Insert battery

Moto Rumi technical problems or solutions
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Elie
Posts: 97
Joined: Mon Jul 01, 2019 11:02 pm

Insert battery

Post by Elie » Thu May 28, 2020 10:09 pm

I am working on the electric of the Rumi, about this some questions. Is the voltage supplied by the motor ac or dc?, if i want to insert a battery then I need to put a rectifier to power the battery if voltage is ac? What voltage does the motor in volt and amp?, does any of the members have a drawing of such battery installation?, Thank you in advance

hugomez
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Re: Insert battery

Post by hugomez » Thu May 28, 2020 11:16 pm

Hi Elie,

I am not sure if this may help you, but there is an Scoiattolo that was coming out from factory with dynastart, so it also has battery on it.

I know is not exactly what you are looking for, but as I said, maybe can be helpful for you to figure out how to do the wiring in your Formichino.

LINK: viewtopic.php?f=17&t=783

Greets,
Hugo
My little Formichino here: http://www.formichino.com/pictures1.html

Lars
Posts: 306
Joined: Fri Nov 02, 2012 3:09 pm
Location: Sweden

Re: Insert battery

Post by Lars » Fri May 29, 2020 7:15 am

Elie wrote:
Thu May 28, 2020 10:09 pm
I am working on the electric of the Rumi, about this some questions. Is the voltage supplied by the motor ac or dc?, if i want to insert a battery then I need to put a rectifier to power the battery if voltage is ac? What voltage does the motor in volt and amp?, does any of the members have a drawing of such battery installation?, Thank you in advance
The voltage supplied by the motor is AC. The voltage is totally unregulated and varies wildly, depending on rpm and load. The lighting coil was designed to produce around 6 volts at high rpm with headlights on. Without the headlight lights on, it may produce 9 volts or more. That is tthe reason for the resistor - or coil as it originally was - to protect the tail lamp from the exessive voltage.

If you want to have a battery connected, you must have a rectifier installed. (Several problems with that, you can only use a half-wave recitifier, not a bridge, unless you modify the lighting coil, etc., etc.) You would also need a voltage regulator to protect the battery from excessive voltage, otherwise the battery would not last very long.

With a battery, you are really talking about re-engineering the electrical system of the Formichino. If you insist on having a battery, a much better way would be to convert to an elctronic ignition system, as Hugo said in the thread he linked to. Those systems are already prepared for addition of a battery.

UHJ200
Posts: 560
Joined: Mon Aug 17, 2009 1:37 pm

Re: Insert battery

Post by UHJ200 » Fri May 29, 2020 10:54 am

Not nearly as difficult as you might imagine. I installed a battery on my Tipo and it worked a treat. There are safety issues in today's traffic that alone make it worthwhile, you can have a decent stop light for a start, (won't stop some silly blighter rear ending you of course but it does at least remove one of their excuses). Also if for some reason you loose the engine you don't do a Lucas and suddenly reinvent darkness too! A battery acts as an energy sink, hold the voltage stable and so is kinder to the bulbs.

The first thing to note is that the lighting coil and ignition coil are independent, they might share the Dansi stator plate but that is it. It is correct that the lighting coil does produce an AC voltage so it will need a rectifier. I do not agree that rectification can only be half wave.

The trick is to un-solder the earth wire of the lighting coil from the stator. Dansi were kind enough to supply a spare thread on the black insulated output connector so it is a simple enough matter to extend and reroute the un-soldered earth wire to that terminal.

From the Dansi terminal the now two wires from the lighting coil are fed to the AC side of a bridge rectifier located wherever convenient. I used a 10A rectifier that I had to hand and at 30mm square hardly space hungry.

For a 6V battery I employed five standard "D" sized NiCad cells that live in a box fixed inside the headlamp nacelle. I chose them because they are cheap, clean, (no sulphuric acid), and robust. A Lead acid battery would do the job too but requires more maintenance.

One last point, on the basis of "first do no harm" everything is reversable.

