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battery system upgrade question

7K views 51 replies 11 participants last post by  sailingdog 
#1 ·
I have a 1984 Tartan 3000 with two group 27 batteries. I installed a Xantrex Trucharge 20 battery charger and now I am thinking of what else I should be doing to upgrade the system. I have had several thoughts and I wonder how to priortize them. I don't have refridgeration but I did install radar, autopilot and a chartplotter this year. I intend on mostly day sailing with a trip from Lake Champlain to LI Sound next Spring for some coastal cruising, overnights are a definate possibility.

Some of the questions I have:
1. Should I install a starting battery, and if so any installation advice, and what type of battery. (I believe my battery charger can charge only one type of battery at a time)
2. How do I monitor the charge in the batteries when not on shore power?
3. Should I buy a small gas generator or can I rely on the diesel engine to charge the batteries.
4. Wind generators and solar panels?

So many choices, you can spend a fortune, how do you get what you need for the least cost?

Thanks for your thoughts.

Bud
 
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#29 ·
I just read the microlog blurb and it appears to have no ability to acually tell you amp HOUR usage and amp HOURS remaining in your battery bank....only real time use of AMPS.
If what I am reading is true...then it is missing THE most important part of the LINK systems IMHO....the ability to say " On my 500AH battery system I have now used 200 AH and at my present rate of discharge I will need to re-charge in 6 hours. "
Simple voltage and amp readings do NOT let you do this. You need an ability to tell the instrument how big your battery bank is in amp hours and it needs to provide you with a contiuous reading of how many AH's you have left and your present rate of use.
 
#32 ·
Do I need an external regulator for my alternator? Will my existing alternator with a built in regulator definately cook my batteries? Is there another way to protect the batteries without adding another regulator??????,,,an echo charge or battery combiner?
 
#33 ·
Do I need an external regulator for my alternator? Will my existing alternator with a built in regulator definately cook my batteries? Is there another way to protect the batteries without adding another regulator??????,,,an echo charge or battery combiner?
Ralph
An internal reg won't cook the batteries assuming it is operating properly. The disadvantage of an internal regulator is ptimarily that it cannot easily be controlled to prolong a high charge rate which is the desirable characteristic of an ext regulator. Consequently, the internal reg will typically under-charge rather than overcharge.

An eco-charger can serve to ensure a separate start battery is not over-charged during that phase of charging a house bank when the regulator is charging a house bank at a higher rate than the start battery requires.

A combiner is simply a relay which parallels both house bank and start battery during charging above a pre-set voltage.
 
#35 ·
Your right John!
1. I was assuming from his description that the charger was wired through the switch. Your way is preferable.
2. My recommendation on the Perko switch is out of excessive caution as turning the switch in the wrong way can cost $$...but obviously you CAN turn to any position except off with the engine running.
 
#36 ·
John and Camaraderie,
I just came back from my boat, where I took pictures of my battery hookup. My battery charger (Truecharge 20) is hooked up directly to one battery's positive terminal. However, each of the positive battery cables from both batteries go into the Guest battery switch. I have the remote charging panel and things don't seem to charge correctly (that is the lights on the remote panel don't appear correct) unless the battery switch is on "Both", (I shut off the Main switch on the DC panel before I leave the boat). Should I add another positive cable the connect the two batteries together of would that screw up the purpose of the switch?
If I can switch the Guest battery switch from 1 to Both to 2 while running the engine it solves some problems. How would you manage the switch so that when I add a starting battery I keep both the house bank and the starting battery properly charged? If I need to leave the switch on "Both" to charge both the house bank and starting battery will the batteries charge properly or do I need an eco-charger or something similar.

thanks
 
#39 ·
John and Camaraderie,
I just came back from my boat, where I took pictures of my battery hookup. My battery charger (Truecharge 20) is hooked up directly to one battery's positive terminal. However, each of the positive battery cables from both batteries go into the Guest battery switch. I have the remote charging panel and things don't seem to charge correctly (that is the lights on the remote panel don't appear correct) unless the battery switch is on "Both", (I shut off the Main switch on the DC panel before I leave the boat). Should I add another positive cable the connect the two batteries together of would that screw up the purpose of the switch?
Ralph, I am by no means an expert in this area, but the installation you describe above sounds like a pretty standard configuration to me. Here is my amateur understanding -- subject to correction by some of the electrical experts here on Sailnet.

There should only be a single positive wire from the charger to one of the battery's positive terminals (preferably via a fused cable) and then another negative wire to the negative DC bus. Since your batteries are wired in parallel, the charging current will flow to both batteries.

The True Charge 20+ can charge up to three separate battery banks. You essentially have only one battery bank for charging purposes. So when you look at your remote monitoring panel, you probably see an "Amp" reading in the middle column, and a "Voltage" reading in either the right or left hand column. The other "Voltage" column probably just flickers very low or doesn't seem to show a reading. Is that right? If so, that's normal in my experience. The column with a reading is showing the voltage of your ENTIRE battery bank (i.e. both batteries). I don't know why the other column would suddenly show voltage if you activated the battery switch -- I've never tried that. But I do know, by using our separate battery voltage monitor, that both batteries are getting the current they need to charge in this configuration with the battery switch in the "OFF" position.

