Re: [EVDL] Wooden Electric Cat; PS
PS, forgot to mention my balancer circuit and battery scanner for the LiFePO4 T-Sky etc batts are on www.evdl.org/lib/mh/
From: [email protected]
To: [email protected]
Subject: Wooden Electric Cat
Date: Mon, 30 Aug 2010 10:47:10 -0400
Hi,
I also have a wooden boat, a Cat built by Jerry Dycus (havn't heard from Jerry, is he ok?) which from what I've measured is about 28% more efficient (V hull) than a O or U shaped hull pontoon or displacement boat. My max speed 1.5 x sqr-root of 18' = 7mph which is about it with 16ea 200ah (actually 100ah with 32 60A fuses buddy pairs) of ThunderSky 50V $5k worth of batts, 200lbs total. The cat weighs 1700 lbs. I hasd solar panels on top but due to the displacement/HP formula in Dave Geer's prop handbook, I found it was more efficient to orient them on my house and plug into the solar panels when I got home from the lake (saved 127 lbs). Weight is the enemy especially on a cat for efficiency, HP, displacement.
I'm presently drawing 80A at 50V about 4kw or 4hp with efficiencies factored in on the E-Tek PM motor with my homebuilt controller & charger. The uWave oven transformer charger secondary was tweaked to allow 1/2 amp final taper at EVcomponents Dave Kois recommendation of 3.8VPC for Thunder Sky LiFePO4 batts. The only problem I see with the balancers as previously pointed out, is if one dies, that cell can either jump up in voltage, frying it or a scwartz if the fet gets stuck on. Fortunately that hasn't happened but secondary monitoring would be good to add. Keeping final taper charge current low at 61V (final at 16 x 3.8V) 1/2 amp keeps things subdued if a balancer goes bonkers. I also have a battery scanner while driving so I can see if any cell drops below 2V. So far knowing 15 mile range with a Garmin GPS, I havn't gone below 3.0Vpc even after this week-end of lake bar hopping, from the Marina with live bands, to an sandy island with ice cream, to a tiki bar (with !
a Mississippi style paddle-boat), then a beach area with slides, dinner at a China restaurant & floating dock putt-putt golf and back to the put in 10am - 8pm on SML. Sunday we went on lake MooMaw wilderness lake, lotsa wildlife but the 1.5khz eeeee scared them away, so usually just ron in bypass (may bump up switching freq or change controller).
BTW, I tried Minnkota trolling motors but reliability for electric drive wasn't that good (for one season) but was improved with copper impregnated brushes. The E-Tek Briggs & Stratton 8x8" prop has been very reliable about $1.5k and was cheaper than the Ray $5k 48V with a 12.5 diam x 10 pitch prop (Curtis & GE GC motor). I'm thinking about trying a used outboard with the Etek-RT 2k rpm at 48V with a 2:1 reduction. I tried the inboard drive with a 16x16" prop but it wasn't more efficient despite the claims I found in boat books I also measured 80A at 7mph so i took it off & saved the weight. A larger slower turning prop would be quieter (like the Ray).
Have a renewable energy day,
Mark in Roanoke, VA
www.reevadiy.org
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PS, forgot to mention my balancer circuit and battery scanner for the LiFePO4 T-Sky etc batts are on www.evdl.org/lib/mh/
From: [email protected]
To: [email protected]
Subject: Wooden Electric Cat
Date: Mon, 30 Aug 2010 10:47:10 -0400
Hi,
I also have a wooden boat, a Cat built by Jerry Dycus (havn't heard from Jerry, is he ok?) which from what I've measured is about 28% more efficient (V hull) than a O or U shaped hull pontoon or displacement boat. My max speed 1.5 x sqr-root of 18' = 7mph which is about it with 16ea 200ah (actually 100ah with 32 60A fuses buddy pairs) of ThunderSky 50V $5k worth of batts, 200lbs total. The cat weighs 1700 lbs. I hasd solar panels on top but due to the displacement/HP formula in Dave Geer's prop handbook, I found it was more efficient to orient them on my house and plug into the solar panels when I got home from the lake (saved 127 lbs). Weight is the enemy especially on a cat for efficiency, HP, displacement.
I'm presently drawing 80A at 50V about 4kw or 4hp with efficiencies factored in on the E-Tek PM motor with my homebuilt controller & charger. The uWave oven transformer charger secondary was tweaked to allow 1/2 amp final taper at EVcomponents Dave Kois recommendation of 3.8VPC for Thunder Sky LiFePO4 batts. The only problem I see with the balancers as previously pointed out, is if one dies, that cell can either jump up in voltage, frying it or a scwartz if the fet gets stuck on. Fortunately that hasn't happened but secondary monitoring would be good to add. Keeping final taper charge current low at 61V (final at 16 x 3.8V) 1/2 amp keeps things subdued if a balancer goes bonkers. I also have a battery scanner while driving so I can see if any cell drops below 2V. So far knowing 15 mile range with a Garmin GPS, I havn't gone below 3.0Vpc even after this week-end of lake bar hopping, from the Marina with live bands, to an sandy island with ice cream, to a tiki bar (with !
a Mississippi style paddle-boat), then a beach area with slides, dinner at a China restaurant & floating dock putt-putt golf and back to the put in 10am - 8pm on SML. Sunday we went on lake MooMaw wilderness lake, lotsa wildlife but the 1.5khz eeeee scared them away, so usually just ron in bypass (may bump up switching freq or change controller).
BTW, I tried Minnkota trolling motors but reliability for electric drive wasn't that good (for one season) but was improved with copper impregnated brushes. The E-Tek Briggs & Stratton 8x8" prop has been very reliable about $1.5k and was cheaper than the Ray $5k 48V with a 12.5 diam x 10 pitch prop (Curtis & GE GC motor). I'm thinking about trying a used outboard with the Etek-RT 2k rpm at 48V with a 2:1 reduction. I tried the inboard drive with a 16x16" prop but it wasn't more efficient despite the claims I found in boat books I also measured 80A at 7mph so i took it off & saved the weight. A larger slower turning prop would be quieter (like the Ray).
Have a renewable energy day,
Mark in Roanoke, VA
www.reevadiy.org
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If I sold this boat I
