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BobJ
10-04-2009, 10:09 AM
Was October 19, 2009 at KKMI's Boathouse . . . thanks to all who attended!
____________________________________

Race Co-Chair Rob Tryon is working on this one and needs your questions! We want to keep this relevant to the race, and questions from YOU will help us do that.

I'll "prime the pump": My engine panel is installed low in the back of the cockpit. If it gets soaked, the key may not work and I won't be able to start my engine to charge batteries. I made a cover for the panel but it still isn't completely watertight. This leads me to my question:

Having grown up in East Oakland, I know you can hotwire a car pretty quickly. If necessary can I start my diesel that way? How?
___________________________________

Please send your electrical system questions to Rob or me at:

SHTransPac@yahoo.com

Also, be sure to put the seminar on your calendar.

Thanks!

Alchera
10-04-2009, 12:50 PM
I'll add this to the problem - even if you jump-start the engine, you may still not be able to charge the batteries because power to the regulator may come off the failed ignition switch! (At least it does on mine..) Now what do you do?

Oh, and here's another one. If you don't have an energy monitor installed, how can you tell how many amps your alternator puts out to charge the batteries?

- Mark

BobJ
10-04-2009, 02:13 PM
Hmm, my regulator is also wired to the key switch - I hadn't thought of that.

I have a 35 amp alternator (and a battery monitor) but the monitor rarely shows the batteries getting anywhere close to 35 amps - sometimes it shows as little as 3-4 amps. Is my alternator not working?

Critter
10-05-2009, 12:30 PM
I'll add an alternator question.

We all know we musn't switch off the electrical system while the engine is running, because it can blow out the alternator diodes. But is this supposed to be instant irretrievable disaster, or is it just a risk, and how big a risk?

A couple of times I've absentmindedly switched off when I intended to pull the fuel cutoff, and my alternator still seems to work.

Has anyone thought of wiring a relay into the system so that as long as the engine is running you can't switch off the electrics? What would you tap into to energize the relay? Any risk in doing this, eg fire hazard?

I know I could add a Zap-Stop. Is this a one-time sacrificial fix, or is it good indefinitely? And what exactly is a Zap-Stop? Can I scrounge a cheap substitute, or do I have to pay the ~$30 for the real thing?

OK, I guess that's several alternator questions.

Max

Culebra
10-05-2009, 03:28 PM
Okay, several pretty basic questions I think.

I have 2 house batteries, and I typically use one to run the systems while keeping the other in reserve for starting the engine or for emergency. Both are AGM, deep cycle but rated for starting also. (I would prefer a dedicated, third starting battery, but I'm hoping not to add that project to the list.)

Using the engine to charge the batteries:
1. If one battery is fully charged (or very nearly full) and one is 50% down, should I charge both or each one separately?
2. If I leave them both in the charging circuit, do I risk damaging the full one, and how could the regulator possibly know the difference?
3. Will it take longer if I leave them both in the circuit, or perhaps will one not receive a full charge (because of how the regulator works, perhaps)?
4. I have a wired-in voltmeter and ammeter, nothing sophisticated, and with these can I determine when (let's assume) a single battery is fully charged? (I have read that the voltage on a battery should be read after it has "rested" following a charge--something to do with equilibrium between the electrolyte, cathode and anode?)
5. Wishing it were not true, but guessing it is... related to the last question: obviously the output of the regulator is above the battery's present voltage, so while charging, the reading on the wired-in voltmeter must be higher than the battery's voltage, right? so would I need to turn off the engine (or take the battery out of the charging circuit) and wait until the battery is rested before using the voltmeter reading to assess state of charge?
6. The simple question is, how can I know how long I should charge? and one at a time or both?
7. What RPM is best?
8. Can I switch from 'Battery 1' to 'Battery 2' on the fly, while the engine is running, without damaging anything (the switch does not pass through 'off' to go from '1' to '2'... I think it passes through 'both'.. i'll have to check this)
9. If it is recommended to add a monitor for state of charge, is there one that does the trick while charging? high, med, or low install challenge?

