Hi Welton,
Thanks so much for the reply, which helps us see that in your case an Elco system is OK it seems. My statement "I don't see them as a realistic option due to weight and form factor for sail boats around 10m.", was deliberately non committal and challenging, in wanting to be shown differently.
My vague reasoning was based on some loose assumptions, in that ideally we want, when converting, to have a similar weight in the same place or lower as the old diesel. I'd also assumed it would be the much heavier 48V Elco with a min of 4 x 8D batteries rather than the http://www.elcomotoryachts.com/ep-600.shtml
In that case and certainly in my 8m double ender there would be no space for their http://www.elcomotoryachts.com/ep-1200.shtml, plus batteries etc and it would be heavier overall than the original diesel system with weight further aft than desirable and no easy access to batteries and my shaft seal. I also wanted 8D battery sizing as I believe they are cheaper in the long run and that larger AGM batteries are better suited to EP. Can't afford the newer battery tech! Note, getting to my shaft seal in an emergency with the old diesel was nigh on impossible. Now it is easy.
I like the IP rating of the Elco and integration, yet I know little of the numbers that matter to me i.e. Voltage and torque constants, motor/controller temps etc.I love Elco's history and that beautiful British Racing Green and polished alloy look. Do you have full specs for comparison? I'd also be curious to know what prop and shaft speed you intend. John Fiorenza/James Lambden designed/built motors/systems and Lynch/AGNI et al. have well documented dyno type facts and figures.
I'd also like to see motor efficiency maps such as the one at the bottom of this page http://www.yasamotors.com/products/yasa-400/
Here's how I went about my comparison when designing my system.
Replace Volvo MD2010 113 (249) kg (lb) Crankshaft power 7.5 kW (10 hp) with batteries in place of old engine for weight and access, motor in place of old gearbox gave:
2 x AGM 260 Ah 8Ds 20 Hr rate (Don't know their RC), 527mm length, 279 mm Width, 208 Height, 69 Kg ea = 138 Kg. Lynch motor Ip20 rated 11 Kg, Pancake form factor direct drive.
So 113 Kg compares to (138 + 11) = 149Kg
Difference = EP 36 Kg Heavier
Not accounting for a 50l diesel fuel tank removed, which in time will be replaced by a potable drinking water tank to trim differences, plus a small hot water system, which is why I have room left in the engine bay. I'm just ordering a Honda 1kW Genny too which is kept outside.
Other weights/considerations.Battery Charger, Battery Mounting, Cables etc, DC - DC Converter, Controller, separate 15 l Eberspecher bio diesel heater tank.
Having said all that I think Volvo was conservative and did not account for ancillaries, as my trim is a little bow down now (although I fitted a 40Kg offshore Liferaft on the foredeck too) until I do the other upgrades mentioned.
After 600miles on EP last year I have now also been able to afford some upgrades. I've increased the separate old domestic/start batteries to 2 x 130 AH AGMs running an inverter/charger. This is a stand alone battery string, that can silently charge the main EP bank. Handy, if inefficient, at a quiet overnight anchorage. An upside is if a string goes down I only have 2 batteries to replace at any one time and the inverter bank can also (if needed) charge the main EP string. A reserve tank if you like or just kettle boiling or shower tank heat topping off power..
I also have a little solar to fit aft on the boat. My personal rules. Minimise batteries as much as possible. Maximise solar and buy a hand held genny. You can't beat the bang for your buck in 5l of petrol and a small Honda genny. And finally, pray we get solar cloth main sail panels at affordable prices soon, along with metal/air batteries.
I do so like the modular nature of EP systems. Out of interest (apart from the batteries) my whole conversion was done with a shoulder bag, carrying parts from my flat to the boat.
Anyhow, this all adds up to a similar weight and distribution with my EP system compared to the diesel, with 9.6kW of battery power on board plus solar, plus a 1kW genny (900 Watt rated|) that will drive the boat and charge both banks in battery assist mode, whilst using less than half the fossil fuel when compared to the old diesel at 4 Knots.
Footnote. As I run a brushed motor I also use a bio-ethanol cooker as clearly one cannot have gas onboard safely. I prefer the cooker anyhow ,as it is stand alone (take to the beach for a BBQ) and any fire can be put out with water. Also fuel comes in 500ml bottles, so no heavy gas/propane canisters to carry.
I enjoy all the variables and decisions we have to make and look forward to hearing more of your conversion process Welton.
John
| Reply via web post | Reply to sender | Reply to group | Start a New Topic | Messages in this topic (72) |
No comments:
Post a Comment