Cruisers & Sailing Forums (https://www.cruisersforum.com/forums/)
-   Electrical: Batteries, Generators & Solar (https://www.cruisersforum.com/forums/f14/)
-   -   Troubleshooting Drained batteries and Dead Charger. (https://www.cruisersforum.com/forums/f14/troubleshooting-drained-batteries-and-dead-charger-226232.html)

rbk 11-11-2019 15:55

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by Santiano (Post 3013981)
Thanks to everyone who replied!
I bought a cheap automotive 2-amp trickle charger as an emergency device to stop my house bank from losing its ability to hold a charge. I disconnected the two older batteries, and have charged them up to hopefully use as an emergency bank. The two new batteries are charged and running nicely, although I'm careful to use very little power because of the tiny charger.

I'll be ordering about 200watts worth of solar panels, along with a charge controller, by next weekend. The current plan is to rely on solar for the foreseeable future. I'm in a slip for the most part right now, but will be leaving to begin cruising within a year.
I learned a good number of details from yous all, and a few contradictory bits that I'll have to work out for myself!
Cheers, and thanks again!

Read the article under ďNo,no,no, no!!!!!!!!!Ē :facepalm:
https://marinehowto.com/installing-a...ttery-charger/

Santiano 11-11-2019 16:03

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by rbk (Post 3014010)
Read the article under ďNo,no,no, no!!!!!!!!!Ē :facepalm:
https://marinehowto.com/installing-a...ttery-charger/

Jaysus, I can't get anything right!

Fair enough, I guess I'll unplug the damned thing and just not use my batteries until the PV panels arrive.

Would it be that hazardous to use the car charger for just a week, though?

rbk 11-11-2019 16:19

Re: Troubleshooting Drained batteries and Dead Charger.
 
You really need to purchase a proper shore charger to properly charge and maintain them for a bit; right after you determine if theyíre shot. Buy a multimeter and figure out why they went dead in the first place I.e. find the power draw that killed the bank, which may be something wired direct to the bank or a short somewhere. If thereís a short the auto charger can make the situation worse. Spend the time and read Trentís advice in this thread, read rest of the articles in the link I provided and save yourself money and time. Not trying to be critical but you shouldnít just try and throw more power (solar) at it until you know where your power is going.

Boatpokers website has good examples of why you should be trying to track this down, read thoroughly:
Marine Surveyor, Port Credit Marine Surveys, Toronto, Ontario

TrentePieds 11-11-2019 18:04

Re: Troubleshooting Drained batteries and Dead Charger.
 
Santiano:

I cannot endorse strongly enuff what rbk has told you. Don't press ahead too fast - listen to your elders ;-)! You can spend a lot of money to no effect by not being careful about how you treat your batteries and your electrics generally.

Get you head around the time it takes to charge a battery using ANY kind of charger. Getting impatient and "forcing" the charge is VERY costly in terms of battery damage. That is why I mentioned the matter of a "power budget" and the desirability of tracing your entire installation to makes sure there are no short circuits anywhere.

None of this stuff is difficult to get you head around. Do take a coupla hours to read up on power management generally. Since forcing the rate of charge is NOT an option you need to REDUCE CONSUMPTION to keep your batteries from "going too low" so you cannot get them up again quickly enuff. It's just a fact of cruising that you cannot be as cavalier about your electrical power as you can be on land :-)!

TP

Stu Jackson 12-11-2019 14:33

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by Santiano (Post 3011495)
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
I went to the batteries to check for loose connections and found a negative terminal sparking where the charger was connected. Without turning the charger off, I rearranged and tightened the connection to the negative terminal. The terminal sparked as I did so, and the charger light went from "batteries full" to dead. No lights.>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>


Cheers,

Santiano.




It appears that the charger was still on when he played with the negative wire.


Next time you mess with connections, please make sure everything you are working on is turned OFF.


And while you're doing all this troubleshooting, draw yourself a wiring diagram so you'll begin to see how it all works together.


Good luck.

Santiano 13-11-2019 14:48

Re: Troubleshooting Drained batteries and Dead Charger.
 
Right, so. I've got a new 20 amp marine charger coming today. This time I will only be charging batteries with the same Ah rating and use in a single bank.

