Charging leisure batteries effectively

[tommyleyland]

After an hour it's down to 12.6, possibly because it wasn't charged enough from the alternator. Annoying stuff.

When I get the generator, do I connect it to the mains socket as you would from a hookup or do not all boats have a charging system from that?

[Paul C]

After an hour it's down to 12.6, possibly because it wasn't charged enough from the alternator. Annoying stuff.

When I get the generator, do I connect it to the mains socket as you would from a hookup or do not all boats have a charging system from that?

 

You're right - not all boats have a charger. You need to look at your own boat and know what it has, or hasn't. And how to make whatever it has, work. I guess this is a new boat to you - feel free to take a bunch of pics and post them on here and people can look at them and help.

 

Make/model of any equipment will really help too.

[tommyleyland]

 

You're right - not all boats have a charger. You need to look at your own boat and know what it has, or hasn't. And how to make whatever it has, work. I guess this is a new boat to you - feel free to take a bunch of pics and post them on here and people can look at them and help.

 

Make/model of any equipment will really help too.

 

It was constructed in 1976, not sure if that helps.

It's a bit dark for pictures, I presume I'm looking for some connection from the main hookup to a battery charger of some sort? I might try hooking it up with the generator and checking the voltage difference in the batteries.

It has a 12v port if the hook up doesn't work.

[Paul C]

A lot's happened in between 1976 and 2015!!! Its perfectly possible a battery charger has been retrofitted between then and now. I imagine the mains hook up has been retrofitted too, although I don't know the date of the first ever mains hookup etc.

 

A battery charger is typically a box, hopefully permanently mounted, in a reasonably (you'd hope) accessible area of the boat, with both a connection to the mains and a connection to the batteries.

 

Yes, hooking up a generator and accurately observing voltage will help - but its possible you have a battery charger which isn't working, or needs to be switched on somehow etc.

[Alan de Enfield]

 

It was constructed in 1976, not sure if that helps.

It's a bit dark for pictures, I presume I'm looking for some connection from the main hookup to a battery charger of some sort? I might try hooking it up with the generator and checking the voltage difference in the batteries.

It has a 12v port if the hook up doesn't work.

 

Don't bother with the generator 12v output. It will be a maximum of 8 amp which isn't worth bothering with. You will just be wasting petrol.

 

Find the boats battery charger ( hopefully it has one and hopefully its 30 amp +) and set it running.

[nicknorman]

It was constructed in 1976, not sure if that helps.

It's a bit dark for pictures, I presume I'm looking for some connection from the main hookup to a battery charger of some sort? I might try hooking it up with the generator and checking the voltage difference in the batteries.

It has a 12v port if the hook up doesn't work.

However, those "12v ports" typically only supply a small amount of current. If you are going to the bother of getting a generator, you should also get a decent charger else it will be not much use. If your boat was built in 1976 it probably didn't have a charger when built, but that is not to say someone didn't retrofit one.

[tommyleyland]

Found this little bugger hiding away. I presume this answers my question? http://imgur.com/oGJj8cQ

[nicknorman]

Found this little bugger hiding away. I presume this answers my question? http://imgur.com/oGJj8cQ

Well don't get too excited! That is rated at 11A but in reality will probably give less. It is not a marine charger, it's a car charger. It will work, but slooowwwwly. You really need a proper charger

[tommyleyland]

Are there any that are remotely affordable?

[Paul C]

Are there any that are remotely affordable?

 

Not dedicated marine ones. By that, I mean actually properly designed to last a long while in a marine environment. There's loads available which might be marketed as marine but in reality, aren't brilliant quality but do the job and have happy customers.

 

Have a look at (for example) Midland Chandlers, for an idea of the range of types and sizes (charger rating) and the features they have etc. For example you will see "3-stage charger", "4-stage charger" etc, various control of different battery types, various ratings etc etc

 

Oh, and their prices vary a lot too!!!!!

[tommyleyland]

Thanks I'll take a look. What amp do you think for two 110amp batteries?

Is this worth the bother? http://www.ebay.co.uk/ulk/itm/271499013884

[nicknorman]

Thanks I'll take a look. What amp do you think for two 110amp batteries?Is this worth the bother? http://www.ebay.co.uk/ulk/itm/271499013884

Firstly, what generator are you getting, since it has to have enough power to run the charger continuously?

 

There is no "right answer" for charger size. Some folk think that about 25% of the AH capacity is optimal (ie around 50A in your case). A 30A one will do the job but take longer (ie more fuel and noise).

 

The other thing to consider is, will you be happy with just 2 X 110AH batteries in the future? If you add another one or two, then 30A is getting pretty small. It's a toss up between minimising cost now, vs future proofing. Old adage "buy cheap, buy twice" is something to bear in mind. As to that particular model it is unbranded and so it's reliability cannot be known. Often with these cheap Chinese things they work OK, but occasionally they go on fire etc. It depends on how lucky you feel!

 

Personally I would go for the electroquest, which is a better known brand, and maybe the 45A one but as I said it is all a compromise and only you know what you can afford.

Edited November 19, 2015 by nicknorman

[tommyleyland]

I'm getting a Honda EX1000, yeah you're right, I usually don't like to buy cheap but that generators going to sit there for a while until I can afford a decent charger. My electric usage is quite small so I think the 2 batteries are OK for now but when I get some more cash in I'm hoping for 4 xTrojan 6v deep cycle batteries.

[nicknorman]

I'm getting a Honda EX1000, yeah you're right, I usually don't like to buy cheap but that generators going to sit there for a while until I can afford a decent charger. My electric usage is quite small so I think the 2 batteries are OK for now but when I get some more cash in I'm hoping for 4 xTrojan 6v deep cycle batteries.

