Reply
 
Thread Tools Search this Thread Display Modes
 
Old 08-28-2017, 04:38 AM   #1
Guru
 
Seevee's Avatar
 
City: st pete
Country: usa
Vessel Model: 400 Mainship
Join Date: Sep 2016
Posts: 2,186
Combiner or Isolator

All,

Looking for some advise on what is better, and isolator or combiner.

On my 40ft Mainship, I have a isolator downstream of the output on the engine alternator. Voltage going in is fine, voltage out on one leg is poor and the other leg is good. Suspect a failed isolator and will replace.

The combiner won't have the slight voltage drop that the isolator has, but are there other advantages or disadvantages?

One side note: I can't figure out what the good side of the isolator is charging. It's not charging the house, starter battery or generator battery. Volts measured on the batteries. Ideas?
__________________
Advertisement

__________________
Seevee
Seevee is offline   Reply With Quote
Old 08-28-2017, 06:50 AM   #2
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,732
I love KISS , so chose a selinoid isolator as the seamless method of automatically seperiating and joining the two systems as needed. Engine Key switch ACC operated.

No thought required , no effort required and no voltage drop between systems when combined.

Nice that it costs under $20.00 too.

With an external 3-4 stage V regulator , and a SOC meter a boat is ready to cruse well for little cash, or effort.

KISS
__________________

FF is online now   Reply With Quote
Old 08-28-2017, 06:57 AM   #3
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 7,590
Regarding isolator versus combiner, they both can fail. The continous duty solenoid works well bet they do have a finite life, keep a replacement on board. When I used one on my charter boat, they typically lasted 3 or 4 years. Isolators seem to work ok, but need to be rated well above maximum amperage of the alternator. Had one fail where the primary diode failed which spiked the voltage to the secondary battery way up. This was a function of how the alternator sensed battery voltage. There may be a better way to wire them into the system, but this spooked me away from using them.

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is online now   Reply With Quote
Old 08-28-2017, 09:42 AM   #4
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,385
A combiner works just like a battery switch but it's automatic. There's no voltage drop or loss. An isolator uses diodes to separate the batteries and there's a one half volt drop. You don't want that.

Battery combiners are much more popular and are made by several different companies. I think the "under $20.00" quote above is way too low. The price for name brand marine battery combiners is more like $80 - $150 depending on capacity. Still, they are worth it.
rwidman is offline   Reply With Quote
Old 08-28-2017, 09:52 AM   #5
Guru
 
psneeld's Avatar
 
City: AICW
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 19,975
From Victron energy site....

https://www.victronenergy.com/batter...tery-isolators

"Argo FET Isolators are High Efficiency - Low Voltage Drop!

Victron Energy FET Battery IsolatorsSimilarly to silicon diode type battery isolators, FET isolators allow simultaneous charging of two or more batteries from one alternator (or a single output battery charger), without connecting the batteries together. It allows discharging of batteries independently of each other without effecting the other. Popularly used on Rv's, Boats, Commercial vehicles where both starter and house batter banks exist.

In contrast with diode battery isolators, FET isolators have virtually no voltage loss. Voltage drop is less than 0.02 Volt at low current and averages 0.1 Volt at higher currents. "
psneeld is offline   Reply With Quote
Old 08-28-2017, 10:08 AM   #6
Scraping Paint
 
City: CT
Country: US
Join Date: Mar 2017
Posts: 963
https://www.bluesea.com/products/762..._-_12V_DC_500A

Super robust and reliable.
john61ct is offline   Reply With Quote
Old 08-28-2017, 10:36 AM   #7
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,732
"I think the "under $20.00" quote above is way too low."

Not for a solenoid , I think even a Cole Hersey can be had at that price.

Electronic stuff is pricey , esp if sold on the boat market , but solenoids are 70+ year old tech , with lots of competition.
FF is online now   Reply With Quote
Old 08-28-2017, 11:38 AM   #8
Member
 
Gary's Avatar
 
City: Merlin
Country: usa
Vessel Name: True Grit
Vessel Model: Hankinson 25ft Alum
Join Date: Oct 2007
Posts: 8
Cool

The isolator or any PN junction is a .6 volt drop. I once had a motor home that had lots of toggle switches with no labels. Well after the battery went dead, I discovered that there was a few solenoids in the battery charging system. Then there was 3 fuel tanks that had solenoids valves to isolate the tanks. Well they averaged 3 amps when on. So the switch to shut them off is a great idea, but it has to be like the ign or start/run switch. I also borrowed a car from a guy and he said the battery went dead over night. So when you disconnect the battery and it arcs when you hook it back up you would think there is a problem. Well I climbed into the trunk and said close the lid. The trunk light was on. I was the hero. After the owner had paid several people to fix it. So you gota be vigilant. gary
Gary is offline   Reply With Quote
Old 08-28-2017, 11:39 AM   #9
Guru
 
City: Fairport
Country: United States
Join Date: Jan 2017
Posts: 1,682
The solenoid is to accomodate a bad starting battery. And, I like and use them. The iso vs combiner is different mission. Charging. What I like about the mometary emergency solenoid is that it is manual, reliable, and doesn't connect a good and a bad battery together for long. Bad things can happen if you do (like using that evil 1, 2, both off switch).
diver dave is online now   Reply With Quote
Old 08-28-2017, 12:07 PM   #10
Guru
 
psneeld's Avatar
 
City: AICW
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 19,975
I believe the new genetation of "isolaters" are wuite different than their older cousins.

