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 > > >
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