Thanks,

Paul
Culebra

BobJ
10-05-2009, 03:48 PM
I'm dyin' to answer some of these but I don't want to steal Rob and Ron's thunder!

Great real-world Q's - keep 'em coming!

Travieso
10-05-2009, 09:54 PM
If you are planning your electrical setup I might have some good deals for you....

I have 2 8G31DT Gel batteries, 98Ah each that I'm happy to part with (only used for 1 Transpac Race)

I also have a never used Balmar 712-80 alternator with the MC-612 regulator. I had to do a full repower prior to my Transpac and the alternator didn't fit the new engine.

All combined should be upwards of $1200, first $500 can take it all!!!

jfoster
10-06-2009, 08:30 AM
I am curious about the possibility of an adverse interaction of solar panel pulse charging systems and the electronics systems in use during the race.

A small power example of such a system is found at the link

http://www.aircraftspruce.com/catalog/elpages/batteryminder11-02008.php

Anybody using a pulse charging sytem?

BobJ
10-07-2009, 09:07 AM
For aspiring SH TransPac'ers who are racing to Vallejo this weekend: Ragtime! will be available for inspection up there. Her electrical system is closer to the "minimalist" end but has most of the components recommended at SHTP Electrical Seminars over the years. Maybe I'll install the solar panels too so the whole system will be in place.

I'll be somewhere in the VYC basin so just track me down.

Matt
10-07-2009, 09:32 AM
I saw "Black Feathers", a Cal 20 equipped for ocean voyaging that competed in last years Transpac, parked at the South Beach Marina a couple weeks ago. This has gotten me thinking that I might actually be able to equip Tinker with what is needed for the Transpac in 2-3 years.

My general question about electrical systems is: "Typically, how many solar panels and how many Amp hours of batteries are needed on a small boat without a generator?" If this is too general of a question or the answer requires a specific watt by watt accounting of everything electrical on the boat, I understand.

Black Feathers has a couple nice sized solar panels bolted to his stern railing that looks like more than enough. I've seen similar setups on Starbuck, Mirage and other boats that have done the Transpac. Is there any general rule of thumb on the number, size or wattage output on the solar panels needed for the Transpac?

BobJ
10-07-2009, 09:41 AM
You need to do a load chart/budget to estimate it, but solar alone probably won't do it. Take a look at Ragtime!'s energy budget worksheet (linked on the 2008 SH TransPac page) and you'll have an idea what my two 43-watt panels contributed to the overall budget.

Andy got by with solar only in 2006 and I think I could have, but the batteries got pretty low at times. We had even more overcast in the 2008 race.

Culebra
10-07-2009, 10:48 AM
For the seminar, or now if anyone is so inspired...

I haven't yet explored installing solar panels for augmenting the battery charging (primary is engine). But if I do tackle this, I would want the solar to also provide an emergency source of electrical power in the event the batteries or engine charging system totally die. Do I need to include a method of isolating the batteries from the solar-powered instruments circuit, on the assumption that (if they are really dead) the batteries could draw too much current? I'm thinking the panels would have limited wattage, and not enough to supply both battery charging and instrument usage at the same time.

Thanks, Paul
Culebra

BobJ
10-07-2009, 11:22 AM
I don't have a complete answer to your question Paul, but I recall that Greg Nelsen (Outsider/Starbuck) had a solar panel that was dedicated to his tillerpilot if "all else failed."

Maybe Greg will stop in here and explain how that worked.

Alchera
10-07-2009, 12:16 PM
For the seminar, or now if anyone is so inspired...

I haven't yet explored installing solar panels for augmenting the battery charging (primary is engine). But if I do tackle this, I would want the solar to also provide an emergency source of electrical power in the event the batteries or engine charging system totally die. Do I need to include a method of isolating the batteries from the solar-powered instruments circuit, on the assumption that (if they are really dead) the batteries could draw too much current? I'm thinking the panels would have limited wattage, and not enough to supply both battery charging and instrument usage at the same time.

