weird house boat problem

[oops!]

hi all tekkies !

just visiting form the dry dock.

i am repairing all systems on a 50 foot house boat.

we have a bank of 4 new lead acid marine deep cycle 12v batterys......a start battery. and an inverter. (sorry, we dont know the name or type.....someone painted the thing and we cant see anything on the inside that tells us the mfgr or model. but it is industrial looking, 8 inches wide, 8 inches deep by 20 inches long).
we have an isolator between the start and house batts.

the problem is , that after full charge on the batts. i can only run a little 110v for a few hours.......and then, when the inverter shuts off due to lack of juice...i only have an hour of 12v.

i am only using a car radio (not loud at all) , one 110v 4 foot florescent light bar (2 lamps) and a squirrel cage heater fan (that i believe is 12 v) and the house water pump (12v sure flo).
i only get a few hours !

obviously the boat has many other systems. but these are the only ones i run.......(i take power form the genny for tools).

ill run the genny, supplying shore power, then after charging between 14 and 12.8 v for 6-8 hours...then shut the genny off. go to house power (inverter) turn the above on.....and its dead in just a few hours !
if i turn on the microwave or fridge.....bring a flash light !

this is a house boat and should be able to run for a long while between charges.

oh.....the boat also has a large solar panel for charging the 12v batts (set to charge the house batts)

any common problems i should be looking for or any basic checking i should be doing?

thanks all.....
cheers
oops

 

[bruceb58]

Re: weird house boat problem

What is the battery voltage after you end charging?(You need to put a tiny load for a few minutes to get rid of the surface charge) Should be reading 12.6V. Doesn't sound like you are charging them fully if you are only charging them for 6 hours. For example, if you have 4 70amp/hr batterries that are 50% discharged and you are charging them with one 10A charger, it is going to take over 18 hours to charge them. Generators typically don't put out a lot of DC current. How are you actually charging these? Is the generator powering a charger?

What is the battery voltage after the inverter turns itself off?

What is the current draw off of the battery bank? Are all these batteries in parallel?

Also, an isolator is keeping your batteries from getting fully charged if its a diode based isolator.

 

[Don S]

Re: weird house boat problem

Start by charging, then load testing each battery individually to find if one is bad.
It only takes 1 bad battery to drain them all, and yes a new battery can be bad.

 

[bruceb58]

Re: weird house boat problem

For house battery banks, I would normally prefer to use a couple large 6 Volt Trojan batteries in series. Or if you need more capacity, 4 of the 6 volt Trojan batteries. 2 would be in series in parallel with another 2 that are in series.

 

[oops!]

Re: weird house boat problem

i charge them for 6 hours EVERY DAY....thats why its so weird.

the voltage is reading 12.3 ish after shutting the genny off, and bleeding some power.

when the inverter shuts down, its at 4 v.

the solar charger has an indicator that tells how much reserve is in the batts, and most of the time i am reading full. after charge. (this depends on if i stay an hour or two on the boat after work, or just shut off the genny and go home) if it reads full....i have just slightly more time than i would with 3/4 or half reserve.

the batts are all tied together pos to pos. neg to neg.

 

[oops!]

Re: weird house boat problem

Start by charging, then load testing each battery individually to find if one is bad.
It only takes 1 bad battery to drain them all, and yes a new battery can be bad.

ill bring the load tester out next time and do each of the five total don

 

[bruceb58]

Re: weird house boat problem

At 12.3V your battery is around 60% charged. By discharging them down to 4V you are killing them. Never discharge a battery past its 50% point which is around 12V.

When you eventually find these batteries are not going to be good enough for your application, get a couple t-105 Trojans.
http://www.trojanbattery.com/Products/Marine-RV.aspx

 

[oops!]

Re: weird house boat problem

yeah....that is the problem. the inverter just shuts off then.....unless you are standing there watching it....you have no idea its athat low....if the owner rents the boat,.....the renter wont know to look for 4v and worse off.....they will complain about no juice after the first night.

is there any links to a 6v multiple batt diagramme?

