What Size Alternator Fuse ?

[donradcliffe]

Charlie, you of all people should know a zapstop isn't going to work if you have an externally regulated alternator where the regulator is sensing voltage at the battery terminals--that alternator is going to keep pumping out juice long after the zapstop is vaporized.

[sailvayu]

I read where several folks seem to think running the alternator wire directly to the house bank is somehow better. They talk about using an echo charger to charge the engine battery. I do not understand this logic really. And I know there are going to be a lot folks to jump in my cornflakes over this but here is my logic. First by using an echo charger (which by the way is really designed to be used with an inverter for long duration charging and really only to keep the engine battery topped off not recharging) you are seriously limiting you recharging ability of your engine battery. From the xintrex web site it looks like the echo charger will charge at about 8 amps, kinda slow if you ask me. It is rated at 15 amps max. Now what if this little bugger fails? You run your engine a few times and it starts ok then the next time click click click damn it is dead and guess what so is your house bank because you have been listening to the stereo all day or whatever. Now what? Also by doing this you are running a longer wire from your alternator to the house bank maybe it is the right size to handle the alt output maybe not likely it is ok but there could be some voltage drop along the way. Why not simplify your wiring run the alt output to the starter where you have a nice fat wire the will easily handle the full output. Now you are charging your starter battery first so you know even if the combiner you are using fails you can still start your engine. Oh yes I would use a 300 amp combiner not that wimpy echo charger so that the full charge rate goes to both banks and tops everything off quickly not just the house bank. Just my thought fire away boys and girls I can take it lol and if it gets too much at least I can start my engine to get away lol. Now if I could just find that damn fuse around here somewhere ………………………….
Wayne Canning, AMS
Projectboatzen.com

[CharlieJ]

That is a nit...my definition of connection was one that had to be made up by the installer as in crimping a termination, etc. You are using contact point as the definition of a connection...not where I was going in the context of the discussion.

[Maine Sail]

Originally Posted by sailvayu

I read where several folks seem to think running the alternator wire directly to the house bank is somehow better.

Not better but less connections and less chance of frying diodes and also less potential for human error factor.

As I stated the other day many, many boats out there are not wired to have a dedicated & direct wired start battery as you do. The OP of the thread I think you're referring to also did not have his start battery set up direct wired either.

For those thousands & thousands of boats out there with a 1/2/ALL/OFF switch the start/emergency battery will rarely if ever need to be used if proper battery management practices are adhered to. If it is not used often, and you are doing everything off the house bank, why do you need or want the ability to feed a start battery any more than 15 amps?

I also posted in that thread a video I made showing just how little starting a motor consumes. My 44hp four cyl diesel engine does not even consume .1 ah from a 240 ah bank for starting. An Echo charge will do just fine putting back .1 ah into a battery bank still above 99% state of charge. Also, if you're Echo or your combiner should fail you can always go back to the old way of charging both banks which is to simply switch to the "ALL" position.

Video here:

YouTube - What Happens When I Start My Engine

Originally Posted by sailvayu

They talk about using an echo charger to charge the engine battery. I do not understand this logic really. And I know there are going to be a lot folks to jump in my cornflakes over this but here is my logic. First by using an echo charger (which by the way is really designed to be used with an inverter for long duration charging and really only to keep the engine battery topped off not recharging) you are seriously limiting you recharging ability of your engine battery.

Battery acceptance and state of charge are the real questions. We must ascertain just what "limiting your recharging ability of your engine battery" is. As I mentioned above small diesel enginess really don't take much battery capacity to start. In the context of battery acceptance you would really need to discharge a a start battery considerably before a 15 amp charge could even be considered limiting. If you regularly discharge a start battery by say 20% of total capacity when starting your engine you have much bigger issues to deal with than the 15 amps an Echo will deliver.

A fully charged start battery might wind up at 95-98% of capacity after a worst case scenario start up that involved more cranking than normal this is an acceptance rate on wet cells far lower than 15 amps.

I have actually pulled my stop lever, closed my seacock and cranked enough, intermittently of course, to have water-locked my engine if I had left the seacock open. I still used only about 1% of the banks capacity leaving me at a 99% state of charge. Even one full minute of cranking with a 150 amp starter draw is still only 2.5 amp hours from a battery.

