Echo Charge vs. battery maintainer

[4arch]

I'm in the process of setting up a reserve starting battery separate from my house bank. It seems to be the general consensus around here that the best way to charge the starting battery is to use an Echo Charge. I'm wondering though, what would be wrong with saving $75 to $100 by getting this:
Amazon.com: Sunforce 50022 5-Watt Solar Battery Trickle Charger: Automotive
or this:
Amazon.com: Duracell D2A 2 AMP 12V Battery Maintainer / Charger:…
in lieu of the Echo Charge to keep the starting battery topped up? Anyone see any potential downsides to having a separate maintainer on the starting battery? The boat's at the dock on shore power the majority of the time.

[scraph]

I have another solution that I've been happy with.

I just installed a total of 6 Group 27s on my boat. 5 of them are for the house bank and 1 is the starter battery.

I use a simple 2-bank battery switch. House bank is on switch position 1. Starter battery is on switch position 2. I have the starter connected to the common terminal of the battery switch.

Battery charger is wired to the house bank.
Alternator charging lead is wired to starter battery.

Switch position 1: I can start the diesel off the house bank.
Switch position 2: I can start the diesel off the starter battery.
Switch position 1+2: I can start the diesel off all 6.
Switch position OFF: House bank powers switchboard, house bank only charges off battery charger, and no power is available to starter.

1+2 is also where I leave the switch when running the diesel and also when running the battery charger since that parallels all batteries and allows them all to charge from whichever source.

Sure, you have to flip the switch to OFF when sailing ... 2 to start ... 1+2 to run ... but everything is an evolution with a procedure on a boat so why not have this flexibility?

[4arch]

I thought about doing a similar switch configuration but my concern is that the starting battery would get overcharged

[floatsome]

I'm happy with the Blue Sea Automatic Charging Relay, but there are lots of options now.

[scraph]

Yeah, it could require a little finesse. The real concern, I'd say, is if you parallel the starting battery (generally always charged) to a discharged house bank. There would be a large discharge from the starting battery. A starting battery doesn't really need to be "charged" ... since starting requires so little Ah from a battery, it should never be at a very low state of charge.

I generally, when house bank is very low, charge the house on the battery charger until finished and then parallel to the starting battery. I don't really overthink it ... because even a poorly treated Gp 27 will start my Yanmar 2GM for years, if that's all it's doing.

If I were dealing with something other than $90 batteries ... I'd probably go a more "intelligent" route.

[mitiempo]

4arch
As far as I can tell the second item you linked to plugs in to AC power so that's out except at the dock. The first item, the solar panel is only 5 watts which is less than 1/2 an amp in ideal conditions which you can only count on for 5 hours a day if the sun is shining.

scraph
With the switch "OFF" all should be isolated except the bilge pump. The "switchboard" should not be on if the switch is off.
The alternator should be fed to the bank most in need, almost always the house bank. Starting a diesel only takes an AH or less. The other problem is that the charging direction is totally reliant on you. With a properly wired system there is no switching necessary to charge all batteries from any source.

The advantage of the Echo Charge is that it knows when to supply charging current to the start battery and it also knows when to stop that current.
With an Echo Charge all charge sources go to the bank most in need - the house bank. When the start battery is down it gets charged if the Echo Charge senses a need. When it is charged the current from the Echo to the start battery ceases. All without any input from you. And the best option is to start the engine from the house bank as well and treat the start battery as an "emergency" battery. This means you turn the house bank on when arriving at the boat and off when leaving. That's it and no other switching required. And the emergency battery is always ready.

[btrayfors]

Spend the extra $75 for an EchoCharge. You can buy one new on eBay for $117 plus $10 shipping.

Install it...easy....3 wires. Forget it. No switching. No worrying about the position of a 1-2-ALL-OFF switch. No worrying about hooking a fully-charged start battery up to a much-depleted and much larger house bank.

Peace of mind and effective hands-off operation are worth something these days, IMHO.

Bill

[arf145]

Installed an EchoCharge on my boat this winter to keep my backup batt charged. The Echo was one of the simpler boat projects I've done--no surprises. As Bill said, 3 wires and it's always on the job.

[scraph]

Originally Posted by mitiempo

4arch
scraph
With the switch "OFF" all should be isolated except the bilge pump. The "switchboard" should not be on if the switch is off.
The alternator should be fed to the bank most in need, almost always the house bank. Starting a diesel only takes an AH or less. The other problem is that the charging direction is totally reliant on you. With a properly wired system there is no switching necessary to charge all batteries from any source.

With all due respect, Sir, your series of "shoulds" are not necesarilly "shoulds" at all ... but dogma.

I don't use the 1+2 switch as a battery isolator ... so no, OFF shouldn't isolate all but the bilge pump. I use it as a starter select switch ... so OFF should isolate the starter.

My switchboard has it's own main breaker, located next to this switch ... as well as all the breakers on the switchboard ... it has enough breakers and does not require further isolation from a switch.

The bilge pump, of course, is wired to the house bank and is non-isolable from it (save for it's own AUTO/OFF/MAN switch).

The alternator feeds the starter battery because, with the way I operate and use the boat, that is the only battery that the small alternator has any hope of helping with. It lives in a slip ... I take it out on daysails. The house battery is maintained/charged by the battery charger. The diesel is started only for entering/exiting the slip and is not relied upon (except when necessary) for supplying/charging the house bank.

Thus, the house bank/battery charger and starter battery/alternator are on two seperate 12V buses unless manually combined by the starter switch. I can combine them ... but 99% of the time, do not.

There is no "should". There is certainly no single, "correct" electrical system as you would imply. There is ... a number of different solutions. I don't worry about the position of the switch because I operate it myself. It doesn't operate on it's own.

[4arch]

Originally Posted by mitiempo

4arch
As far as I can tell the second item you linked to plugs in to AC power so that's out except at the dock. The solar panel is only 5 watts which is less than 1/2 an amp in ideal conditions which you can only count on for 5 hours a day if the sun is shining.

Since I'm mainly doing daysailing with only the occasional weekend or week long cruise, I don't see why this is a big problem. The reserve starting battery would sit idle 99-100% of the time and may well never be used if the house bank is kept up and looked after. For a battery there purely for emergency backup, it seems the main purpose of any charging scheme would be to prevent the self-discharge. In the event the battery did actually get used to start the engine, it would recharge through the alternator.

I don't mean to be argumentative, but the Echo Charge seems like it might be overkill for my needs. I just want to make sure there's not some huge hole in my logic here.