Battery charger always on?

[paulga]

The boat has 7 agm house batteries that look like below




The boat is connected to the pedestal. I have been leaving the charger always on. The charger gauge always has a positive reading when I checked. Is there risk of overcharging/gassing?

 

[O C Diver]

Do you have any draws that explain the charger staying on? As an example, things that are instant on, ofter have power draw even when off. Multi function displays that aren't turned off with a circuit breaker, often draw power. A refrigerator with an electronic thermostat, constantly draws power. TVs and computers with instant on, consistently draw power. An inverter / battery charger constantly draws power.

Not saying there aren't other issues, but first you need to know how much power is being used by things you think are off.

Ted

 

[Xlantic]

Most newer charger are "intelligent" and will go through a bulk-absorption-float charging cycle. When they get to "float" they can remain at that level indefinitely.

You need to confirm that your charger does this. The manual will say it.

If so, you can leave it on all the time.

But you should see what that almost 10A reading is ...

 

[High Wire]

And check the voltage at each battery’s terminals. Above the battery manufacturers specified float voltage may cause damage. Odessey AGM specification is 13.6V floating.
This is a good reason to have a DC clamp-on ammeter on board a cruiser because we use parallel batteries in banks. You could detect current going into one battery (possibly going bad) but not the others.

 

[Comodave]

Also your battery terminals should have a non conductive cover on them. If you drop a tool across the terminals it will get your attention very quickly. Ask me how I know. I had the covers off to work on the cables and dropped a wrench across the terminals. It left a metal dust from what used to be the wrench. Now when working I lay a cloth over the terminals and try to use a rubber coated wrench.

 

[paulga]

Do you have any draws that explain the charger staying on? As an example, things that are instant on, ofter have power draw even when off. Multi function displays that aren't turned off with a circuit breaker, often draw power. A refrigerator with an electronic thermostat, constantly draws power. TVs and computers with instant on, consistently draw power. An inverter / battery charger constantly draws power.

Not saying there aren't other issues, but first you need to know how much power is being used by things you think are off.

Ted

the lights e.g. er lights are on when I check the reading on the battery charger. these lights use DC power from the battery.

fresh water pump, bilge/sump pumps are also instant on appliances. in addition one DC outlet was also draws powers

fridge/tv/computers/other battery chargers are connected to ac outlets.
inverter/mfd are off

 

[paulga]

thanks for highlighting this. the surveyor also recommended a rubber booty on battery terminals.

is metal dust kind of an image of wrench printed by the high dc current?

Also your battery terminals should have a non conductive cover on them. If you drop a tool across the terminals it will get your attention very quickly. Ask me how I know. I had the covers off to work on the cables and dropped a wrench across the terminals. It left a metal dust from what used to be the wrench. Now when working I lay a cloth over the terminals and try to use a rubber coated wrench.

 

[High Wire]

Do you remember the first War of the Worlds?

 

[paulga]

Do you remember the first War of the Worlds?

No. I don't remember the second either.
How is the battery charger related to the war?

 

[Bacchus]

Above are good suggestions...
Do you have a CO detector? They are notorious draw that mfg typically wire as always on... similar to auto bilge pumps except that have a constant draw.
My bilge lights alone were close to 20A draw before switching them all to LED.

Clamp on DC ammeter is a great tool to diagnose & troubleshoot.

 

[C lectric]

Get and install some terminal covers. All it would take for a catastrophe is to drop a wrench, or any piece of metal that bridge the positive and negative battery posts.

The battery itself could actually explode covering you with stuff you do NOT want to be covered with.

I too have had it happen. I got lucky, my glasses were in place and the short was over quickly since the wrench did not make full contact with the posts but it still blew out part of the battery side.

It was enough to cover my face.

Don't discount the dangers that batteries , not treated properly, can present.

 

[BruceK]

I think this is the Manual for your charger:
https://www.charlesindustries.com/wp-content/uploads/2021/04/LT-5000SP-1.pdf
Yours looks more like an old type ferro resonant charger which excel at frying batteries when left on permanently but, that`s at odds with the Manual.
If it`s showing 10A charge all the time, it`s never reaching float. Could be something drawing constantly, or a battery issue. You can buy an inexpensive electronic battery tester on ebay.

 

[High Wire]

No. I don't remember the second either.
How is the battery charger related to the war?

The Martian ships would fire their weapons and turn their targets into smoking dust outlines.

 

[paulga]

I think this is the Manual for your charger:
https://www.charlesindustries.com/wp-content/uploads/2021/04/LT-5000SP-1.pdf
Yours looks more like an old type ferro resonant charger which excel at frying batteries when left on permanently but, that`s at odds with the Manual.
If it`s showing 10A charge all the time, it`s never reaching float. Could be something drawing constantly, or a battery issue. You can buy an inexpensive electronic battery tester on ebay.

disconnect the negative post then use this tester to read voltage. if the volt is lower than 13.6 then it needs to be replaced?

I have a fluke 117, does it also work in place of the tester?

 

[paulga]

The Martian ships would fire their weapons and turn their targets into smoking dust outlines.

batteries are one of their ammunitions?
I plan to get some rubber butties, I just have not got there yet.
the batteries are installed inside a hard plastic container with a lid straped on top. the closed container insulated the battery all the time.

 

[BruceK]

disconnect the negative post then use this tester to read voltage. if the volt is lower than 13.6 then it needs to be replaced?

I have a fluke 117, does it also work in place of the tester?

That`s the kind of tester I had in mind but "full" indication for 12v batts is 12.6 or above, was 13 a typo for 12? Mine tests more than voltage,by applying a load test.