Thanks, Paul
Culebra

Solar panels typically put out 18-20+ volts when not connected to a battery, so controlling the voltage to the instruments without a battery connected to keep the voltage in the proper range would be a big problem I would think. You could get a solar regulator, but how well that would work just running instruments is anyone's guess, and they work on the principle of 'wasting' excess power which could have been used to charge your batteries! Plus your instruments are going to fail everytime the sun goes behind a cloud.

I would keep the panels hooked up to the batteries. If your batteries are truly discharged, isolate the one with the smallests AHs, and hook the panel to that so that it will get some charge in it quicker than having to charge the entire bank.
- Mark

blighbaum
10-07-2009, 01:38 PM
My engine (and alternator) croaked the day before the start of the SHTP. I sailed with 2 40-watt Kyocera panels on the pushpit, and two 20-watt Flex Pro flexible panels on the dodger, connected to a 10-amp Morningstar regulator and two 105 amp batteries. As far as I could tell from the battery monitor, the panels generated something even when the weather was overcast, and the batteries were well-charged all the way over. I kept my radio, GPS and AIS on at all times, and my strobe and lights on all night. My lights had LED bulbs, and I used a Monitor windvane (not an autopilot) for steering. One man's experience, for what it's worth; it made me a big believer in solar power.

- Tom Kirschbaum, Feral

jakmang
10-08-2009, 12:28 PM
For the seminar, or now if anyone is so inspired...

I haven't yet explored installing solar panels for augmenting the battery charging (primary is engine). But if I do tackle this, I would want the solar to also provide an emergency source of electrical power in the event the batteries or engine charging system totally die. Do I need to include a method of isolating the batteries from the solar-powered instruments circuit, on the assumption that (if they are really dead) the batteries could draw too much current? I'm thinking the panels would have limited wattage, and not enough to supply both battery charging and instrument usage at the same time.

Thanks, Paul
Culebra
I agree with what Mark said. Unless there is a catastrophic short in the system, the batteries should not "compete" with the devices that use power, they should just conduct it. In most cases, you need a solar charge regulator so that you don't overcharge the batteries or put too much voltage into the system. All regulator/panel circuts should have a fuse between the regulator and the rest of the system, so that voltage spikes don't reach the panels or the regulator.

A battery monitor is a really good idea. These can be simple volt meters or fancy monitors that will show you how much is going in and out of the batteries as well as the current state. I have found that this is the only way to truely understand your electrical system. It can show you how much a particular device draws.

You also need to think of the ways the primary system might fail and how to handle these in the simplest manner. I am always nervous about extra circuits/pathways that are not well tested by a lot of use (I'm a software guy).

One thing to watch out for when adding panels to a system is that the panel may raise the voltage of the system slightly, so that the alternator charge regulator will turn off with the engine running. This may mean that you will not be charging via the alternator at a time when you really want to. There are ways to wire the system so it does not happen. A simpler way is to be aware of the possibility, monitor the regulator and voltage and disconnect the panels with the engine running, if need be. Another way would be to run the engine at night.

brianb
10-08-2009, 10:24 PM
Hi Paul,

Solar panels, in an open circuit configuration, IE not connected to any load, can develop a lot more than 12 volts. 20 volts is not uncommon. If you were to run your instruments only, say a set of Raymarine instruments, they draw very little current and hence would not load the solar panels enough to pull them down to less than 13 volts. Without a battery in the circuit to absorb the additional current, or a voltage regulator, you run the risk of cooking the instrument set. I notice that some newer instruments are rated for operation from 10 to 30 volts, so they are very tolerant.

A battery that has dropped below 11 volts is very dead. I don't think in a no load situation they would be much lower than 10.5 volts. This means that if your solar charger came on line and the battery was that dead the current upon reasonable sunshine would pull the battery up near 12 volts so you could run the instrument pack easily. Auto pilot current draw could alter all this tremendously as at peak load you could easily consume the total capability of the solar panel when struggling with heavy seas. Of course you would need many hours of sunshine to bring the battery up to charge, or a large solar array.

What I am saying is:

1. You need the battery in teh circuit to help regulate a solar panel output.
2. A dead battery will come up to about 11 volts pretty fast under charge.
3. Your instruments are little load (new chart plotters are pretty high load), your AP is a relative large load. If it is just the instruments, you could run them.
4. To run the AP with dead batteries present you likely have to get them charged up for some time to be able to handle the peak current loads.

