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Dave is correct on this one. virtually any AC charging system made today will sense and automatically adjust amperage output by sensing battery voltage. this is why DC generators are no longer used. An alternator making AC voltage then converting it back to DC is much more easily regulated by the ECM, this is why almost all light duty systems be it automotive marine or aviation have gone this route.

To a point this is correct, unfortunately if some aren't already they will use a "drop charge" or variable system like auto's which when the primary battery is charged they can drop back to 12.7 volt and not cut back in until 13.1 which effectively cuts out a system like the Yandina without extra wiring especially if it is remote doubt if boat alternators do this yet but?
Also if using or charging two batteries in parallel with a normal alternator for the house batteries, the charging source will only sense a common voltage as Brian said, so if one is crook and calls for more it will supply more but that (voltage) will also be available to the other battery/s that doesn't require it and also to the start battery, a diode will only stop back feed from one battery to another it won't stop any battery calling for power (load) otherwise they would not charge.
You can also get into trouble with voltage drop if the batteries are not all in one area, the ones furthest away won't get full charge, this is why chargers such as the d250s are used rather than basically vsr type ones like the Yandina especially if solar is being added as it does it all in one go and is a fully isolated 6 stage charging system that delivers the absolute best supply right at the house batteries and the start battery is charged by the engine alternator seperately.
As Ray says why waste a perfectly good battery when needed just starting a small motor, at least the Yandina has the facility to be bypassed so it can, but with the addition of a switch and/or relay so can the Ctek.
I notice with the Yandina if you need to charge a bank of two or more batteries, there basically needs to be a seperate unit for each battery.
There is absolutely no end to the combinations needed or available but if you are too far out of the ordinary with your requirements you need to modify or adapt to suit.
Non of the above alters the basic aim and that is to keep your batteries fully charged for as long as possible while getting the maximum use out of them, this applies more to boats than most other applications as carrying more weight than needed is detrimental and charging sources are limited especially on a sailboat.

Edit you posted while I was typing Brian, are you and Dave sure that the Yandina does anything more than combine? from what I can see it would still cause the alternator to supply a voltage to the battery calling for the highest charge and unless this is seperately regulated within, that voltage would be available to both ie where one is fully charged and requires float voltage the other would be calling for bulk charge, of course in practice unless one battery is crook or under heavy load they would balance but still one would recieve more and one less than needed I see in the circuit on their site you can use the blue wire to limit the voltage in one battery to 14.2v but even thats above float level?

I will say this once again as I have stated this in above post.
You connect Solar panels direct to your controller than only to your House Batteries. You by pass the Yandina.
You want the solar only to house batteries.
The Yandina is used for when engine is turned on and charges both banks of batteries chosing weaker ones first for charging and keeps both banks separate so one bank doesn't discharge to other incase one battery fails.
It's that simple, please do not confuse people who are trying to do their system right.

Dave

Boblee wrote:

Dave is correct on this one. virtually any AC charging system made today will sense and automatically adjust amperage output by sensing battery voltage. this is why DC generators are no longer used. An alternator making AC voltage then converting it back to DC is much more easily regulated by the ECM, this is why almost all light duty systems be it automotive marine or aviation have gone this route.

To a point this is correct, unfortunately if some aren't already they will use a "drop charge" or variable system like auto's which when the primary battery is charged they can drop back to 12.7 volt and not cut back in until 13.1 which effectively cuts out a system like the Yandina without extra wiring especially if it is remote doubt if boat alternators do this yet but?
Also if using or charging two batteries in parallel with a normal alternator for the house batteries, the charging source will only sense a common voltage as Brian said, so if one is crook and calls for more it will supply more but that (voltage) will also be available to the other battery/s that doesn't require it and also to the start battery, a diode will only stop back feed from one battery to another it won't stop any battery calling for power (load) otherwise they would not charge.
You can also get into trouble with voltage drop if the batteries are not all in one area, the ones furthest away won't get full charge, this is why chargers such as the d250s are used rather than basically vsr type ones like the Yandina especially if solar is being added as it does it all in one go and is a fully isolated 6 stage charging system that delivers the absolute best supply right at the house batteries and the start battery is charged by the engine alternator seperately.
As Ray says why waste a perfectly good battery when needed just starting a small motor, at least the Yandina has the facility to be bypassed so it can, but with the addition of a switch and/or relay so can the Ctek.
I notice with the Yandina if you need to charge a bank of two or more batteries, there basically needs to be a seperate unit for each battery.
There is absolutely no end to the combinations needed or available but if you are too far out of the ordinary with your requirements you need to modify or adapt to suit.
Non of the above alters the basic aim and that is to keep your batteries fully charged for as long as possible while getting the maximum use out of them, this applies more to boats than most other applications as carrying more weight than needed is detrimental and charging sources are limited especially on a sailboat.

