discussion petrol engines

[Guest]

hi guys

i have not got a clue on petrol engines just looking for some advice ,how reliable are they im looking at putting a petrol engine in my boat instead of my electric motor as the batterys dont last long as cos of the weight .

can you get a engine that not to noisy and reliable ,would need it to move a boat 2ft long x 1ft wide

weighing around 3kg

want it to move at a decent speed around 5-10mph

is there anything out there ??

 

[Guest]

I think you are getting confused with a glow engine. To get a petrol engine for that sized boat would have to be specially made, and v-e-r-y expensive.

You have to realise just what you will be giving up if you fit an ic engine in your boat.

Forwards only, no reverse, and unless it has a clutch, no stopping either. Plus you will be restricted on where you can run it. You will find that most sailing areas are sail, steam or electric only. The ic engined lads usually have specially designated waters they can sail on.

It isn't just a matter of popping an engine in and running, there is a lot more to it than that, just spilling a drop of fuel onto the paintwork will lift the paint off, so it would have to be fully fuelproofed inside and out.

I think you really need to go into it a lot deeper before deciding to go ahead and get rid of the electric system.

Bogs

 

[Guest]

I'm also a bit confused with your requirements, a 2 ft boat at 3kg should last quite well with a suitable motor and a good battery pack. You can even go down the path nowadays of Li-Pol batteries and brushless motors which will last for a very long time in the water.

Maybe if you give us a bit more of an idea of the boat you want to propel we can help with some suitable motor, prop and battery combinations.

 

[Guest]

I'm also a bit confused with your requirements, a 2 ft boat at 3kg should last quite well with a suitable motor and a good battery pack. You can even go down the path nowadays of Li-Pol batteries and brushless motors which will last for a very long time in the water.Maybe if you give us a bit more of an idea of the boat you want to propel we can help with some suitable motor, prop and battery combinations.

is my fishing bait boat i have got and was advised on A 700 7.2V LOW DRAIN.running a 6v 12amp hr batters not got a clue wjat prop it is but its starts of great then the battery is draining within 5 mins

 

[Guest]

There seems to be a bit of a confusion in your description. Motors are normally classed in a voltage range whereas batteries have a specific voltage. If your battery is a 7.2v battery and it is only a 700mah battery it won't last long driving a 6v motor drawing 12 amps!! But I strongly suspect that your figures are not quite giving us the whole picture just yet.

First can you tell us exactly what is written on the motor and then on the battery labels. If you can't find anything then take a picture.

For a start you don't want to consider IC engines for a bait boat, you won't see a fish for miles. A low drain motor of 6-12 V driven by a 7.2 v pack of around 2800-3000 mah will last you a couple of hours so we only need to get the right bits together here I'm sure.

As many accurate details as you can put together, preferably with pictures, would be a good start!

 

[Guest]

There seems to be a bit of a confusion in your description. Motors are normally classed in a voltage range whereas batteries have a specific voltage. If your battery is a 7.2v battery and it is only a 700mah battery it won't last long driving a 6v motor drawing 12 amps!! But I strongly suspect that your figures are not quite giving us the whole picture just yet.First can you tell us exactly what is written on the motor and then on the battery labels. If you can't find anything then take a picture.

For a start you don't want to consider IC engines for a bait boat, you won't see a fish for miles. A low drain motor of 6-12 V driven by a 7.2 v pack of around 2800-3000 mah will last you a couple of hours so we only need to get the right bits together here I'm sure.

As many accurate details as you can put together, preferably with pictures, would be a good start!

my batter is 6v 12 amp hours so should last long but its not ,when i did a test drive yesterday its was working great forabout 5 mins then the power just seemed to drop once i got it back to check if there was and weed around the prop it was clear ,i then tested it out the water and it was working fine but once its in the water and got resistance the power just goes .i was told 6v was alot better than 12v ,im am sure the motor is 7.2v low drain ,one thing i have done is but a bigger propeller on from 35mm to 50 mm as the lower one was not moving the boat hardly in the waves

please help me as already spend over £100 on bits and its getting me down now

 

[Guest]

OK what do you use to charge the battery and what procedure do you follow?

 

[Guest]

OK what do you use to charge the battery and what procedure do you follow?

i bought a propper charger from the model shop .i put the connectors on and charge is the only way really ??

 

[Guest]

so any ideas why its draining so fast

 

[Guest]

ok did a test today .i had the batterys fully charged and set a stop watch on the boat .its only lasted 8min then the boat power drops and hardly get anything ,if i take it out the water it workds fine just noth neough power is i put it in the water as getting resistance

 

[Guest]

The reason I asked about the charger is to determine whether it is the correct charger for the battery and you have it on the correct settings.

From what I can see your battery should last for quite a while unless the motor is drawing a huge current. The large prop won't help but I wouldn't have expected it to be a huge issue, I suspect that the fact that the prop rotates when you take it out of the water is simply allowing the small charge left in the battery to rotate it.