I've gone through and checked for loose/corroded connections. I've also tried to identify faults in the DC circuits with my multimeter, but I'm not really sure what I'm looking for. Voltage drop? Resistance? Any recommendations or resources that will describe what I should be paying attention to? I'd rather not burn out a second charger.

a64pilot 13-11-2019 15:00

Re: Troubleshooting Drained batteries and Dead Charger.
 
Your not going to burn it out, if you make your connections before you power it up.
Now if it wonít work, take a voltage reading of the bank, if itís too low a lot of modern charges wonít come on line, I assume itís some sort of safety issue?
Whatís too low? I donít know, but would guess about 10 V or so, but that is a guess.

Santiano 13-11-2019 15:15

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by a64pilot (Post 3015221)
Your not going to burn it out, if you make your connections before you power it up.
Now if it wonít work, take a voltage reading of the bank, if itís too low a lot of modern charges wonít come on line, I assume itís some sort of safety issue?
Whatís too low? I donít know, but would guess about 10 V or so, but that is a guess.

Battery voltage shows 12.8 volts. I've topped it up with an automotive charger, which may have been unwise. But I couldn't just leave it discharged.
What's the best way to check connections with a multimeter?

a64pilot 13-11-2019 15:29

Re: Troubleshooting Drained batteries and Dead Charger.
 
Checking connections you look for zero resistance.
But battery connections you can almost always do visually. However it might not hurt to ohm out the wires themselves, especially if they are old.
Iíve seen the inside end of wires under the insulation be black and or green and have significant resistance as corrosion set in.

rbk 13-11-2019 15:35

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by a64pilot (Post 3015236)
Checking connections you look for zero resistance.
But battery connections you can almost always do visually. However it might not hurt to ohm out the wires themselves, especially if they are old.
Iíve seen the inside end of wires under the insulation be black and or green and have significant resistance as corrosion set in.

^^ x2 Just because the connection looks good on the outside and is tight, it does not mean there ins't more going on inside the casing, more so if the connections are open ended, the corrosion can creep way up inside the wire.

TrentePieds 13-11-2019 17:09

Re: Troubleshooting Drained batteries and Dead Charger.
 
Santiano:

Sounds like you are on the right track now :-)

There are, conceptually, only three circuits in your boat: 1) the 120V circuits which we will ignore for now. 2) the "housekeeping" circuits operating on 12V and demanding only low "draws", i.e. they are "low ampage" circuits, and 3) the Engine Starting circuit which is also a 12V circuit but carrying HIGH ampage (draw). High ampage circuits have FAT wires, low ampage circuits have skinny wires. Both kinds of circuits get their current from the battery/batteries.

There are different kinds of batteries, distinguished sometimes by their internal construction and sometime by their chemistry. Most likely what you have is "flooded" batteries with a liquid electrolyte. Such batteries require maintenance and therefore they have "caps" that permit you entry to each cell. What I do to know the SOC ("state of charge") of my two 27 series flooded (fake marine) "deep cycle" batteries is remove the caps, suck a little of the electrolyte from each cell into a hydrometer (a five-dollar gizmo that measures specific gravity), read it, put the electrolyte back in the cell from which it was taken and record the hydrometer reading in my log. We can come back to what the readings "should" be and what it means if they are not what they should be. You can get all sorts of fancy little meters to tell you SOC and other things about you electrics, and they are nice to have,but I think it's a wise sailor who can get along without them.

I imagine that you have about a 30HP engine. It matters not whether its the old Atomic 4 gas pot or whether it's a diesel. The AMOUNT of current required to start it is so little that you DON'T need a separate "starter battery". I don't have one, and I "even out" the "wear" on the batteries by setting the selector to Batt #1 on odd numbered dates and to Batt #2 on even numbered dates. So think about this: My little Beta 20HP engine requires 15 seconds of preheat. Let's call it 1/4 minute drawing 75 amps. 1/4 minute is 1/4 x 1/60 of an hour = 1/240 hour. 75 amps for 1/240 hour = 0.3125 amp hours. After that the starter motor will require 200 amps also for 15 seconds. Same kinda calculation: 200/240 = .83333 amp hours for a total of 0.3125 + .83333 = 1.1458 amp hours, so let's be generous and call it 2 amp hours to start.