On even the smallest group 24 start battery, with roughly 65 amp hours available, this still leaves you at over a 96% state of charge. Considering the acceptance rates of wet cell batteries is roughly 25% of the 20 rating the MAX a 65 ah group 24 wet cell will accept, when it is flat out dead, is about 16 amps. The 16 amps only happens of course when the battery is basically dead. At 96% SOC you'll be lucky to force even one or two amps per hour into it. Even if you were to consume 5% of the ah capacity your battery will still barely be accepting 1-2 amps at the most depending upon the start bank size and chemistry, AGM's of course accept a lot more. Xantrex understands acceptance and it is probably why they designed it to only ever deliver up to 15 amps.

The Echo charger is not just designed to work with an "inverter", or more correctly stated an inverter/charger, because an inverter alone will not power the Echo. An Echo charger is designed to work with "any" charging source. I quoted Xantrex below:

Originally Posted by Xantrex

The Xantrex Digital echo-charge is specially developed for charging an
auxiliary battery with FreedomTM or Fleet Power® Inverter/Chargers or with any charging source.

Any charging source could be another brand of batery charger other than Xantrex, an alternator, solar or wind.

Originally Posted by sailvayu

From the xintrex web site it looks like the echo charger will charge at about 8 amps, kinda slow if you ask me. It is rated at 15 amps max.

See acceptance above. I can't imagine a sutuation when starting a small aux engine that a fully charged start battery would require more than even 8 amps, based on battery acceptance, unless you had AGM's than can take it. At a 100% charge, pre-start, my battery bank will only accept about 1 amp max after starting my engine from a cold start.

Originally Posted by sailvayu

Now what if this little bugger fails? You run your engine a few times and it starts ok then the next time click click click damn it is dead and guess what so is your house bank because you have been listening to the stereo all day or whatever. Now what?

What if your regulator fails, your alternator, what if you fry your diodes, what if you don't have a spare alternator belt, what if your water pump driven by the alternator belt seizes, what if your starter fails? What if's are fun but we could go on for days and days... The answer for me is redundency which is very simple when using an Echo or ACR with a 1/2/ALL/OFF switch.

If you are like the thousands and thousand of boats out there with a 1/2/ALL/OFF switch, and you have an ACR or an Echo, you simply flip it to "ALL" to re-charge just like before you installed teh Echo or ACR.

If you are using the house bank for everything, including starting, as many do who have a 1/2/ALL/OFF, and have proper volt meters to monitor your system this is a very unlikely situation. Most boaters upgrading to an ACR or Echo probably also have a way to monitor charge voltage of both banks. If you notice it low on the start bank you now know the ACR or Echo are not operating and can flip to "ALL" when running the engine to charge.

Also prior to an Echo or an ACR failing the battery would have likely been at or near 100% especially if your eside dock side with shore power and charger. This allows a lot of starts and plenty of opportunity to notice the voltage is not right and address a failure. If in a remote place, and you have a 1/2/ALL/OFF and this happens, the simple fix is to flip to "ALL" when charging until you can fix the ACR or Echo.

Considering I have personally had three Balmar regulators fail an ACR or Echo failure is so far from the radar of concern. It's a non-issue for me especially when I have redundency & the ability to always flip to "ALL" to charge both banks in a pinch. My boat had and still has a Yandina combiner (wired as a back up now) and she has probably 15-20k nm of 24/7 live aboard cruising under her belt with zero issues.

Originally Posted by sailvayu

Also by doing this you are running a longer wire from your alternator to the house bank maybe it is the right size to handle the alt output maybe not likely it is ok but there could be some voltage drop along the way.

I guess this depends on the situation and the boat and clearly does not apply to all situations. Going through the starter to the batt switch is a longer run on my boat than direct to the house batts. You will only have bad voltage drop with bad connections, too many connections and or improperly sized cable. One would hope that folks doing an upgrade or system change like this would properly size the alternator wire.

Originally Posted by sailvayu

Why not simplify your wiring run the alt output to the starter where you have a nice fat wire the will easily handle the full output.

I used to do that when I had a dedicated and direct wired start battery. If you have a dedicated start battery this is fine but most boats I have worked on do not have dedicated starting banks they have a 1/2/ALL/OFF and the alts charging source is dictated by the position of the battery selector switch. You're a surveyor what percentage of boats out there have a dedicated and direct wired start battery. In my experience it seems less than 10% until you get into big poer vessels and sail over 45 or so feet.

