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Mac McQuinn
12-11-2012, 11:17 PM
Working on trouble shooting a 1950's motor scooter which has a 6V system. I was finally able to locate a 6V, 11AH Battery which fits the factory specifications and bracket. Unfortunately it's the old style non-sealed lead acid battery with filler caps and vent hose. I have a 6V/12V charger/maintainer although don't feel comfortable sticking the battery under the bench with filler caps off allowing fumes to constantly escape during the charging process in my shop.

I was in hopes of finding a sealed unit to avoid this, I did find a 12AH sealed battery which could be installed although the bracket would need to be modified. Oddly enough, all the sealed units I've found in this AH size have what I feel are lightweight spade terminals or a built-in wiring harness with approximately 10 ga. wiring. I'm no electrician although question if the terminals or lighter wiring are sufficient for the scooter's electrical system. The scooter's factory battery cables are very heavy, about 7/8 the size of automobile battery cables.


Has anyone any thoughts on this?

Mac

Shawn Pixley
12-11-2012, 11:48 PM
I just looked at my Vespa battery. Though it is twelve volt, it is the compact size. It is a sealed unit with the spade terminals. I would say go for it. The battery is really as a buffer on the magneto for lights at idle. It is not as though you are starting from it.

Mac McQuinn
12-12-2012, 12:06 AM
Shawn, thanks for the input although this scooter(Maico) does have a electric starter of sorts powered by the battery.
Mac




I just looked at my Vespa battery. Though it is twelve volt, it is the compact size. It is a sealed unit with the spade terminals. I would say go for it. The battery is really as a buffer on the magneto for lights at idle. It is not as though you are starting from it.

Shawn Pixley
12-12-2012, 12:21 AM
What does the starter motor draw? You should be able to match the wire gauge to the draw & terminal.

Mac McQuinn
12-12-2012, 12:30 AM
It doesn't have a starter motor per se although uses current through generator coils to control cams and contact points along with a reversing switch to cause a rocking type action against compression to pull fuel in and start the engine. Certainly a unusual method and possibly the weak spot of the scooter.
Mac




What does the starter motor draw? You should be able to match the wire gauge to the draw & terminal.

Rick Potter
12-14-2012, 8:30 PM
Don't worry about the cables being thicker. A 6 volt system needs heavier wire than a 12V system. That is one of the reasons cars went to 12V in the 50's. A 6 volt starter will just wind faster on 12V, should be ok, but if there is a generator or alternator, it won't work right. Bulbs need to be changed to 12V.

Rick Potter

Mac McQuinn
12-14-2012, 9:53 PM
Rick,
Thanks for the info.
Mac



Don't worry about the cables being thicker. A 6 volt system needs heavier wire than a 12V system. That is one of the reasons cars went to 12V in the 50's. A 6 volt starter will just wind faster on 12V, should be ok, but if there is a generator or alternator, it won't work right. Bulbs need to be changed to 12V.

Rick Potter

Rick Potter
12-15-2012, 11:50 AM
Mac,

Just reread about your starting system. Just wanted to clarify........never heard of that type system, and have no idea if 12V will damage it. Might want to talk to someone knowlegable about that part.

Changed out a lot of old cars, and the problem areas were always bulbs and gages.

Rick P

Mac McQuinn
12-15-2012, 2:43 PM
Rick,
Yes, it's a odd duck w/ a pretty complicated system, that's for sure. I'm in hopes of getting started troubleshooting this thing soon. I went through the 6V to 12V deal years ago with my 49 OLDS, 47 Ford PU and 51 GMC PU, I drove them daily and during the winter when temps dropped below 0, I would take a 12V with me and jump them after work with no damage to show. The Ford was a bit of a pain as it had a + ground system. Seems like the local Farm store carried a 8V battery that some of the other guys would install w/o changing bulbs, etc although they sure burned bright!
Mac



Mac,

Just reread about your starting system. Just wanted to clarify........never heard of that type system, and have no idea if 12V will damage it. Might want to talk to someone knowlegable about that part.

Changed out a lot of old cars, and the problem areas were always bulbs and gages.

Rick P

Shawn Pixley
12-15-2012, 3:05 PM
I've changed two cars from positive ground to negative ground (english sports cars). It is pretty easy. The advantage is that you can use other products (radio, etc) then. Additionally, you can swap out inferior components. I changed from a Lucas generator to a Ford alternater. Dependability went up substantially.

is your scooter intended as a pure restoration or are modifications acceptable?

Rick Potter
12-15-2012, 3:24 PM
You also mention charging the battery on the bench. They make a small battery tender for bikes, etc. Size of a pack of cigs, stays on the bike, you just plug it in when storing it.

Got the big version for cars, works great.

Rick P

Jim Koepke
12-15-2012, 4:00 PM
A 6 volt system needs heavier wire than a 12V system.