[I will add that the battery monitor panel for the TrueCharge does not provide particularly useful info. The Link systems seem to be much more informative.]

If I can switch the Guest battery switch from 1 to Both to 2 while running the engine it solves some problems. How would you manage the switch so that when I add a starting battery I keep both the house bank and the starting battery properly charged? If I need to leave the switch on "Both" to charge both the house bank and starting battery will the batteries charge properly or do I need an eco-charger or something similar.
Take a look at the current West Marine Master Catalogue (p. 443), they have a pretty good description of how to add a starting battery. Or go to Blue Sea System's website, I think they have info there as well. The wiring should not be too difficult -- usually the tricky part on a small boat is finding space for the battery.

I take issue with the 'commonly faulty' statement re the switch...I haven't seen or heard of a faulty switch in years...if at all.
keiper
Sea Quest
berkeley
I agree, the design of these switches makes them virtually fail-safe. I suspect most of the "problems" are operator error, i.e. accidentally switching to "OFF" while the engine is running.
 
#42 ·
That's the scuttlebutt from a marine engineer who I reference for my electrical stuff. I spent many a year as an journeyman electronic tech, and it wouldn't surprise me at all, given the environments and loads.
Remember that it takes a very low resistance to introduce significant voltage drops at the kind of current we are talking about. Low voltage and high current applications are extremely sensitive to circuit resistances, which is why it is important to reduce number of connections, and increase the reliability of those connections.

There is also the safety factor. While power losses are undesirable in themselves, a small resistance under high current quickly heats up, leading to further contact degradation and increased resistance and heat, which can cascade into an electrical fire.

Either way, from an engineering standpoint it is a very bad idea to have the switch on the output. aside from the polemics of switch reliability, the notion that if you turn a switch the wrong way you will destroy an expensive component is just not acceptable. Not when it can be done otherwise with minimal changes.
 
#40 ·
John,
Your are right on the remote panel display lights. It seems to act as you say, I'll double check next time I am at the boat. I guess my final question is do I need an eco-charge to properly charge the starting battery I am going to add? The easiest way for me to add a starting battery is to leave the setup the way it is,(with two group 27 batteries wired to the switch) and add another group 27 to the number "2" battery, then I will have the number "1" battery(group 27) for starting purposes. Will that work, are there any serious issues not using a group 24 battery?
 
#44 ·
In the standard configuration? None. The two banks (starter/house) should be charged together through a diode isolator, and the house bank output controlled (on/off) by a standard marine power switch.

An alternative is to use a solenoid relay that powers on when alternator B+ voltage is present. B+ output is always connected to the starter battery, but when the relay energizes it bridges B+ across to the house battery as well. When the engine is turned off, the relay opens and separates the starter battery and house battery again. That way the starter battery is ONLY connected to the starter, and the house battery is ONLY connected to the house, and there is a permanent connection to the alternator B+.

Note that a diode isolator imposes a .7 volt voltage drop across it, so voltage sensors for a 3 stage charger must be on the battery side of the isolator or it will read battery voltage incorrectly.
 
#48 ·
Ralph, I only just discovered what others here have known for a long time: When looking at a ".jpg" webpage, you can paste the image into a Sailnet reply by copying that address. You then come back here to Sailnet, and begin composing your repply. If you click on that little yellow icon with the mountain and sun image, you can then paste the web address into the field in the dialogue box. Press "Okay" and the image gets embedded in your reply. I don't understand how this works -- but I think it's magic.

This is the same method used for posting photos here, except you will first need to upload your photos to a photo-sharing website such as Flickr.
 
#47 ·
Lets say I add a starting battery to my existiing system with the 1,2, Off, Both switch and I leave the switch aways on "2" (the house bank) and only switch to "1" if the isn't enough juice to start the engine. Will starting battery charge while the engine is on and the switch is on "2"?
 
#49 ·
Ralph,

If you are going to go to the trouble of adding/replacing battery switches, I would just follow the West Marine advice and have two switches. One would be for the house bank (in your case consisting of two batteries), the other for the starting battery. Both switches would be the "On/Off/Combine" variety. You would then leave them both "On" at all times while you're aboard. The ACR would see that the house bank was charged first and then it would shunt charge to the starter battery.

In this way, you avoid any of the concerns raised above about switching to "Off".

Edit: I can't recall whether WM advises two on/off switches AND a third "combine" switch, or the configuration I described above. Consult them or Blue Sea for definitive advice. I have pretty well exhausted my knowledge of this subject matter.
 
#52 ·
John-

I was clarifying because BlueSea does make a few switches that have an option for an AFD...but this ain't one of 'em.
 
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