Originally Posted by sailvayu

Now you are charging your starter battery first so you know even if the combiner you are using fails you can still start your engine.

With a 1/2/ALL/OFF, as most boats have under 40 feet have, how do you determine you are charging the start battery first unless you manually select this?

Originally Posted by sailvayu

Oh yes I would use a 300 amp combiner not that wimpy echo charger so that the full charge rate goes to both banks and tops everything off quickly not just the house bank.
Wayne Canning, AMS
Projectboatzen.com

Read about acceptance. The amp rating of the combiner does not determine how much goes into the start battery. State of charge and the acceptance rate of the battery chemistry will determine this.

[GordMay]

Originally Posted by CharlieJ

... By the way, the ABYC Standards require an OCPD where a conductor connects to a source. The alternator output is one source and the alternator's conductor is connected to a battery/bus bar/battery switch at the other end which could become a source if the alternator failed. That other end needs to be protected by an OCPD also. That's right; each end of the alternator's output conductor requires an OCPD...

CHARLIE:
I’m no longer an ABYC member; so cannot submit a Request for Interpretation.
I think that your interpretation of rules 11.10.1.1.1 and 11.10.1.1.2, (which you belive) requires an OCPD at both ends of an Alternator to Battery cable, would make an excellent question, the answer to which might be very enlightening.

Can you submit such a request for interpretation?

➥ American Boat and Yacht Council (ABYC) - Contact Us

[CharlieJ]

Charlie, you of all people should know a zapstop isn't going to work if you have an externally regulated alternator where the regulator is sensing voltage at the battery terminals--that alternator is going to keep pumping out juice long after the zapstop is vaporized.

Don-
I do not understand your comment. The zapstop doesn't enter the picture until the output from the alternator opens and the alternator creates a large, diode destroying spike. The zapstop shunts that spike to ground.

[CharlieJ]

Gord-
I don't think any interpretation is required. Here is E-11.10 regarding OCPD and alternators and battery chargers:

11.10. OVERCURRENT PROTECTION
11.10.1 LOCATION OF OVERCURRENT PROTECTION - DC CIRCUITS
11.10.1.1 General Requirements
11.10.1.1.1 Overcurrent Protection Device Location - Ungrounded conductors shall be provided with overcurrent protection within a distance of seven inches (175mm) of the point at which the conductor is connected to the source of power measured along the conductor. (See FIGURE 15.)
EXCEPTIONS:
1. Cranking motor conductors.
2. If the conductor is connected directly to the battery terminal and is contained throughout its entire distance in a sheath or enclosure such as a conduit, junction box, control box or enclosed panel, the overcurrent protection shall be placed as close as practicable to the battery, but not to exceed 72 inches (1.83m).
3. If the conductor is connected to a source of power other than a battery terminal and is contained throughout its entire distance in a sheath or enclosure such as a conduit, junction box, control box or enclosed panel, the overcurrent protection shall be placed as close as practicable to the point of connection to the source of power, but not to exceed 40 inches (1.02m).
4. Overcurrent protection is not required in conductors from self-limiting alternators with integral regulators if the conductor is less than 40 inches (1.02m), is connected to a source of power other
than the battery, and is contained throughout its entire distance in a sheath or enclosure.
5. Pigtails less than 7 inches (175mm) in length are exempt from overcurrent protection requirements.
11.10.1.1.2 In addition to the provisions of E-11.10.1.1.1 the ungrounded conductors to a battery charger, alternator or other charging source shall be provided with overcurrent protection within the charging source, or within seven inches (175mm) of the charging source, based on the maximum output of the
device.
EXCEPTION: Self-limiting devices.

I will call ABYC's Technical Director this week and ask for an opinion.

[GordMay]

Originally Posted by CharlieJ

Gord-
I don't think any interpretation is required. Here is E-11.10 regarding OCPD and alternators and battery chargers ...
... I will call ABYC's Technical Director this week and ask for an opinion.

Thanks!
I look forward to reading their interprettion.

[Extemporaneous]

Originally Posted by sailvayu

From the xintrex web site it looks like the echo charger will charge at about 8 amps, kinda slow if you ask me. It is rated at 15 amps max.
Wayne Canning, AMS
Projectboatzen.com

I think Maine Sail pretty much took care of your Corn Flakes.

