Battery isolator / voltage regulator / batteries

[rmbrown]

All:

I appreciate all I've read on the subject, and I've read a lot, both here and on Maine Sail's page but I have a couple of questions.

I'm considering the GC12's rather than the 6 V golf cart batteries and I can find no mention of them here on the forum.  That makes me think I'm not searching properly since everything seems to be on here somewhere!  Maine Sail doesn't have an issue with them so I'm thinking that maybe they don't fit?

Also, I'm looking at the promariner proisocharge (http://www.promariner.com/en/products/proisocharge-series) rather than an ACR.  Pros?  Cons?

Lastly, I'll upgrade the alternator in the next year or so and my understanding is that I'll need an external voltage regulator to really take advantage of it.  Is there a single device, or recommended pair of devices, that will give me the desired voltage output from the new alternator, while still isolating the batteries and being relatively smart about directing the charging current?

Mike

[KWKloeber]

Mike,

I don't recall the exact issue or configuration, but my bro (with a trawler) wanted to install an ACR and there was an POTENTIAL issue of blowing it up from an overcurrent situation with the charging being in a certain situation and potentially operating a high current (his windlass.)  It turned out that the ACR he was planning would (could) have blow up and he went w/a different one.  He worked with Mainesail to do what he wanted -- you may want to drop RC a note. Again I cannot recall the particulars (CRS) , just recalling the caution and eventual outcome/solution.

ken

All:

I appreciate all I've read on the subject, and I've read a lot, both here and on Maine Sail's page but I have a couple of questions.

I'm considering the GC12's rather than the 6 V golf cart batteries and I can find no mention of them here on the forum.  That makes me think I'm not searching properly since everything seems to be on here somewhere!  Maine Sail doesn't have an issue with them so I'm thinking that maybe they don't fit?

Also, I'm looking at the promariner proisocharge (http://www.promariner.com/en/products/proisocharge-series) rather than an ACR.  Pros?  Cons?

Lastly, I'll upgrade the alternator in the next year or so and my understanding is that I'll need an external voltage regulator to really take advantage of it.  Is there a single device, or recommended pair of devices, that will give me the desired voltage output from the new alternator, while still isolating the batteries and being relatively smart about directing the charging current?

Mike

[rmbrown]

Hey, you guys will be glad to know that I searched again, found several articles on the proisocharge and how, while it works fine, it isn't worth the extra hundred bucks.

I'm in the process of comparing the blue seas ACR to the echo charger so I can understand the pros and cons.

I'm also reading through the wiring diagram changes so I can get things working right on my boat.  Don't waste time posting links... I got 'em. ;>)

[J_Sail]

You are absolutely correct that the ProIsoCharge is not worth the extra. In fact, the added complexity can be a drawback, and the benefits they quote look good on paper but are not there is a real-life use case.

I posted a reply the other day on this forum in a thread on solar charging that might be relevant. The link is:
http://c34.org/bbs/index.php/topic,9283.msg70047.html#msg70047

I can also share some more thoughts on the pros/cons of each, as well as a tiny bit on the selection of which of the three BlueSea units might make the most sense if you want. I do have a few links I found that might make good reading, so when you are done with the ones you found, if you still want more, let me know. In the end, either a combiner or Echo can provide great results if installed correctly (including wiring your alternator directly the house bank, not to the load side of a selector switch.)

BTW, to answer your earlier Q, I do not believe there is an all-in-one device that incorporates external regulator with distribution to two separate battery banks. For external regulator, when you upgrade your alternator, get the  Balmar Max Charge MC-614 along with temperature sensors for the alternator and batteries, and be sure to wire it to utilize the external remote sense of battery voltage. Details if you want...

[rmbrown]

I'd appreciate any and all additional info.  I was leaning towards the SI model ACR based on the price point and the fact it's the one Maine Sail sells, but if there's a reason to consider another one, or even an echo charger, today's the day to educate me as I expect to order tomorrow!

[Stu Jackson]

I'd appreciate any and all additional info.  I was leaning towards the SI modem ACR based on the price point and the fact it's the one Maine Sail sells, but if there's a reason to consider another one, or even an echo charger, today's the day to educate me as I expect to order tomorrow!

Hard to tell, Mike, what you've read or not.  Have you read all of the Elec Systems 101?  Like this one?

What are ACRs, Combiners & Echo Chargers?  (by Maine Sail) [scroll to the top]
http://forums.catalina.sailboatowners.com/showthread.php?p=742417

and

Echo Charger Use Warning from Maine Sail:  http://www.sailnet.com/forums/electrical-systems/72295-xantrex-echo-charger-rant.html

I've had a Yandina combiner on my boat for 18 years.  Flawless operation.  And they still have a lifetime waranty - which I've never had to use. 