Two possible options are post loads of pictures and we may see what the issue is or take the entire set up back to where you purchased it from and ask them what they think is wrong.

I need to be able to investigate this a bit more by measuring the current drawn by the motor etc to try to see if the set up is simply wrong or the battery isn't either holding charge or being charged correctly.

Can you connect an ammeter to it and try it in the bath again? Do you know where to connect the ammeter?

Where are you?

Pictures of all the bits would be a great help.

 

[Guest]

The reason I asked about the charger is to determine whether it is the correct charger for the battery and you have it on the correct settings.From what I can see your battery should last for quite a while unless the motor is drawing a huge current. The large prop won't help but I wouldn't have expected it to be a huge issue, I suspect that the fact that the prop rotates when you take it out of the water is simply allowing the small charge left in the battery to rotate it.

Two possible options are post loads of pictures and we may see what the issue is or take the entire set up back to where you purchased it from and ask them what they think is wrong.

I need to be able to investigate this a bit more by measuring the current drawn by the motor etc to try to see if the set up is simply wrong or the battery isn't either holding charge or being charged correctly.

Can you connect an ammeter to it and try it in the bath again? Do you know where to connect the ammeter?

Where are you?

Pictures of all the bits would be a great help.

hi mate thanks for getting back to me ,i am from sthlens merseyside

my mate who is a sparks with have a tester what to i need to find out how much the motor is drawing ?? and how much the batterys is holding ???

where will he need to test the draw from mate ,regarding pics its hard really as my proper pc is away being fixed so cant transfer any to this pc,there is not much really to look ate really i would of though as the motor connects to the speedcontroller .sc connects to battery and everything plugs into

i can see it being the battery as i bough 2 and both doing the same.i just found an old 12v battery in my shed and tried that and wow the speed was alot better but did not last long at all i am more and more thinking the motor is drawing to much

 

[Guest]

You need to connect the ammeter in line to the motor, i.e. break one wire and connect the ammeter to the two ends. You may have to turn them around if you get a negative reading.

When you run the motor see what current is being drawn. A 12 Ahr battery should be able to deliver 12 amps for somewhere in the region of an hour so if yours is lasting five minutes it is either drawing 144 amps, in which case just about everything would have been fried long before now, or something else is wrong.

Is this for RC use and is there a speed controller in the circuit? Let's see what current you get.

 

[Guest]

You need to connect the ammeter in line to the motor, i.e. break one wire and connect the ammeter to the two ends. You may have to turn them around if you get a negative reading.When you run the motor see what current is being drawn. A 12 Ahr battery should be able to deliver 12 amps for somewhere in the region of an hour so if yours is lasting five minutes it is either drawing 144 amps, in which case just about everything would have been fried long before now, or something else is wrong.

Is this for RC use and is there a speed controller in the circuit? Let's see what current you get.

batterys where bought from the model shop along with everything else ,im running a 20amp viper marine controller ,mate is going to calll tonight and test it for me

 

[Guest]

latest update ,before i found a old motor in my shed and put that on my boat and took it to my local pond for a test ,what i found is the boat run alot longer than the one i had on ,

i was mistaken the motor was 600 SPEED so for some reason the 600 motor is draining it like mad will find out more after when my mate tests them

ian

 

[Guest]

ok did a test today .i had the batterys fully charged and set a stop watch on the boat .its only lasted 8min then the boat power drops and hardly get anything ,if i take it out the water it workds fine just noth neough power is i put it in the water as getting resistance

Doing a load test on the battery first might show the battery is the problem, how old is the battery? and do you allow the battery to run right out before re-charging, is the wiring getting hot while the load is on the motor, chuck it in the bath and allow it to push against the end of the bath and check the wiring while running.

 

[Guest]

the batterys are only a month old .

i am getting told the motor is a big problem of a guy on a fishing forum as it runs at 18000rpm and i really only need arounf 800-900 also the prop is to big at 50mm needs to be around 30mm

 

[Guest]

the batterys are only a month old .i am getting told the motor is a big problem of a guy on a fishing forum as it runs at 18000rpm and i really only need arounf 800-900 also the prop is to big at 50mm needs to be around 30mm

The larger the prop the greater the current draw and load on the motor sometime no extra speed or power, if you reduce the rpm of the prop but increase the pitch you will find for adaptation you are wanting a slower turning prop with a longer pitch will give you what you want, again the greater the pitch the more load on the battery.

 

[Guest]

Looks to me like a cell burn out. Have you tried another battery pack. The binding on the prop would have caused a high drive resistance and the battery would have overheated and probably cooked a cell. Putting this accidental resistance on the battery would have the same effect as using a higher load motor on an inadequate source. The result would be that after short use the pack will give up the gohst. Rapid discharge would certainly damage the pack. try to borrow one of a mate and see how it goes.

Andy