The drive belt is as much a limiting factor as anything else. I've been using an adapted Delco 105A alternator for at least 12 years with no bad outcomes to my Yanmar 3QM30 other than a new belt every year or so. Also I seldom see the charge rate exceed 70A.
Rich > On Dec 18, 2013, at 11:18, Steve Thomas <sthom...@sympatico.ca> wrote: > > Excellent comments Rich. > > I would add that one needs to confirm that the power take off available for > driving a proposed larger alternator can handle the increased load. This is > especially true for engines where the power take off is through a gear train, > and not directly off one end of the crankshaft. In these circumstances it may > not be just a question of how large a fraction of the engine's output do you > want to direct to the alternator. The maximum load presented by the proposed > alternator, plus the water pump load, must not exceed the power take off > design limits. This is at least an issue with the Yanmar YSE, YSB, and YSM > series of engines. I don't know if there are any other common engine with > designs similar in that respect, but it is worth checking before going and an > buying too large an alternator for a specific engine. Yes the specific > engines I mentioned are smaller than 20-35 HP, but there are many of us that > do have em. An alternator that can actually deliver 100 amps will need around > 3 horsepower to drive it. > > Steve Thomas > C&C27 MKIII > Port Stanley, ON > > > -----Original Message----- > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com]On Behalf Of Rich Knowles > Sent: Wednesday, December 18, 2013 7:38 AM > To: cnc-list@cnc-list.com > Subject: Re: Stus-List Battery charger recommendations? > > And to increase the presumptuous factor: > > The alternators that were supplied as original equipment with most small boat > engines until recently were from 35 - 55 A with internal, single voltage > output regulators. A good percentage of the engines were destined for use in > small motor vessels and these alternators were adequate for that application. > For our use, which sees greatly increased loads from, as Rick notes, radar > and refrigeration, and lengthy battery discharge periods between charges, > those alternators are bordering on inadequate, and certainly not as efficient > and appropriate as higher power units with multi stage regulators. > > For sailing vessels, a central component of optimizing the electrical system > should be upgrading the generating capacity of the charging system. This will > involve replacing the alternator with the largest unit that can be fitted, > taking physical restrictions, drive belt capacity and depth of pocket book > into account. For most 20-35 HP engines, around 100A works well. There are a > number of external regulators available that should be considered for > installation as part of the new system. A new alternator with a multi-step > regulator will considerably reduce the engine run time needed to replenish > the batteries. Other devices such as wind generators and solar panels are > important for long range travels as well to further reduce the dependency on > the engine. > > For calculation purposes, I generally consider the usable capacity of > batteries to be 30% rather than 50% of rated capacity. This stems from the > fact that a 50% discharged battery will charge to around 80% at a fairly > linear rate which will drop significantly as the state of charge nears 100%. > Trying to achieve the last 20% can take a long time compared to the first > 30%. This will vary depending on battery type and condition, so my 30% figure > is somewhat arbitrary, but fairly realistic. > > A shore power fed battery charger from 20-40A will generally suffice to > sustain loads from refrigeration, lighting and entertainment devices > operating while the boat is alongside, and also provide enough power to > replenish the batteries. Again, a multi-step unit designed for marine use > should be chosen. There are lots of good marine chargers on the market. > > I note that non-marine AC chargers may not completely isolate the input from > the output, a potentially dangerous situation on the water, and should be > avoided. > > As Rick notes, designing an efficient, reliable electrical system is complex. > > It's snowing again. Grrrr! > > Rich Knowles > INDIGO - LF38 > Halifax, NS > > >> On Dec 17, 2013, at 20:45, "Rick Brass" <rickbr...@earthlink.net> wrote: >> >> Curtis; >> At the risk of being presumptuous, I think you have the cart before the >> horse. >> If your intent is extended cruising – particularly offshore cruising where >> you will not be using your engine for power (and to recharge the >> batteries) every day – you will first need to think about the systems you >> have on board and how much power they will draw. Refrigeration is a major >> draw. Radar? Autopilot? What instruments? What lights? Power for >> entertainment like radio or TV? Small things like a 12 v electric coffee >> maker or a microwave draw a shocking amount of power out of your batteries. >> Once you know how many amp hours you will use on average, you can figure out >> how many additional batteries you need, what type, and where to put them. My >> average consumption right now is under 100 amp-hours/day. But I plan to run >> refrigeration (45 more AH) and to anchor out for extended periods. So