Hope this helps some.
Brian




For the seminar, or now if anyone is so inspired...

I haven't yet explored installing solar panels for augmenting the battery charging (primary is engine). But if I do tackle this, I would want the solar to also provide an emergency source of electrical power in the event the batteries or engine charging system totally die. Do I need to include a method of isolating the batteries from the solar-powered instruments circuit, on the assumption that (if they are really dead) the batteries could draw too much current? I'm thinking the panels would have limited wattage, and not enough to supply both battery charging and instrument usage at the same time.

Thanks, Paul
Culebra

Ergo
10-09-2009, 07:14 AM
I think Tom's experience is highly relevant and brings up a big consideration for folks who are equipping for their first long passage. He notes that solar panels were adequate for his basic needs BUT he used a wind vane; not an autopilot (AP).

If you are planning on using a robust, below deck AP, you need a robust charging system. An AP is much more forgiving of bad sail trim than a wind vane but the cost is paid in amps. This fact is very apparent in light conditions and on a run with a spinnaker up. When working in those conditions, my AP eats 4+ amps an hour. A wind vane uses 0 amps but the cost is paid in time - time spent learning how to use it and becoming very proficient at sail trim. Again, think light conditions and running down wind.

The critical systems: steering, electrical, communications and the skipper's skill level are closely interrelated. In deciding to go "Green" skippers would be well advised to take a very realistic look at how good they really are at balancing their boats.

Bill Merrick

Eric Thomas
10-12-2009, 06:35 PM
On Polar Bear 2008 SHTP I had 130 watts of solar on the pushpit, fixed not gimbaled, I had an additional 65 watt panel in cockpit under the tiller that I would toss and around and prop up to catch sun as possible. I had two 100 ah agm batteries and a morningstar 10 amp regulator. In the overcast skies of the first 10 days I lost 3% of the bank that I could not get back the next day. After ten days I was at 70% then the sun came out and I was fully charged. I ran 5 raymarine ST60 displays, a VHF, LED running light, mac laptop, satphone, S1G GP Pilot and the SSB for all call ins and some chatting. A link battery monitor is really great to have to fully understand your usage and charging ability.

Lucie Mewes
10-16-2009, 07:01 PM
Did you sell this stuff? We MIGHT be wanting a balmar...have to check with the guru!
Lucie

pmummah
11-03-2009, 01:41 PM
From the previous post, my answers are embedded.

