Re: [electricboats] First run

Sounds like Matt and I may find better numbers once our shafts are better aligned then! 

With the batteries my primary worry is about them sliding around. The AGM are so heavy that they *appear* as if they would stay put, but I would hate to find out the hard way that they won't, so in addition to the ventilated box they are shown in there is an additional cover that latches down in between the batteries and the engine.  

On Aug 31, 2020, at 14:17, John Theune <jatheune@gmail.com> wrote:



I like your stacking platform.  I have 2 of the four batteries in front of the motor and the other two to the side where the gas tank used to live but now I'm thinking I need to look at a platform.  I will also look at mounting additional supports on the top of the gear reduction mount.

As a side note I was disappointed with the performance of  my 10KW Thunderstruck system with a top speed of 4 knows drawing 100amps.  I had a diver go down and clean the prop and the speed went up .3 knots but the current draw dropped from 104 amps to 51 full throttle.  I still think I need to change props but this was a big improvement.

John

On 8/31/2020 3:08 PM, Ryan Sweet wrote:

Well your basic power curve looks very similar to mine. I haven't been able to make adjustments yet but will report when I do. 

I have the Thunderstruck gear reduction/engine mount and am using 2:1. 

I tensioned the belt to where it could just barely be deflected by hand. 

I was able to greatly reduce vibration by connecting the top nuts on the reduction frame with 1"x 1/4" steel plates at an angle to the other mount. (Pic below) They were thin enough to bend into place but vertically rigid. I put a rubber grommet in between the plate and the reduction. That stopped the top of the reduction frame from shaking back and forth. 

I think to fix my angle I am going to take out the lags that are going through the horizontal angle-iron and cut the wood away a bit, then install post bolts and lock nuts that I can use to adjust the angle up and down. my worry is that then more of the vibration will transfer through the bolt into the hull but if I can get the alignment right that seems preferable to destroying the cutlass bearing and stuffing box.  I have a cover to fit over the exposed batteries and wiring in the pic below, but showing basically I built a platform for the batteries where the old engine was, keeping the weight as much in the same place (low and central) as possible. With the thunderstruck reduction the new engine sits entirely aft of where the old one was, but having removed all of the old exhaust system etc there is still tons of room. 

I haven't noticed the motor whining but the shaft is pretty loud still.  Equally irritating is that my Noco Genius 48v battery charger makes a very high pitches whine whenever it is running. 

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On Aug 31, 2020, at 10:46, Myles Twete <matwete@comcast.net> wrote:



Sounds like a data range/wraparound issue---could be a parameter isn't configured right or perhaps the wrong shunt or ???

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of MATT
Sent: Monday, August 31, 2020 10:11 AM
To: electricboats@groups.io
Subject: Re: [electricboats] First run

 

Hi Ryan, 

We also just launched a couple weeks ago after our big conversion.  Right now, we are using the CAN translator and the Torque app on my android tablet which is supposed to show amps out, watts, and SOC% but none of those are working correctly.  When I get up to 16 amps, it resets to 0 and starts counting up again.  Since the watts are calculated from the amps, they also reset at about 1250 and start back at 0.   It is hard to trust the numbers when it's doing that.  I'm in touch with Thunderstruck to try and figure out the issue but nothing yet.  We use the Curtis battery monitor to show the SOC and it works pretty well.  Link HERE.

We also are having a hard time getting the alignment just right.  Pretty much exactly as you said, the shafts look aligned but the prop shaft is not perfectly straight through the cutlass.  We get some vibration, especially at higher RPM.  What surprises us the most is the very high pitched whine that comes from the motor.  It's far from silent.  I don't know if it's normal or if maybe the belt is too tight.  Do you have a gear reduction?  

Here are our very very preliminary numbers considering the watts I'm showing are slightly untrustworthy.  We are also in the puget sound where it's damn near impossible to get away from any currents and our speed log doesn't work, so we are relying on SOG.  Boat is a 39', 20k lb, sloop with the motenergy 1616 at 72V and 180ah (13kw) bank.  17'' 2 blade maxprop.  

WATTS   RPMS    SOG(KTS)
1000       1500       3.1
2100       2000       3.7
3600       2500       4.5
6000       3000       5.6

Let us know how your shaft alignment goes.