I'm in the process of installing a separate starter battery (Optima) to complement my house bank (2 4D's). Engine is a Yanmar 4JH-TE. I will ultimately replace the Hitachi 55 amp alternator with a high output/externally regulated alternator, but cannot afford to do it all in one step. My plan is to wire the alternator directly to the house bank (suitably fused), and to use a Heart "Digital Echo Charger" to maintain the starter battery. Here's the problem I came up against: I thought it would be a good idea to keep all of the "ignition" circuitry (ignition key, starter solenoid, tachometer, engine panel, etc) associated with the starter battery, so that a depleted house bank would have NO effect on starting. However, when I looked at the electrical schematics in the Yanmar Service Manual I found that the alternator output is internally connected to one of regulator terminals (I think it is the "L" terminal), which goes to the ignition switch. This means that if wired as I proposed, the house and starter banks would be paralleled through the ignition switch and regulator as soon as the switch is turned on (even before the engine was started). Not a good thing - especially with a depleted house bank, when very heavy currents would flow! So, unless there is an error in the Yanmar regulator schematic, it looks to me as if all engine control wiring MUST be connected to the battery bank to which the alternator is connected (the house bank in my case). It could have been a costly mistake! I don't think the same problem would exist with an externally regulated alternator.
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On the bright side...
that would help protect the alternator diodes. Let's say the starter was wired to it's own battery and the alternator output went back to the house bank (through a selector on/off switch). Then if you had the house bank turned off and started the engine with the starter battery the alternator would open circut and burn out the diodes since there would be no battery hooked up to take the charge. Of course you could be sure to always have the house bank online or get a zap stopper thingy but it would still make me a little nervous. I'm trying to figure out the best way to do the same thing so your post is quite interesting. I hadn't even considered that the batteries might be paralleled through the switch, that wouldn't be good at all. Hmmmm, back to the old drawing board...
that would help protect the alternator diodes. Let's say the starter was wired to it's own battery and the alternator output went back to the house bank (through a selector on/off switch). Then if you had the house bank turned off and started the engine with the starter battery the alternator would open circut and burn out the diodes since there would be no battery hooked up to take the charge. Of course you could be sure to always have the house bank online or get a zap stopper thingy but it would still make me a little nervous. I'm trying to figure out the best way to do the same thing so your post is quite interesting. I hadn't even considered that the batteries might be paralleled through the switch, that wouldn't be good at all. Hmmmm, back to the old drawing board...
Wiring
You could run the alternator output to the battery selector switch (1, 2, both, off). That way the charging output would be manually directed to whichever battery combination you choose. If I understand your post correctly, the terminal on the regulator (internal?) is the exciter voltage from the ignition switch. On my boat I ran the alt. output directly to the starter terminal and charge the house bank batteries with the battery selector switch in the "both" position.
You could run the alternator output to the battery selector switch (1, 2, both, off). That way the charging output would be manually directed to whichever battery combination you choose. If I understand your post correctly, the terminal on the regulator (internal?) is the exciter voltage from the ignition switch. On my boat I ran the alt. output directly to the starter terminal and charge the house bank batteries with the battery selector switch in the "both" position.
On-Off
Derek, I'm In the middle of the same project on my O'28. The starting battery is wired direct to the engine as if it were the only battery on board. That way there is no possibility of damageing the diodes. A short length of cable is attatched to the positive terminal of the starter battery and then to an on/off switch connected in line to the panel 1/2/both/off switch. As soon as we anchor the on/off is turned to off and then we proceed with normal battery management with our 2 house group 27's. In the morning after we start the engine, I turn the on/off to the on position and then charge the house batteries as needed. If the starter battery were to somehow lose a charge the house bank can be put back on line to help the starter battery. So far so good and a very simple inexpensive system. Good Luck,PM
Derek, I'm In the middle of the same project on my O'28. The starting battery is wired direct to the engine as if it were the only battery on board. That way there is no possibility of damageing the diodes. A short length of cable is attatched to the positive terminal of the starter battery and then to an on/off switch connected in line to the panel 1/2/both/off switch. As soon as we anchor the on/off is turned to off and then we proceed with normal battery management with our 2 house group 27's. In the morning after we start the engine, I turn the on/off to the on position and then charge the house batteries as needed. If the starter battery were to somehow lose a charge the house bank can be put back on line to help the starter battery. So far so good and a very simple inexpensive system. Good Luck,PM
Why no combiner?