Edit you posted while I was typing Brian, are you and Dave sure that the Yandina does anything more than combine? from what I can see it would still cause the alternator to supply a voltage to the battery calling for the highest charge and unless this is seperately regulated within, that voltage would be available to both ie where one is fully charged and requires float voltage the other would be calling for bulk charge, of course in practice unless one battery is crook or under heavy load they would balance but still one would recieve more and one less than needed I see in the circuit on their site you can use the blue wire to limit the voltage in one battery to 14.2v but even thats above float level?

The simple system Dave is speaking of really is just a diode that prevents back flow from one battery to the other. The reason you can gang charge both from a single connection to the alternator with diodes in place is that the battery with the lower charge has higher "acceptance" (I.e., lower resistance) and will charge preferentially until both batteries are at the same resistance, and from that time both batteries will charge evenly. No sensing is required, the only thing required is that properly rated diodes are in place to prevent one battery from charging another, which is what kills unbalanced batteries.

But I have to say, I think most people are way over-complicating their electrical systems on these boats. A single high capacity deep cycle marine battery, along with LED conversion of lights, does the job just fine and avoids all these issues. And I have and constantly run all the typical trons except a fridge, including an autopilot, for days on end. I run everything DC and won't have a permanently installed AC system. With the ability to emergency pull start the motor, I simply don't see why carrying around all the weight and complexity is worthwhile to obviate a very rare failure case.

Who here has actually ever run their battery dead under normal usage conditions? What were the circumstances?

I've killed batteries by a, forgetting to put water in them, b using a cheap, or not using at all, a charge regulator, and c, running lights during long periods of cloudy weather.
I run light loads, like led interior lights, off the starting battery, and heavy loads like my 350 watt inverter and dc vacuum cleaner, on the deep cycle house battery. I think having two is perfectly fine generally. If I had a trolling motor for sneaking around the bird flats, I might want two just for the motor.
I have remedied the above problems by getting a good regulator, that shows percentage of charge, getting sealed batteries, and upgrading my cabin lights to led.
Some people like to customize things just because they like to. I like to keep electrical systems as simple as possible, but other people have lots of doo dads that use lots of electricity.
Ix

When I swapped out the wet cells for Optima's I forgot to change the charge setting and the house battery was not receiving any charge whatsoever. It took three days of using lights (incandescent) and stereo for the single house battery to lose enough juice for the stereo to shut itself down. The weather was terrible and this is all at dock so no chartplotter, or AP but we were using 12-14 hours a day for the stereo and 6-8 for lights aprox. Glad the starter battery was isolated. Used jumper cables to parallel and tricked the charger, bought a day of temp power and had everything back to normal within a few hours. I was very surprised once I learned how long we had run the battery with no additional charge. This experience has prevented me from becoming a "power nazi" with the house electronics. I'm very unconcerned about our usage, and the solar panel does a great job keeping the house topped up over the week. I still plan on putting the LED lights in I bought three years ago as well, but theres sailing to be dine and fish to catch. Maybe next time the weathers crap.

Dave
For most users with one start battery and one house battery all in one location the Yandina is great as I also stated but thats only good if you only want or need one start battery and one house battery in fact a day sailor could possibly get away with the standard factory supplied house/start battery with absolutely no need for any more except provision to fully charge all batteries as often as possible otherwise be content to replace regularly and not get full capacity from those batteries.
If anybody is confused as Dave says to this point stop reading.
Anything more than the above gets complicated especially if you want to maintain full charge on batteries or select which ones are fully charged first.
Even your installation Dave with the two house batteries tied together allows them to bleed into each other especially if one is crook Yandina say an extra unit is needed (your way better), you would possibly also need a diode between the solar regulator and your house batteries (I haven't) see note at bottom .
As you say the Yandina will supply to the most discharged battery (or bank) but it will not supply the correct voltage to the individual batteries to where they actually are in the charge cycle ie what voltage each battery would be if charged individually that can only be done if it is internally and individually regulated especially if using a smart charger rather than the alternator to finish, as I said I can't see that? ie dual channel supplying different voltages, if so they are great value.
Some auto combiners bring the primary (start) battery up very high before allowing the second undercharged battery to cut in yes it will balance the charging to a point but that means the batteries will all ultimately be charged at a constant common voltage near the end which means that they can all be left undercharged if not enough time is allowed to charge and it can take longer than individually.

