Okay to charge batteries while connected?

[ejbpesca]

Is there a problem to charge my 12v batteries with a portable charger while the batteries are still connected to the system? Okay to just put charger clips to battery posts pos/neg and charge away? I have AGM batteries, a new smart charger, battery switch 1-2- Both - OFF.

Should I set switch to OFF before charging? The shore power charger is old and will fry the batteries so I must use a portable till I get it replaced.

And, is there a way to connect the charger so both batteries charge at one time or since they are wired to be one battery at times (both) will the current from charger flow to both anyway no matter where the battery switch is positioned?

Please advise and thank you.

 

[northern]

If in engine room. Spark=Boom if gas vapour there. Best to turn every thing off then when all connected energize the system.

 

[boatman37]

i have a smart charger connected to mine that i leave connected using the clamps. i leave the switch on 'both' while docked but i have an isolator so my understanding is it will charge both batteries no matter where the switch is. my charger until sits above deck under my rear bench seat with the cables running down behind the engine hatch. i hope to have a permanent, hard-wired charger before we drop it back in the water this spring

 

[War Eagle]

Your best bet in the near term is to turn the battery switch to off and charge them one at a time. There is a way to charge them together but requires some hardware and often results in not fully charging either. Longer term, install a proper marine charger for your system ASAP.

 

[BlueYonder]

Is this portable charger marine UL listed? If not, you could be setting yourself up for a dangerous situation with the AC Ground and neutral wires being tied together. There is also a potential for an explosion if the charger is placed in the same compartment as a gasoline motor. This article from Pbase is worth reading.

NO, NO, NO, NO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!​

Okay how do I put this politely with regard to using automotive or non-marine UL chargers on boats? Oh yeah I know..... NO !!!!!!!!!!!!!!!!


Still not getting it? Okay.......


#1 Car chargers when used on boats can be one of the worst offenders & cause of stray current corrosion due to their internal architecture which very often does not isolate AC & DC sides like a UL Marine charger will. So this = NO !!


#2 Most of the car/auto type battery chargers use what is often referred to as an "autoformer" or autotransfomer. These are transformers with just one winding. Cheap, dirty and they can work ON LAND. Because of this single winding they share a common internally. Portions of the same winding act as both the primary and the secondary. This is bad news and not how a "marine" charger is built. With a marine charger all AC source current runs through the AC hot wire of the charger and is fully returned to shore via the white/neutral wire. The "case" is also grounded to the ships DC ground just in case it becomes energized in an internal fault. Again this = a big NO !!!! DO NOT USE AN AUTOMOTIVE CHARGE ON A BOAT......


#3 If the "car charger" has a two prong plug, many do, especially the older ones we all seem to have lying around the house, these can inadvertently become reversed. This is especially true if your boat has old AC outlets.. Follow me here, if the AC feed neutral & hot are reversed the ships DC negative bus can now become 120V AC with a "car charger"... This is what Mr. Konz observed in my statements in the last photo. You don't want to be a swimmer near a boat with a cheap car charger on-board, trust me. You also do not want to be the cause of an Electric Shock Drowning or ESD.. So again this = a BIG NO!!!!!!!


PLEASE, PLEASE, PLEASE use a proper marine UL charger not a cheap Wal*Mart type automotive charger..

 

[ejbpesca]

If in engine room. Spark=Boom if gas vapour there. Best to turn every thing off then when all connected energize the system.

Okay..my plan is to use this charger by 1st use blowers to clear gases, everything off, boat is on trailer, connect, leave small section of hatch open to allow cables down, close large section to keep rain off engine, turn it on. Hoping that seems a safe plan till I can get boat to mechanic for some new gear (like a new smart shore power charger) and some DC repairs (cabin lights, 12v outlets, and cockpit lights not working) I think those are all on the same circuit.

 

[dpmulvey]

Not enough info. First question is WHY? What situation is there that precludes you from plugging into shore power. The absence of a 30 amp shore connection should not deter you. I used to use an adapter and plug my Regal into shore power via a 120VAC 30 amp to 120VAC 15 amp adapter. Boat was in the driveway. All connections were in the garage. 30 amp cord went under the garage door. Worked like a champ. If you have the ability to plug in a car charger, you have the ability to plug in an adapter cord. Far easier and safer IMHO.

