Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: U-33 on March 20, 2012, 08:49:28 am

Title: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 08:49:28 am
I keep hearing that I really should keep my battery packs disconnected from the esc's when the boat isn't in use, but in the Queen Mary 2 it would save an awful lot of mucking about to be able to leave them connected up. I should add that the esc (an Mtroniks Viper) has it's own on/off switch.

So, the question is..is it vitally important to disconnect the battery packs when the boat is in storage for a couple of days? We normally sail every other day, weather permitting, so the batteries are regularly used and charged.


Rich
Title: Re: Batteries...disconnect or not?
Post by: essex2visuvesi on March 20, 2012, 09:03:40 am
If they are lipo type cells then yes its wise to disconnect

As for the others not so important, but it is good practice to disconnect all batteries after use

Maybe you can wire an inline fuse on the +ve lead between the battery and esc and pull the fuse after use
Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 09:12:31 am
Just good old fashioned NiMhs, no lipos...2 x 7.2v 1600a/h packs wired to give me 7.2v @ 3200a/h.


(http://s7.postimage.org/lcolhlr9j/DSC00141a.jpg) (http://postimage.org/image/lcolhlr9j/)


Rich
Title: Re: Batteries...disconnect or not?
Post by: Netleyned on March 20, 2012, 09:16:21 am
Quote from Mtronics Instruction sheet

'NOTE ALWAYS DISCONNECT ESC FROM BATTERY CELLS WHEN NOT IN USE,we recommend fitting an in line fuse
in the positive wirebetween the cells and the ESC. (Usually 5A lower than the ESC's stated limit. eg.. 10A fuse for a 15A ESC)'

There you have it  O0 O0 O0

Ned
Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 09:28:06 am
Naff.


Thanks Ned and Essex...point taken.


Rich
Title: Re: Batteries...disconnect or not?
Post by: essex2visuvesi on March 20, 2012, 09:34:03 am
Maybe you could bring the fuse through into the deck somehow making it easier to remove
Title: Re: Batteries...disconnect or not?
Post by: Circlip on March 20, 2012, 09:47:55 am
Errr, isn't it not advisable to wire these in paralised configuration?

  Regards   Ian.
Title: Re: Batteries...disconnect or not?
Post by: malcolmfrary on March 20, 2012, 09:51:44 am
The ESC switch only cuts power to the control part of the box, not the power transistors.  With earlier transistors, there was always a bit of leakage, modern ones are much better meaning that the battery will take several weeks rather than several hours to discharge.  An in-line switch that can handle the current or as suggested previously an accessible fuse is the best idea.
Title: Re: Batteries...disconnect or not?
Post by: malcolmfrary on March 20, 2012, 09:56:25 am
Errr, isn't it not advisable to wire these in paralised configuration?

  Regards   Ian.
If they are permanently connected, there is no reason not to to get the required capacity.  Any potential drama only happens on connection, and that when the packs are not equally charged.
Title: Re: Batteries...disconnect or not?
Post by: Timo2 on March 20, 2012, 09:59:47 am
Hi All

  I would be looking at a ACTion  P103 unit   : -   http://www.action-electronics.co.uk/pdfs/P103.pdf

    Plus extra charge leads wired in to recharge the battery's one that a time

    Timo2  :-))
Title: Re: Batteries...disconnect or not?
Post by: Tug-Kenny RIP on March 20, 2012, 12:13:51 pm

Why had no-one mentioned putting an ON/Off switch in the Positive from the battery. I do this with all my boats.

regards

ken

Title: Re: Batteries...disconnect or not?
Post by: Netleyned on March 20, 2012, 12:36:42 pm
It might be a bit difficult to hide a switch on Rich's model.
I think he was asking if he could get away without one.
Otherwise it's a fairly standard fit to have a switch in the
battery pos lead.

Ned
Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 12:54:56 pm
You're right, Ned...it is difficult to hide a switch on the deck anywhere. I've been sat sitting here studying the decks as they go on, and I may have just found a place to locate a small switch, that's in either of the two stern swimming pools.

The other way I've thought of is to place a switch inside the hull, on the forward bulkhead, and activate it by either a wire hook with access via a porthole.



Rich
Title: Re: Batteries...disconnect or not?
Post by: barriew on March 20, 2012, 01:16:37 pm
Or you could use a magnet operated switch as you submariners use :-))

Barrie
Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 01:25:07 pm
I do have a water activated switch which JR built for me...just two contacts in the hull of the ship that activate a circuit when the boat is placed in the water.
Title: Re: Batteries...disconnect or not?
Post by: Netleyned on March 20, 2012, 01:29:42 pm
Make sure the switch is capable of carrying the current demanded by the motors  O0 O0

Ned
Title: Re: Batteries...disconnect or not?
Post by: Martin (Admin) on March 20, 2012, 01:44:00 pm

Fit a 'push on -push off' switch under the superstructure and leave a hole where can poke a stick through the funnel to get to the switch.
a DPST switch would be best.

Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 02:19:57 pm
"....double pole, single throw?"
Title: Re: Batteries...disconnect or not?
Post by: Martin (Admin) on March 20, 2012, 02:37:33 pm
 O0
Title: Re: Batteries...disconnect or not?
Post by: U-33 on March 20, 2012, 03:08:30 pm
.
Title: Re: Batteries...disconnect or not?
Post by: bbdave on March 22, 2012, 06:27:02 am
Yep double pole switch will do the job

Dave