Now, the alternator on the Beta is rated at 40A but in actuality it wouldn't like to be asked turn out 40A continuously. When the engine starts it will turn out something like 15A and do that continuously. But I only need to replace 2 amp hours after starting, so at 15A it will take 60 minutes x 2/15 = 8 minutes to replace everything I took out of the batts to start. In practice, that means that just getting out of my slip replaces all juice used to start the engine. Your numbers will be slightly different, and you should determine what they are and do the calculations just because being able to do that confers protection against eager salesmen :-)

The charger you just bought will be made so it can tell the SOC of your battery bank. It's probably got two output terminals so you can wire each terminal to a separate battery. It will also have a special third terminal from which you take wire to the NEGATIVE terminal on one battery. This is how the charger gets to know whether the batteries are charging "too fast" which could happen because the charger is able to "push out" juice faster than is good for the batteries. The charger also senses the SOC of the batteries, and knowing that it will adjust itself to charge at one of three rates: 1) Bulk, 2) Absorption and 3) Float. On my charger they are called "Equalize", 'Bulk" and "Maintenance", That doesn't matter because both the charger and I know what the charger is doing. What happens chemically and electrically at each of these rates of charge is really, really fascinating, but there is no need for you know it at this point. Your new charger is gonna see you right. Provided you connect it correctly :-)

So if your entire wiring system is neat and clean so there are no short circuits or loose terminals anywhere, you troubles should be over. Remember that your bilge pump is wired for safety's sake so it will switch on automatically when required even when there is no-one in the boat. That can drain a battery fairly fast if you are taking in water, say through the stuffing box. But with your new charger more juice will be supplied to the batts than a bilge pump will drain out of them so you'll be okay in that respect.

Before you spend money on extra charging capacity I recommend that you spend it on REDUCING DRAW. The more modest your energy budget, the quicker you can get back to "full charge" after a night on "the hook" Wherever you can, substitute LED lights for incandescents. Learn to live without a refrigerator, learn to live without a water maker. Your expenditures of both money, effort and emotions will be reduced drastically if you go that way about it :-)!

All the best

TrentePieds

Santiano 13-11-2019 17:46

Re: Troubleshooting Drained batteries and Dead Charger.
 
Awesome write-up, TreintePieds!

I'm already doing without a reefer system or water maker, and have just ordered a bunch of LEDs to replace all my old incandescents. On the right track, as you say.

I've just been reading up on the "marine surveyor" link, and the man cited a report saying it's bad for 12v batteries to be wired in parallel! Everyone I know wires a 12v bank in parallel! Should I ignore this injunction?

boatpoker 13-11-2019 18:03

Re: Troubleshooting Drained batteries and Dead Charger.
 
The 12volt Bible
https://www.amazon.com/12-Volt-Bible.../dp/0071392335

noelex 77 14-11-2019 04:05

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by TrentePieds (Post 3015291)
My little Beta 20HP engine requires 15 seconds of preheat. Let's call it 1/4 minute drawing 75 amps. 1/4 minute is 1/4 x 1/60 of an hour = 1/240 hour. 75 amps for 1/240 hour = 0.3125 amp hours. After that the starter motor will require 200 amps also for 15 seconds. Same kinda calculation: 200/240 = .83333 amp hours for a total of 0.3125 + .83333 = 1.1458 amp hours, so let's be generous and call it 2 amp hours to start.

The amp hour draw starting a diesel engine is tiny, as you have pointed out. 2 AHrs is nothing even to a small battery. Ten AA batteries contain more than this amount of energy.

However, the current draw is very significant. The battery must be healthy to supply a high starting current.

The idea behind separate start and house banks is to ensure that one system will be available that can supply this necessary current. Without the ability to deliver these high currents, the engine will not start. There is little point calculating the energy draw because this not the limiting factor.

GordMay 14-11-2019 04:45

Re: Troubleshooting Drained batteries and Dead Charger.
 
Quote:

Originally Posted by noelex 77 (Post 3011628)
...
A 6 amp charger is small but providing your electrical needs are modest it should manage fine. 6amps over 24 hours is 144 Ahrs. Many battery chargers will not supply their rated capacity continuously and there are some conversion inefficiencies, so you might have a little less than this, but providing you are not using more than around 120AHrs a day the battery should slowly charge...

The coulometric charging efficiency of flooded lead acid batteries is typically about 70 - 80%, meaning that you must put as much as 142 amp hours into the battery for every 100 amp hours you get out. This varies somewhat depending on the temperature, speed of charge, and battery type.


All times are GMT -7. The time now is 06:06.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.


ShowCase vBulletin Plugins by Drive Thru Online, Inc.