 

[bruceb58]

Re: weird house boat problem

How many square foot solar panel do you have? Realize that every square foot of panel may only be 8 watts. Which means 2' x 4' panel is only 64 Watts and going to be slightly less that 4A/hour charging. Since you are in BC, you are probably only getting a couple hours of equivalent full sun a day assuming the panels are angled properly. If they are just flat, even less.

 

[bruceb58]

Re: weird house boat problem

there any links to a 6v multiple batt diagramme?

 

[Don S]

Re: weird house boat problem

I'm with Bruce on the the fact that the batteries are not getting charged if you only see 12.3V..

The other thing is, an inverter is NOT designed for renters, owners have problems with running them. Renters use them like a generator and don't usually have a clue why it works. Many will actually turn on the inverter and the battery charger and expect the battery to charge. Disconnect it. If they want AC power, use the Generator.

 

[bruceb58]

Re: weird house boat problem

Read this article:
http://rvroadtrip.us/library/12v_system.php

 

[oops!]

Re: weird house boat problem

Read this article:
http://rvroadtrip.us/library/12v_system.php

great article.im still reading.

 

[oops!]

Re: weird house boat problem

I'm with Bruce on the the fact that the batteries are not getting charged if you only see 12.3V..

The other thing is, an inverter is NOT designed for renters, owners have problems with running them. Renters use them like a generator and don't usually have a clue why it works. Many will actually turn on the inverter and the battery charger and expect the battery to charge. Disconnect it. If they want AC power, use the Generator.

with this information, it looks like im going to have to a a re design.

.the fridge is set up for 110v (inverter) it is also propane.....if the propane side works....ill have to add some carbon monoxide dectors.
but i think im going to suggest a 6 v system....if i can get him to spring for some more new batts.

 

[bruceb58]

Re: weird house boat problem

Running a fridge on an inverter is bad news. Batteries will not last long at all. Should always be run on propane and switch to 110V only when 110V shore power is hooked up.

The houseboat electrical should be setup like an RV.

If the isolater is a diode based you need to ditch it and get an ACR set up so you don't have the charging loss.

One thing I would always install is a digital panel meter with a pushbutton to turn it on to allow the battery voltage to be monitored while being used. This way, you can have an idea of when you are getting down to that 50% discharge point(12.0V) so you don't discharge too far. It can also be used to make sure you are getting a good charge voltage. This is a standard item in RVs.

 

[oops!]

Re: weird house boat problem

the 4x2 solar panel has a read out that tells the condition of the batts and voltage....it is not uncommon to see between 8 and 11 volts.

fyi....the panel is on a angle at the front of the boat

here you can see it above the front patio doors below the upper command bridge.

and a side shot

i will see if i can get the owner to ditch the isolator.....we have no idea about it, as it came with the boat. but i think its a diode

 

[bruceb58]

Re: weird house boat problem

the 4x2 solar panel has a read out that tells the condition of the batts and voltage....it is not uncommon to see between 8 and 11 volts.

fyi....the panel is on a angle at the front of the boat

here you can see it above the front patio doors below the upper command bridge.

Lucky guess on my part that it was a 4x2 panel. Angle is good only if the panel is facing south. If it isn't, you aren't going to get full affect...not that you have control of this if the boat swings on the mooring..

 

[Grandad]

Re: weird house boat problem

i am only using a car radio (not loud at all) , one 110v 4 foot florescent light bar (2 lamps) and a squirrel cage heater fan (that i believe is 12 v) and the house water pump (12v sure flo). i only get a few hours !
oops

Hi oops,
I can't add much to what others with more marine experience than myself have already said, but I am wondering just how much current is being drawn by the squirrel cage heater fan. If this appliance uses 12 volt resistance elements, the current draw could be substantial. What is the wattage/current rating of the unit? I'm not suggesting that's the cause of your problem, but perhaps a significant contributor. - Grandad

 

[PS94]

Re: weird house boat problem

is there a diode on the solar panels? If there's no diode, and they're not charging, then they're dis-charging. My motorhome would die overnight with a bad solar panel diode.

 

[bruceb58]

Re: weird house boat problem

is there a diode on the solar panels? If there's no diode, and they're not charging, then they're dis-charging. My motorhome would die overnight with a bad solar panel diode.

The solar panel likely has a controller. The only panels that rely on diodes are those little cheap ones that barely put out any power.