Black and decker smart start

[normanr]

Hi All
I know we have been up this road before but would anybody recommend one of these for the Mercedes up to 2litre.

http://www.diytools.co.uk/diy/Main/...30-simple-start-emergency-battery-booster.asp

 

[television]

Do be careful, I see that they contain 3 x 6 volt batteries, that means 18 volt into your system and that is not good.

There is no miracle way to charge a flat battery fast, and even on a 124 I would think twice before using such a thing

 

[vijilants]

Agreed.....the ad on TV is very misleading !!!! It tries to make it look as if all women who drive should have one of these because it fixes the car !!!!!

The truth of it is, if your car breaks down whilst driving, the last thing it will probably be is the battery !!!!

 

[Sp!ke]

You can get better 12v ones at machine mart IMO.

3AH is pretty pathetic and I doubt would start much from a flat battery.

http://www.machinemart.co.uk/shop/categories/search/clarke-jump-starts

 

[normanr]

AS always Malcolm we can depend on you for good advice but just wondered about a well known company like Black and Decker leaving themselves open to something they produce causing damage to the electrics on modern cars.

We all know it is very easy to zap your ECU that is why I would never use a jump start on my car.

 

[Will]

Would it really use the 3x 6V batteries in series to provide an 18V output? Seems very strange and certainly risky.

I would have thought it might be 2x 6v batteries in series for the jump start/12v output and the other 6v battery for the lighting feature built in on the unit?

If it does put out 18v to a car's electical system, aren't Black & Decker liable for some expensive claims from people damaging their cars?

Will

 

[normanr]

As Will says I think they are leaving themselves wide open to claims problems if they have not done there homework on this gadget.

It is advertised on the television as being able to start a car from a flat battery and I am sure they will sell a lot of these this time of the year due to as we all know lots of people do not maintain there cars correctly and flat battery's seem to be quite common.

 

[Will]

That's why I would be very surprised if it really did put out 18v to the car's electrical system.

There must have been some sort of R&D in developing the product? Black and Decker have been around for quite a while.

Will

 

[andy_k]

As the ampage is relatively low surely 18 volts with no load will very rapidly translate to 12 volts under load?

Not sure of the maths but I know that many 9 volt power supplies (phone etc) chuck out in excess of 15 volts if checked on a meter

Andy

 

[television]

The chances are that this is is just something with a Black and Decker Badge, and their marketing guys think it will be something to earn on. If one of the Sales people thought it was a seller, its doubtful if they asked anyone other than the manufacturer íf there was any danger on some cars

There will be lots of of old cars that will be unaffected by it, if the car went wrong, it would be very hard to prove.

There are many things sold not fit or dangerous to use. Perhaps the worst is with many mechanics who do not understand one bit about electronics and the antics that they get up to and the stories they give the customer about the faults on their cars

 

[Will]

Question remains though - is it actually supplying 18v to the car's electrical system?

That's the bit that I find surprising, and there's no real reason why they'd do that.

Will

 

[BTB 500]

This is basically a self-contained battery charger, designed to partially recharge the car battery. It's not a jump start device.

The fact that it contains 3x 6V batteries doesn't necessarily mean it outputs 18V (this is highly unlikely IMO). The output voltage depends entirely on the circuitry - I have chargers that supply anything from 6V up to 50V from a 12V input.

A 3AH 18V supply will put 4.5AH into a 12V battery.

Incidentally, Black & Decker also make a more powerful one with 6AH batteries:

http://www.blackanddecker.co.uk/automotive/productdetails/catno/BDV040/

 

[television]

Look at the basic maths, you cant charge another 12v battery with another 12v one across it, nothing would happen. They say it will charge the battery in 3 hours, to do that it need 18volts.

There is a lot of difference between a cheap power plug adaptor off load and fixed voltage batteries.

 

[television]

Question remains though - is it actually supplying 18v to the car's electrical system?

That's the bit that I find surprising, and there's no real reason why they'd do that.

