How to tell what battery my alternator will charge?

[Halifax Sailor]

I have a 1978 Yanmar ysb8. Looks like the original alternator. It works fine, no issues charging. However, looks like one or two of my group 27 lead acid batteries may need replacing. The types are confusing. Will agm fit/compatable? How about gel? I can get replacment lead acid but if I am going to replace then why not upgrade? But what I read is that not all alternators are compatable with some battery types. Is there a thread somewhere where it is explained? I also have a small solar panel/controller that has a programable battery function. We day sail for now, small fridge, led lights everywhere, usual stereo, no heavy draw. Marina most nights with shore power charger.

Signed: confused about alternators vs batteries

[tkeithlu]

To me, the question is more what voltage regulator, not what alternator. Alternators just produce electricity while a voltage regulator may, if sophisticated, be programmed to match the charging needs of one type of battery, just as sophisticated battery chargers can be. Therfore my house bank is charged by either a sophisticated battery charger or by a Balmar voltage regulator that can be programmed. My two starter batteries are charged by very simple generic alternators with internal regulators, and as a result are never charged perfectly. I lose some efficiency in them, but they are good enough to spin the starters on the main engine and the genset.

So, choose a type of battery, and match your charging to its characteristics.

Past threads have recommended the Duracells sold by Sam's. Ditto Balmar's alternator/voltage regulator pairs.

Oh, and choose alternators with enough amperage to not be running full time, or they will burn up.

Good luck with it.

[glenn.225]

Of the two Gr27, is one house and one starter?

I would probably stick with lead acid if you are unsure of the other batteries.
Maybe you could go AGM, like Optima. Not so cheap.
Golf cart 6 volt in series are a good option also. That what I use.

[TrentePieds]

Halifax:

The Mirage27 is a sweet little boat, in fact it is probably my favourite among the "baby boats". It is simplicity itself and does NOT require a lot of battery capacity. So don't overthink the battery thing!

Two "group 27" lead-acid batteries are MORE than enuff for this little boat, provided you know how to care for them and feed them. If you don't know that, then "upgrading" to "better" batteries will just complicate your life. There can be no better choice for a Mirage27 than two so-called "deep cycle" L/A batteries that you can buy at any Canadian Tire store :-)!

Batteries are consumables. They do "wear out", slowly if you are good to them and rather quickly if you are not. "Being good to them" means cleaving to the charging regime they require, and never letting them discharge below, say, 80% capacity. How do you know the "state of charge"? You "dip" the batteries with a hydrometer that you can buy at CanTire or any other autoparts supplier for ten bux or so. It measures the specific gravity of the electrolyte of each "cell" of the batteries, and that's what counts. "Upgrading" to AGM denies you the possibility of doing that, and therefore to know how your batteries are doing.

My two Gr27 L/As in a thirty footer with a 20HP BETA are usually good for 4 years and at $110 a piece, replacement is just part of the normal maintenance expenses.

All the best :-)!

TrentePieds

[HeywoodJ]

One thing you can know for sure, a 1978 engine electrical system was designed around a flooded lead-acid battery (FLA). If you’re not familiar with dealing with electrical then stick with the original design. It works, and it is probably the lowest cost option.

If you really want an “upgrade” then you could drop in an AGM. They’re close enough in charge characteristics that you can generally get away with drop-in replacement. You only really gain not having to water your batteries. How much trouble is that? (real question, sometimes on a boat it can be a lot of trouble -> doesn’t get done as often as it should.) I’d stay away from anything other than FLA or AGM unless you want to have a real think about the whole system, which to me would be the result of troubles with the existing system. I’m a proponent of new battery technologies, but they only really make sense in a heavy-use scenario.

[Halifax Sailor]

Thanks for all the input. A little more info, in case theres any different scenarios. The batteries are 2013 vintage, have never failed, one is starter, one is house. House is 650, starter is 550. Both are hooked to shore power charger when at marina, most nights. Either one spun the engine no issues last summer. Have the 50 watt solar panel that can feed both but I usually have it on the house. Figure the engine will keep the starter in good shape. Again, very little load even with the fridge. I was leaning to flooded replacement but just wondered what options were out there. I do understand boat electrical, thats not an issue. BUT do not want to get into extra expense if not needed. Eight years so far from these flooded Interstate batteries so I figure I need to start looking. I have checked water at least twice a season and keep levels right where they should be. No bulging, no spills or leaks, just seem like they are long in the tooth and should look at replacing before they fail. Going to try testing actual load to see what they can run and for how long just to check capacity this weekend so may know more after that.

As TrentePieds says, its a baby boat but is great for any coastal or day sailing around here and I can easily single hand. Can also handle up to 8 adults if they behave!! I will get a hydrometer and check the levels, thx Trentepieds!!

