Adding extra house battery

G

GraemeC

Member
Joined
Jul 23, 2017
Messages
13
Fluid Motion Model
R-21 EC
Hi.

I hope these are 2 simple questions. I recently moved my C-28 out of a marina where it was connected to shore power onto a mooring. I now seem to be regularly in trouble with insufficient power in the house bank.

1. I am thinking about adding another battery to the house bank to bring it up to about 300aH. My question is this: the wiring to the battery terminals is really tight and won't extend to reach a third battery, so can I just add the 3rd in parallel and leave the original wiring alone, or will I need to replace the wiring (either +ve or -ve leads) so that they connect at battery 1 and battery 3.

I found a site which said, "you CAN connect your load to ONE of the batteries, and it will drain both equally. However, the preferred method for keeping the batteries equalized is to connect to the positive at one end of the battery pack, and the negative at the other end of the pack …" but it is the internet so you never know if it is good advice.

2. My second question is about the solar panel. The meter in the cave tells me I am only ever getting abut .13 amps out of the 140w panel which strikes me as way too low. Other posts on Tugnuts say people get about 6 amps and sometimes more. I keep the panel clean, and I have read about shifting it away from the radar shadow, but is there likely to be some other cause? Previously, I had put this low output down to the batteries being fully charged but I wonder if there might not be some other well-known problem?

Thanks for the any suggestions.

GraemeC
 
GraemeC,

You don’t state what items you are leaving running when on the mooring. If you are drawing more than the solar panel puts out on average over 24 hours then another battery will not help as it will eventually be drained as well.

The advice to wire the batteries with one end at the positive and the other at the negative is good advice but is not required. The reduction in performance/life should be fairly minimal if you just add to the side. You will need to buy/build new cables for the new battery anyway so you may be able to reuse the old cables in another position and still accomplish the balanced approach at no extra cost.

The solar panel output will vary significantly throughout the day and with the weather. If you are only getting .13 amps it is likely you are measuring early in the morning or late in the evening, when it is raining, or the batteries are fully charged. 6 amps would be for near mid day with direct sun. There is a function on the controller that measures total amp hours. Pick a time when you will be at the boat for two days in a row at the same time. Reset the total amp hours and then check it at the same time the next day to see your 24 hour production. Your 24 hour amp hour usage needs to be less than this. To measure your 24 hour usage you need a multimeter with a current clamp (and multiply by 24 hours) or a have a battery monitor installed such as the Xantrex Link Lite. If your draw is more than the production you will need to reduce your draw or add an additional solar panel. An additional battery only helps to extend the time but will not help over the long term when moored. If you have refrigerator, freezer, or cooler turned on that is the likely culprit. Shading can have a significant impact but is not likely the cause of a more than a 10 times reduction.

Hope this helps,

Curt
 
Thanks Kurt -- I appreciate the comments, and I agree that adding batteries isn't going to solve the problem, only delay it. But I am reluctant to ad another panel -- this one hasn't been such a success that adding another looks like a promising strategy.

Should have mentioned the devices! As far as I can tell, nothing is on when I leave the boat [the fridges / stereo / etc are Off at the device and 4 Master switches are all Off] and it's a pretty dry boat so I don't think it is the bilge pumps kicking in. I performed a test to see if I had a parasitic leak but it came in at 33 mA (and I undertand anything under 50 mA is regarded as acceptable) so I don't appear to have a leak anywhere.

Still a mystery. Maybe it's actually the batteries; they are both brand new but I guess that's no guarantee.

With regard to the solar panel, I am in Australia -- it is about 95F and clear sky today, and has been for the last week -- so I don't think the conditions account for the poor output. I wasn't aware of the test function on the controller so I am definitely going to try that as I would like to know just what the daily output is from the panel. As for measuring daily draw, I will try the test you mention just to be sure that what I think is Off really is off.

Thanks again for your comments,

GraemeC
 
My apologies -- thanks Curt.

(You would think with a name like mine I would be more attuned to getting spelling right 😉 )
 
With clear skies and everything off you should have no problem keeping the batteries charged with one panel. Something else is going on.

Good luck and keep us informed on what you find out.

Curt
 
you want to check there is no shadowing on the panel from the radar mast but I cant see how in the Australian climate the one panel cant keep up with everything off.

There are a few items that are on with the switches off. such as the propane solenoid and bilge pumps but these should be easy to keep up with with the panel. I think you are going to have to get the multimeter out and see if there is a bad circuit leaking amps with the switches off somewhere.
 
But I am reluctant to ad another panel -- this one hasn't been such a success that adding another looks like a promising strategy.
I'd re-think the solar panel options. As others said, adding a third battery won't help in the long run.
Last spring I installed a 265 watt residential grade solar panel and a good quality Morningstar MPPT charge controller. I live in the Pacific north west (Vancouver Island) which is a relatively poor part of the planet for solar panel performance. This combination allows the refrigerator to be left on all summer. The two batteries are enough to run through the night and get recharged during the day.
Mark
 
Thanks everyone. All good suggestions and I do appreciate people taking the time to reply. But it still has me beat. Today was about 95F and clear skies and the meter says I am still only getting .16 amps out of the solar panel (although it did get up to 0.2 at one point).

