New Batteries won't fully charge

06Rinker270

Been two weeks since I was at boat, noticed when I left before I was getting a slow blink which means they are at low charge.  Batteries are new from April 2015.  I have been on shore power the entire time.  Battery charger breaker is on.  I am at 120 AC volts.  What is the proper steps to take to find out if it's the batteries or the charger?

The meter rest at 0 DC AMPERS.  Does it only read when something is pulling?

thank you 

frenchship

Best way is to use a hydrometer and check the specific gravity of each cells, this will tell you exactly the condition of the battery's 

frenchship

Your 13volts is it with the charger on or off. A fully charge battery at rest after being charge should be around 12.7~12.8 volts 

Handymans342

Try turning off the charger then back on and see what happens on the meter. 

06Rinker270

I will try a hydrometer.  Excuse my ignorance, same thing you use as a Brewer?

13 volts is on shore power.  I'll see what it reads when I disconnect.

I shut off the breaker for the battery charger and turned back on, same thing.

MarkB

Are you running a load off batteries. If you are and the charger isn't showing any amps I'd be suspect of the charger.  However, having said that 95% of the time it's the battery.

frenchship

Similar to the one used by the Brewer as it measure the specific gravity of battery electrolytes
 But do used one for battries (acid) the are available at any auto stores and follow the instructions. Do not take a measurement when the battery is just out of the charger or with the charger on you will get a false reading let the battery rest for a few hours before using it

06Rinker270

@MarkB At shore power I have the fridge on and that's it.  Is this what you mean?

When I turn on the blower I see the meter go up to 5.  Guessing it shows only when the DC is at load.  Is this correct?

@frenchship is this right?



How can batteries be bad after 6 months? 

frenchship

You have the right tool. Check each cell and note the reading the should be all in the green section with not much difference. Be careful it is an acid and can damage clothing and other materials. As far as batteries being bad after 6 months it is rare. By the way did you check the level of electrolyte in each cell. The level is important if too low and below the plates it will damage the battery. 

212rowboat

standing charge is 12.7 on healthy batteries, unassisted... 

full voltage charge on a battery that's lost some juice is 14.5vdc on lead acid, but as high as 15.5vdc on gels/glass... 

here is where it gets tricky:  smart chargers will sense the standing charge and adjust what it sends to it... a lead acid battery only needs 13vdc to maintain charge, 13.5vdc is most common, though- depending on how smart it is...  

I don't think you have a problem, man. 

MarkB

The fridge switches to 110V automatically when on shore power so no load on the batteries. 

If the charger is pushing out 5 amps when the blower is on then I'm pretty sure it is working.

What is your voltage without the shore power on?

Dream_Inn

You definitely do not have any problems.  What you are stating seems consistent with what I have seen with the same charger (I now have a different charger, but still have that one on my thruster battery).

06Rinker270

Thank you guys.

When I disconnect batteries next Tuesday I will test them with hydrometer and check electrolytes level.  

At beginning of season the charger showed full power(fast blink).  What would cause it to not show that anymore if all is ok?  

I disconnected from shore power and I was at 12.8.  Opened and closed the engine hatch and ran the blower for 4 minutes.  I am at 12.1-12.2.

Took two cranks(maybe because it dropped to below 40F last night?),started engine and ran now I am at 13.6 - 13.8 with engine on.

Turned off engine, not connected to shore power let sit for 50 minutes with only the fridge pulling and it dropped to 12.5.  Immediately after I shut off engine it was 12.9 for 15-20 minutes.

06Rinker270

Is it possible I am leaving the battery switch on the wrong battery?  I leave it on #1 which I believe is the engine/crank.  Maybe do #2?  Does the charger trickle to both batteries to keep them charged?

MarkB

The charger should not be wired through the switch. It should charge no matter what.