I've been getting some sailing/motoring in with the Turnigy Watt Meter installed. It's great having the data that the meter provides right at the helm.
I read on another E-propulsion site that a useful function of the watt meter is the volt to current ratio. While motoring if you back off of the throttle and watch the voltage recover you can find a sweet spot with minimum current draw and max voltage. I know this basic knowledge for many here but it's really apparent watching the voltage react to the current draw on a micro scale with the watt meter right in front of me.
Mark
Santa Cruz
--- In electricboats@yahoogroups.com, "acsarfkram" <acsarfkram@...> wrote:
>
> Thanks Denny.
>
> --- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@> wrote:
> >
> > Mark,
> >
> > Color me jealous - it was 3F here in Michigan this morning. I'd have to chop a hole in the ice to launch a boat.
> >
> > You different voltages under load are likely due to the resistance of the power wires if the Packtracker is connected to the battery and the Watt meter is getting its voltage signal at the shunt near the motor. Sounds normal.
> >
> > Denny
> >
> > ----- Original Message -----
> > From: acsarfkram
> > To: electricboats@yahoogroups.com
> > Sent: Wednesday, February 09, 2011 7:43 PM
> > Subject: [Electric Boats] Re: Turnigy Watt Meter
> >
> >
> >
> > Hi Denny,
> >
> > I wish I was the clever one, Jeremy over at the Endless-Sphere website came up with that modification. You can see it here; http://endless-sphere.com/forums/viewtopic.php?f=2&t=21976
> > He used two of the modified meters on E-Boats.
> >
> > That's great - doubling the range on the Minn Kota.
> >
> > I look forward to having a meter right at the helm. I took the boat out today to check out the watt meter (it had nothing to do with the clear skies and warm temps :-). The Turnigy Watt Meter monitors the motor current and voltage the PakTrakr reads the battery's current and voltage. I noticed that the voltage at the motor is lower by a few 1/10's of a volt than the battery voltage under load. Does that sound normal? Once the motor was off for a while they were the same. I've heard battery loads and motor loads are different.
> >
> > Next I want to install a switch so I can see regen numbers.
> >
> > Mark
> > Santa Cruz
> >
> > --- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@> wrote:
> > >
> > > Mark.
> > >
> > > I would set the speed control to draw a fixed number of watts and then run for 30 seconds and note the GPS average speed for the period. With cheapo $3 RC model props I could try lots of different sizes. Most speed for least watts = best prop.
> > >
> > > Bottom line, a 34# thrust MK trolling motor with a 10 x 6 airplane prop, a PWM controller meant for a model car and a fairing around the motor tube I more than doubled the range over the stock motor clamped to the hull.
> > >
> > > This set-up will push my 18', 450# sailboat 4 mph for 10 miles on one Gp 24 12v AGM battery plus I have juice for the electric bilge pump and GPS.
> > >
> > > Your use of the external shunt is very clever - for $60 you have as much function as a $200 Link 10.
> > >
> > > Denny
> > >
> > >
> > > ----- Original Message -----
> > > From: acsarfkram
> > > To: electricboats@yahoogroups.com
> > > Sent: Wednesday, February 09, 2011 2:16 PM
> > > Subject: [Electric Boats] Re: Turnigy Watt Meter
> > >
> > >
> > >
> > > Hi Denny,
> > >
> > > The Turnigy is a little different - its rated at max amps of 130 the Watts Up is lower. That said I removed the shunt in the unit and installed a beefier shunt remotely. That way I could hard-wire(no connectors)and use "thin" wires running to the helm.
> > >
> > > What was your process when you were using the Watts Up for prop sizing?
> > >
> > > Mark
> > > Santa Cruz
> > >
> > > --- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@> wrote:
> > > >
> > > > This same unit is sold as a "Watts Up" meter. I have one and it was invaluable for evaluating different props on my sailboat drive. Be sure to use quality connectors, though. I first used the flat spade connectors from the auto parts store and they heated up noticeably. The gold plated bullet connectors used in the RC world work much better.
> > > >
> > > > There are a lot of interesting products in the electric RC hobby - including motors and controllers that can propel a 20 lb. plane straight up.
> > > >
> > > > Denny Wolfe
> > > > www.wolfEboats.com
> > > >
> > > > ----- Original Message -----
> > > > From: acsarfkram
> > > > To: electricboats@yahoogroups.com
> > > > Sent: Tuesday, February 08, 2011 9:39 PM
> > > > Subject: [Electric Boats] Re: Turnigy Watt Meter
> > > >
> > > >
> > > >
> > > > I finished the Turnigy Watt Meter modification today. It works great so far. now I have amp draw, voltage, watts and some other information at the helm. It mounts next to the compass and is held in place with a nylon wedge and Velcro. When not in use it is covered under the compass cover. I'll add some photos to the Lotus Flower folder.
> > > >
> > > > Turnigy Watt Meter $30, Bogart shunt $30, misc. wiring and connectors $40, time scratching head - priceless.
> > > >
> > > > Mark
> > > > Santa Cruz
> > > >
> > > > --- In electricboats@yahoogroups.com, "acsarfkram" <acsarfkram@> wrote:
> > > > >
> > > > > I stumbled on this inexpensive watt meter;
> > > > >
> > > > > http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080
> > > > >
> > > > > and ended up at this E Propulsion website;
> > > > >
> > > > > http://endless-sphere.com/forums/viewtopic.php?f=2&t=21976
> > > > >
> > > > > while researching installing it at the helm. The issue is that the shunt is mounted inside the unit so you have the mount it near the batteries or run heavy wire to the helm. I ended up ordering a shunt;
> > > > >
> > > > > http://www.bogartengineering.com/sites/default/files/images/high-res/100A-100mV_shunt.jpg
> > > > >
> > > > > and plan to locate that near the batteries and running small gauge wire to the helm. I know I could spend more and have a more robust setup but this gives me the tinkering fix that I have been missing lately :-)
> > > > >
> > > > > Mark
> > > > > Santa Cruz
> > > > >
> > > >
> > >
> >
>
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