Not sure I understand what you are trying to accomplish Derek. Maybe you can explain why you would NOT wire yours like mine. Starter battery to battery switch position #1. House batteries to position #2. Main battery cable from switch to starter post. On this same post is the alternator output and the 12V supply wire to the panel. Then I have a battery combiner connecting the two banks. My battery switch is always on #2, for starting and all other uses. When the engine is running it charges the house bank. When the house bank is fully-charged the combiner opens and the starter battery(which is never used) gets charged. When I am plugged into shorepower the battery charger works the same as the alternator. It's not necessary but I do have a Link 2000 to watch it all work. How are you improving on that wiring setup?
Not sure I understand what you are trying to accomplish Derek. Maybe you can explain why you would NOT wire yours like mine. Starter battery to battery switch position #1. House batteries to position #2. Main battery cable from switch to starter post. On this same post is the alternator output and the 12V supply wire to the panel. Then I have a battery combiner connecting the two banks. My battery switch is always on #2, for starting and all other uses. When the engine is running it charges the house bank. When the house bank is fully-charged the combiner opens and the starter battery(which is never used) gets charged. When I am plugged into shorepower the battery charger works the same as the alternator. It's not necessary but I do have a Link 2000 to watch it all work. How are you improving on that wiring setup?
Responses...
Ed and others, I am basically wiring the three on/off switch configuration advocated in the West Advisor. The Heart Echo-Charger is basically a "kinder, gentler" combiner that allows a controlled uni-directional charge current (limited to 15 amps) from the house-bank to the starter. It is connected just like a combiner. If I was to use a real combiner there would be no problem, I would simply charge the starter battery first (which a lot of people advocate). However I have purchased the Heart unit, and it has to work the other way around -otherwise I would be charging the house at a maximum of 15 amps. By the way, I'm becoming more suspicious of the Yanmar wiring schematic in my service manual. I will check it with a meter next time I'm at the boat.
Ed and others, I am basically wiring the three on/off switch configuration advocated in the West Advisor. The Heart Echo-Charger is basically a "kinder, gentler" combiner that allows a controlled uni-directional charge current (limited to 15 amps) from the house-bank to the starter. It is connected just like a combiner. If I was to use a real combiner there would be no problem, I would simply charge the starter battery first (which a lot of people advocate). However I have purchased the Heart unit, and it has to work the other way around -otherwise I would be charging the house at a maximum of 15 amps. By the way, I'm becoming more suspicious of the Yanmar wiring schematic in my service manual. I will check it with a meter next time I'm at the boat.
speaking of batteries
I need to know from all you electric gurus if my expectations are within the realm of possibility: I have two Trojan 8D house batteries for a total of 432 A/Hs. It seems to me that I should be able to follow the 50% rule and get down to about -200 amp/hours before I have to recharge, but typically the system only goes to about -75 amp/hours before voltage falls to 12.2, at which the refrigeration compressor won't come on. The batteries are three years old and I've never been happy with their performance. Am I expecting too much?
I need to know from all you electric gurus if my expectations are within the realm of possibility: I have two Trojan 8D house batteries for a total of 432 A/Hs. It seems to me that I should be able to follow the 50% rule and get down to about -200 amp/hours before I have to recharge, but typically the system only goes to about -75 amp/hours before voltage falls to 12.2, at which the refrigeration compressor won't come on. The batteries are three years old and I've never been happy with their performance. Am I expecting too much?
New thread Larry.
I think your question is going to confuse Derek's issue. It's a good question and deserves its own thread I think. I am still wondering why the three switch example from the West Adviser. Why so complicated unless there is some advantage? One thought is the fear of fried diodes. But the AFD battery switches prevent that for a nominal cost. I am probably missing something.
I think your question is going to confuse Derek's issue. It's a good question and deserves its own thread I think. I am still wondering why the three switch example from the West Adviser. Why so complicated unless there is some advantage? One thought is the fear of fried diodes. But the AFD battery switches prevent that for a nominal cost. I am probably missing something.
