Two ammeters in parallel

[Indy Jess John]

I used the power from my dynamo to drive the starter motor in the other car.

Jim

[tony sayer]

Ever thought of converting to an Alternator?.

Did this with several old cars over time and it worked very well:)...

[alan_m]

Hasn't it always been and what are the specifications that we should really question?

Buy a 4 jewel watch or a 8 jewel watch? How many are just stuck inside of the case rather than being used as bearings surfaces?

Anyone remember the early front panel marketing for CD players, the more bits for the DAC quoted on the front of the box the better the player! A "48 bit" player may have only had a single bit DAC.

Obviously an amplifier that quotes music power rather than RMS power is better because the numbers are much bigger.

Is a 20 mega-pixel camera better than a 10 mega-pixel camera? Probably not if the overall detector size is the same. The latter could have a better sensitivity and a better signal to noise margin.

Can you really hand hold a camera with a x15 zoom as shown in the adverts?

Those cheap (£3) panels meters from china are possibly no better than 5% accurate, but maybe better. The chances are that they all use the same IC which requires a couple of non-critical external components. The precision reference and comparison circuits are all inbuilt in the IC. I agree that not quoting a specification should be a major warning sign about purchase if the item is intended for serious measurement rather than just a handy-wavey indication but if you don't want to spend maybe

10x to 20x more their readings could be compared with that of a multimeter meter to check accuracy.

As for just lying about specifications just go on Ebay and just look at the quoted specifications for some rechargeable AA and AAA batteries and the specification for replacement phone batteries that will last 4x longer than those fitted by reputable manufacturers. A single AA battery is now capable of powering an electric car for 250 miles!!!!

[Indy Jess John]

I have kept the car configured as it was when it left the factory, and the dynamo and control box combination works OK (and I have a spare dynamo in my garage in case it is needed).

I am also aware that I could convert the electrics to negative earth, but I haven't done that either, though I have installed a cigarette lighter socket delivering a negative earth connection so that I can use a car battery powered tyre pump or other gadgets like a Satnav which require that polarity.

Jim

[John Williamson]

Converting to negative earth will reduce corrosion, and is worth doing for that reason alone. The only reason not to do it is of the existing factory fitted radio needs a positive earthed supply.

It does not affect the originality, and is easily reversed.

[tabbypurr]

how does that work exactly?

[John Rumm]

I think my irony meter just went FSD...

[J. P. Gilliver (John]

[]

[]

That was me. When I first got my (Diesel) ?koda Felicia (far from new! But I presume it had recently had the 'plugs replaced), it seemed to start within a quarter of a turn, if I waited for the light to go out before cranking; I'm not exaggerating, it really did seem to fire as soon as the engine was turned. It progressively got harder to start, so I eventually had them replaced, which brought it back to similar (though not quite as good). I don't think it had any fancy diagnostics, though if your neighbour's is modern, that might have.

(I loved the "peer pressure" response!)

Ah, so I guessed wrong.

It always struck me as odd - especially in the days of dynamos - that cars had the two devices; surely one could serve as both. Presumably the design differences needed for operation at different speeds/durations made it less bother just to fit two devices. []

[charles]

There was a car in the 60's that had a unit doing both jobs. Was it the Beetle?

[Paul_news]

Trouble is trying to do 2 jobs it likely does neither well. Starters are quite low geared but dynamos about engine speed. At least 1 cheap (eastern-european?) car had a combined starter-dynamo. I can't remember the make. As a car tinkerer I was asked to look at 1 by a co-worker, took 1 look at the manual and declined.

Paul.

[T i m]

<snip>

Well, my Messerschmitt KR200 has a 'Dyna-Start' unit that does both and does so pretty well (in that it's never been a problem)?

It's also interesting that it can also start and run the engine both ways, giving you 4 speeds in reverse. ;-)

Not sure it could be classified as a cheap car though, then or now, more expensive than a Mini at the time I think?

;-)

Cheers, T i m

[Bob Eager]

These young 'uns won't understand FSD...

[Indy Jess John]

My brother bought an old Gogomobile in the 1960s, dirt cheap because it was advertised as a non-runner and he had to get a friend with a car to tow it round to his house. It was a Gogomobile Royal, like this

It looked like a Daf 33 in body shape, but it had a BMW horizontally opposed twin air cooled engine in the front to power it via the rear axle, and it came with a handbook written in German which nobody could understand. However it had pictures and diagrams so it was possible to work out most things, and when I went round to help him work out why it wouldn't go, there was a diagram in the middle of a lot of German words of something that could have been a fuel filter. So we followed the fuel pipe back from the carburettor and eventually found this fuel filter behind the rear axle, and when we removed the very mucky glass bowl the filter inside was completely clogged with muck. The quick answer was to throw away the filter and reassemble it without one.

Then the way the engine started was a puzzle, because there was no sign of a starter motor, or any kick start mechanism but there was a diagram showing that there was a "lichtsmaschin" (I can't remember exactly how it was spelt) on the front of the engine underneath some airflow cowling for cooling. That was wired through some complicated relay arrangement to the ignition switch and the battery. When the key was turned it operated a relay and connected the battery to one set of wires going into the cowling, and when the key was released it dropped the relay and connected another set of wires to the battery. It was a single device attached to the crankshaft that turned the engine to start it and one started it charged the battery.

After charging the battery and winding the engine over for a while for the mechanical pump to get the petrol from the tank to the engine it did start.

Gogomobiles were made in a Bavarian factory, so not quite eastern European, and BMW bought the company in 1967 to gain ownership of some useful patents.

Jim

[tabbypurr]

If he thinks this thread does demonstrate the group's understanding of electronic basics maybe he could moonlight as a standup comedian. Some do but so many replies show no grasp of elementary stuff.

NT

[williamwright]

Ah! I'm not sure if my skills of comprehension are failing or if your account was slightly unclear!

Bill

[williamwright]

Sounds risky!

Bill

[Indy Jess John]

It is in an non-conducting box. It works perfectly.

Jim

[Indy Jess John]

1 Heavy duty[1] jump leads connect my battery to neighbour's flat battery. 2 I intend to keep the neighbour's starter motor turning for as long as it takes to get an engine designed to be assisted by glow plugs to start from compression alone on a frosty morning. 3 I expect that to take more Amp Hours than my battery holds so I run my engine at enough revs to get plenty of supplementary power from my dynamo. 4 I get in neighbour's car and turn the ignition key and hold it in the Start position. It does take quite a while but neighbour's engine finally starts, by which time the windings in my dynamo have got hot enough to start smoking. 5 Disconnect jump leads, so that neighbour's alternator charges her battery and my dynamo recharges mine. 6 Neighbour drives off. I go back to my parking place and then run the engine for another 5 minutes to get a reasonable level of charge in my battery before switching off. [1] Home made jump leads using cables intended for an arc welder.

Jim

[Java Jive]

But potentially good for lighting cigarettes!

[No Name]

That reminds me.... When I was doing work experience with the electricity boards in the very late 1980's, all their works vehicles all had signs on the dashboard saying

WARNING THIS VEHICLE IS POSITIVE EARTH

and negative earth became commonplace in the 1970's.....

I enquired around other vans for the water and gas companies then and they all had the same warning sticker

Does anyone know why?

S