 

[paulga]

That`s the kind of tester I had in mind but "full" indication for 12v batts is 12.6 or above, was 13 a typo for 12? Mine tests more than voltage,by applying a load test.

the battery volt is 13.6v. see below - from Nigel's version 4 P176

 

[BruceK]

the battery volt is 13.6v. see below - from Nigel's version 4 P176

View attachment 146614

I would not regard a battery that does not hold 13.6V as defective. The charger can keep batteries around that voltage,it usually does, but 12.6 and above is regarded as "full". It`s preferable to test a battery a while after it`s been taken off the charger. I think you are conflating 2 separate matters.

 

[paulga]

its mainly the er lights drawing power. turning them off cuts the batt charger reading half to 5a. in addition turning off stove and dc outlet breakers (cigarette lighter for usb), the reading is still 5a.

is it the best practice to leave the batt charger on ?

I think this is the Manual for your charger:
https://www.charlesindustries.com/wp-content/uploads/2021/04/LT-5000SP-1.pdf
Yours looks more like an old type ferro resonant charger which excel at frying batteries when left on permanently but, that`s at odds with the Manual.
If it`s showing 10A charge all the time, it`s never reaching float. Could be something drawing constantly, or a battery issue. You can buy an inexpensive electronic battery tester on ebay.

 

[BruceK]

It`s best practice to leave it on but with no draw it should go to float and at 5A no matter what, seems it`s not doing that. Without knowing your total battery amps it`s unclear, but if you had 500A capacity and 5A charge that`s 1% of capacity, which might be normal maintenance charge. Hopefully one of the electrical gurus gets involved.
When my charger was doing more than I expected of it, I found the bowthruster battery and the genset battery, both fed off the 2 main 8Ds, needed replacing. After that the charger was putting out less,3 days ago when we went onboard it was asleep, but we do have a modest 160watts of poorly placed aging panels. I suggest checking the batts. How old are they? It`s complicated by living on board, there have to be loads occurring.

 

[Bacchus]

In order to get accurate V readings as an indicator of SOC the batty needs to be disconnected or be sure no charge or discharge for several hours. During that time the surface charge (charging V) will decline slowly to the SOC voltage.
IMO If not a modern multi stage charger that drops back to a float V recommended by the batty mfg, it's not a good idea to leave it connected 24/7.
Most modern chargers have several charging profiles and some are capable of custom settings, to match different batty chemistries and mfg recommendations.

 

[Portage_Bay]

OP is asking if he should leave his charger on full time. Lots of good advice and suggestions here. However many of his other threads indicate he is a full time liveaboard. If that is the case IMO it is best to leave the charger on full time. There will almost always be some load on the house bank. Rarely will there be times when there is no load and those times should be brief.

 

[SteveK]

That charger has a selector switch for lead acid, gel & AGM. The picture of the battery an Odyssey, says AGM. Do you have the selector set to AGM.

I wonder why the manual says;
Note: If using Odyssey batteries, the switch should be set for LEAD ACID.

 

[BBS]

I have the same AGM batts in my boat...believe the are 102 AH each. Looking at the picture, I can't tell the install date, but each battery has a mfg. date code on it. I believe that model replaced the PC-2150 model, so they are more than likely only a few years old.....

 

[paulga]

That charger has a selector switch for lead acid, gel & AGM. The picture of the battery an Odyssey, says AGM. Do you have the selector set to AGM.

I wonder why the manual says;
Note: If using Odyssey batteries, the switch should be set for LEAD ACID.

havn't checked.
the battery is odyssey AGM battery, why should it set for lead acid rather than agm?

 

[paulga]

OP is asking if he should leave his charger on full time. Lots of good advice and suggestions here. However many of his other threads indicate he is a full time liveaboard. If that is the case IMO it is best to leave the charger on full time. There will almost always be some load on the house bank. Rarely will there be times when there is no load and those times should be brief.

if the boat stays in water all year round, and I only visit her twice a month. what's the best way to use the batt charger?

 

[BruceK]

havn't checked.
the battery is odyssey AGM battery, why should it set for lead acid rather than agm?

The float charge is higher(13.6) for LA than AGM (13.4). Maybe it`s an Odyssey requirement. You could search Odyssey to see what is specified. But, Charles, a venerable charger mfr, seem very clear about, so don`t dismiss it. Could be relevant, wonder if the constant 5A output is related, depends how it is set now.
Well spotted SteveK. Where is that switch, back of the charger box which screws to a bulkhead or to one side?

 

[SteveK]

The bulk volt is also higher at the LA setting. Another note the charger comes preset for Gel.
As Bruce said maybe the charger manufactorer knows something. Why else would their manual tell you to do it their way.
The selector switch appears to be at the back against the wall it is mounted to.

 

[ranger58sb]

havn't checked.
the battery is odyssey AGM battery, why should it set for lead acid rather than agm?

The charger settings are just shorthand, to cover several likely possibilities. Newer chargers offer many more settings, and on some you can also specify exact voltages -- without regard to the pre-sets.

Check the Odyssey manual for their recommended voltages.

Then check your charger manual to see what setting gives you what voltages.

Chose the charger setting that comes closest to battery maker's recommendations. Probably give precedence to float voltage choices, given that's the one that can often boil batteries over time.

-Chris

 

[sunchaser]

AGMs are lead acid batteries, but not a FLA plate design. As noted by others, Odysseys are not quite the same AGM internal design as say a Lifeline thus the requirement for a different switch setting on the charger.

Does the vessel in question have an inverter charger as well. If so and the inverter is off the pass through itself will consume amps.

Lastly and pardon my ignorance, isn't the amp reading on the Charles 12 volt? If so a weak or dead cell on a battery could require more charge amps than a fresh battery. Some testing around the circuit has been suggested and should reveal an issue or two.