Lastly, I'll upgrade the alternator in the next year or so and my understanding is that I'll need an external voltage regulator to really take advantage of it.  Is there a single device, or recommended pair of devices, that will give me the desired voltage output from the new alternator, while still isolating the batteries and being relatively smart about directing the charging current?

Jeremy is also right about the regulator.  What you suggest simply doesn't exist.

[rmbrown]

Thanks, Stu.  Some I'd read and remembered. Some I'd read and forgotten.  Some I hadn't seen yet.  In any case, the fog is clearing!


Jeremy, you mentioned having done insight into which ACR?  I see three from blue seas... The mini is only good to 65A.  Might work now but not after alternator upgrade.  The ML is much higher current rated than I think I'd ever see with a single alternator, even a high output.  That leaves new with the SI, good to 120A.  In the immortal words of Goldilocks... Just right.  That sound like a reasonable assessment or did I miss something?

[J_Sail]

Basically the SI is the one to get; 120 amps is fine for anything you will throw at it.

You have no need for the larger 500amp ML-ACR. It's key advantage (other than handling 500 amps) is the availability of a remote switch/indicator that lets you override the operation. That only really comes into play for configurations that need to support an electric bow thruster pulling from a combined set of battery banks when needed, or for setups where the ACR with remote control is used instead of a master battery switch. In that case it has to carry engine started current. It also latches into each position without any stand-by current, which matters in only a few cases. None apply to your setup.

By the way, you could probably even use the smaller m-ACR. That's because when wired appropriately, it only carries the charge current to your smaller single battery (the alternator feeds your larger house bank directly). The smaller battery is unlikely to pull more than 65a charge current for long enough to be a problem (* see note). But the cost difference is not large, so I would play it safe and go for the 120 amp SI.

I'll try to post something on the Echo alternative in a bit.

Jeremy

* Note: There is a scenario that could fry a smaller ACR. The scenario comes into play if ones second battery is set up as their "engine battery", the windlass is wired to it and they have a high-output alternator. In that case, when the windlass puts a big drain on the relatively small engine battery with the engine running, it could result in heavy current being drawn from the house bank plus alternator through the ACR. With a large windlass that current could exceed 65 amps. That is probably the scenario that Ken was saying his brother was worried about running into when designing a solution for his trawler. Not an issue on your C34.

[J_Sail]

The bottom line is that either is fine and will work great for most users. But if you want details...

Pros and Cons of each:
ACR
Pros

• Fully waterproof
• Simple and extremely reliable

Cons

• Requires high-current fusing, large gauge wire and large lug terminations

Xantrex Echo Charge
Pros

• Can be wired by smaller gauge wiring without needing heavy gauge crimp lugs, as it carries <20amps
• Somewhat simpler wiring than ACR (assuming ACR is wired with starter-suppression)
• Less labor and wiring cost to install

Cons

• Not weather/water-proof, must not be mounted in battery compartment
• More complex than ACR, so more parts to fail (though no relay contacts, and in general are reliable)
• Charge current limited to 15 amps (but that's more than plenty for a reserve/starting battery)

Note: Some Xantrex write-ups have suggested that the Echo Charge bulk and float charges a secondary battery independent of the voltage delivered to the primary battery. This is misleading and has caused people (including me) to incorrectly suggest that it is especially useful for systems where the house battery is one type and the starting/reserve battery is another. That is untrue; the Echo is a voltage-follower device whose output is always lower than the input and lacks any intelligence to implement its own charging profile. If one truly needs such independence (which is unlikely), then look at the (more expensive and bulky) Sterling Battery-to-battery chargers. For most applications, an ACR meets all the requirements, is simpler, and possibly more reliable. Battery banks charged in parallel (even ones where the house bank is flooded and a small start/reserve battery is AGM) work just fine.

Interesting link:
http://c34.org/bbs/index.php?topic=7986.0

[rmbrown]

You guys are fantastic.  Thanks for the info.  I really appreciate the effort it takes!

[mainesail]

For the average boat owner the marketing spins and wives tales usually force one to use some common sense & critical thinking...

All of these devices are in what I call "Charge Management Devices" or CMD's. I lump them into four categories.

Diode or FET Isolating CMD's: These devices split charging and isolate banks for back drain via FET's or Diodes. They induce voltage drop and can not be used with most smart chargers or solar controllers etc. that require a 12V signal to boot up. In today's day and age they are akin to dinosaur saddles or buggy whips and have very few justifiable uses on boats. They are usually easily identifiable with their input & output studs & aluminum heat-sinking fins. These cooling fins are there for a reason. The reason is that voltage drop creates waste heat and that waste heat needs to be dissipated.