my >> house bank is 4 deep cycle group 27 batteries with 460 AH capacity. That >> gives 230 usable AH (50% discharge) and should let me go for 2 days between >> charges. In addition I have a group 29 marine starting battery as a second >> bank, and a deep cycle group 24 under the v-berth to power the head and the >> anchor windlass. >> The 400+ AH house bank dictates at least a 40amp, multi bank charger. I have >> an older Xantrex 40+ wired to the house and starting bank. There is a solar >> charger for the group 24 battery that is OK for now, but I plan to install >> an ACR that will top up the charge on that battery when I’m hooked to shore >> power or running the engine. >> To put 100 AH into my house bank by running the engine (with a 45 amp >> alternator installed) will take at least 3 hours of run time – which is OK >> when I’m traveling on the ICW but not acceptable when at anchor. SO I plan >> to install a bank of solar panels over the Bimini, and maybe a wind >> generator as well, to maintain the batteries at anchor. >> As you can see, the process starts with determining how much power you will >> be using each day, and that will depend on what systems you have installed >> for cruising. >> You said you had an “OEM” battery charger installed. Probably not really >> OEM, but the question is: is it still working? If it is, spend your money on >> the other systems you will be installing, and the additional batteries, and >> worry about a new (probably more efficient) charger in 2017 or so. >> Rick Brass >> Washington, NC >> From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Curtis >> Sent: Tuesday, December 17, 2013 1:16 PM >> To: cnc-list@cnc-list.com >> Subject: Re: Stus-List Battery charger recommendations? >> I picked up the one noted above to maintain the battery's. In my first post >> I was trying to explain I needed something to keep the batt's charged while >> sailing ever couple of weeks. "For Now" In 2018 We hope to shove off for >> some extended cruising. >> I will need to install a Good expensive on board fixed mount bank charger. >> This is what I was hoping to get advice on. the Good one that will give me a >> charge on all my batt's when I come in from off shore. >> Sorry for the confusion. >> >> On Tue, Dec 17, 2013 at 12:52 PM, Josh Muckley <muckl...@gmail.com> wrote: >> Evidently, we all misunderstood the question. The battery minder is >> advertised to provide a "de-sufating" pulse charge to prevent loss of >> capacity. This is fine and may or may not add value for your purpose. Had >> any of us realized that you simply wanted to keep the batteries from self >> discharging during winter storage you would have received drastically >> different answers. >> >> For ultra cheap $20 you can find 2amp smart chargers that cycle to prevent >> over charging. If conditioning or de-sufating was the goal then I would >> have possibly recommended a higher power portable unit with a conditioning >> feature. 10-40amps, 3 stage, and conditioning mode, $50-100. Stanley, >> Schumacher, Vector all have similar units available at the big box, auto, >> and boat stores. I'm not convinced that the battery minder has a more >> effective de-sulfating feature than any of the others. >> >> Many people prefer to occasionally visit the boat to top up the batteries. >> This eliminates the risks of overcharge, electical fire, and galvanic >> corrosion. >> >> What type of charger did you already have? What was wrong with using it? >> >> Josh Muckley >> >> On Dec 17, 2013 10:29 AM, "Curtis" <cpt.b...@gmail.com> wrote: >> Battery Tender Plus 12v 1.25 Amp 3 Stage Smart Charger BT-021-0128 >> Sorry I posted the wrong model. >> Wal-mart >> $66.48 >> >> On Tue, Dec 17, 2013 at 9:59 AM, Bill Bina <billb...@sbcglobal.net> wrote: >> Hopefully you can return it. You need a 12 volt charger, not an 8 volt >> charger. You also need substantially more than 1.25 amps. This thing will >> barely charge an 8 volt motorcycle battery. >> >> Bill Bina >> >> >> On 12/17/2013 9:47 AM, Curtis wrote: >> After much study and review I purchased a portable charger last night >> >> Battery Tender Plus 8v 1.25 Amp 3 Stage Smart Charger BT8v021-0152 >> This is a very popular 8 volt unit for battery storage. The Battery >> Tender Plus is a 1.25 amp battery charger designed to fully charge a >> battery and maintain it at proper storage voltage without the damaging >> effects caused by trickle chargers. The E-Z quick disconnect harness >> (1 of each ring ends and alligator clips included) allows you to leave >> the charger wiring attached to the battery while operating the >> vehicle. Battery Tender Plus will not overcharge or boil battery when >> connected long term. >> >> I hope it will keep them topped off when I'm not there. >> >> >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com >> >> >> -- >> “Sailors, with their built in sense of order, service and discipline, should >> really be running the world.” - Nicholas Monsarrat >> >> >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com >> >> >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com >> >> >> >> -- >> “Sailors, with their built in sense of order, service and discipline, should >> really be running the world.” - Nicholas Monsarrat >> >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com
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