Wouldn't a relay also maintain float? The relays aren't supposed to turn on until the house battery is full (~13.5v) so when the relay closes the starting battery is actually to largest "load" on the charger. Right?
Josh On Mar 28, 2015 1:42 PM, "Peter Fell via CnC-List" <cnc-list@cnc-list.com> wrote: > It also says when the output voltage reaches 14.4 volts, it reduces the > output current to maintain a float condition. There's also a curve in the > owner's manual that relates difference in voltage between banks to output > amperage. When the voltage difference is low, the amperage is high and it > decreases as the voltage difference increases. > *From:* Josh Muckley via CnC-List <cnc-list@cnc-list.com> > *Sent:* Saturday, March 28, 2015 10:26 AM > *To:* C&C List <cnc-list@cnc-list.com> ; Rich Knowles <r...@sailpower.ca> > *Subject:* Re: Stus-List New Wiring Diagram Draft (Edd Schillay) > > > Rich, > > Great explanation but don't the other combiners turn off once the starting > battery is greater than or equals to the house? As was pointed out to me > the echo-charge is simply a voltage follower with a limit of 14.4v. At > least one relay style combiner I've seem has an adjustable high voltage > shutoff. > > Josh > On Mar 28, 2015 10:51 AM, "Knowles Rich via CnC-List" < > cnc-list@cnc-list.com> wrote: > >> I didn't realize I'd start such a lengthy discussion. Sorry for the late >> reply. Work... >> >> I like the EchoCharge unit for the following reasons: >> >> When you combine batteries for charging using an automatically actuated >> combiner, or by manual switching, all the batteries combined will receive >> the same voltage at their terminals. While each battery will absorb >> different amounts of amperage depending on their state of charge, a battery >> that is fully charged will start losing electrolyte if it is continuously >> provided excessive voltage when it is combined with a battery needing high >> voltage to efficiently recharge it. >> >> In a well designed system, the engine start battery should be reserved >> for just that and nothing else. Although it will need to deliver high >> amperage to the starter, it will do so for only a few seconds to start an >> engine in reasonable condition, and that energy can be quickly replenished, >> usually within a few minutes. An average size 27 or 24 fully charged >> battery in good condition should be capable of starting a 30 hp diesel many >> times before requiring recharging. Once recharged, the presence of >> excessive voltage as charging of house batteries continues will cause the >> start battery to lose electrolyte. If this process is repeated often or >> long enough, the start battery will eventually lose enough fluid to be >> unable to start the engine. This situation is exacerbated by the use of >> smart alternator controllers and multi step AC chargers which cause higher >> charge voltages to be present than those produced by internally regulated >> alternators and simple single voltage chargers. >> >> Directing all charge capacity direct to the house battery, and using the >> EchoCharge or a similar device to maintain a single purposed, isolated >> engine start battery, ensures that the start battery only receives enough >> charge voltage to recharge it to full capacity. Barring a failure, there >> will always be reliable power to start the engine. Switching should be >> provided to enable emergency use of the house battery to start the engine >> or the engine start battery to provide house power. >> >> I have also used EchoCharge units to provide charge power to windlass >> batteries installed in the bow near the windlass. That saves a stack of >> money for expensive heavy copper wires to feed the windlass from the main >> house battery. If you install an EchoCharge, make sure it is in a dry, >> ventilated, relatively cool location. It is not waterproof, the principal >> cause for failure I have seen. >> >> Multiple output AC chargers are OK to use but should be carefully chosen >> and installed. If batteries are in parallel, only one charge leg should be >> connected to that bank. If an automatic combiner is used, only one battery >> charging source is required. For systems I design, I use a single output >> smart charger to charge the house battery and rely on devices such as the >> EchoCharge to distribute charge current as needed to start and other >> auxiliary batteries, one device for each battery. That charger is connected >> to the same point in the system as the alternator, as are any wind >> generators and solar panels on board. >> >> As an aside, I'm intrigued by the discussion about installing ever larger >> battery banks. Is this based on real calculated daily need, inefficient >> charging systems or other factors? Average daily power consumption for our >> boats including refrigeration, modern nav gear, sailing instruments, >> lighting and entertainment should not exceed 150 A/hrs per 24 hour period >> and generally will be much lower. A well maintained 450 A/hr house battery >> bank should be plenty in my opinion. More than that is excessive weight >> that simply slows down the boat and extends time between longer charges. >> >> Controversy is welcomed! >> >> Rich Knowles >> Nanaimo, BC >> INDIGO LF38 >> For sale in Halifax, NS. >> >> >> >> >> >> Rich Knowles >> Nanaimo, BC >> INDIGO LF38 >> For sale in Halifax, NS. >> >> >> >> >> >> >> _______________________________________________ >> >> Email address: >> CnC-List@cnc-list.com >> To change your list preferences, including unsubscribing -- go to the >> bottom of page at: >> http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >> >> >> ------------------------------ > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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