* I ran a few load tests yesterday to check the batteries are good, but found no evidence of shorted cells or other problems with them

* I checked the solar controller today -- the flashing lights say we are in 'Bulk charging" mode pretty much all of the time, which I take to be a good thing. And the dip switches are in the right configuration.

* I have checked all the connections from the panel to the controller and they all seem to be strong

* There is some shadowing from the mast / radar dome. I have seen this problem referred to in other posts, but I don't think that should account for such low output.

Maybe the more powerful panel is my best option but like I said, it's got me beat. Thanks again,

Graeme C
 
The best way to solve current problems and track lines is with a good clamp meter. They run about 100 dollars because you need a DC meter, the easier ones to get and the least expensive only do AC current. With the meter clamp the line from the solar panel, befor the controller, at various times a day and you will see the current the panel is making. You can use the meter to run arounfpd the boat and find where current is being used directly from each battery and to each line going to a device. It is th pe best way to trouble shoot and 12 volt system. With all battery switches off you can determine if there is a current leak by testing the lines at each battery, you can clamp the alternators line with engine running and determine the current it is making. A good investment all round. You will also be the go to guy in the marina to those who ave not yet bought one.
 
Graeme
I'm sure you've done this but just in case, have you checked your solar charging current (mid day) after running the batteries down a bit? The inverter and microwave is a good way to kill the batteries in a hurry. (and of course don't run the engine during the testing) You won't get much of a charge if the batteries are already at their happy state. Also at the same time, turn the boat around to make sure any shadowing is gone.
I'm not sure how Ranger Tug wires the controller but the one I installed has two outputs. One to load and the other to battery. Is it possible you are only reading 1.6 amps to one output? I didn't connect anything to the load output on my installation.
When you checked the dip switches did you match the battery type? The originals in the boat would be lead acid or maybe called flooded cell.
Maybe you have a bad controller or panel.
Mark
 
Graeme,

I agree with Mark. From your description it appears the batteries may be fully charged. The solar panel can only produce power if it is needed. What is the battery voltage when you have “insufficient power”? What is the solar amp output reading when the battery is first drawn down to 12.2 volts or so? Use the Inverter and microwave to draw down the battery as Mark suggests.

I wouldn’t buy a new or additional panel until you understand what is going on. You should not need additional power if you have most everything turned off when moored.

Curt
 
Thanks for the collective wisdom. There's only one other Cutwater in Australia so I do appreciate having the benefit of your ideas (and I'm sure the other owner appreciates the respite 😀 )

I will definitely look around for a DC clamp meter -- probably a good gadget to have in any case, and I can never have too many gadgets.

I have thought about the possibility that the controller is kicking in to reduce the charge because the batteries are full, but this all began when I was away for a week in December; when I got back, the batteries had diminished from 12.7v to about 12.2v for no apparent reason and the Morningstar meter panel was showing the amber light for the house bank:

* the batteries were brand new and after I re-charged them overnight, they tested out OK with the multimeter and a battery condition tester

* no equipment had been left on, the 4 isolation switches were off and I couldn't find a parasitic leak in the system, and

* I couldn't understand why the solar panel hadn't kept things stable. The weather in Sydney had been excellent (the weather in Munich was not so great).

But I will definitely do the depleted battery test again on a day when I have time to recharge the batteries from the engine if the panel doesn't kick in with some serious current. I will take them down to about 12.5v and we will see what happens!

Thanks again to everyone,

Graeme
 
Graeme,

Thanks for the info about your previous results, it helps. If you were down to 12.2V on you battery and still no solar current something else is going on. A couple of additional thoughts:

- there should be 30A fuses between the controller and batteries. Have you checked them? There should be one in the house connection and one in the start battery connection. On our boat the connections are made at the ACR and the fuses are near there.

- some boats had the house/start swapped from what the solar controller expects. The controller expects the house battery to be #1. If swapped, the house will only get 10% of the charge in the default setting with the start getting 90%. You want the other way around. You can set the dip switches on the controller to 50/50 but to get 90% the house needs to be #1. If yours is wired wrong just swap the wires at the controller. The ACR should combine these batteries anyway if you are above 13 volts on the panel but it is possible you have one fuse blown or a bad ACR.

Hope this helps.

Curt
 
Thanks again Curt.

I hadn't thought about the fuses -- I was thinking the problem was somewhere between the solar panel and the Morningstar meter, and a blown fuse would have meant no readings at all at the meter, but checking the fuses is just good practice and I should have thought about it.

And I hadn't thought about the ACR either. That's a good tip. I am not sure just how to check if it is OK but it sounds like a good project for a quiet day to find out.

More importantly, I think I now have the answer to my original question: whether there is some well-known problem with the solar system on the C-28 that a few people have encountered. Sounds very much like there isn't -- which is the good news. I suspect I just have a unique problem somewhere and now I need to try to isolate it without getting too aggravated -- that will be the real challenge.

Thanks,

Graeme
 
You must log in or register to reply here.

  • Tugnuts.com is the community hub for Ranger Tug, Cutwater, and Solara owners. Since its inception in 2008, the Tugnuts forum has grown into an active and thriving community of more than 9,000 members. It serves as both a meeting place for the best boating community online, and an invaluable archive of information.

  • User menu
Back
Top