battery ?

[jennykatz]

WE have been running a f-115 yamaha we have 2 batteries one a series 24 the other a series 27 ( 115 amp hours ) . WE have charged the batteries while running .The gps 498 says it goes from 13.8-14.4 volts when using the both feature on the battery switch (1,Both,2 battery switch)I don't have an isolater on this system just 2 batteries with switch.

When i started to run the refrigerator (tundra ) now the gps and yamaha gauges say 11.8-12.4 volts ? Just wondering why such a discrepancy in voltage.any thoughts on this matter

Also thinking about changing the series 24 to a series 27 same as the other to equal(115) the amp hrs out?

[Wefings]

Jim are both of these voltage readings with motor running,same switch position and same RPM ? Just the fridge is the variable ?
Marc

[Sea Wolf]

JIM-

Once you turn that refrigerator on, the amperage draw from it will lower the apparent voltage available to other devices such as your GPS, and the voltage meter on your Yamaha motor gauge will go down, whether the motor is running or not.

The drop will be a lot less with the motor and alternator running than it will be once the motor's off, but, but the load of the refrigerator will pull down the voltage left for rest of the system simply because the refrigerator puts the batteries under a discharge load.

Refrigerators typically pull a fairly large amperage load, regardless of whether they are a compressor or other type.

Changing over the smaller battery from a group 24 to a group 27 will help some, but much the same will still happen, only to a slightly smaller degree because of the newer slightly larger capacity battery.

If the motor's off, the refrigerator will also run a bit longer before the voltage drops to the point you should shut it off or restart the engine to protect the battery from being overly discharged and shortening it's life expectancy with another 27.

So the switch of the one battery from a 24 to a 27 is a good idea, but I'd just wait until it naturally needed replacing, anyway, since the change will not be dramatic.

If you really need a lot of power to run the refrigerator for long periods without starting the engine (and being off shore power), consider going over to still larger batteries, like a pair of 31's or, better yet, four 6 volt golf cart batteries rigged into two banks of 12 volts (link two 6 volt batteries in series to get a 12 volt battery). This will give you quite a bit more total Amp-hours available for house use, including your refrigerator.

Joe.

[journey on]

You know, I'm having a hard time having people taking a picture with a phone. Now, I'm trying to adjust getting a voltage reading from a GPS.

The higher voltage is what I'd expect from a set of batteries being charged. And the lower voltage is typical from batteries being used. What I don't understand is a range of voltage. A battery voltage should be constant, only changing gradually. They put out DC. I assume that you separate the batteries after you end charging.

12.4 is OK 11.8 is discharged and that's a no-no.

Boris
KE6QWS

[jennykatz]

Marc,Joe
Yes the eng is running from 1200rpm -4800rpm or WOT It does not matter
When we went out the battery switch was on both and it started out at 13.3 then within a few min. it went down to 12.4 then went to 11.8 We had a garmin fishfinder and garmin 498 gps plus the tundra refridge on.
We were out for about 2hours of running .We have been out for 3days about 2hours each day , so the batteries should be charged
Right now I'm charging them with a charger that came with the cape cruiser same as the cd-25.This week I will go down and check the acid level in each battery , and run the boat without the fridge on .I'll let you know how it turns out.

[JamesTXSD]

Hi Jim,

Check that Guest charger. When we picked up Wild Blue, we were running the boat almost daily. The alternator on the motor kept the batteries topped off nicely. When I checked the batteries on shore power, they were low. It was then I discovered the charger wasn't working. I replaced it under warranty from Guest. The charger puts power back into the batteries slow (5 amps tops), so it can take a full day to top off the batteries.

C-Dory originally had a Grp 24 battery as our only house battery... I had ordered it with 2 Grp 27s. They just put a 27 in with the 24. I also discovered that the batteries were "months old" (one was 13 months old when installed) according to the #s from Interstate. Two new matched 27s are doing a MUCH better job these days.

When setting at anchor for a while, I use an automotive charger with the Honda generator (allows me to put more power back into the batteries faster than the onboard Guest).

Good luck with this.

Best wishes,
Jim

[jennykatz]

Jim are you coming down to fla again this winter The St. Johns would be nice to do .Mike needs to take out his cdory

I will know a littl;e bit more this week I will check the batteries and then maybe just buy that other series 27 and put it in . I really don't need battery problems Thanks for the suggestions

[JamesTXSD]

[Sea Wolf]

[jennykatz]

Joe how do I check to see if alt is giving out 20amps? also where should i look for a short ?
and how do you find it (short) what , where and how?
I think after i check this out i will need a few of these Thanks

Are any more c-brats coming down to fla.for winter

[Doryman]

[Sea Wolf]

Joe how do I check to see if ilt is giving out 20amps?