I have 2 house batteries, and I typically use one to run the systems while keeping the other in reserve for starting the engine or for emergency. Both are AGM, deep cycle but rated for starting also. (I would prefer a dedicated, third starting battery, but I'm hoping not to add that project to the list.)
Adding a third to the system is easy. I recommend being able to switch it in/out easily so you can isolate it and put it in only when you have a true emergency. Make it easy to connect for charging though. Have one bank (battery) for the house and one for the engine. The third can be switched in if needed for the engine which presumably would be able to charge the other two if they are discharged.
Using the engine to charge the batteries:
1. If one battery is fully charged (or very nearly full) and one is 50% down, should I charge both or each one separately?
It does not matter. (With a small exception.) If one battery is charged and the other is discharged, when you connect them together with no charger they will begine to equalize their charge, which is, the discharged battery will begin to suck power from the charged battery. As soon as you put the charger on then the voltage on the system will be above both batteries and the charge will go from the charger to the batteries, with most of the current going to to the discharged battery. Batteries "suck" power, chargers do not "push" power. The discharged one will draw more current. After you remove the charger (turn off the engine etc) then the batteries will again start to equalize their charge if they are not both fully charged.
The one small exception is that if one battery is defective, then it could cause a problem. Usually battery cells fail "open" as opposed to "shorted". They don't draw a charge or store a charge. If a cell in a battery fails open then it will not affect the other battery. If a cell shorts, then it could prevent the other battery from charging. Extremely rare though.
2. If I leave them both in the charging circuit, do I risk damaging the full one, and how could the regulator possibly know the difference?
No risk of damage the charged one, assuming the regulator is working fine. A regulator controls the voltage to the batteries so they are not over charged. A float voltage is usually applied, after a battery is charged, to maintain the charge. This voltage is about 13.2 volts on a wet lead acid battery.
3. Will it take longer if I leave them both in the circuit, or perhaps will one not receive a full charge (because of how the regulator works, perhaps)?
No risk of one not getting a charge if both are connected. I am assuming that both batteries are of the same type (do not need to be the same size) and are both functional, that is, no cells are dead.
How a regulator works: It puts out a voltage. The battery "sucks" current from it. As long as current is available (alternator is fine and wires are large enough) then current will go into the battery. The battery charge increases and the current "sucked" by the battery decreases until it reaches a very low value when the battery is fully charged.
4. I have a wired-in voltmeter and ammeter, nothing sophisticated, and with these can I determine when (let's assume) a single battery is fully charged? (I have read that the voltage on a battery should be read after it has "rested" following a charge--something to do with equilibrium between the electrolyte, cathode and anode?)
When a battery is discharged it will draw a large amount of current when a charger is connected. As the battery's charge increases the amount of current it draws decreases. You can tell the state of charge by the amount being drawn. Also, the voltage value when the charger is off is a good indication. A small load should be applied. 12.8 volts is a good charge. 11.9 indicates a very low charge.
5. Wishing it were not true, but guessing it is... related to the last question: obviously the output of the regulator is above the battery's present voltage, so while charging, the reading on the wired-in voltmeter must be higher than the battery's voltage, right? so would I need to turn off the engine (or take the battery out of the charging circuit) and wait until the battery is rested before using the voltmeter reading to assess state of charge?
Correct. Put a small load on the battery also. Maybe 5 or 10 watts. A light is sufficient.
6. The simple question is, how can I know how long I should charge? and one at a time or both?
Both is fine.
Charge until the current drops to a couple of amps.
Charging too long, assuming the regulator is functional and not putting out too much voltage, does no harm. It might cause the liquid to go down a bit in wet batteries, but that is about all. You should check the liquid level of wet batteries every month or two if you are working them.
7. What RPM is best?
Check your amperage. Generally 1400-1800 RPM will get the alternator to full output. If you increase the RPM and the current does not go up then you don't need to increase the RPM. Idle is usually not enough.
8. Can I switch from 'Battery 1' to 'Battery 2' on the fly, while the engine is running, without damaging anything (the switch does not pass through 'off' to go from '1' to '2'... I think it passes through 'both'.. i'll have to check this)
If it passes through both then you are fine. You want a "make before break" switch.
9. If it is recommended to add a monitor for state of charge, is there one that does the trick while charging? high, med, or low install challenge?
Monitors are only as good as the "efficientcy factor" that you put into the monitor. That is the factor that gives the ratio of amount of charge in versus the amount of charge you get out. You get less out than you put in. It is about 1.1 for most batteries. If you charge and discharge the system a lot and monitor it to verify that the monitor is tracking the charge correctly then they are great. I can explain how to verify the efficiency factor is correct if you want.
I have a monitor on board and find that the efficiency changes as the batteries age. Also the shunt value (the thing used to monitor the current going in and out) changes as it ages and salt water gets on it. (I will encapsulate the next one I get in plastic. ) I use voltage under load to determine the state of charge of my batteries. When they get to 11.9 they have very little left. I can run them down more, but not much more. I know many people will think monitoring voltage is not as accurate but it does work for lead acid batteries pretty well.
Think of charge in a battery like honey in a jar. If you draw it out slowly then you will get almost all of the honey. If you draw it out fast (large load on the batteries) then you will leave a lot more in the jar. Monitors don't handle that very well. That is why it is best to get a larger battery bank. The load is a smaller percentage of the battery capacity and huge loads in relation to the battery bank don't exist. With a small battery, the same load will be large for the bank and you won't get all the capacity out.

pmummah
11-04-2009, 04:08 PM
I'll add an alternator question.