Paralleling CMD's: ACR's, Combiners, VSR's, ProSplit R's, CVSR's etc. etc.
This article can explain anything you ever wanted to know about ACR/VSR/Combiners:
Making Sense of Automatic Charging Relays (LINK)

These devices simply parallel banks when charging voltage is present and isolate/unparallel them when not. They combine/close on voltage rise and isolate/open on voltage fall. This is essentially a fully automatic BOTH switch.

Voltage Following Buck Type CMD's: Echo Charger & Duo Charger

These devices follow the voltage of the house bank and can only impose voltage and current limits on the output side. They do not independently float or feed a different charge profile to a start battery as many incorrectly assume they do. 

Independent DC to DC Buck or Boost CMD's: Sterling Power DC to DC Battery to Battery Chargers or B2B's

These devices are essentially a full featured, fully independent battery charger that is powered by 12V DC on the input side as opposed to 120V. The newest Sterling B2B chargers are capable of 30A - 60A and are fully programmable including absorption time parameters. They are equivalent to the smartest battery chargers only they are powered by a battery bank not 120V..



What about the ProIso:

IMHO the ProIso is a marketing gimmick and is really the work of Sterling. PM wound up with it through a joint venture with Sterling. I would suggest avoiding it unless you like getting legally mugged. There is no need for any of the features in that unit other than to add complexity that is not necessary and to scare and mislead the under-informed boating public about what it is they are actually getting.

Don't get me wrong Charlie Sterling can and does build some great stuff but the ProSplit-R/ProIso are not one of them. As a Sterling dealer I am not a huge fan of this product because I don't see any need for it nor for the complexity of it. There are numerous features that make it "less than ideal" compared to other products. This is especially true when comparing it to a much simpler product, with a virtually impeccable reliability rating, such as a Blue Sea ACR or ML-ACR. Charlie is well known for praying on the fears of consumers & then developing a product that sells to those fears. Some of his products are great, such as his DC-DC battery to battery chargers, and some are not so "wow" like the ProSplit R.

One thing Charlie mentions in his manuals, that PM often fails to counsel their customers on, is that any un-used output needs be tied to another used output. If this is not done the unit won't work.

"Please note in the event of any outputs on the ProSplit not being used then they must be linked to one which is, i.e. all outputs must be used, one must not be left unconnected."


What is the ProIso or ProSplit?

This product is nothing more than a stepped voltage sensitive combining relay. For added complexity and additional failure points the units often have multiple relays in one box and it's installed in-between the alternator and the bank not between batteries like other charge management devices... The PI or PS combines batteries based on voltage in a priority order or steps. It waits until each battery has come to 13.3V before bringing another bank on-line. That's it, so fancy I know.......

With a near fully charged start battery this can literally be just "a few seconds". In other words your 99% SOC start battery exceeds 13.3V in a matter of seconds once the charger source fires up, because of its SOC. Once start is at 13.3V the device brings the house bank on-line. When the house bank hits 13.3V it then brings a third battery on-line, if you have a three bank model.

All sorts of wild marketing claims are made such as; "Priority setting for the START battery to ensure a completely charged start battery[/b]."

I can see the product development meeting now;

"Let's pray on the fears of boaters who worry they may not be able to start their boats engine.". "Yeah, yeah boss we'll call it "priority start" and throw so much confusing lingo at them they'll think they are getting something they're not."

If someone can explain to me how a start battery, at the point in its Coulombic curve where it is the most inefficient, eg: 97-99.5% SOC, can become "completely charged" in "a few seconds" (quoting Sterling manual) at just 13.3V you've discovered best battery storage medium in existence....

That last 2% of the SOC curve is the absolute longest & excruciatingly slow part of the charging curve that exists.. Are we just to assume Ohm's law & Coulombic efficiency do not apply to these products? "Completely charged" in just "a few seconds" at 13.3V......

"Wow, I must have that." says the under informed boating public. This is how you are being mugged by marketing...

With these devices the start battery is always connected to the alt meaning charging begins with the start battery, all "few seconds" of it.. Oh and please remember that 13.3V does NOT charge a battery.  This also means a less than direct path to the bank that actually needs charging. Because this device sits smack dab in the alternator path, the closest we can sense voltage is at the unit itself. It can not account for any voltage drop between the unit and battery bank. This = Non optimal.

The unit also requires an "ignition feed" to turn it on. So, if you're planning on using it for all your charge sources, such as wind, solar, hydro, shore charger etc., like many do with ACR's, combiners, Echo's, Duo's etc. you'll probably want to know what the quiescent draw of the unit is when powered up 24/7, not just when "ignition activated"... Oh wait, neither Sterling or ProMariner tell you this critical specification in the manual.....??? All that marketing and they just happened to leave that piece of critical information out....??

