2A Micro USB input port
- DC12V 10A input port
- Operating temperature: -40 to +65 Celsius
- Short circuit/Reverse polarity protection
- Fault/Override indicator
- 203 x 124 x 50mm, 1.18kg

Elsewhere ...

https://www.jaycar.com.au/jumpstarters

The Capacitor Based 12V Jump Starter (MB3765) uses a super capacitor to store energy. This technology means it stores energy perpetually - just charge it once then store away until needed.

On one page Jaycar claims that the product has a 10 Year shelf life, but provides no clarification. This would suggest that you just throw it in your tool box. However, the other URL states that the device needs to be charged before being stored.

Moreover, all the datasheets seem to suggest that the leakage current for the 500F caps is 1.5mA.

Assuming these caps are charged to 2.7V, and assuming (conservatively) that a loss of 1V renders the device incapable of starting an engine, then ...

How does 3.86 days translate to "perpetually"? Or do I have some fundamental misunderstanding?

-- Edited by dorian on Thursday 31st of August 2017 10:24:02 AM

Mike Harding · Guru

dorian wrote:
As per my first post ...

"Capacitors: 2.7V 500F x 5 Pieces"

Yep, fair enough, they do state that.

So I guess we'll just have to wait until next week to see if the place is filled with the aroma of burning capacitors and the cries of Aldi executives jumping off high buildings :)

Warren-Pat_01 · Guru

I guess technology is continually changing but I think I'll wait until further testing is done. I hope they don't produce a spike that will damage newer vehicles' electronics although a battery itself acts as a dampener.

Besides, Aldi doesn't want to come to NQ.

Warren

RustyD · Guru

rgren2 wrote:
Dont know about the capacitor ones. I have one of these and it'll start my 6.5 litre diesel.
https://no.co/gb70

So tempted to get one. http://www.ebay.com.au/itm/NOCO-Genius-Boost-HD-GB70-2000-Amp-12V-UltraSafe-Lithium-Jump-Starter-BRAND-NEW-/162556459229?_trksid=p2349526.m2548.l4275

Even it's it not just for me. A neighbour had a visitor in a Landcruiser parked in her driveway with a flat battery yesterday. My normal jump starter would never start it or my Ranger. It's not always your own battery that can be an issue, it's the vehicle blocking you in.

-- Edited by RustyD on Friday 1st of September 2017 12:44:47 PM