We all know we musn't switch off the electrical system while the engine is running, because it can blow out the alternator diodes. But is this supposed to be instant irretrievable disaster, or is it just a risk, and how big a risk?

A couple of times I've absentmindedly switched off when I intended to pull the fuel cutoff, and my alternator still seems to work.

Has anyone thought of wiring a relay into the system so that as long as the engine is running you can't switch off the electrics? What would you tap into to energize the relay? Any risk in doing this, eg fire hazard?

I know I could add a Zap-Stop. Is this a one-time sacrificial fix, or is it good indefinitely? And what exactly is a Zap-Stop? Can I scrounge a cheap substitute, or do I have to pay the ~$30 for the real thing?

OK, I guess that's several alternator questions.

Max


Actually, it really is just one question, can I damage anything if I turn the on/off switch off while the engine is running?
The short answer is, In a properly wired system you can not.

Details....
An alternator generates AC, which is converted to DC with diodes. The diodes are located inside the alternator.
Alternator connections: Most alternators (Including Balmar alternators) have a ground, output voltage (armature), field input (used to regulate the output), charging indicator output and AC output used for a digital tachometer.
The armature DC out is connected to the battery and solenoid with very large wire and the on/off switch in not in this circuit. These must never be disconnected while running. That will do damage.
The field input comes from the regulator. The charge output goes to the "idiot" charging light on your panel.

The on/off switch usually has two sets of contacts. One is between the start switch and the solenoid. So if it is off you can start the engine with the start button. A second set of contacts is between the output of the alternator and the engine instrumentation. Note, the boat instrumentation is not on this circuit. Only the idiot lights (oil, charging, temp) and any engine gages such as tachometer.
One "instrument" in this circuit is the regulator.
When you are running, if the on/off switch is opened (turned off) then power is removed from the start switch which prevents you from starting the engine (good since you are already running).
Power is removed from the engine instruments and alternator regulator. Your over temp, low oil pressure and charging lights will no longer work. The warning buzzer is part of this so it no longer works either. Nothing to warn you the switch is off.
Power is also removed from the regulator which will remove power from the field on the alternator. This will cause the alternator output to go to zero.
The on/off switch is not connected to the alternator or it's diode circuitry, so no damage will occur to either.

With the engine off you can verify if your system is wired like this.
First, check the number of contacts on the on/off switch. Four wired connections would be two switches. Verify you can not start the engine with the switch off. If you can maybe this set of contacts is present. The only down side is you can start the engine with the switch off. No big deal. The other set of contacts should supply power to the engine instruments. This can be tested by seeing what gets powered when the switch is on.
There should be nothing between the output of the alternator and the battery. This connection should not be opened when running.

Zap stop: This is a thermistor or zenor diode which prevents spikes. They will not absorb much energy though before they fail, which is why they come with a fuse. It is connected to the alternator ground and output. Frankly, it is not as good protection as a battery is. A battery will absorb voltage spikes. A zap stop might be desired if the battery is very far from the alternator as very high frequency spikes will not be dampened by the battery if the distance is far. Also if the battery is disconnected from the alternator when running you need protection (or change the wiring).
If the output of your regulator goes to zero when the switch is turned off then the output of the alternator will go to zero also. This is what Balmar regulators do. I don't think a Zap-Stop is necessary, but it won't hurt if it has a fuse in series with it.
One issue with a Zap-Stop is when they fail they short and thus the fuse blows, but there is no indication that this happened. So if you do not constantly check the fuse you will never know if it is providing protection.
My opinion, thermistors and zenor diodes fail much more often than the circuits you are worried about.

Intended or unintended consequence: If the switch is turned off, the regulator is turned off and no charging occurs. The load the alternator puts on the engine goes to zero. The boat is now running on your batteries. Why could this be good? A 100 amp regulator takes about 4 horse power to run at full output. If you have a small engine and want all the power to go to the prop, then turning off the switch will reduce the load the alternator puts on the engine. You loose your warning lights but the option is there if you want to use it.

Culebra
11-07-2009, 03:09 PM
Wow... thank you everyone. It's so great to draw from everyone's experience and ideas. Thank you.

Paul
Culebra