How it "completely charges" your start battery (wink):

When the start bank hits 13.3V it then combines/parallels with bank #2. When the system voltage (combined voltage of bank 1 & 2) is again at 13.3V it then parallels in bank #3 and so on. That's it!!

It does not prioritize and "completely charge" a start battery first, as they like to suggest through marketing, it simply brings it to 13.3V before paralleling it with the house bank. This would be no different than you removing 1.5Ah's from your start battery, at home, then turning on the charger until the battery voltage hit 13.3V then turning it off. You can't replace those 1.5Ah in a "few seconds" so suggesting the units "completely charges" your start battery based on "priority" is misleading at best.

They way it can completely recharge your start battery is no different than an ACR or Yandina Combiner, in parallel.... However PM and Sterling lead you to believe this "priority step" is completely charging your start battery first and this is not at all true.. With most start batteries this voltage rise happens in "a few seconds" and even with the minimal consumption from starting, the battery Ah capacity has not really been replaced before it has been placed in parallel with the house bank. Misleading? Absolutely.. The device simply begins with the start battery then brings the others in parallel as voltage attains the 13.3V level.

Even for a 50% discharged house bank attaining 13.3V does not take a long time with a properly sized charging system. For example even a high acceptance rate Lifeline AGM discharged to 50% SOC (in lab conditions for accurate measurements) then recharged at .2C, this is 20% of Ah capacity or 20A on a 100Ah battery, will attain 13.3V in about 20 minutes. This is why for a start battery North of 98% SOC this voltage rise takes "a few seconds".

The Sterling battery to battery chargers are excellent and are the only true "independent" buck or boost 12V to 12V chargers out there. Echo Chargers and Duo chargers are "buck" (drop voltage) devices but they can not float or boost voltage to another bank. Combiners & ACR's are paralleing devices.

   

[mainesail]

I'm considering the GC12's rather than the 6 V golf cart batteries and I can find no mention of them here on the forum.  That makes me think I'm not searching properly since everything seems to be on here somewhere!  Maine Sail doesn't have an issue with them so I'm thinking that maybe they don't fit?

Mike

Sorry I forgot about this part.

The GC12 is essentially GC2 plates in a 12V form factor. They are pretty much identical in height but the foot print of a GC12 is longer.

Because the GC2 is so popular the price per Ah is extremely low. At my local distributor I pay about .90¢ to $1.07 per Ah for a GC2. The GC12's start at about $1.33 and up, per Ah. The GC12 is the same height and width as a GC2 but has about the length of a Group 27 or 31 battery at approx 13" vs. 10.25" long for a GC2.

Two GC2's would give you 225Ah and two GC12's would yield about 300Ah.

[KWKloeber]

Saw this on another Catalina forum.  Food for thought.

ken

Just got off the phone with my instructor at the Marine Electrical courses I took last week at the Annapolis School of Seamanship. (Great hands on courses as are their marine diesel courses). He gave me a few suggestions which I'm going to take the next few days to mull over. He is an advocate of space between the batteries as a means of dissipating the charging heat and thus prolonging the life of the batteries. Will send along what we come up with.

-Bob.

[rmbrown]

Good info... I haven't fastened my batteries down yet. :)

I ended up with three GC12's.  I paid 199 each for them so 1.28/Ah.  This is more expensive, I grant you, but I can put three of them in the box so no rewiring... I'm using one as my reserve and two as my house bank.  I figure that gives me 310.  I get 50% (155) of that on a one day trip, but only 35% (108) daily on a multi day trip when I'm charging with alternator.  Since I'm not sure if I'll have my fridge working, or how much juice my instruments and autopilots will use, I'm going to go with that for a bit.  If that's not enough, I'll turn it into a three battery (465 Ah) bank and add a reserve battery elsewhere.    In that event, I'd probably convert to the 4 T105's the next time I have to replace batteries.

Doing a new charger since my Xantrex went belly up since i purchased the boat and and Blue Seas ACR-SI as well while I'm in there.

Right or wrong, I'm one step closer to the water.

[KWKloeber]

I get 50% (155) of that on a one day trip, but only 35% (108) daily on a multi day trip when I'm charging with alternator.  Since I'm not sure if I'll have my fridge working, or how much juice my instruments and autopilots will use, I'm going to go with that for a bit.  If that's not enough, I'll turn it into a three battery (465 Ah) bank and add a reserve battery elsewhere.    In that event, I'd probably convert to the 4 T105's the next time I have to replace batteries.

Doing a new charger since my Xantrex went belly up since i purchased the boat and and Blue Seas ACR-SI as well while I'm in there.

As I've said oftentimes before, why not do an energy use/recharge budget and figure out what you need for the conditions you sail?

What charger are you going with?

kk