For the same current (amps), the wire stays the same size. To achieve the same wattage, 12V only needs half the current of 6V, hence the smaller wire on 12V automotive systems. (Volts times Amps = Watts)

10 gauge copper wire is usually good up to 30 amps.

http://www.cerrowire.com/ampacity-charts

jtk

Mac McQuinn
12-15-2012, 4:45 PM
I have a 6V/12V 1.5 Amp Charger/Maintainer although with the factory Battery hold down bracket in place, I can't access the (3) filler caps to remove them for breathing when charging. I'm not sure if the tenders were designed with non-sealed batteries in mind.
Mac



You also mention charging the battery on the bench. They make a small battery tender for bikes, etc. Size of a pack of cigs, stays on the bike, you just plug it in when storing it.

Got the big version for cars, works great.

Rick P

Mac McQuinn
12-15-2012, 4:49 PM
Shawn,
While I'm going to try to keep the restoration pretty authentic, I always keep a open mind to increased Reliability/Durability/Safety. I have no issues with improving things.
Mac



I've changed two cars from positive ground to negative ground (english sports cars). It is pretty easy. The advantage is that you can use other products (radio, etc) then. Additionally, you can swap out inferior components. I changed from a Lucas generator to a Ford alternater. Dependability went up substantially.

is your scooter intended as a pure restoration or are modifications acceptable?

Mac McQuinn
12-15-2012, 4:55 PM
Jim,
Good info although through personal experiences I've come across connections to batteries which use larger than required wire sizes. Not sure of the reason as I'm no electrical wizard. There must be some purpose to the overkill application.
Mac




For the same current (amps), the wire stays the same size. To achieve the same wattage, 12V only needs half the current of 6V, hence the smaller wire on 12V automotive systems. (Volts times Amps = Watts)

10 gauge copper wire is usually good up to 30 amps.

http://www.cerrowire.com/ampacity-charts

jtk

Ken Fitzgerald
12-15-2012, 5:20 PM
Mac,

Generally....given the same materials, larger wires and connectors are made to handle higher current.

John Coloccia
12-15-2012, 5:42 PM
Jim,
Good info although through personal experiences I've come across connections to batteries which use larger than required wire sizes. Not sure of the reason as I'm no electrical wizard. There must be some purpose to the overkill application.
Mac

Voltage drop. For small currents, you usually size for the current carrying capacity for the wire, i.e. you size it so it doesn't catch fire. For large current, you need to consider the resistance of the wire. For example, for batteries that are meant to start vehicles (or run motors), you often have to size the wire much larger than what is considered safe or you loose significant performance to resistance.

One FYI: lots of us in the experimental aircraft world (or at least I WAS in that world) use welding wire as our battery connections. It can carry monstrous current, but it's also so finely stranded that it's extremely flexible AND it's been designed for repeated flexing. It holds up extremely well in high vibration environments.

Mac McQuinn
12-15-2012, 9:30 PM
John,
Thanks for the help, I had an idea this might be the case. In the Scooter's parts manual which is in German, the cables both have #10 in the description. I've made direct physical comparisons and it's certainly not 10 Ga wire. Something must be lost in the European translation. I figure I'll cut off a chunk of the old leads and take it to a welding supply to purchase some bulk that matches. My original idea of possibly installing a sealed 6V battery with built in 10ga leads and plug would possible be a mistake. I certainly don't want to chance smoking something irreplaceable to find out.
Mac




Voltage drop. For small currents, you usually size for the current carrying capacity for the wire, i.e. you size it so it doesn't catch fire. For large current, you need to consider the resistance of the wire. For example, for batteries that are meant to start vehicles (or run motors), you often have to size the wire much larger than what is considered safe or you loose significant performance to resistance.

One FYI: lots of us in the experimental aircraft world (or at least I WAS in that world) use welding wire as our battery connections. It can carry monstrous current, but it's also so finely stranded that it's extremely flexible AND it's been designed for repeated flexing. It holds up extremely well in high vibration environments.

John Coloccia
12-16-2012, 12:40 AM
Marine battery cable in the right gauge is an excellent choice also. Just another idea if you need it.

Rick Potter
12-16-2012, 1:43 AM
Hey Mac,

I just looked up Maico scooters. Interesting. What model is yours??

Rick P

Mac McQuinn
12-16-2012, 10:21 AM
248066

(http://www.esivart.com/pics/img_m1.jpg)Rick, Here's a picture, Right out of the barn. It's a 1959 Maicoletta 250cc
Mac



Hey Mac,

I just looked up Maico scooters. Interesting. What model is yours??

Rick P

Rick Potter
12-18-2012, 1:47 AM
A lot classier than the '47 Cushman I had back in the day. Nice, never seen one before.

Rick P