Read up on them, they have advantages in terms of no moving parts or arcing contacts if what I have read is accurate.

Not to say other stuff might not be better, but dont didmiss the new ones based on older models.
psneeld is offline   Reply With Quote
Old 08-28-2017, 12:22 PM   #11
Scraping Paint
 
City: CT
Country: US
Join Date: Mar 2017
Posts: 963
Yes, not only ArgoFET, also these guys

http://www.perfectswitch.com/isolators/

When you really want a one-way only flow.

Personally I'd go B2B intelligent DC-DC charger once things get that expensive.
john61ct is offline   Reply With Quote
Old 08-28-2017, 01:03 PM   #12
TF Site Team
 
Bacchus's Avatar
 
City: Seneca Lake NY
Country: US
Vessel Name: Bacchus
Vessel Model: MS 34 HT Trawler
Join Date: Nov 2014
Posts: 2,916
Here's a link to what I did on our MS 34HT

See charging system mods.
http://dkloeber.wixsite.com/bacchus/project-pg-4

It includes a link that compares several good combiners.
__________________
Don
2008 MS 34 HT Trawler
"Bacchus"
Bacchus is online now   Reply With Quote
Old 08-28-2017, 02:50 PM   #13
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,385
Quote:
Originally Posted by FF View Post
"I think the "under $20.00" quote above is way too low."

Not for a solenoid , I think even a Cole Hersey can be had at that price.

Electronic stuff is pricey , esp if sold on the boat market , but solenoids are 70+ year old tech , with lots of competition.
A marine battery combiner is not just a solenoid. It contains circuitry that monitors the voltage and switches the batteries together for charging or apart for use when not charging.

No human intervention is necessary for use.
rwidman is offline   Reply With Quote
Old 08-29-2017, 07:04 AM   #14
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,732
"It contains circuitry that monitors the voltage and switches the batteries together for charging or apart for use when not charging."

Great , but why bother, with costly complex electronics??

There is no charge unless the engine is running , so joining the house to the start batt , after engine start is all that is required .
FF is online now   Reply With Quote
Old 08-29-2017, 09:30 AM   #15
Guru
 
City: Fairport
Country: United States
Join Date: Jan 2017
Posts: 1,682
Quote:
Originally Posted by FF View Post
"It contains circuitry that monitors the voltage and switches the batteries together for charging or apart for use when not charging."

Great , but why bother, with costly complex electronics??

There is no charge unless the engine is running , so joining the house to the start batt , after engine start is all that is required .


All true. But lots of folks love automation

Then there are those that hate automatic chokes on lawnmowers.
diver dave is online now   Reply With Quote
Old 08-29-2017, 09:58 AM   #16
Guru
 
Seevee's Avatar
 
City: st pete
Country: usa
Vessel Model: 400 Mainship
Join Date: Sep 2016
Posts: 2,186
As for the automation... I could lean toward KISS, however, I need to figure out what I'm going to replace my failed isolated with.

And there's a ton of good info on this thread, just need to digest, but leaning toward a combiner (or similar).

I don't understand how the solenoid protects the batteries, is there a diode built into these? And are they manual or automatic?
__________________
Seevee
Seevee is offline   Reply With Quote
Old 08-29-2017, 10:21 AM   #17
CMS
Senior Member


 
City: Casco Bay
Country: USA
Join Date: Feb 2016
Posts: 217
Quote:
Originally Posted by FF View Post
"It contains circuitry that monitors the voltage and switches the batteries together for charging or apart for use when not charging."

Great , but why bother, with costly complex electronics??

There is no charge unless the engine is running , so joining the house to the start batt , after engine start is all that is required .
Maybe because a VSR can work with multiple charge sources, does not require key on excite, and some, like the Blue Sea version, are extremely reliable.

I can't even count how many Blue Sea ACR's I have sold or installed over the years but it is many, many hundreds and I have yet to see one actually fail. Sure a few of them got miswired (only three wires but still that can apparently get messed up) and the owners claimed they were not working but in the end it was a DIY wiring mistake and the ACR was actually fine.

The Blue Sea ACR in-particular is one of the most reliable pieces of gear I have come across in the marine market. I say this when I currently have two failed Mastervolt Battery Mate low volt drop mosfet isolators in my trash bin as well as an old school diode isolator..

Rather than using gimmickry, in an attempt to protect a cheap relay, like some VSR makers try, Wayne K. spent a long time working on the actual contacts for that relay so they could handle the abuse of the designed duty.

