Confused - Batteries / Alternator / Refrigerator

[outdoor]

OK.

So i'm not sure what my problem is:

1) Batteries
2) Refrigerator
3) wiring

I have 3 battery banks. 1st Bank with 1 Trojan type 27 deep cycle, 2nd bank with 2 Trojan bat, 3rd 1 type 24 starting battery

I have left the batteries connected to a charger all winter long that outputs up to 15 amp per bank and trickles when fully charged.

When connected to dock, same thing.

It appears at times when the refrigerator compressor (cold plate fridge) comes on uses about 6.5/7 amps. it sometimes causes lights to flicker and 12 volt outlets to not provide full power.

I was out motoring (100 amp Alternator) on Friday for a few hours, had my vhf radio on, Autohelm 800 and Magellan GPS plugged into 12 volt outlet

at some point the vhf started making clicking noises, GPS reboot and the amp usage indicator started jumping back and forth.

Does this sound like it could be my batteries? Though if I'm motoring with 100amp alternator would that not output enough to begin with to not impact my power?

Or is it some other issue with wiring interference/connections or refridgerator ?

[S/V_Surya]

Sounds like a bad connection or battery selector switch needs servicing. Your batteries should have more than enough to power those loads. Check water level in batteries also.

[Strygaldwir]

Measure your voltage at one of your failing devices. I'd wager you'll have a significant voltage drop from your source origin. Could be corrosion, could be wiring, could be connectors. Identifying the problem will help optimizing a solution.

[outdoor]

If there is enough power at times, would it likely be corrosion? The VHF works most of the time, GPS in 12volt outlet works most of the time

It is it likely corrosion? working, working, working then problem

[Strygaldwir]

I find that additional loads going off and on at various times can have a significant effect on electronics. I wondered for months why my autopilot would suddenly stop auto-piloting. After replacing the control head and the corepack and still not finding the problem. I took out the drive unit, noticed the power lines to the drive were corroded. Replaced this short line and, 3 year, not a problem since!!!

I have experienced this same phenomenon more than once. Marginal power to digital electronics can cause unexpected and sometimes difficult to diagnose failures. To the point, whenever there is an electronics issue aboard my wife always say "Check the connections!" and she's right 80% of the time.

[btrayfors]

Yes, by all means check all connections.

However, IMHO your problems are likely to be more systemic, i.e., more than just connections.

A compressor may draw 6-7 amps when running, but the start-up amperage draw can be MUCH more....sufficient to tax what already appear to be inadequate connections.

When the compressor starts, it will draw down the voltage significantly. And, it appears, your wiring setup is marginal anyway. In addition, when a compressor STOPS, it creates a nasty surge sufficient to affect some electronics.

Also, it sounds like you're running those three Trojans as 2 different banks. You'd likely be better off to have a single large house bank (wire all three batteries together if they're of the same type), and a separate start battery which you already have.

Before you go replacing batteries or blaming them, you need to take a good look at your overall wiring schema and, of course, at the quality of the existing connections, including wire size.

Bill

[outdoor]

Correct me if I'm wrong, but the advantage to having 2 banks is I would know when one is depleted and switch to 2nd and know 1st has to be charged up?

I'm no electrician, seems owning a boat if you don't have the money to pay professionals everytime you encounter a little problem you a SH*T out of luck. Or you start to learn slowly.

I just bought the boat last fall put in water this year. Was hoping/thinking that everything is in working shape and would not have to frig around with toilets, pumps, water taps, wiring, refrigerators, depth sounders, thru-hulls.

This is getting costly above what I already paid for the boat that was supposed to be in good condition

[Strygaldwir]

Cruisers forum is an outstanding resource for optimizing what you have. There are many threads available to help YOU make informed decisions.

On two battery banks. Many issues. But, to simplify. The slower you take energy out of a deep cycle battery, the more energy you'll have available, and the longer the battery life. If you view your consumption as a fixed constant say 10 amp hour's per hour and take it out of one 100 amp bank, you might have 4 hours before you should start recharging that bank. If you take 10 amp hours from a 200 amp bank you might have 10 hours before you should start recharging the bank. So, 2 100 amp banks would provide you with 8 hours of usable energy, 1 200 amp bank would provide you with 10 hours (Many discussions by many learned folks, see Peukert's law for more info!) This can also be readily seen from the discharge graph battery manufacturers provide for their products.

2nd point. It is considered to be a requirement to have a good battery monitor on board. One that will let you see how many amp hours you are consuming and putting back. This will help you maximize the life of your batteries and give you a much better sense of what you are consuming and producing. Both, which are excellent things to know to help you optimize your usage of your system.

Nigel Calder has an excellent series of books that are fairly exhaustive in their explanation of ships systems. Check it out! Probably available in the library, but well worth the purchase cost!

[btrayfors]

Outdoor,

I feel your pain :-)

Been boating all my life, and professionally for much of it. The learning curve can be steep, both for learning to sail, navigate, etc. and, especially, to maintain your boat.

There's no boat afloat which doesn't require maintenance....even the multi-million dollar ones. Doesn't matter what you paid for it, there's gonna be some maintenance. If you're handy and you want to learn, there are TONS of good sources out there, including this forum and the books mentioned. For electrical stuff, you might also look at Charlie Wing's book...simpler than Nigel's and very much to the point.

Strygaldwir's right about running the batteries together. The preferred method these days is to connect the house batteries as one large bank, with a separate start battery maintained by, e.g., an EchoCharge device. Automatic...does the job. You'll cycle your batteries less, be able to charge them faster, and eliminate some problem areas. BTW, the idea is not to run batteries down til they're depleted, but rather to aim for not less than 50% charge (12.2 volts resting) before charging them.

You didn't mention what type/size boat you have. On smaller boats there are some "tradeoffs" which can save $$$, but on any sizeable cruising boat a good electrical system is required for trouble-free performance over time.

Bill

[outdoor]

I have a C&C 27

[Highlander40]

Ditto on the 1 house bank and 1 starting bank.
Keep it simple and as automatic as you can.
Remember, all the gear is just a rental.
On a boat it's just a mater of time.
Break Out Another Thousand - BOAT

[perchance]

If you have a dmm you can do a simple voltage drop test on your connections.This test will tell you if you have a poor connection or bad wire.

[outdoor]

This weekend I will bring my Digital Multimeter and first check the voltage of the batteries without any load or charger running. Hope to read roughly 12.6 volts

I will then check at various connections I guess (not sure how to get to some or which ones to check) But maybe the main switch and a few 12 volt outlets.

I will then turn the fridge compressor on and check to see how much amperage is being used, not sure what that will tell me.

[rtbates]

Originally Posted by outdoor

Correct me if I'm wrong, but the advantage to having 2 banks is I would know when one is depleted and switch to 2nd and know 1st has to be charged up?

I'm no electrician, seems owning a boat if you don't have the money to pay professionals everytime you encounter a little problem you a SH*T out of luck. Or you start to learn slowly.

I just bought the boat last fall put in water this year. Was hoping/thinking that everything is in working shape and would not have to frig around with toilets, pumps, water taps, wiring, refrigerators, depth sounders, thru-hulls.

This is getting costly above what I already paid for the boat that was supposed to be in good condition

welcome to the world of boats! You are 100% correct. You either need money or talent...And in lots of places no amount of money will get the job done, so go for the talent...