[MJH]

Originally Posted by Halifax Sailor

I have a 1978 Yanmar ysb8. Looks like the original alternator. It works fine, no issues charging. However, looks like one or two of my group 27 lead acid batteries may need replacing. The types are confusing. Will agm fit/compatable? How about gel? I can get replacment lead acid but if I am going to replace then why not upgrade? But what I read is that not all alternators are compatable with some battery types. Is there a thread somewhere where it is explained? I also have a small solar panel/controller that has a programable battery function. We day sail for now, small fridge, led lights everywhere, usual stereo, no heavy draw. Marina most nights with shore power charger.

Signed: confused about alternators vs batteries

It is best to keep things simple by choosing a battery chemistry and have all batteries the same chemistry. For your boat and use I would stay with flooded batteries.

More importantly, I would recommend an automatic charging relay (such as a Blue Sea Systems #7610) between your house and starter banks to insure that you will always be able to start the engine.

Oh, and replace your current batteries if they need replacing.

Enjoy the summer.

~ ~ _/) ~ ~ MJH

[TrentePieds]

MJH said: "More importantly, I would recommend an automatic charging relay (such as a Blue Sea Systems #7610) between your house and starter banks to insure that you will always be able to start the engine."

Absolutely sound advice in the general case, but if I were in Halifax's shoes - or boat - I would go "retro" as far as the actual battery installation is concerned, i.e. two Gr27 L/A batteries receiving and delivering via a simple "1-2-B-Off" switch.

On "even" dates I set my switch to "2" and on "odd" dates I set the switch to "1". That assures equal use (sort of) of each battery. The quantity of juice drawn from a battery to start a willing engine is very little indeed, and is generally replaced on the run under power coming out of the marina, so no worries there. And if your engine isn't willing, you'd best get after THAT problem and not abuse your batteries :-)!

In a Mirage 27 in the use posited by the OP and fitted with all LED lighting, the emergency starter battery, in case you do drain the batts accidentally, can be one of those new-fangled "booster" jobs you an buy at Canadian Tire for a hunnert bux.

Halifax said that he already has a modern charger that is always active when the boat is alongside, so I think that he really already has a setup that is optimal for the boat and its use.

TP

[Boatyarddog]

Originally Posted by Halifax Sailor

I have a 1978 Yanmar ysb8. Looks like the original alternator. It works fine, no issues charging. However, looks like one or two of my group 27 lead acid batteries may need replacing. The types are confusing. Will agm fit/compatable? How about gel? I can get replacment lead acid but if I am going to replace then why not upgrade? But what I read is that not all alternators are compatable with some battery types. Is there a thread somewhere where it is explained? I also have a small solar panel/controller that has a programable battery function. We day sail for now, small fridge, led lights everywhere, usual stereo, no heavy draw. Marina most nights with shore power charger.

Signed: confused about alternators vs batteries

Do a capacity test, even with an automotive load tester.
Separately, test each battery independently, if these cells can be opened like in FLA Batteries.

Check the electrolyte in each cell and charge batteries before testing.
Then apply the load tester.
Check each cell in FLA Batts.

For variances between cells, should be very little "specific gravity" levels between.
You'll need a Hydrometer for this, very inexpensive item.
Use distilled water for any top up of your cells.

Remember for accuracy, top up first the charge completely, then test.
If you want to use a different battery type,

Be sure the battery you charge with the Alternator is compatable with the Alternator, probably a FLA, bank.
Then for your house bank/s you can purchase those DC to DC chargers, and use it to charge your other type batteries.

DC to DC chargers if "smart enough" will allow you to select the Charge Profile for your House bank whatever Type it requires.
Boatyarddog

[Popcorn]

Hi All.
If your engine has one alternator 80 Amp and is insufficient to charge AGM', 330 Ah's, can if possible add another alternator to the engine suffice if it can be done and charge two batteries of the three with the 80 amp alternator and the other with lets say an 60 Amp alternator. I do realize that it may use more diesel but that would be acceptable to me.

[MJH]

Originally Posted by Popcorn

Hi All.
If your engine has one alternator 80 Amp and is insufficient to charge AGM', 330 Ah's, can if possible add another alternator to the engine suffice if it can be done and charge two batteries of the three with the 80 amp alternator and the other with lets say an 60 Amp alternator. I do realize that it may use more diesel but that would be acceptable to me.

This reads like a different post.

Normally, folks will have two banks, one house and one starter. The house bank is usually made up of two or more batteries, the starter with one battery.

The alternator should be sized at 25% or more of the total Ah in the system.

So, the 80A charger should be able to handle the 330Ah AGM. Only problem is that that 80A alternator is probably not operating at max output at normal cruising speed rpm.

Yes, you can add a second alternator. I looked into this for my boat and found out that it was not cost effective because of all the changes that had to be made to the engine to do it. It would have been cheaper to get a larger alternator. But there are limits there two. They say that the normal 1/2 inch belt is good up to around 100A after which you need to go with a serpentine belt...and that can take some other changes as well. I had many belt problem after upgrading to a 110A alternator and eventually changed to a serpentine belt to solve the problem.

To increase total Ah in your system you need to think of the entire electrical system, not just one part. How many Ah do you want, how many batteries and chemistry type will achieve that, and how are you going to supply the proper amount of charging for that system?

Good Luck.

