Using battery charger as a power supply

Refueler said:
Nowhere does he say the charger is not keeping up ....
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Forgive me.

OP says that he is rarely in a marina. It is I who added the statement that 5A won't keep up with the fridge.

I think my dumb charger (which I used for some months in this way) may only put 3A, not 5A, so OP may have a little more headroom than I, but not much. A single LED bulb draws 2W or 3W - I'm drawing 11W right now and the boat is quite dimly lit.

Refueler said:
But anyway ... all this forgets the fact that OP is drawing power from the batterys while charger is connected .... seems people are intent on ignoring that important fact ...
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And surely all the devices will pull down the voltage so there's no risk of high voltage damaging the battery?
 
noelex said:
I have one of these chargers (the 24v 8A version) and they are very good for not much money. Completely user adjustable so you can select the right parameters, which is especially important if you are planning to leave the boat for long periods with no load. They are reasonably waterproof, double insulated (so do not require an earth connection ), have a Bluetooth interface and will put out their full rated power continuously, unlike some other chargers.

They do have some shortcomings. They will not operate on 110v AC and cannot act as a power supply. Mastervolt and others offer similar chargers with these facilities, but the user adjustability and the interface is not as good as the Victron product.

There is no doubt that a charger like this would be kinder on the batteries than simple dumb 5A charger. However, is it worth the extra cost?

We need some more answers, such as voltages seen under use, before being able to answer that definitively, but I suspect given the limited information in the original post the extra battery life achieved would not be enormously greater.
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Couple of errors in there, but otherwise OK

They do make a 120v model and it can act as a power supply.
 
PaulRainbow said:
Couple of errors in there, but otherwise OK

They do make a 120v model and it can act as a power supply.
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Sure, but if you buy the 230v version, as most UK owners will do, it will not work on 120v. It will also not work as a power supply. If you buy the 120v version it will not work on 230v.

Alternative products from other companies will work on all voltages worldwide: 120v and 230v on both 50hz and 60hz. This is discinct advantage when traveling to different countries. Some will also work as a power supply independent of the input voltage.

Despite these drawbacks the Victron chargers linked above are excellent. Their user adjustability is exceptional, as is their Bluetooth interface, but their advantages and drawbacks need to be considered when contemplating purchase.
 
noelex said:
Sure, but if you buy the 230v version, as most UK owners will do, it will not work on 120v. If you cruise further afield it will also not work as a power supply. If you buy the 120v version it will not work on 230v.
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They do act as power supplies.
noelex said:
Alternative products from other companies will work on all voltages worldwide: 120v and 230v on both 50hz and 60hz. This is discinct advantage when traveling to different countries. Some will also work as a power supply independent of the input voltage.

Despite these drawbacks the Victron chargers linked above are excellent. Their user adjustability is exceptional, as is their Bluetooth interface, but their advantages and drawbacks need to be considered when contemplating purchase.
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PaulRainbow said:
They do act as power supplies.
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I have checked the specifications and you are right they will act as power supply (y)

The voltage input restriction is unfortunately true. The very small 1.1 A version will operate on USA voltages, but otherwise you will need to purchase another charger if you need a 110-120v input.
 
Many thanks for all of your replies. I use a small CTek 5 amp charger because that's all I have. I reckoned that if the fridge takes 4 to 5 amps intermittently, then 5 would be good enough to keep the battery topped up. But I don't understand how modern battery chargers are programmed so just wanted to check some opinions.

One precaution I take is not to turn any electronics on when using the charger in case it is in a high voltage mode. In practice, it tends to sit at 14v trickle charge all the time. I haven't noticed any excessive heating of the charger, the batteries or excessive gassing. So, I think I'll continue this on the odd occasions I visit marinas. 👍😊
 
Oily Rag said:
Many thanks for all of your replies. I use a small CTek 5 amp charger because that's all I have. I reckoned that if the fridge takes 4 to 5 amps intermittently, then 5 would be good enough to keep the battery topped up. But I don't understand how modern battery chargers are programmed so just wanted to check some opinions.

One precaution I take is not to turn any electronics on when using the charger in case it is in a high voltage mode. In practice, it tends to sit at 14v trickle charge all the time. I haven't noticed any excessive heating of the charger, the batteries or excessive gassing. So, I think I'll continue this on the odd occasions I visit marinas. 👍😊
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Glad to read that common sense prevails .....

(y)(y)(y)(y)(y)(y)(y)
 
Refueler said:
OK .. but doesn't really change the gist of his question and some of the replies.
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Not wishing to start an argument, but he said...

"a small 5 amp battery charger connected just using crocodile clips as I would do if charging the battery on a bench at home"

That does sound like an old style automotive type charger, which could prompt people to suggest a better charger.

"I use a small CTek 5 amp charger" is a different beast altogether, no need for a change.
 
PaulRainbow said:
Not wishing to start an argument, but he said...

"a small 5 amp battery charger connected just using crocodile clips as I would do if charging the battery on a bench at home"

That does sound like an old style automotive type charger, which could prompt people to suggest a better charger.

"I use a small CTek 5 amp charger" is a different beast altogether, no need for a change.
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Quite!
 
Apologies. I should have been clearer. Back on a swinging mooring now! (And solar panel just about keeping up with the fridge during daytime.)
 
Refueler said:
OK .. but doesn't really change the gist of his question and some of the replies.
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Too many people with an opinion! I have qualifications in electronics and electrics and agree with you.
My battery has been on charge for 3 years now!! Use for lighting and water pump.
 
Paulg25 said:
Too many people with an opinion! I have qualifications in electronics and electrics and agree with you.
My battery has been on charge for 3 years now!! Use for lighting and water pump.
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Same here, cheap charger off Amazon, have left it on for several days at a time sometimes with car radio on, have not noticed any difference in the voltage it can hold (12.8). Not that it matters but the previous owner had wired a cockpit hookup straight to the battery, assuming he did the same, granted no high consumers except a cigarette lighter.
 
Oily Rag said:
Apologies. I should have been clearer. Back on a swinging mooring now! (And solar panel just about keeping up with the fridge during daytime.)
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Don't worry we all are guilty of not supplying enough data - we often simply don't know what is important or not. If we knew it all ...... we would not start a new thread :)

Jonathan
 
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