You really need an ammeter for this, connected in series with the current flow out of and into the motor. The ammeter is best connected between each
battery post, one at a time, and the "+" cable coming to it from the battery switch. Test each battery separately with the motor running and also off. An automotive ammeter will tell you if current is flowing, how much, and which way (charging, discharging).

I also suspect the diagnostic program that Brent has could tell you if the alternator isn't working.

In a simpler vein, if you've got good batteries, you've done the test below and have no shorts, the refrigerator is off, and, after starting the motors, the batteries loose their charge, something's not charging them, so it must be the alternator is bad, or some connection is loose.

Always make sure your battery cables are tightly connected. Use nuts and a wrench and keep the posts, connections and cables clean. If you must use wing nuts, tighten them with a pair of pliers. Loose cables can keep electronic devices from working, or even cause damage to them!

also where should i look for a short ?

Start with the batteries. Charge the batteries independently and leave them sit w/o a load on them for a day or two with the battery cables detached. Check the voltage on each one every six hours or so. If either one of them drops voltage dramatically, it's either got one or more dead cells, or a internal short.


and how do you find it (short) what , where and how?

To check for an power robbing short in the wiring, turn every switch in the boat off and with the batteries removed. Then check the resistance in Ohms between the hot lead coming out of the battery and the ground cable for that battery. Do this for each battery hookup one at a time with the battery switch turned to that battery. Generally the meter ought to show "Open Load" or a LOT (hundreds or thousands) of Ohms resistance.

You can also do this with the batteries installed and a continuity light test probe, which lights up when current flows. Turn everything off as before, then flip the switch to one battery at a time. Put the continuity tester between the "+" battery post and the disconnected "+" cable. With everything off, no current should flow, and the light should not go on. If it does, you've got a short or some unit is turned on somewhere. Leave the light clipped to the post and the cable, and one by one, remove fuses and turn off circuit beakers until the light goes off and you find where the current is flowing. You can do the same with the digital meter. Set it on resistance, and watch the Ohms as you one by one disconnect the fuses and open the circuit breakers. When the meter goes from a few Ohms to "Open Load", you've found the circuit that's providing the path for the power to flow through.


I think after i check this out i will need a few of these

Thanks,

jennykatz

Are any more c-brats coming down to fla.for winter?

*********************************************************

Did you want lime with the beer? We've got an extra one or two left over from Tom, too!

Hope this helps!

Joe.

[jennykatz]

Thanks Joe I'll bring my laptop down to the boat and follow step by step thanks again .Joe hope to see you in Seattle 23-25

Warren hope to see you in Jan .I'm hoping to go to the Seattle Boat show the 23-25 of Jan.

here is my e-mail address give me a heads up widmannfla@aol.com

Jim on Jennykatz

[Matt Gurnsey]

Thoughts off the top of my head, and not necessarily good one:

When two dissimilar batteries are hooked up, the smaller one will usually dictate the charge level- Meaning that once the group 24 is charged, the regulator may think the job is done and drop voltage to stop charging.

Are both batteries deep cycle? Or are they Starting batteries? Or combination?

I am beginning to really like Blue Seas Dual battery system (part number: 7650)- it has a charging relay that automatically isolates the batteries (simple On-Off switch) and still allows combining batteries in an emergency. This will also take care of having batteries with dissimilar characteristics. One of the cool things- if your electronics are on the house bank, cranking the engine will not shut down the electronics.

Does the refer really only use 3 amps? I haven't looked at the specs, but that seems exceptionally efficient.

I think the computer and injectors in the Yamaha take more than 5 amps. But still- the voltage drop seems excessive.

Start with the connections, especially the grounds.

[thataway]

My experience is that the refigerators run more like 5 amps when running, and average about 3 amps--since they don't run all of the time.

Agree with the posts that it is best to have "equal" batteries. Group 31's would be best with the refigerator. You also want to isolate the house battery, so the refer will not run down the engine start battery.

Measuring voltage with the GPS--gives you voltage at the GPS--not the battery--there can be resistance along the way (undersized wires--which is common, corrosion, poor connections etc). Use a volt meter dedicated and connected directly to the battery, rather than a analogue guage or GPS.

I have a 115 Yahama--and they put out 14.4 volts when running. So unless you are having a large loss, or resistance, your voltages are low--and suspect some charging problem as Joe suggests.