Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: wallace on January 24, 2011, 09:21:39 am
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Can anyone tell me what to do about recharging my 12v battery's in the boat with out always taking of the superstrut to recharge
I have heared it can be done with a lead connected to the battery HELP
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Its just a case, basically, of wiring the battery to a pair of metal terminals that you can connect the charger to, if its one with clips. Alternatively, to a socket that matches the plug on the charger. This can be hidden under whatever the switch is hidden under.
A caveat - sealed lead acid are not totally sealed, and can vent toward the end of the charge. What they vent is likely to be a mixture of hydrogen and oxygen, and there are reported instances of model subs exploding. These were reckoned to be due to a lack of ventilation after charging. Another point is that along with the H2 and O, sulphuric acid droplets tag along, more so if motor cycle type batteries are used. Without plenty of ventilation, this soon has a bad effect on any metal in the boat.
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I'm presuming that you are using gel cell batteries?
Simply add another set of leads that go direct from the battery terminals to a suitable plug that could be hidden somewhere or on a fly lead and connect to charger. Even if you have multiple batteries - work on one set of leads to each battery and charge in turn ( unless you have multiple chargers too)
As long as you're only slow charging you shouldn't have an issue with gassing cells or other such problems - BUT - I would still allow for proper ventilation anyway.
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I've had various means of connecting a battery to a charger without having t remove the battery. Most of them include a jack you can plug into, hidden under something on the deck. Another method I've used is a pair of brass bollards, on the deck. The underside of the bollards has leads soldered on and connected to the appropriate terminals on the battery. Alligator clips connect the charger to the bollards. Works well. Here's a picture of them on my Amsterdam.
John
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Hi, good idea, I did this on one of my boats a few years ago. On my boat I did, Port = Red = positive to battery.
regards Roy
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Even better is to connect the terminals to the "~" connections of a bridge rectifier (pretty cheap from such as Maplin) and the "+" and "-" to the battery. That way you dont need to remember which terminal is which.
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Even better is to connect the terminals to the "~" connections of a bridge rectifier (pretty cheap from such as Maplin) and the "+" and "-" to the battery. That way you dont need to remember which terminal is which.
Malcolm,
Being faaaar away down under, Need elaboration on
"~" connections of bridge rectifier
Thank you
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If I'm not stepping on Malcolm's toes here, the "~" symbol denotes the connections for alternating current (a.c).
A full-wave bridge rectifier always consist of four diodes connected in the configuration as shown in the sketch, and its job is to change (rectify) an alternating current into a direct current (d.c). On the d.c. side of the bridge, you simply connect the "+" (Cathode) terminals to the battery positive and the "-" (Anode) terminals to the battery negative.
The output of most every battery charger is already rectified for d.c. but the clever thing with the bridge is that is ensures the output always remains the same with respect to positive and negative, regardless of how the battery charger is connected. In other words, the two wires from the battery charger can be connected any way around to either of the "~" connections, but the positive output from the bridge will always be positive and negative output will always be negative. In essence, you can be safe in the knowledge that you will not damage your battery, regardless of how you connect your battery charger.
A typical 25-Amp bridge might look similar to that in the sketch. The physical size will vary depending on how much current the bridge is designed to handle, and therefore can become warm in use. Some even have a metal plate attached to the underside - the idea being that the metal plate should be bolted to a larger metal surface in order to dissipate the heat.
Here in Blighty, it's simply pronounced as "AC/DC". Down there in Oz, now you know why Angus Young pronounces it as "Akky-Dakky".
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Forgot to mention...
As with all good things in life, there is always a pay-off. In this case there will always be at least two diodes conducting in the bridge at any one time. Since all bog-standard silicon diodes will drop approximately 0.7 volts, it ultimately means that the output voltage from the bridge will be roughly 1.4 volts less than what is going in. In reality, especially with SLA-type chargers, this shouldn't be a problem. On the other hand, those chargers with in-built Delta Peak Detection may suffer a problem of failing to charge the battery to its full capacity, or may even fail to turn off once the battery has reached full capacity.
Just something you might want to be aware of.
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I have been told by a number of people that sealed lead acid (SLA) batteries should always be charged in the upright position. Does anyone have any comment on that?
Peter.
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PMK,
Absolutely terrific and here I was thinkin AC/DC was a band {-) {-)
Seriously, was not aware of the AC symbol, should have looked it up.
That is a smart piece of work using the bridge rectifier.
We need to save these gems in a hints and tips setion, also the use of bollards as deck battery connections.
Thanks to you and Malcolm much appreciated.
:-)) :-)) :-)) O0 O0 O0
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I have been told by a number of people that sealed lead acid (SLA) batteries should always be charged in the upright position. Does anyone have any comment on that?
PeeWee, you might want to take another grok at this thread: http://www.modelboatmayhem.co.uk/forum/index.php?topic=8284.0
Personally I'm in the habit of installing SLA's in their usual upright position and charging them thus. Although, just out of curiosity, I have charged SLA's while on their sides and not noticed any adverse long-term effects. Although, for reasons which I'm not sure of myself, I have never attempted to install, nor charge, a SLA while it's inverted. Perhaps one day, just for the sheer hell of it, I will have a stab at doing so... if only to learn what bad effects (if any) that it may have and will hopefully end up with the answer to your query.
