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.
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