I understand that power in automotive applications comes from the source (alternator or shore power) to the batteries and then to the load. On my coach the smart charger seems to be adjusting the charge to the load of the house batteries resulting in a constant charge and thus boiling the batteries dry in about a month. I had hoped they would be worry free so they did not charge except when low. Since I have several parasitic loads (dash stereo system alarm etc) I don't see a way to really charge and yet not boil them over time. I keep the coach plugged in so the ac can keep the temp and humidity controlled in our heat. Any advice would be appreciated.

A newer charger is preferred over 18 year old technology. The older style chargers are just not as good as what they should have been.

You said "Smart Charger". How old is yours/what brand and model number do you have?

I too, have been thinking about alternators not being the best battery chargers around. They don't really look at the condition of the battery like a smart charger would.

There are a few alternator charge controller on the market but I have no idea how well they work.

To add to the conversion, what is you opinions on these remote rectifiers sold here? Any of you have experience with such a setup?

Quicktifier Remote Bridge Rectifier System

quote:

Originally posted by Tom K:
On my coach the smart charger seems to be adjusting the charge to the load of the house batteries resulting in a constant charge and thus boiling the batteries dry in about a month.

What particular make and model is the smart charger?

Do you have a good digital voltmeter? I would suggest leaving it hooked up and watching it closely. I suspect the voltage is too high. Once a wet battery is fully charged, it should float at around 13.2 volts.

Another way is how I've done it since forever. That is to have a garage sale charger or a trickle charger on a timer. By trial and error, I set the timer so the resting voltage and/or hydrometer reading stay at or just beneath a full charge. This has worked with boats, jetskis, dune buggies, motorcycles, etc. Batteries of all sizes.

None of this is a big deal. Trojan says it is OK to let batteries sit as long as you recharge when they get down to 75% or so. I personally think this is really the best, if you use a large charger. A battery can sulfate at float, and will respond very well to a vigorous charge every so often. A few smart chargers or maintenance chargers have that feature built in. My own approach on that is to run the batteries down to about half and then give them a full charge with as much current as they will take. This is only done if the coach has not been used for over a month. I have done this for decades on general suspicion, but now that I have conductance tester, I can see real numbers that show it really does work. Battery calisthenics.

It is possible to have a small trickle charger that would be of the size to match your battery bank. Just leave it on all the time and monitor the SG. Once you know it is right, all is well. Plug and play.

Yet another way would be to use a battery maintainer. There are a number of brands, from Harbor freight to some really sophisticated ones. They are true set and forget items, and lots of my co workers reported good results them with summer only boats, toys and RVs.

Yet another option is a small solar panel outside your storage area. On one car that is not near a plug in, I use a small solar panel. It was originally used by a German auto company to keep batteries charged during on-deck ocean transportation. It just plugs into the cigarette lighter. It, of course, is sized for just one battery, but the principle would apply to a larger battery bank. Our Barth sits in a lot and the solar keeps the batteries happy.

Some of this might seem like technobabble or overkill, but we boondock exclusively, for periods up to three months, and I rely on machinery to stay alive, so batteries are really important.

I am surprised that you all are surfing when you should be watching football and eating. I have a Todd 75pc charger that has an internal Intellitec disconnect panel. My book says to switch the battery off when plugged in to avoid boiling the batteries. Something about connecting to the negative side f a solenoid. While I am on shore power this switch does not work - it says on. If I disconnect the shore power it switches off normally. I don't know the age. I did replace the converter with an IOTA PC 50r that says it is intelligent. I received a flyer with the converter suggesting an IOTA DLS-75 IQ as an upgrade. I am ready to upgrade if that is possible.

quote:

Originally posted by Bones:
I too, have been thinking about alternators not being the best battery chargers around. They don't really look at the condition of the battery like a smart charger would.

Yup. Several reasons for that:

1. Heat, as discussed below.

2. Diode isolators. A silicone rectifier has a built in voltage drop of .7 volts. This affects both starting and coach batteries, cheating them both.

3. In a typical setup, the alternator is reading and responding to the internal resistance of both starting and coach batteries. This is not ideal, as it will usually adjust itself to the needs of the battery that is at the highest SOC. This can be corrected by switching, but only by using a non-interrupting set up. Boat stores sell switches for this. It can also be done with battery green knob switches, knife switches or relays, but this setup is not Murphy proof.
There are a few alternator charge controller on the market but I have no idea how well they work.

quote:

To add to the conversation, what are your opinions on these remote rectifiers sold here? Any of you have experience with such a setup?

Quicktifier Remote Bridge Rectifier System

That setup addresses and mitigates the heat situation in a lot of alternators. Like our BB Chevies with the alternator right against the hot RH cylinder head.

To make matters worse, the alternator cooling air comes in the back and is thrown out the front. My own design would reverse that, taking some advantage of cooler ram air. It is a good cooling idea for heavy charging loads, but does nothing about tailoring the charge current curve for our RV batteries.

This does not address the situation in Delcotrons where the regulator adjusts the output by sensing heat. The theory is that by the time a car or truck engine is warmed up, the battery has had all the charge it needs. This, of course, is accurate, but does not address the needs of us RVers wanting to charge our house batteries.

I have stuck an asbestos/foil mat between the back of the alternator and the head to keep some of the cylinder head heat away.

That same company has a cooling fan that blows on the back of the alternator. Good idea. I plan to make a fiberglass muff that will terminate in an inlet for a cold air duct and remote fan. That way, all the air will come from outside and all the air will go directly into the alternator. The limited space there will be a challenge. When I get to a non-inspection area, I may remove the AIR pump and mount the alternator down there (using the same belt) to get away from engine heat and make cooling duct connection far simpler. Or a second alternator.

quote:

There are a few alternator charge controller on the market but I have no idea how well they work.