The "solenoids" used by most builders (Cole Hersee etc.) are quite often not up to that duty and I replace a quite a lot of them that have failed. Builders such as Hunter, a number of Downeast builders and numerous others used cheap solenoids over the years that have cost a number of my customers some good money on towing when they failed without warning.

I have a customer with a thruster circuit that burned up five paralleling solenoids over a few year period. This all at total cost to him, from various boat yards, of well over 1.5K in repair and trouble shooting bills. None of the yards ever solved the problem because they kept replacing a relay that could not handle the amperage or duty cycle.

When I was called in the problem was obvious and solved in about three or four minutes of glancing at the system and builder schematic.. His Blue Sea ACR has been plugging away now for over 8 years, in this same system, with zero issues. It also charges both banks, via solar, when his boat is on the mooring at his island house.

While those relays are certainly inexpensive they can be less than reliable with the current that can be expected to pass through them on many boats.

For a few dollars more you can get excellent reliability, start isolation, charging from multiple sources etc. with a product actually designed from the ground up for the task. One of the first things I noticed Marlow did when they bought Hunter Marine was to do away with the unreliable Cole Hersee key-on solenoids for paralleling. I can't even recall how many of those I have replaced that have failed, but it is far more than I ever should have..
CMS is offline   Reply With Quote
Old 08-29-2017, 10:59 AM   #18
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,385
Quote:
Originally Posted by Seevee View Post
As for the automation... I could lean toward KISS, however, I need to figure out what I'm going to replace my failed isolated with.

And there's a ton of good info on this thread, just need to digest, but leaning toward a combiner (or similar).

I don't understand how the solenoid protects the batteries, is there a diode built into these? And are they manual or automatic?
Simply put, a "battery combiner" or "automatic charging relay" ( Blue Sea ACR is one brand) senses a charging voltage from the engine's alternator or battery charger and connects both batteries together so they both receive charging current. This is what the "Both" position of a typical battery switch does. When the charging voltage goes away (engine stops or the charger is unplugged), the combiner disconnects the two batteries from each other. Hopefully, you have wired your house loads to one battery or bank and the starter to the other. Now, you can run your house loads with no danger of draining the starting battery and not being able to start your boat.
rwidman is offline   Reply With Quote
Old 08-29-2017, 01:08 PM   #19
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,732
"a charging voltage from the engine's alternator or battery charger and connects both batteries together so they both receive charging current. This is what the "Both" position of a typical battery switch does."

The problems come up when the BOTH switch is not rotated to seperiate the batts after engine shut down,

OR when rotated to OFF with the alt operating , and the switch was installed with out hooking up the usually built in field cut off .

"I don't understand how the solenoid protects the batteries, is there a diode built into these? And are they manual or automatic?"

No diode is used as the solenoid is open when the engine key is off.

The signal that operates the unit to close is power from the ACC position on the engine key switch.

A secured engine will usually have a low oil pressure alarm , which is enough to trigger the boat operator to turn off the key.

"The "solenoids" used by most builders (Cole Hersee etc.) are quite often not up to that duty and I replace a quite a lot of them that have failed."

The better boat assemblers will read the stamping on the units.

Most are rated 80A cont. duty , so they spring a second $20 cost and install 2 in parallel, if a 135 A truck alt or other big amp unit is installed.

A DN 50, 24V up to 300A is not usually a small boat item, and $20 units are not suitable.
FF is online now   Reply With Quote
Old 08-29-2017, 01:18 PM   #20
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,385
Quote:
Originally Posted by FF View Post
"a charging voltage from the engine's alternator or battery charger and connects both batteries together so they both receive charging current. This is what the "Both" position of a typical battery switch does."

The problems come up when the BOTH switch is not rotated to seperiate the batts after engine shut down,

OR when rotated to OFF with the alt operating , and the switch was installed with out hooking up the usually built in field cut off .

"I don't understand how the solenoid protects the batteries, is there a diode built into these? And are they manual or automatic?"

No diode is used as the solenoid is open when the engine key is off.

The signal that operates the unit to close is power from the ACC position on the engine key switch.

A secured engine will usually have a low oil pressure alarm , which is enough to trigger the boat operator to turn off the key.

"The "solenoids" used by most builders (Cole Hersee etc.) are quite often not up to that duty and I replace a quite a lot of them that have failed."

The better boat assemblers will read the stamping on the units.

Most are rated 80A cont. duty , so they spring a second $20 cost and install 2 in parallel, if a 135 A truck alt or other big amp unit is installed.

A DN 50, 24V up to 300A is not usually a small boat item, and $20 units are not suitable.
I'm having a hard time understanding this post but I will address the first three paragraphs:

No switch is required when a battery combiner is installed. The combiner takes the place of the switch. In most cases the switch should be removed. The wiring instructions furnished with the combiner will show the correct wiring.
__________________

rwidman is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 10:27 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×