 

[ejbpesca]

Not enough info. First question is WHY? What situation is there that precludes you from plugging into shore power. The absence of a 30 amp shore connection should not deter you. I used to use an adapter and plug my Regal into shore power via a 120VAC 30 amp to 120VAC 15 amp adapter. Boat was in the driveway. All connections were in the garage. 30 amp cord went under the garage door. Worked like a champ. If you have the ability to plug in a car charger, you have the ability to plug in an adapter cord. Far easier and safer IMHO.

''

The why is this: My onboard charger/shore power is the wrong type for the new batteries I have and will fry them..and it is very old. Until I can get the boat to have the new shore power unit installed..a smart modern shore power charger, I need to keep the batteries up to be able to get the boat ready to haul. It is a temporary thing. At present I have two fried batteries and a messed up shore power charger. New batteries will be here tomorrow for installation by my brother's help, but I won't have him do the shore power charger installation..let mechanic do that. I can't get down,nor can brother, in the engine compartment to wire it all up and mount it..orthopedic problems...but I can clip on two leads from the portable charger after a friend installs the batteries for me. That's the why.

Oh..the mechanic is 50 miles away and I must get boat to him and it is not going anywhere till 12v system is up and running to adjust outdrive, pump out water system, pump in anti freeze to it..all done at home then haul to mechanic. Yep..a mess. Just trying not to fry anything else.

 

[ejbpesca]

Yep..like you I would have asked "why." I did attempt to charge the batts from the current bad charger and fried them.

 

[northern]

As much as we dislike codes and satandards there is a reason, to keep things safe and you alive. Sounds like you need to consult a real electritian who can help you do what you need doing. Gas vapours and gases of batteries are explosive. Venting gets rid of them but does not prevent them form coming back thus the need for explotion proof engine room equipment.

 

[ejbpesca]

As much as we dislike codes and satandards there is a reason, to keep things safe and you alive. Sounds like you need to consult a real electritian who can help you do what you need doing. Gas vapours and gases of batteries are explosive. Venting gets rid of them but does not prevent them form coming back thus the need for explotion proof engine room equipment.

I understand and will take every precaution to not allow gases to form and not create spark for this temporary battery charging. With all advice I've gotten I feel pretty confident this will work until the permanent mounted charger can be installed. I would have been much better if boat designers had placed batteries up and away from engine compartment. This is one over several boats I've owned that dealing with the batteries is one big hassle because of how difficult it is just to access them. I've got a plan now and thank you all for advice. Tomorrow is hopefully new battery installation day to bring the boat alive again.

 

[trflgrl]

Question: how soon do you plan to winterize/pump antifreeze through everything? On the assumption you're going to do it soon, fresh batteries shouldn't discharge quickly enough for you to need to leave them on a charger for an extended period of time.

A thought: leave the new batteries disconnected until the day you plan to winterize/adjust the engines to transport it. When you're ready, vent the engine hatch(es) for a long period to allow any gases to dissipate, connect the batteries, then do the necessary work. Disconnect the batteries again to transport. When the shop/marine electrician installs a new charger, the batteries should still be in good shape to take a charge.

My boat was on land for three weeks recently for major maintenance, and we had a similar need to move the drives periodically and do a couple of other things. Although we turned off all battery selector switches, helm breakers, and cabin breakers, there was still a draw on the batteries so we disconnected them entirely. (We haven't traced our wiring to figure out what might have been pulling current, aside from the integrated CO monitor.) Each time we were ready to test the fixes, we reconnected the batteries--which are more than two years old, but did just fine with this method.

Not an electrician, not certified in anything, just hoping there's a safer way for you to handle your situation than using a charger that may not be well suited for this environment.

 

[ejbpesca]

Is this portable charger marine UL listed? If not, you could be setting yourself up for a dangerous situation with the AC Ground and neutral wires being tied together. There is also a potential for an explosion if the charger is placed in the same compartment as a gasoline motor. This article from Pbase is worth reading.

NO, NO, NO, NO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!​

Okay how do I put this politely with regard to using automotive or non-marine UL chargers on boats? Oh yeah I know..... NO !!!!!!!!!!!!!!!!


Still not getting it? Okay.......


#1 Car chargers when used on boats can be one of the worst offenders & cause of stray current corrosion due to their internal architecture which very often does not isolate AC & DC sides like a UL Marine charger will. So this = NO !!


#2 Most of the car/auto type battery chargers use what is often referred to as an "autoformer" or autotransfomer. These are transformers with just one winding. Cheap, dirty and they can work ON LAND. Because of this single winding they share a common internally. Portions of the same winding act as both the primary and the secondary. This is bad news and not how a "marine" charger is built. With a marine charger all AC source current runs through the AC hot wire of the charger and is fully returned to shore via the white/neutral wire. The "case" is also grounded to the ships DC ground just in case it becomes energized in an internal fault. Again this = a big NO !!!! DO NOT USE AN AUTOMOTIVE CHARGE ON A BOAT......