R.A.Gunner: For recharging purposes I tend to use a standard quarter-inch mono audio jack socket (the type normally used on guitars and amplifiers, etc.), usually accessible through a small, removable deck hatch or somesuch. I find that the contacts, along with a matching quarter-inch jack plug soldered to the charger leads, is more than sufficient for charging at normal SLA low rates. The two wires from the jack socket are soldered to a DPDT 16-Amp rocker switch. The idea being that when the switch is in the OFF position the battery is routed to the charging socket; and when the switch is in the ON position means that the charger socket then becomes isolated and at the same time the battery is routed via the appropriate fuse panel and then sent to the motor ESC and all the other circuits.... if you get my drift.
Although, now that I've seen Old Iron's idea of using brass bollards as the charging connections, must say that I'm rather taken with that nifty idea.
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PMK
:-)) :-)) :-))
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Oh..as a great topic...Friends, we can fix a power female socket, anywhere in our craft, in disguise, along with a powerdiode, to avoid short circuit...its too easy...
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you might want to take another grok at this thread: http://www.modelboatmayhem.co.uk/forum/index.php?topic=8284.0
Thanks for that PMK. I knew I'd seen it somewhere, but it was 3 years ago, and my memory's not what it was {:-{ {-)
Peter.
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Thanks guys for replies to my question BUT Im no good at these things now all I want to know or what to buy is
I WANT TO LEAVE THE BATTERY IN THE WELL OF THE BOAT ALL CONNECTED UP FOR SAILING ETC,BUT i DO NOT WANT TO REMOVE ALL THE RIGGING AND SUPERSTRUCTOR TO KEEP TAKING OUT THE BATTERY SOMETHING WILL GET BROKEN SO i WOULD LIKE TO POWER POINT NEAR THE STERN TO RECHARGE BATTERY IS THERE A DOUBLE LEAD TO GO ONTO THE BATTERY PLEASE WOULD LIKE TO KEEP IT SIMPLE. WALLACE
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What type of connectors do you have on the battery?
Barrie
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Barry just the normal connection I call them spades which are already on the battery
wallace
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probably the simplist method is to fit two leads to each of the battery terminals , then a switch , one side of the switch will connect the battery to the esc , the other wires to a charging socket that you can easily get to under a hatch etc . with a corrisponding plug on your charger you will be able to charge your battery .
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Barry just the normal connection I call them spades which are already on the battery
wallace
In that case you can buy some "spades" that connect your boat supply to the battery and also have another "male" spade attached (look in Halfords). You can connect another sets of leads to these, again using spade connectors, and terminate these leads in a suitable connection for your charger. If you have a switch in the supply from the battery to the rest of the boat equipment you don't need another. Just make sure this power switch is off before you start charging.
I have used this system in the past without any problems.
Barrie
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Piggy Back Connectors
Craplins do them as well as Halfords
Ned
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Hi thanks alot Barrie and the others you have made it easy for me to understand once again thanks
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Pictorial:
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Lot good hints and tips here
:-)) :-)) :-))
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nice..super guidance...thank you...
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Gentlemen a question from the resident in-house electrical dumbo - I can fit and disguise a jack-plug for the charging circuit
but have absolutely nowhere I can fit a switch to isolate the battery from the boats circuit - if I have to take off the superstructure to get at the main switch
I may as well just charge the battery out of the boat SO can I charge the battery still connected to the boats circuit without
damage to the components
Geoff
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Geoff
Use a jack socket with a shorted jack plug
as an on/off switch or a 'normally on' magnetic reed switch under the deck with the magnet housed above it
lift magnet off the deck power on. Put back on deck power off
Ned
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Geoff
Use a jack socket with a shorted jack plug
as an on/off switch or a 'normally on' magnetic reed switch under the deck with the magnet housed above it
lift magnet off the deck power on. Put back on deck power off
Ned
Finding a reed that will handle the boats current draw involves a lot of luck. The easily obtainable ones are sub-half amp, nothing like enough even for mine, and "normally operated" are even rarer. It is possible to put some electronics around the reed, but this is moving well away from the concept of keeping it comprehensible for those who are not comfortable with building their own electronic circuits.
One trick I did use was to mount a lifeboat on top of the slide switch - slide the lifeboat 1/4" to switch on or off, virtually invisible.
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Pugwash, since you have no available room for a separate on/off switch, you might consider staying with the jack plug/socket idea since the particular socket shown in the sketch serves double duty, acting as a power on/off switch while at the same allowing you to recharge your battery without recourse to removing the battery from the boat.
A 'blank' plug (a plug without any wires soldered to its connections) serves as your on/off switch. Push the blank plug into the socket to turn off the battery supply; remove the plug in order to supply power to your ESC.
The socket in this case, although still of the mono flavour, has four connections - not two as depicted in the previous sketch above. You might try Maplin or ESR or most any electronic supply company for the socket.
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PMK very many thanks that is just the ticket
Geoff