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S/V The Goonies · 18-06-2008, 15:35

Thanks , I bookmarked that page for future use. :-)

DeepFrz · 18-06-2008, 16:14

Also Balmar make a good one. Also Mastervolt. Those are just a couple that come to mind.

MarkJ · 19-06-2008, 05:29

OK so reading the posts I set a test to do:

Check voltage before, during and after charging.
The 'Lights' mentioned are 4 cabin lights.

Results:

12.32 volts at 6.59pm
Started engine 7pm.
13.30 volts 7.01pm
13.55 volts 7.30pm with lights on 13.38 volts
13.61 volts 7.50pm with lights on 13.44 volts
13.60 volts at 8pm with lights on 13.42 volts
Stopped engine 8.01pm
12.77 volts with lights on 12.57 volts
12.68 volts 8.06 after a drain to remove surface charge.

Does this help with diagnosis at all? Or perhaps there is no problem at all?

Thanks for your help.

PS I am NOT spending money on some new system, just trying to fix this one

Mark

Joli · 19-06-2008, 06:04

The good news is your charging.........

Couple thoughts: You don't have a three stage regulator.
How many amps is the alternator putting out?
How big is your bank (not the money kind) Ah?
How old are the batteries?
Can you equalize them?

You may have to run the engine more then you had planned to keep the batteries topped up, maybe several times per day, depends on your draw.

Wire the mulitmeter right into the panel and keep an eye on it. You are full charge at ~12.6v, 50% charge at ~12.3v, and 10% charge at ~11.7v. This is guessing you have 200 Ah.....

Joli · 19-06-2008, 06:12

Here you go Mark, one more. Note I did not include any cold weather sailing locations.

Joli

Temperature: 57 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.258 12.59
75 1.203 12.26
50 1.153 11.96
25 1.113 11.72
0 1.093 11.60

Temperature: 67 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.262 12.61
75 1.207 12.28
50 1.157 11.98
25 1.117 11.74
0 1.097 11.62

Temperature: 77 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.265 12.63
75 1.210 12.30
50 1.160 12.00
25 1.120 11.76
0 1.100 11.64

Temperature: 87 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.268 12.65
75 1.213 12.32
50 1.163 12.02
25 1.123 11.78
0 1.103 11.66

Temperature: 97 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.272 12.67
75 1.217 12.34
50 1.167 12.04
25 1.127 11.80
0 1.107 11.68

Temperature: 107 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.275 12.69
75 1.220 12.36
50 1.170 12.06
25 1.130 11.82
0 1.110 11.70

s/v Thea · 19-06-2008, 06:21

Mark,

I think you should be seeing a higher voltage when charging then 13.6. If the alternator belt is tight I'd take the alternator off and take it to an automotive electric place and have them test it.

MarkJ · 19-06-2008, 06:26

Quote:

Originally Posted by Joli

The good news is your charging.........

.....

Couple thoughts: You don't have a three stage regulator.
Yes I do have a '3 step regulator' on the sales documents but I don't know what/where it is or how to then test it.

How many amps is the alternator putting out?
It is 80A alternator but I dont know how to test its actual running output as my multimeter only goes to 10 amps

How big is your bank (not the money kind) Ah?
110 AH not big but I only need run auto pilot

How old are the batteries? all 3 are new: 1 engine start and 2 x 55ah house batteries.

Can you equalize them? Don't know what you mean but I havent changed the connections so they are as they were set up.

You are full charge at ~12.6v, 50% charge at ~12.3v, and 10% charge at ~11.7v. This indicates I am charging fine but as you say, maybe not as they should which is a waste of diesel but otherwise ok.

Thanks for your help.

Mark
PS I never intend on sailin out of the tropics again in my life! LOLOL

MarkJ · 19-06-2008, 06:29

Quote:

Originally Posted by s/v Thea

Mark,

I think you should be seeing a higher voltage when charging then 13.6. If the alternator belt is tight I'd take the alternator off and take it to an automotive electric place and have them test it.

Yes the belt is tight. Taking the alternator to the auto electrician wont help if its a regulator problem, but if I can't test it on board then its the best idea. Even I can take an alternator off! <<Touch wood!>>

Mark

s/v Thea · 19-06-2008, 06:33

Most likely the regulator is built into the alternator. Have you checked that all the elec connections are tight?

Doug

Joli · 19-06-2008, 06:47

It does not sound or act like a three stage regulator. If it were 3 stage it would be bulk charging at over 14 volt for the first 30~40 minutes. With an 80 amp alternator you'll be fine as long as you don't let the voltage (discharge) get too low. Maybe run the engine twice a day for an hour or so? What is your tankage?

ssullivan · 19-06-2008, 07:53

[hitting my forehead with my palm]: DUH! of course!

Joli's chart above regarding specific gravity is the best to determine your state of charge. It will do so without any error. Forget everything you are doing with the volt meter and get yourself a $2 hydrometer!

This way you can have a second source of data - the actual state of charge of the battery, and you can stop guessing about voltages. The hydrometer will show actual state of charge.

MarkJ · 19-06-2008, 08:05

Quote:

Originally Posted by ssullivan

[hitting my forehead with my palm]:
This way you can have a second source of data - the actual state of charge of the battery, and you can stop guessing about voltages. The hydrometer will show actual state of charge.

Not on a sealed battery

hellosailor · 19-06-2008, 08:21

I wouldn't waste money on the $2 hydrometer, for ten bucks you get one a foot long that is much easier to read and includes a CASE. A hydrometer is a turkey baster full of acid, it will drip and it will eat clothes and wood trim and whatever else it can find, a case should not be optional. Treat it as a hazmat source and you may only need to replace a t-shirt and old pair of jeans every year.

And IIRC, the hydrometer still isn't perfect because it can take 24 hours for the acid in the battery to circulate and even out. That's literally the surface charge being redistributed, and the SG will vary depending on how much acid you slurp up and 'average out' in each cell. Personally, I'm convinced the clothing industry invented the hydrometer.<G>

Mark, if you have a three-stage regulator locate it. If it isn't hardwired in between the alternator and the battery, it is in a box someplace uninstalled. Should be a gizmo between the size of a cigarrette pack and a paperback book with 4(?) wires going in and out, to the alternator and battery.

It certainly sounds like your alternator is not putting out 100% power. Most of them will put out 14.4 volts under normal cruising speed, i.e. 2000 rpm on the engine. 13.6 is at the very low end of adequate, I'd expect that at low idle speeds only. There are some tests you can run on the alternator, but it may be simpler to take it out to a shop and have them check it. If the alternator is typical, there is one output lead (by itself, connected hot to the battery, so make sure to disconnect the battery power before you work on that output lead!) and then a 2-3 wire "pack" connector with the other leads, which are for the idiot light (if any), the field coil power supply, and a voltage sense lead. If the external regulator isn't wired into that "pack" of wires--it's off watch and needs to be roused!

With 2x55AH for a house bank (those are wee little things!) and one SLI battery, an 80AH alternator should be plenty good enough. But if it only has an internal regulator--it needs some help, unless you're motoring from time to time.