Note from Ctek engineer re solar and other

You need to be care full when using two DC charging sources on one battery at the same'
time as they can form current loops and burn each other out.

Unfortunately these things can start off with a simple request but as each hypothesis is added for different situations they can become quite complicated especially on our boats which are rarely the same as they are used so many ways.

Well said again Mastreb interestingly Yandina say no diodes that burn out are needed maybe it would actually be better if the diodes were external then only they would be replaced rather than the whole unit if they burn out internally.
I won't go into the number of times I have had flat batteries or batteries that have been discharged too far over the years but not lately unless a crook battery is involved and another with a crook connection.

Yeah, Boblee – I got that too- the Yandina does not appear to tailor the charge output of the alternator for each battery, but it merely combines them for that purpose. The d250 is a perfect choice for the multi-stage charging functionality for each battery.

Yeah mastreb – as you describe, that's exactly how batteries connected in parallel got charged in times gone by, before the advent of multi-stage, and multi-output “smart” chargers. And the battery banks of simple solar arrays, with matching batteries are commonly charged in this way.

It could be described as the “quick and dirty” way to do it, but it's more accurate to call it “slow and dirty” because charging takes way longer than necessary; it is harder on the batteries because it relies on heat buildup in the batteries (that's their internal resistance talking); and (particularly with non-matching batteries) presents the risk of undercharging and the resulting sulphation of the plates, reducing lifespan. But it works, as no one is disputing.

The combiner is a voltage sensing relay, and so fully switches the connection either on, or off. Though, hypothetically speaking, a “diode” as used to describe it, can perform that function non-mechanically in a solid state. A diode is what might be needed between the solar charge controller and the connections between the two batteries for complete separation of the two if that's what is wanted, if they are connected that way. Dave's suggestion to only connect the solar to one battery avoids this need.

Yeah – much to be said for keeping it simple, and reducing power needs on a boat. A great mantra, as appropriately repeated by many here. But then things just always have a way of getting complicated, even when you try and keep them simple!

-B.

Not at all arguing the merits of the smart charger--don't get me wrong. The primary benefit of the smart charger besides switching to and charging each individual battery is that they pulse the charge power, which gives the battery time to cool down between pulses, thus keeping heat low. This is what allows rapid charging, because resistance increases dramatically with heat. Simply finding the right pulse frequency for different chemistries and with the newest chargers, actually testing the acceptance rate under different pulse regimes is what allows these chargers to charge so quickly.

So knowing all of this, I hook up my single 105ah to the ETEC-60, I don't use a shore charger, and I cross my fingers that I'll only cause myself a pullstart maybe once every five years.

But hey, I only spent 54 days on my boat in 2013, so what do I know about power cycling? And never once longer than two weeks at a stretch.

Yeah Mastreb I think the simpler the better, which is the reason that we only have the perko switch between the start and house batteries and the second house battery can be easily disconnected with an anderson plug, much better to be all manual where possible.
The more automation you put in the more complicated it gets especially as the needs change trying to adapt it, we charge from the tow vehicle, the christy 50 amp, the outboard, solar from one or two ends of the boat or both(at once), the inverter hooked up to the Ctek 25amp, and the Ctek on mains, we also have the inverter for charging phone and laptop etc batteries.
To work out all the combinations to do it in auto would be too hard and need too many new gizmos, it's just too easy to look at the solar regulator to get the full rundown on the batteries and act according to the present situation ie camped on land, camped on water, running on motor or planning too, driving on road or planning too, using fridge as freezer or just refridge, ambient temp either cold or tropical, putting large fish in, making ice etc etc, we also can have the second fridge in place prior to coming home and it can be in the boat or in the truck.
Just too easy to have basic hook up and manually adjust to the battery state as per the regulator or even use a multimeter sounds hard but too easy.
I also bring the dinghy battery in for charging if it gets down and it just plugs into where the second house battery does but two other points for it as well or charge it on the spare solar panel.
For some the simple basic setup though with eg a Yandina and/ or perko with checking for full charge is all thats needed or even with a second house and periodic checks both batteries are ok.
Most importantly we don't leave the boat or truck for any period unless all batteries are fully charged which is why we are still using the original 2006 battery.

I now have two Optima blue top batteries in a bank as house batteries . This bank is directly connected to the 200 watts of solar cells via controller . They power the cabin and the Ingle freezer .
I also have two yellow top batteries in the second bank . These batteries are for cranking and they run the 400 watt inverter . They charge directly from the engine .
I also have a Perko switch that allows me to charge house batteries from the engine and vice versa .