Will

If the battery that being charged was very low or flat, then you can put very high voltages through them, and under these conditions the 18volt would not soon disperse or drop, but do remember that on a car with a wake up circuit its live all of the time and you cant turn that part off

 

[BTB 500]

Look at the basic maths, you cant charge another 12v battery with another 12v one across it, nothing would happen.

However simple voltage boost circuitry can output whatever you want from a 12V input. It is certainly possible to make a charger that will fast charge a 12V battery from another 12V battery, I own one

 

[Will]

Look at the basic maths, you cant charge another 12v battery with another 12v one across it, nothing would happen. They say it will charge the battery in 3 hours, to do that it need 18volts.

There is a lot of difference between a cheap power plug adaptor off load and fixed voltage batteries.

Yes but a flat 12v probably wouldn't read 12v, likewise a fully charged pair of 6v batteries in series would probably read more than 12v, put in parallel to a flat car's electrical system it would probably provide the desired 'boost' that it's aimed for? Why else would anyone 'jump start' one car from another (ignoring the ~14v or so alternator charging output with the engine running)

Does anyone know for certain whether this device is really designed to put 18v straight into one's car? The fact that we've all picked up on this seems to be an terrible oversight by the manufacturer if this is the case. Unless of course they deem this to be safe?!?

Will

 

[television]

You cant get away from the physics involved here, you cant charge a flat or low battery with less than 18volt, so yes 18volts is going into the car electronics, this is why some many times the 203 (the worst) and others have these SAM and other problems, It would do no harm to a 124 and the cars of that time like 201 and 126, or a Non DAS 202 or 210

Do they work on the basis that an MB owner with a newer car does not do these things himself

What ever you cant change the fact that 18 volts is going in, and our newer cars will not like that, I must have been involved on at least 1000 post on this subject, and there has been no way round the problem as yet

 

[BTB 500]

Yes but a flat 12v probably wouldn't read 12v, likewise a fully charged pair of 6v batteries in series would probably read more than 12v, put in parallel to a flat car's electrical system it would probably provide the desired 'boost' that it's aimed for? Why else would anyone 'jump start' one car from another (ignoring the ~14v or so alternator charging output with the engine running)

Does anyone know for certain whether this device is really designed to put 18v straight into one's car? The fact that we've all picked up on this seems to be an terrible oversight by the manufacturer if this is the case. Unless of course they deem this to be safe?!?

Will

A fully discharged 12V lead/acid battery is actually 11.9V. Fully charged the 'resting' voltage is 12.7V (straight off a charger it will be higher).

As mentioned, the fact that this device contains three 6V batteries is irrelevant. The output voltage depends totally on the circuitry and could be anything from 1V to 1000V. The same would apply if it contained two 6V batteries. I am sure that a major company like B&D would not sell a device that was potentially going to fry a car's electronics.

 

[television]

Yes but a flat 12v probably wouldn't read 12v, likewise a fully charged pair of 6v batteries in series would probably read more than 12v, put in parallel to a flat car's electrical system it would probably provide the desired 'boost' that it's aimed for? Why else would anyone 'jump start' one car from another (ignoring the ~14v or so alternator charging output with the engine running)

Does anyone know for certain whether this device is really designed to put 18v straight into one's car? The fact that we've all picked up on this seems to be an terrible oversight by the manufacturer if this is the case. Unless of course they deem this to be safe?!?

Will

You can push this any way you like, and yes, a 12 volt battery virtually flat will read 12 volt, you must remember that the usable part of the curve on a battery is not the rise from zero, its the flat top of the curve that contains the storage of that battery, and that will be basically 12volt.

When a battery is flat you could put 30volt to get it to start to charge, as the battery voltage rises then you cannot put this high voltage through it, if you try then the current would be so high, the battery would boil, and thats the end of it

 

[BTB 500]

You cant get away from the physics involved here, you cant charge a flat or low battery with less than 18volt

In which case the car's own charging circuit would also need to supply 18V?

Of course you can charge a flat 12V battery (11.9V) with anything from 12V upwards. The voltage simply determines the charge current.