But I'll say that I chose to go with the Digital Duo Charger over the Echo charger. It can be used with different battery types then the source type (Echo charger can't do this) and puts out 30Amps (Echo charger 15Amp??).

The Digital Duo Charge delivers a new level of safety and intelligence to starting battery charging. Simply connect your house battery directly to your alternator and regulator, and connect the house and starting batteries via the Duo Charge. When house battery voltage exceeds 13V, a regulated current of up to 30A brings the start battery to its full charge.
Four pre-set programs: Std. Flooded, Deep Cycle Flooded, AGM and Gel, ensure proper voltage control to the start battery, no matter what type of house battery you’re using. Optional solenoid control and battery temperature sensing. 12V or 24V operation. Auto or manual control. Fused 10-ga. input and output wiring included.

Regards,
Extemp.

[donradcliffe]

If a fuse in the alternator-battery line blows, with a battery sensed alternator regulator like the Balmar 612, you are not going to have a short time transient. The field current is going to stay on and the output of a 100 amp alternator is going to blow the 20 amp fuse in the zap stop in very short order, and then it is going to blow the diodes in the alternator.

My own solution is to size the alternator conductor to take the full output of the alternator and use a diode-type battery isolator to protect against any internal alternator shorts. The isolator also bypasses the battery selector switch, ensuring that the alternator iis loaded regardless of battery switch position.

[Maine Sail]

Originally Posted by Extemporaneous

I think Maine Sail pretty much took care of your Corn Flakes.

But I'll say that I chose to go with the Digital Duo Charger over the Echo charger. It can be used with different battery types then the source type (Echo charger can't do this) and puts out 30Amps (Echo charger 15Amp??).

The Digital Duo Charge delivers a new level of safety and intelligence to starting battery charging. Simply connect your house battery directly to your alternator and regulator, and connect the house and starting batteries via the Duo Charge. When house battery voltage exceeds 13V, a regulated current of up to 30A brings the start battery to its full charge.
Four pre-set programs: Std. Flooded, Deep Cycle Flooded, AGM and Gel, ensure proper voltage control to the start battery, no matter what type of house battery you’re using. Optional solenoid control and battery temperature sensing. 12V or 24V operation. Auto or manual control. Fused 10-ga. input and output wiring included.

Regards,
Extemp.

Extemp,

Agree 100% about the Digital Duo being a better design than a voltage follower. I would have used it had it not been made by Balmar whom I have had horrendous luck with, in both failures, and also lack of the company standing behind the product.. I am waiting to hear some good long term reports before trying one on my own vessel. Keep me in the loop about it's performance as it is truly a better mouse trap!

A start battery generally does not need the 14.2-14.4 volts the house bank does. When a start battery is sitting at 98-99% SOC a device that can send 13.2-13.4 to the emergency/start batt and 14+ to the house bank, is a smart device indeed..

[sailvayu]

Maine sail wish I had as much free time as you do but I do not. So I am not going to go back and forth with this bottom line is there is no single right way to do this as you seem to think. I am offering an alternative set up. Your video is nice so I am assuming based on the info you have a little lawn mower battery as your start battery? You are saying that is all that is needed? I think real world would say other wise. I simply do not have the time to look up numbers and facts to go back and forth with you. You like the 1/2/both switch that worked well for many years. I am saying new technology is around that allows us to do away with that and all its wires and connections. I like things simple and fail safe. I simply do not like those switches and all the trouble you have to go thru to make them work well. The echo charger was designed as a trickle charge not for rapid recharge. Even in your list of uses an engine alternator was not mentioned? Bottom line is we are both right but different. You are not going to convince me to change nor am I going to convince you, but I do think we need to be open to new ideas and not always want to do things because that is the way they have always been done. Both our set ups work and both will be fine but I prefer mine and you yours. But keep in mind yours is not always the best nor the “only” way.
Wayne Canning, AMS
Projectboatzen.com

[btrayfors]

Wayne,

Of course you're right that there's no one single way which is best. However, as a long-time user of the Echo Charge and a full-time marine electrical/electronics technician, I can tell you that Maine Sail is very right about:

1. starting batteries require VERY LITTLE in the way of recharging; starting a diesel engine takes only a very small portion of the battery's capacity, usually not more than 1-2 amp-hours; and

2. the EchoCharge was designed for, and is useful for any situation where you need to maintain an auxiliary (in this case, a starting) battery. It was not designed by Xantrex, but was acquired by them after a successful launch (mine is pre-Xantrex). The 15-amps it can deliver, when needed, is more than enough to maintain most starting batteries.