Combiners & Echo Chargers
The Heart Echo-Charger is basically a "kinder, gentler" combiner that allows a controlled uni-directional charge current (limited to 15 amps) from the house-bank to the starter. It is connected just like a combiner. That's correct. If I was to use a real combiner there would be no problem, I would simply charge the starter battery first (which a lot of people advocate). Makes no sense to charge the starting battery first because it only uses a few amps to turn over the engine. Plus, if you think about the wiring, why run all the amps to the house bank (which always needs it) through the starting battery wiring of the combiner? In fact, regardless of what people may advocate, the combiner instructions say run it to the house bank. Your hous bank will always need more than your starting battery.
The Heart Echo-Charger is basically a "kinder, gentler" combiner that allows a controlled uni-directional charge current (limited to 15 amps) from the house-bank to the starter. It is connected just like a combiner. That's correct. If I was to use a real combiner there would be no problem, I would simply charge the starter battery first (which a lot of people advocate). Makes no sense to charge the starting battery first because it only uses a few amps to turn over the engine. Plus, if you think about the wiring, why run all the amps to the house bank (which always needs it) through the starting battery wiring of the combiner? In fact, regardless of what people may advocate, the combiner instructions say run it to the house bank. Your hous bank will always need more than your starting battery.
For Ed
I don't think the three switch configuration is at all complicated, in fact it is very simple, and has for me a number of advantages: 1) My boat is a center-cockpit Pearson 422 with the house bank under the bed in the aft cabin. The new starter battery will be located about 15 feet from the house bank and I certainly don't want to run 2/0 wire aft to the 1-2-Both switch and then back to the starter motor. I can get a good short run from the starter battery to the motor. 2) I can easily install an on-off switch at the battery. As a matter of fact, I have purchased a remotely operated 300 amp switch (BEP Marine 722) that can be tucked away in a remote corner right next to the battery. 3) The 15 amp limit of the Echo Charger means that I do not have to run large cables between battery, 12 AWG will be quite adequate. 4) The wiring is actually very simple. The third (emergency start) switch will mount in the engine room and use the existing starter wiring. 5) I will leave the existing 1-2-Both switch on the house bank (2 4D's), usually in the Both position. I really see this as a "set and forget" set-up. (An off-topic aside ... a tree right next to our house was hit by lightning yesterday - we lost telephone, cable, internet and power. We've got power and cable/internet back (burned out cables) but the good old telephone company (Verizon) says they can't get to us before Saturday. Makes you wonder about sailing in storms...)
I don't think the three switch configuration is at all complicated, in fact it is very simple, and has for me a number of advantages: 1) My boat is a center-cockpit Pearson 422 with the house bank under the bed in the aft cabin. The new starter battery will be located about 15 feet from the house bank and I certainly don't want to run 2/0 wire aft to the 1-2-Both switch and then back to the starter motor. I can get a good short run from the starter battery to the motor. 2) I can easily install an on-off switch at the battery. As a matter of fact, I have purchased a remotely operated 300 amp switch (BEP Marine 722) that can be tucked away in a remote corner right next to the battery. 3) The 15 amp limit of the Echo Charger means that I do not have to run large cables between battery, 12 AWG will be quite adequate. 4) The wiring is actually very simple. The third (emergency start) switch will mount in the engine room and use the existing starter wiring. 5) I will leave the existing 1-2-Both switch on the house bank (2 4D's), usually in the Both position. I really see this as a "set and forget" set-up. (An off-topic aside ... a tree right next to our house was hit by lightning yesterday - we lost telephone, cable, internet and power. We've got power and cable/internet back (burned out cables) but the good old telephone company (Verizon) says they can't get to us before Saturday. Makes you wonder about sailing in storms...)
I get it.
One scenario I agree with is the batteries not being in the same area of the boat. Then switches in proximity make sense, no long heavy cable runs. On my boat the starter AGM and three gel house batteries are all next to each other and within three feet of the switch. One battery switch always set to #2.
One scenario I agree with is the batteries not being in the same area of the boat. Then switches in proximity make sense, no long heavy cable runs. On my boat the starter AGM and three gel house batteries are all next to each other and within three feet of the switch. One battery switch always set to #2.
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