Lars
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Location: Sweden

Re: Insert battery

Post by Lars » Fri May 29, 2020 12:39 pm

I did say only half-wave rectification "unless you modify the coil", and by that I meant to undo the ground side of the coil and bring out a separate wire to get the coil floating to ground. Which is what you did and described. Good to know that it can be done without too much difficulties, and that you think it was worthwhile.

You did not say anything about a voltage (or current) regulator. If you do not have a regulator, you are violating the operating conditions for the battery. Whether it is a lead acid or a Ni-Cad battery, you will be exceeding the max. allowed charging currents without a regulator.
It may seem like the battery stabilizes the voltage, but it only does so by soaking up heavy and potentially damaging currents.

UHJ200
Posts: 560
Joined: Mon Aug 17, 2009 1:37 pm

Re: Insert battery

Post by UHJ200 » Fri May 29, 2020 2:36 pm

I am a devout follower of K.I.S.S. so didn't bother with regulators and all that jazz, don't really beleive in elektrickery anways, sumfink to do with the dark arts I reckon :!:

We are dealing with 6V at about 5A maximum, the battery pretty much controls the voltage and as we mostly have the lights on day and night these days the system is pretty much balanced anyway, it was made that way.

I entirely accept that it is not very kind to the battery but my battery has put up with it without any obvious signs of distress. Fit a regulator by all means if you consider it worth it but batteries are a life limited replaceable part and not that expensive.

Lars
Posts: 306
Joined: Fri Nov 02, 2012 3:09 pm
Location: Sweden

Re: Insert battery

Post by Lars » Fri May 29, 2020 5:50 pm

I agree that the power is limited and, with the headlight always on, there is not much power left to do any damage.
Well, good to know that you made it work the simple way.


Elie, or anyone else interested, here is the modification we are talking about: One end of the lighting coil winding is normally soldered to the iron poles of the coil (see picture below). This wire has to be unsoldered and spliced with an insulated wire if you want to use a rectifier bridge. The two wires will then have to be brought out from the engine and connected to the AC input of the rectifier.
Attachments
Rumi ignition plate, reduced.jpg
Rumi ignition plate, reduced.jpg (81.25 KiB) Viewed 1287 times

UHJ200
Posts: 560
Joined: Mon Aug 17, 2009 1:37 pm

Re: Insert battery

Post by UHJ200 » Fri May 29, 2020 6:05 pm

One more small point: If you go down this route please install a fuse to protect the wiring from the juce in the battery should you get a short. Something a little over 5A should do nicely.

Elie
Posts: 97
Joined: Mon Jul 01, 2019 11:02 pm

Re: Insert battery

Post by Elie » Fri May 29, 2020 10:15 pm

Thanks to everyone for quick and clear information, looks like many are working on this topic (adding battery), go experiment now. Thanks again

luckner
Posts: 24
Joined: Sun Jun 27, 2010 2:08 am

Re: Insert battery

Post by luckner » Sat Jul 18, 2020 1:56 am

Hi, and excuse myself!
I am wondering... wy does this owner want to create himself a lot of trouble wit the complication with battery, regulator and more?
One of the points I specially love of my Formichino is the ABSENCE of all that. I admit that the lack of enough power at low rpm makes a poor amount of light in head and tail lamps but... is it necessary in a vintage scooter that surely is not going to be used by night?
The argentine Rumis with Magnetti-Marelli magnetos had a coil (double wired) for ignition and a separated coil for the lighting. So, they are independent and the use of lights has no disturbance in the quality of the spark. With both coils in good condition there is no reason to have problems.
The ignition wiring of my beloved Rumi of 1956 is original and I start her without any trouble in any moment with lights switched on. The wiring of the lights dont satisfied myself and I rewired it personally with attention at the diameter and lenght of the wires. The light is not wooow but enough. It can be improved variing lightly the length of wiring but I better decided to go original.
Kind regards,
LUCKNER

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