There can be little doubt that the idea of attaching ALL charging sources -- battery charger, alternator, solar, wind, generator, etc. -- to the house batteries, and maintaining a separate start battery with an EchoCharge or a DuoCharge or one of several other such devices is an efficient and desirable way to go for most cruising boat installations. I have implemented a number of these on client's boats and on my own boat, and they work very well.

However, there are a couple of things to watch out for. In some very few situations, other devices may be loaded onto the starting battery, including blowers, winches, windlasses, etc. In such cases, if these devices are activated when the engine isn't running, but there is still a healthy charge in or on the house batteries, the start battery may try to draw more than 30A from the house batteries. With the EchoCharge, it will only deliver 15A, but won't be damaged...it's self-limiting. However, we have seen a couple of failures of DuoCharge units in such situations. We've talked to Balmar about these, they're aware, and are said to be making changes in the design. Let's hope so, because the DuoCharge is a very good device.

Understand that most cruising boats won't have this problem...but it's good to watch out for.

Bottom line: yes, there are several ways to implement workable 12V setups on cruising boats. What works for you depends on a number of factors which should be carefully considered -- and bounced off a working professional -- before implementation begins.

Bill

[sailvayu]

Bill
Like you I am a marine professional and have been doing this for 35+ years. I am ABYC certified in Electrical. I have been running wire in boats almost all those years. So I am not new to this myself.
You guys seem to really like your echo chargers, that’s great. I am saying that I do not want to limit the ability to recharge my engine battery to a 15 amp trickle charger. You are both right you may never need to charge at a higher rate than that but what if? I have also been sailing for a long time and had many occasions where my start battery was drained very low. I do not want to have to take hours to recharge it with a trickle charger if I do not have to. I too charge my house battery from all sources other than the alternator directly. I charge from the alternator to the start battery so that I do not have to run an extra wire all the way to the house battery it does not make sense unless you are using a 1/2/both switch. Which I am saying you can do away with. Nice and simple. A BEP voltage sensing combiner will sense charge voltage from either house charger or alternator always keeping the batteries charged from any source. And disconnecting if either bank goes too low. What could be more simple. No switch to leave in the wrong position, any time there is a charge source all batteries can take full advantage of that. Nothing to limit the rate of charge either way.
Ok I am done I need to get back to work. Those reading can make up there own minds, like I say there is no single right way.
Wayne Canning, AMS

[Maine Sail]

Originally Posted by sailvayu

Maine sail wish I had as much free time as you do but I do not. So I am not going to go back and forth with this bottom line is there is no single right way to do this as you seem to think.

Wayne,

Please read what I've written in responses to your statements. I DO NOT think there is only one or two "right ways". There is NO right or NO wrong method of wiring your house and start unless you do it in a manner that is not safe.

I have wired many boats quite differently and have myself owned boats with dedicated and direct wired start banks and wired other boats this way too. I like them both, but more often than not the boat, and it's current layout, will determine the best route for the customer in terms of money & time spent.

You can often work with much of what is already there and make a few changes and come out with a very simple and reliable system.

The OP the other day already had a 1/2/BOTH/OFF and that is what I was working with in that thread so as not to entirely re-wire his system. If you will remember I recommended, and always do, either an ACR or an Echo type charger. They both work. No "one" right way.

I've quoted myself below from that thread where I stated there is no right or wrong way. In the context of that poster I was responding and working with the wiring diagram and system he already had on his boat. I recommended either an ACR OR an Echo.

Originally Posted by Maine Sail

Not saying either way is right or wrong either.

There is absolutely nothing wrong with a dedicated hard wired start battery but it is a lot more work to do this for the OP. That is the only point I was trying to make.

As for the Echo if you still think it is not intended to be used with an alternator you may wish to call them, as it is designed to be used with "ANY" charge source.

It's fine if you don't like the Echo but when you post publicly that it's not intended to be used with an alternator, and that is not accurate information, I feel it's something that is fair to clarify or address as best as possible to be fair to Xantrex and others who may be interested in using one.

I will say it again, there is no single right or wrong way to wire a charging system. You seem to think the Echo is not appropriate and don't seem open to it, that's fine.