~ ~ _/) ~ ~ MJH

[Popcorn]

Thanks MJH, I wondered if certain belts vary in performance. When you changed the pulley was that difficult or can I do this myself?
And did the 1/2 inch belt failure occur after long charging periods or just hours of non charging normal use?
Also, the current alternator handles the charging but takes very long to reach full (sort of)charge and requires daily charging. The batteries are fairly new, 4 years old, but I have a freezer and that takes most of the use.

[dlj]

Originally Posted by Halifax Sailor

I have a 1978 Yanmar ysb8. Looks like the original alternator. It works fine, no issues charging. However, looks like one or two of my group 27 lead acid batteries may need replacing. The types are confusing. Will agm fit/compatable? How about gel? I can get replacment lead acid but if I am going to replace then why not upgrade? But what I read is that not all alternators are compatable with some battery types. Is there a thread somewhere where it is explained? I also have a small solar panel/controller that has a programable battery function. We day sail for now, small fridge, led lights everywhere, usual stereo, no heavy draw. Marina most nights with shore power charger.

Signed: confused about alternators vs batteries

An original alternator from a 1978 ysb8 would likely be an internally regulated alternator. It's also possible that it is regulated to have a 13.8V output. That was not uncommon at that time.

What I would do is run the engine, measure the voltage going to the battery and see what it is. If it's 13.8 I'd either see if I could remove the internal regulation and go to an external regulator or I'd change the alternator. You don't say how you use the boat. If you rely on your batteries heavily, I'd go to external regulation no matter.

If your alternator is putting out somewhere in the 14.2 to 14.8V range, and you don't rely heavily on your batteries, you are good to go.

(This is pretty simplified....)

dj

[MJH]

Originally Posted by Popcorn

Thanks MJH, I wondered if certain belts vary in performance. When you changed the pulley was that difficult or can I do this myself?
And did the 1/2 inch belt failure occur after long charging periods or just hours of non charging normal use?
Also, the current alternator handles the charging but takes very long to reach full (sort of)charge and requires daily charging. The batteries are fairly new, 4 years old, but I have a freezer and that takes most of the use.

I don't think there is any significant difference in amp output for a given size belt. If they differ it would be in construction and wear resistance.

I bought a Balmar Serpentine Belt Kit for my engine and did the change myself. It is a straight forward upgrade but do to engine age some difficulties were encountered such as cleaning out old pulley thread holes to allow bolts to enter easily.

I would say the lengthy charging required is a because of the refrigeration. And refrigeration requirements are high primarily because to the generally inadequate insulation that manufacturers use. Then manufacturers place the refrigeration units, in many cases, right next to a high heat source (the engine) and you get the need for more electric power...a vicious circle.

Good Luck.

~ ~ _/) ~ ~ MJH

[Stu Jackson]

Originally Posted by dlj

An original alternator from a 1978 ysb8 would likely be an internally regulated alternator. It's also possible that it is regulated to have a 13.8V output. That was not uncommon at that time.

What I would do is run the engine, measure the voltage going to the battery and see what it is. If it's 13.8 I'd either see if I could remove the internal regulation and go to an external regulator or I'd change the alternator. You don't say how you use the boat. If you rely on your batteries heavily, I'd go to external regulation no matter.

If your alternator is putting out somewhere in the 14.2 to 14.8V range, and you don't rely heavily on your batteries, you are good to go.

(This is pretty simplified....)

dj

Good points, except that a Yanmar engine most likely has a Hitachi alternator, which has severe drawbacks, these:


Hitachi/Yanmar Alternators: (by Maine Sail)

Some alternators though, such as those made by Hitachi and found on Yanmar diesels, are dumber than a pound of beetle poop. Actually, to the alternator, they are pretty smart but to your batteries and the speed of charging they are flat out stupid. Why?

Hitachi alts with dumb regulators, and some others, limit voltage but also reduce voltage based on alternator temperature. This is a self protective feature installed in the internal dumb regulator to prevent the alternator from cooking itself. Remember voltage is the pressure that allows more current to flow. So, if we reduce the absorption voltage, then we also reduce the current the alternator is supplying.. Any battery at any state of charge simply will not accept the same current at 13.4V that it did at 14.4V and as a result the alternator will run cooler. What do you suppose this does to your batteries over time.......?

The problem is that when cold you will get 14.3V to 14.4V out of the Hitachi but as the alternator heats up the dumb regulator begins to reduce the CV/voltage limit based on the alternators internal temperature. It is not uncommon to find a Hitachi alternator at 13.4V when hot. This is REALLY, REALLY DUMB....

If you have a dumb regulator, and notice the voltage dropping, it is likely a temp compensated dumb regulator. Get rid of it or plan to buy new batteries more often.

If you have a temp compensated alternator or a Hitachi alternator on a Yanmar you really are in dire need of external regulation if deep cycling a larger battery bank.

This is from:

http://forums.sbo.sailboatowners.com...d.php?t=125392

and these, too:

http://www.cruisersforum.com/forums/...on-125843.html


http://www.cruisersforum.com/forums/...or-142083.html