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Possible useful item spotted for activators on facebook today :-)


#1

Handy bit of kit possible

Tis 8800mah PSU

Not sure what battery,s they are

at that price and comes with charger be any good for running QRP rigs.

http://www.wemoto.com/parts/picture/bb-b001-uk/

karl


#2

5 volts Karl for charging phones. No use for powering the radios we use.

73 Phil


#3

No it’s for jump starting so it must be 12v


#4

good point PHIL

BUT

It has jump leads for M/C’s there for must be at least 12v to 14v output on that side
shame it don’t put out more info on the jump side of it as M/C’s are 12v systems.

Just phoned them it puts out 12v but not restricted on its amp output not good for radios. Needs additional control.

spotted this on E bay again possible needs control on output

How long would 50800 mah last your radio for LOL

Man that run me radio all week :smile:
Its amazing producing these little power packs now is unreal

karl


#5

We have some battery experts on here…let’s see what they say about this so called “Jump Starter”…

Meantime I’ll stick with my Tekkeon MYPower 3300 MA charger for my FT-817:

Tekkeon MYpower 3300

Now hard to source in the UK. Mine is 10 years old almost and is in a leather case and still works well. I can easily get four X 25 QSO QRP activations out of one charge…

And for my FT-857 I use these - they are excellent and come with a bespoke charger. I have two of these LiFePO4s. It is the best way to go and they are ÂŁ5 cheaper than when I bought mine, and are far superior to Lithium Polymer batteries:

LifePo4

73 Phil


#6

Fair comment - good for a short burst of high power then at 12v - 13.8v whatever… The physical size belies the capacity though anyone can see that unless maybe you are a chinese seller,

73
Sceptical of Tunbridge Wells…


#7

Without looking closely at it, I would say almost certainly 50Ah at 4.2V - same as the power packs they market for charging tablets and phones. The 12V (ish) would be through an inverter (possible noise source) and stepup inefficiencies meaning this would probably give you at most a quarter of this at 12V. So Karl’s one would be maybe 2.5Ah and the second one maybe 12Ah?

Matt
VK1MA


#8

:shit:


#9

Hi,

The battery might be useful for SOTA. Depends on how much you pay and what you actually get. ie is it cheaper than Hobbyking etc for the same capacity? Is it more conveniently packaged?

However I’d want to know the battery weight as the 50,800 mAh capacity claim seems quite over the top. It should weigh at least 7 kg for the battery alone if this claim is true but I can’t see the weight in the spec. Also the capacity is given in the general blurb (salesperson scripted) not in the main spec (engineer scripted).

The starting current for a 2.5 L petrol engine is about 200 A. The battery spec says it can supply this and twice that for a short unspecified time. You should not need to crank for more than 10 seconds to start. So actually only 560 mAh capacity per start attempt is fine. Do the sums yourself as I’m sure you won’t believe that.

5,600 mAh would allow up to 10 start attempts. Small battery capacity works only if the battery can supply the surge without dropping the terminal voltage too far. Modern Li based batteries can do that. Model aero and racing car engines draw maybe 50 A to 200 A and have run times of a few very exciting minutes.

In the past the lead based technology only gave high currents from large capacity batteries, typically 40 to 60 Ah.

But 50,800 mAh? Really?. Look at the size of the battery. It looks as if a standard 8,400 mA battery would be the largest that could be squeezed into the case. I’m assuming the other items in the picture are to the same scale.
Look at the size of the mains charger and the cigarette lighter charger.
Also their leads and connectors are not high capacity. Fine for 800 mAh and up to 8,000 mAh but that would be about it.

The 50,800 number is IMO meant to mislead and conceal the true battery capacity. .

As it will start a car with a dead battery who would question it? 5,080 mAh is more believable and about all that is required. Still a very useful capacity for SOTA.

Modern car batteries are small, about 25 Ah for a typical sedan but can source maybe 400 A at 8 V to 10 V. If your alternator fails the car will not run for very long on the battery especially with the lights on. Emergency service vehicles have one or two 100 Ah batteries fitted to run stuff when the engine is off.

So if 25 Ah is OK why a jump starter at 50 Ah? It all adds up to puffery.

Caveat emptor.

73
Ron
VK3AFW


#10

Yes, but only when you know how they do the sums… which makes VW look the most honest firm of engineers on the planet.

They sum the capacities of each cell. So if there are 6 cells each a nominal 8400mAH then the capacity will be given as 6 x 8400 = 50400mAHr

This is what happens because we don’t educate people properly in engineering / science and you we don’t have strong regulations or sufficient money to enforce them… companies talk complete tosh and the consumers don’t understand that it is complete tosh.

:cry:


#11

That’s brilliant. I’d have never have thought of that. That’s what a top sales rep can do which is why they earn twice an engineers salary.

Nevertheless the kit might be useful for the field day op who operates from the car and sometimes uses all the juice in the battery (you’re not serious if you haven’t done that at least twice) and who might occasionally go for a short stroll to set up a SOTA station.

I’ve been looking at weight reductions in my kit and have two batteries in my wagon so the above is not much interest to me. However I have undone some of my good work according to the bathroom scales. Maybe they need re-calibrating?

73
Ron
VK3AFW


#12

Beware of jump starting using their described method - particularly with wet cell batteries. Direct connection at the battery terminals will cause a spark from the initial transfer of electricity and can cause venting gas to explode. Connect the negative jumper lead to a well earthed point such as an engine lifting bracket that is away from the actual battery.
BTW, Volkswagen Letter with regard to my TD Caddy (Type EA-189 engine) arrived in the mail today!
Tony.


#13

My V6 TDI is one where they didn’t cheat!


#14

Or at least they haven’t had to admit it yet…


#15

No it’s a Euro4 emissions spec… easy to meet. It’s the Euro5 and above that require Urea injection or other magic such as not telling the truth!


#16

“…require Urea injection…”

I have my own method of adding urea to my lemon tree. If I made the same addition to my fuel tank would i improve my economy?

73
Ron
VK3AFW


#17

Only if the emission is up to standard…


#18

If it’s the same colour as the real stuff I’d go and see your doctor :wink:

And putting it in the fuel tank isn’t going to be economical - I have witnessed a hapless lorry driver putting Adblue in the diesel tank his manager wasn’t happy!

73 de Paul G4MD


#19

That probably depends on the amount of Foster’s consumed ahead :wink: On some days I probably could get an extra 10HP out of the engine. Improved economy? Dunno…

73 Bernhard


#20

But you need to inject it into the cat housing not the fuel tank!