On our Key West cruise we had two lead acid start/deep cycle batteries . They were under the settee which we converted to hold the freezer and a pain to get to check the water . As a result , I let them get low on water , tops of the plates were exposed. I didn't want to take an another extended cruise and find out these batteries were damaged by this , so I made the decision to replace them with the yellow tops .

I think we will be happy with this setup

On our dinghy we have a "wheelchair" battery . Its a small sealed battery , good for 5 miles with the two of us in the dinghy .
It charges from its own solar cell mounted on the dinghy .

Here is a copy and paste from a Practical Sailor newsletter that I recently received on their long-term battery testing progress. Thought the info here that might be useful to some...

..."Some old, and some new info here. We are well into the thick of an update of our 2006 test of “sealed” valve-regulated lead acid batteries also known as either gel or absorbed glass mat batteries. For the past several weeks, Rod Collins of Compass Marine has been cycling five different batteries through 30 deep cycles (to below just 50 percent state of charge) and then putting them on the charger for one hour to demonstrate just how quickly a cruising sailor can ruin a good battery. Even after just thirty of these cycles, some of the new absorbed glass batteries in our test never fully recovered to their pre-test capacity.

Although the full report will not be available to subscribers until mid April when the May issue of Practical Sailor is available, here are some tips that came out of our test that can help you prolong the life of your AGM battery.

Charge to full as often as possible, this point cannot be over emphasized.
Get back to at least 80-85 percent state of charge (full capacity) with each charge cycle and get to 100 percent state of charge as soon as you can thereafter.
Don’t regularly discharge your bank below 50 percent state of charge.
Size your most powerful charge source, usually an alternator or inverter-charger, for a minimum of 20 percent of bank capacity. Odyssey TPPL AGM’s prefer 40 percent of amp-hour capacity as minimum charge current.
Use smart chargers. Not all chargers that claim to be smart are in fact smart.
Use temperature compensated charging for all charging sources.
Use smart solar controllers. Some solar controllers start each new day at a new absorption voltage charging cycle. This is not healthy for AGM batteries that have low self-discharge and minimal parasitic loads when left unattended on-the-hook. Smarter controllers have a voltage trigger to pop them out of float mode. If they don’t drop to the trigger voltage they remain in float.
Using the correct float voltages are a critical aspect of AGM batteries. Chargers that use “dip switches” for programming often lack the correct voltages for both absorption and float settings.
Use an alternator temperature sensor and external regulator if possible. AGM batteries can demand a lot from an alternator and the heat created can shorten its life or cause premature failure.
For the best charging performance minimize the voltage drop in system wiring. Even a 3 percent voltage drop at 14.4 volts means just 13.96 volts at the battery terminals. Incorrect voltage sensing robs you of the fastest charging potential, especially during short duration, high current charging events.
Know your correct state of charge at all times. If this means investing in a battery monitoring device it will help in overall cycle life. If you are using voltage to determine state of charge be sure you are getting it as accurate as possible.
Avoid installations in engine rooms or hot areas of the boat. Heat shortens battery life." ...

-B.

Not sure what to make of the info. They start out saying that gel and AGM batteries are the same thing. They are not and they take different charging regimens. Things like this make me want to discount the entire article.

Rich

Yeah, and how can one tell that a smart charge is really smart, among a plethora of chargers that all claim that are smart?

Oy!

Now I'm more confused.
I got.....Keep batts full, they are happier that way. Don't use cheap chargers.


--Russ

It says the two types of batteries are in the same class, both being VRLA, which is true, they both are. They are still two separate technologies. The AGM is the one most likely encountered for our applications, I think gel cells are becoming less and less common anyway (at least that's my sense).

Telling the real smart chargers from the not so smart chargers on the market has always been a problem. The purpose of the article has been served if you were not aware of that before.

It's tough, because the choice is based on trust, and situations based on trust naturally attract untrustworthy people and sales tactics. But sticking to the reputation of name brands is going to increase your odds of getting a good charger. A more expensive one will have more features, like those mentioned, and I think searching on the internet will fill in the details of which models perform well.

Most of this info is not new, but I look at it as a way of objectively validating or refuting previous conceptions, by independent real-world testing. I did not know that VRLA's liked to be charged at a high rate, but I have little experience with them, compared to regular FLA batteries. (And I just like to know "useless" stuff that might suddenly become valuable in the future).

I'm guessing that when the main article is published it will end up saying that VRLA's need more finicky charge/ discharge management to maximize their life span, as compared to the more forgiving regular FLA batteries.

Though synoptic, it is intended to whet your appetite for the main article, which might end some confusion (?) and fill in more details.