Obviously you already have a "generator" in the form of the engine and alternator. But we are unconvinced that this is working properly, perhaps your money would be better spent on getting the engine's alternator working properly? Post some pictures of the engine and alternator and someone should be able to tell what model the alternator is and what you could expect to get out of it if it was working properly. A replacement alternator can probably be had for under £100, depending on the model, repair possibly cheaper.

[Paul C]

Obviously you already have a "generator" in the form of the engine and alternator. But we are unconvinced that this is working properly, perhaps your money would be better spent on getting the engine's alternator working properly? Post some pictures of the engine and alternator and someone should be able to tell what model the alternator is and what you could expect to get out of it if it was working properly. A replacement alternator can probably be had for under £100, depending on the model, repair possibly cheaper.

 

There's another thread relating to the OP's battery selection switch, it might be the alternator is fine but the switch or its wiring isn't. I looked at it but couldn't make sense of the wiring as described.

[nicknorman]

There's another thread relating to the OP's battery selection switch, it might be the alternator is fine but the switch or its wiring isn't. I looked at it but couldn't make sense of the wiring as described.

Thanks. Well with a few photos of the alternator including the connections, we should be able to tell Tommy where to put a meter to check the charging voltage at the alternator.

[Richard10002]

 

This is my thinking, it's at 13.5 at the moment which is better than it's been, I was running 2 laptops from an extension socket so that might be the issue...

 

When my batteries are at a lower state of charge, say 40%, my charger starts at a lower voltage, and rises over time to its' maximum... 14.2V from the alternator or 14.8V from the shoreline charger... so I often see a voltage of 13V or so when I start charging, and I see this rising over time. Whilst the voltage is rising, this is called bulk phase.. when the voltage reaches its' max and remains stable, this is called absorbtion phase, then, when the Amps being drawn have fallen to about 1%-2% of the battery capacity, the charger should have a facility to enter float mode, where the voltage will revert to a bit over 13V.

 

The above will probably be gobbledeygook, but it shouldnt do any harm for you to read some of the terminology, and how things might work, so you can google things, do a bit of research, and gain a bit more knowledge.

 

If I were you, just to be sure you have had a good go at it, I'd run the engine above tickover for most of the day, 8-10 hours, and see what happens. I might run some low powered 12V stuff during the day, but I'd probably avoid the inverter and 240V stuff. I'm suggesting this as a one off test sort of thing, rather than a regular event.

 

I use a 240V Honda Eu20i generator to feed the shorepower socket, then an 80A charger charges the batteries. It takes about 3 hours charging to replace the 100Ah that I might use in a day with this charger, and every now and then, (fortnightly or so), I run the charger for 5 or 6 hours to fill the batteries, then perhaps another 3 hours at a higher voltage, (15.6V), to "equalise" the batteries.

 

If I use the engine with its' 55A alternator, it usually maxes out at 32A, and falls gradually over time... it takes ages to replace 100Ah, (my daily useage), with the engine, and it would never be my preferred method.

[tommyleyland]

Thanks for this, very useful. Maybe I'll try and invest in a higher amperage charger.

 

I'll get some photos when it's lighter and when I figure out where the alternator is

[Theo]

 

Lets talk turkey :

 

My lap top draws 1.4 amps at 220v.

W=A x V so that is roughly 308 watts.

 

times that by 2 laptops and you are using 600w.

 

That 600 watts will take roughly 60 amps out of your batteries (via the inverter)

If you have a 60 amp or less alternator and / or it is running at less than optimum revs ( for the alternator, not the engine) you are taking more out of the batteries than you are putting in.

 

Answer - use less laptops, produce more electricity, get a bigger alternator, buy a generator, move onto a serviced mooring or live in a house

 

My laptop charger while the laptop is on uses a max of 60W. Are you sure that your laptop uses 300W. My old desktop only used 150W and that was with a CRT monitor.

 

N

[Theo]

If the OP is running a significant load off his inverter, his alternator will not see the current to the batteries getting small and will therefore not ratchet up the charging voltage, so the batteries will never be "fully" charged no matter how long the engine runs? Is this true or am I misunderstanding what takes place?

 

You're not misunderstanding. However, if the alternator controller sees a low output voltage it will up the field current and so boost the output current.

 

N

[Theo]

After an hour it's down to 12.6, possibly because it wasn't charged enough from the alternator. Annoying stuff.

When I get the generator, do I connect it to the mains socket as you would from a hookup or do not all boats have a charging system from that?

I recently burnt my fingers by getting a genny that was a little to small for the charger that I then bought. My Sterling charger was said to take 750W so I assumed that the 1000W genny would cut the mustard. It didn't quite and always shut down when I switched on the charger. I have managed to work around it as described in another topic but the charger manufacturer said that I should be using a 1.5kW generator.

 

Just a warning.

 

N

[Top cat]

If you are in the market for a charger look at the C tek range, I've had two (on different boats) both have worked faultlessly for many years. No connection with the company other than as a satisfied customer.

 

Top Cat

[Detling]

Although mentioned in passing given the age of the boat it is quite likely that the alternator is one of the old types that output 13.6 volts and so will never really charge the batteries to 100%. Maybe a change of regulator or a replacement alternator would fix this easily.

[Richard10002]

If you are in the market for a charger look at the C tek range, I've had two (on different boats) both have worked faultlessly for many years. No connection with the company other than as a satisfied customer.

 

Top Cat

 

I dont think there is a Ctek model that produces more than a few Amps, but I may be wrong.

 

Most seem to be less than 10A, and there are a couple that have a max of 25A. I'd be looking at a charger with at least 40A, and preferably more.....

Edited November 20, 2015 by Richard10002

[Top cat]

Mine does 25A and I think that's as high as they go. Does all I need on my 440Ah battery.

 

T C