I have seen them in boat catalogs. Not cheap. Certainly, the ability to adjust the alternator output makes the charging as smart as the operator. I like the idea, but haven't really studied it. Perhaps I should.

Sadly, the boat owners I know are more solar people than smart-charging people, so not much information there.

quote:

Originally posted by Tom K:
I am surprised that you all are surfing when you should be watching football and eating.

LOL. The TV is on, and Susan is programming today's recording during commercials and slow spots in the game. And the Turkey is in the oven. I already had Susan's garlic mashed potatoes (peels included) for brunch. There will be a second Thanksgiving dinner later, too.

So, we are not neglecting the holiday.

quote:

I received a flyer with the converter suggesting an IOTA DLS-75 IQ as an upgrade. I am ready to upgrade if that is possible.

I use the IOTA DLS-75 IQ3, which is an earlier model. The current model is an IQ4, but I believe it is now made in China, so there could be quality/reliability/longevity concerns. Today is not a rant day.

However, the IOTA has an equalization feature. Ours never gets there, as the coach no longer has its plug in cord, and we run the generator only for microwave or lack of solar charging. I don't like equalization, believing it is hard on batteries. Trojan says to only equalize if SG readings vary more than .015.

My conductance tester has shown a drop in battery capacity after equalization.

So, I would not recommend any charger/converter with an equalization feature that cannot be defeated. I do not like the physical violence done by the excessive rate of charge during equalization.

OK, now that I have mentioned SG, NEVER use a hydrometer without splash proof safety goggles. I keep a plastic bag in my battery compartment that I slip over my head if I have misplaced my goggles. I meet interesting people when I wear it. This sounds a little paranoid, but a hydrometer spout can catch on something and then release and flip acid in your eyes. At work the drill was to use a syringe with a rigid pipe to fill a jar, then read the jar with the hydrometer. There was much less acid flung about that way. They got real crabby about acid on aluminum structure.

I am not sure if my coach was different but I have two 8D engine batteries and four Trojan 105 6v golf cart deep cycle ones for the house. Perhaps I need a larger charger/converter for those?

quote:

Originally posted by Tom K:
I am not sure if my coach was different but I have two 8D engine batteries

Your alternator should be enough for them when running. When sitting, keep an eye on the voltage and put a charger on them when and if they get down to 70%. Or use a maintainer or trickle or timed charger as mentioned.

quote:

and four Trojan 105 6v golf cart deep cycle ones for the house. Perhaps I need a larger charger/converter for those?

You should have a charger that delivers somewhere between 10 and 20 percent of the bank's capacity. The textbook rule is 10-13%, but the T-105s can take a higher charge without harm, due to their heavier plates. That means a bank of four T-105s would like 45 to 90 amps at the start of charge. My pair of T-125s took 30 amps right away at 50% SOC, which was at the 13% textbook figure. Sorry to say, I don't have good notes on what our new bank of four T-105s takes, but I expect it to be twice that. The solar has not allowed the batteries to get very low yet.

Now, that does not mean buy a charger rated at the 10-20%, but you need a charger that will deliver that into the batteries when they at 50% SOC. Unfortunately, that information is not out there. You just gotta buy and try, or get info from others. And then, you gotta worry that their info will apply to the current production that week. Components and even factories change on the same product. OH OH.............I said this wasn't a rant day.

Back to size: It is not terrible to use a smaller charger, but the bank will benefit from a vigorous charge to full capacity every week or two. Once the charge tapers off, you are in the float mode. Letting it float longer can often give you SG improvements, but this is best done at home. I like to use the boost mode of the IOTA or a "dumb charger". This can be accomplished by driving, doing it at home after a trip, or running the generator if still out. In our case, the solar is not all that vigorous in winter, so we run the gen every week or two.

I do't have any problems when traveling, just sitting plugged in at home. I don't have a good schematic on the Intellitec Battery disconnect so if I replace the charger I will have to trace it out. I am now seeking recommendations of the size and brand of new smart charger and whether I can plug in the coach for storage and not have the batteries boil out.

I have the Intelli-Power 9260. The coach stays plugged in. It does a desulfating cycle periodically. I usually have to add a little water before each trip.

Your coach is new enough to be 99% certain you have a single-output converter which should mean any new one should be a drop-in (electrically).

quote:

Originally posted by Rusty:
I have the Intelli-Power 9260. The coach stays plugged in. It does a desulfating cycle periodically.

Their literature is interesting. They use the word "Equalize" interestingly. It ways "every 21 hours of storage mode operation, the Charge Wizard switches into equalize mode. This is the same as boost mode, except that it lasts just 15 minutes. This helps to mix up battery electrolytes and prevent stratification from damaging your battery."

The chart below shows the equalize mode to be 14.4 volts. This is way lower than most other manufacturers' equalize voltages. I like it because of that. It would seem not to be like other electronic desulfators, as well, but it provides the vigorous charge that keeps sulfation away.

It kinda does what I mumbled about discharging, then recharging every month of non use. Now that I have a charger with a desulfator feature, perhaps I should desulfate with it, instead.

It would be interesting to use an electronic desulfator on your batteries, with before and after conductance readings. It would compare two different ways of doing the same thing.

I know my battery calisthenics are good, because of the improvement conductance reading, but it is hard to know what is best.

As for stratification, I would like to read a battery's SG at the top, then seal the caps and roll it over a few times and take another reading. Any difference would be evidence of stratification, and how much.

I thought that it would be interesting to learn when the next scheduled "equalize" cycle is, and take a SG reading just before, and then shortly after, but the "after" reading would be sure to be higher from the charge alone, with or without destratification. Do you know if the 15 minute "equalize" is enough time to make bubbles?

Golly, life is just one big Science Fair experiment.