Calypso motor and ballast queries

[Colin BishopModerator @colinbishop34627]

Nick,

Those 385 motors are very nice units and  my ‘go to’ for the models I make. They are very efficient and will probably draw around 1amp each at Calypso’s cruising speed.

When it comes to batteries it depends on how much weight you have available for them and the space available. Check out the Component Shop options here:

https://www.componentshop.co.uk/batteries/radio-control/large-power-packs/7-2v-8-4v.html

For a boat like Calypso Sub C cells are the way to go as they offer lots of choice.

The immediate alternatives that spring to mind are:

7.2v 2600mAh pack which would probably give up to a couple of hours cruising around the pond at a weight of 300 grams

7.2v 4300 mAh pack which would still be running happily long after you have become bored at 408 grams

Or maybe  a 8.4v 3300mAh pack at 457 grams which, if you have the room and weight allowance, combines a bit more ooph with a better endurance than the  7.2mAh  2600mAh pack.

Any of these will do the job. The key factors are will it fit, is the weight OK and is the price right!

If you are really pushed for weight and space then there is an AA cell 7.7v 2600mAh option at 185 grams here:

https://www.componentshop.co.uk/7-2v-2600mah-flat-3×2-aa-nimh-battery-pack.html

Colin

[Richard SimpsonParticipant @richardsimpson88330]

What Colin says! 🙂

With a couple of 385s a 4300 mAh pack will last all morning without worrying about loss of power.  If you want to try a six cell 7.2 v pack first and make the tray a bit longer than needed, which can be filled with a block of foam for a snug fit, then you will also have room to try a seven cell 8.4 v pack at a later date without needing to make any modifications , if you fancy a little more speed.  The normal arrangement for the seven cell is the standard two side by side rows of three with the odd one across the end so the pack is the same width but the diameter of a sub C cell longer.

Having said that Component shop will make it exactly as you want it so you could even have the last cell piggy backed on top of the other six.

[Nick LewisParticipant @nicklewis66033]

Thanks, all.

So, NiMH 7.2V Sub C is the way to go. That’s great. I will get the scales out and do some sums to see if I can get a better estimate of what weight she will outturn at currently to see how much headroom I have.

Out of interest, do people normally disconnect and/or  remove the battery for charging, or provide a wiring solution to charge in situ? Are there pros and cons, or is it just taste?

Nick

[Colin BishopModerator @colinbishop34627]

With my NiMH powered boats I usually leave the battery in the boat and  bring out a charging socket which can be concealed under a deck hatch or fitting.There is no need to fast charge them so they don’t get hot.

Often the battery is buried within the hull and on my paddler I brought the charging ports up to deck level where they can be easily accessed with the deck off. (see black sockets in photo).

The LiPo batteries for my Fairey power boats are kept in a fire retardant pouch inside a tin box though!

Colin

[Nick LewisParticipant @nicklewis66033]

My goodness! That’s busy, to say the least!

Two questions:

• What are the little grey and orange things that look as though they are jointing wires? Never seen anything like them.
• How are you switching the batteries from supplying  power to the motors/ESCs to accepting charge from the sockets?

Nick

[Colin BishopModerator @colinbishop34627]

Nick,

The orange and grey things are WAGO connectors. It is now possible to get smaller ones, the 221 size which includes inline connectors. Google WAGO connectors and have a look at this link:

https://www.wago.com/gb/electrical-interconnections/discover-installation-terminal-blocks-and-connectors/221

You can buy them on Amazon and elsewhere. They are very handy. Better than chocolate block screw connectors. Search on WAGO 221 connector. There are other makes but WAGO are the best.

As far as fitting charging points is concerned I always fit an isolating switch to the positive battery supply so that everything inside the boat can be switched off. The positive charging socket lead is taken directly from the battery terminal connection before the isolating switch and the negative charging lead is taken from the negative battery terminal connection. This does mean that the charging socket is always ‘live’ to the battery of course. (it can be useful in measuring the battery voltage if the battery is buried in the depth of the  boat).

Obviously you won’t want to connect the charger when the main boat circuit is live so an alternative option is to make the main switch a single pole double throw (SPDT) switch so that the connection is either to the charging socket or to the boat system but not both at once. Explained here:

https://www.nextpcb.com/blog/spdt-switch

Hope this helps,

Colin

 

 

 

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