#3 If the "car charger" has a two prong plug, many do, especially the older ones we all seem to have lying around the house, these can inadvertently become reversed. This is especially true if your boat has old AC outlets.. Follow me here, if the AC feed neutral & hot are reversed the ships DC negative bus can now become 120V AC with a "car charger"... This is what Mr. Konz observed in my statements in the last photo. You don't want to be a swimmer near a boat with a cheap car charger on-board, trust me. You also do not want to be the cause of an Electric Shock Drowning or ESD.. So again this = a BIG NO!!!!!!!


PLEASE, PLEASE, PLEASE use a proper marine UL charger not a cheap Wal*Mart type automotive charger..

Polite is appreciated. The portable charger will only be used on land, this is a one or two time use quick charge until the marine smart banked replacement charger can be installed by mechanic. It will be used twice maybe just to top off batteries. You think that current will cross over into the AC side of shore power circuitry? If that is true then would not any connected current source do the same?

 

[ejbpesca]

Your best bet in the near term is to turn the battery switch to off and charge them one at a time. There is a way to charge them together but requires some hardware and often results in not fully charging either. Longer term, install a proper marine charger for your system ASAP.

That is the very goal..proper charger, this is just temporary, will be used on land very little. It will be a couple months before boat heads to mechanic for maintenance and new charger so I'm looking for a temp solution. I guess I could maybe install the ProMariner new proper charger and just not mount it. (I have physical problems or would have the thing mounted and running by now, I have to depend on others to get stuff done.)

 

[ejbpesca]

Question: how soon do you plan to winterize/pump antifreeze through everything? On the assumption you're going to do it soon, fresh batteries shouldn't discharge quickly enough for you to need to leave them on a charger for an extended period of time.

A thought: leave the new batteries disconnected until the day you plan to winterize/adjust the engines to transport it. When you're ready, vent the engine hatch(es) for a long period to allow any gases to dissipate, connect the batteries, then do the necessary work. Disconnect the batteries again to transport. When the shop/marine electrician installs a new charger, the batteries should still be in good shape to take a charge.

My boat was on land for three weeks recently for major maintenance, and we had a similar need to move the drives periodically and do a couple of other things. Although we turned off all battery selector switches, helm breakers, and cabin breakers, there was still a draw on the batteries so we disconnected them entirely. (We haven't traced our wiring to figure out what might have been pulling current, aside from the integrated CO monitor.) Each time we were ready to test the fixes, we reconnected the batteries--which are more than two years old, but did just fine with this method.

Not an electrician, not certified in anything, just hoping there's a safer way for you to handle your situation than using a charger that may not be well suited for this environment.

Yes, I will winterize the plumbing system soon. I will not be leaving this non proper charger on the boat running continuously. I will only use it to top off the new batteries then maybe use it a couple of times to do the same. I am not using this as a permanent installation just a temporary deal to keep the batteries up. At least in my neck of the woods batts com not fully charged from retailers. They are way down and need to be charged. They lose charge sitting on shelves in the stores I guess. Stores here do not keep them charged up so that is goal no one..charge the new batteries. I will be very very careful with fumes, connections, but part of my problem is lack of mobility so just clipping on a gator clip..can do...connecting disconnecting..= 3 days in bed hurting. (I am getting second back surgery soon) I think it will be okay. I have done this hundreds of times with other boats but they had old style lead acid batteries (I am just now learning what an agm is) and were simple. This is my first boat with shore power and I'm trying not to fry anything. Already did fry two other agm batteries using proper shore power marine charger..because it was old style and was not a "smart" charger, I guess. It is going off boat for new one...see I have a charger but it is very old so this is why I got a smart car charger that claims to do agm batts okay..and it is just a temp fix till new ProMariner goes in..then boat will be either charged by engine or at dock with shore power...or run cable to it on land and use correct charger to bring batts up. What I mention here is very temporary and for me a way to charge for a short while without having to disconnect cables...that's why the question. I barely can get into engine compartment (health problems) and that is why I'm not installing the proper charger myself right now out in the driveway as I would have younger and in better shape.

 

[ejbpesca]

I wonder why one post went light gray instead of black and white?

 

[ejbpesca]

I wonder why your post went light gray?