Maybe an electrical question for Bob

[northeast1]

I am looking at adding a 3d chart plotter in next few weeks, borrowed a lads one at work but had a few electrical problems.

Because it takes alot of power i run it off my other battery i fitted last year, the problem is when i start the boat i get a surge of power from the altinator that is turning the 3d plotter off.

I know this happens with alot of cars/boats and you can buy something for it thats only about £5 but just wondering if anyone has any better ideas...dont want to increase the fuse size incase it blows the gps etc.

I really should just stop adding things to the boat

 

[paulthespark]

use a anti surge transformer ,don't take it of the battery side of your electrics take it of the alternator side, the alternator is what the electrics are run from including the batteries wich are being charged up constantly via the alternator ,the main reson for the batteries are to fire up the starter motor for your engines, once the engines are running the alternator takes over. [i think, i,m not that converse with boat electrics hope this helps]

 

[boblydon]

Ritchie, try taking the connections straight to the battery and not from the auxillary panel as this is a common problem, however make sure you have an inline form of isolation and deffo dont increase the fuse size....another problem could be the storage size ( amperage ) of your battery, let me know next time your down at the boat and i will try to come down

 

[Norman]

Rich, dont think it`s a surge, its a voltage drop as your starter consumes amps.
I isolate each of the batteries/systems and keep all the services on one and the engine on the other (only connection is the big battery switch which can direct charge to one or the other or both for emergencies) ...... I get same drop off when starting engine but only if I start it off the services battery accidently while i`m in the process of charging the services battery. hope this helps .............. obviously there are more sophisticated ways of stopping drop off but this works for me ....

 

[northeast1]

All good ideas. i thought it was a surge Norman as i have blown a 15amp fuse twice and it goes just after starting the boat, i fitted the fuse just before the equipment to protect the gps and 3d plotter as dont wish to blow someone else gear

Hoping to take the boat out over xmas if the weather holds and have abash close in.

Was down the Royal Quays at weekend and my word the boats getting a battering from the wind, had a walk around but all seemed tied up ok..last time i had to report one as it had come adrift.

Ow one last thing? anyone filled up at the Royal Quays of late? just wanted to know if anything changed regarding the filling other than the price do you have to fill a form out now or is it all just as simple as filling up paying and going?

You heading out over xmas Norman?

Bob hows the boat coming along?

 

[Norman]

hope to get out sometime rich, just goes to show how the weathers been since i`ve not filled up either since end of october .....

ps does sound "surge" in your case if blowing a fuse, as I say I seperate systems and just switch over to charge services now and again

 

[mark]

definately a voltage drop problem, nothing else, cranking the engine will drop a healthy 12v battery to as low as 4 or 5 volts while its pumping all that current to the starter. Not a huge amount you can do to to prevent apart from a second battery connected via a split charge relay, that isolates the 2 batteries from each other till the engine is running and the alternator starts working which trips the relay to bank the batteries back together

another option would be a very very big capacitor. Some of the head the balls that fit 2kw sounds systems in there cars use them. A capacitor with about 1farad capacity, it'll be about the size of a tin of beans, but would hold the voltage up to the electronics for about 10 seconds

second battery far better idea and safer generally, run all your toys off that in isolation from the engine battery, prevents you getting a flat battery for starting the engine as much as anything...

or just live with it dropping out when you start the engine again

 

[davem2005]

Ritchie,
Marks suggestion is the answer, it also helps negate radio interference.


If you want it wiring up I have the bits and you have my number.

It certainly gives piece of mind that no matter how long you run your electronics you will never have a flat baterry to start the engine with.

A final little tweek would be to fit a battery isolator to Marks setup. This would allow the two batteries to be OFF/BATT1/BATT2 in relation to the starter motor. This allows for the auxilliary battery to be used to start the engine in the event of a main battery failure. Total piece of mind.

The answer is this
40A Relay for Automotive Applications > Maplin

or if you really want to be posh
Lead Acid Battery Split Charge Module > Maplin

Or the deluxe version is to add one of these
12V/ 12W Solar Battery Charger > Maplin

and both of the relays and you will probably never suffer a flat battery again

Cheers
Dave

 

[northeast1]

Ok cheers lads.

Already have a solor generator but have just purchased a relay thing as mentioned above and also something to stop the surge when the engine starts.

Will be down the boat today to fit it, may take her out if time and weather holds.