12v, 6v, is hybrid a thing?

[nelix6030]

Ok, so back into this hobby and coming in hot! Here is what Io am doing, redesign of my U47 tech rack with home made piston ballast. I am still runnin the original 6v brushed motors that came in the kit. I am switching to 7.2v 6200mah x2 batteries (using step down to 6v). So here is my nutty question, my new ballast tank while working at 6v, is much faster at 12v. So should I spend the money and upgrade my motors and ESC to 12v and hook the two batteries in series? Knowing that old rule - Series = more Speed, Parallel = more Play time. Then run the two motors in parrellel off the esc? Or , hear me out, can I hook up batteries in series, run two seperate step down convertors, one at 12v and one at 6v and split power that way? of course then coming off the 6v with a bec for the reciever..... ? am I asking for trouble and a lot of complication. The other thing would be to hook up batteries in parrellel, stay at 6v and have a slower piston.... ok guru's help me out here I need you!

Thanks, any advice would be great, but be gentle you know all us IT guys think we know everything about everything

Kyle

[dono]

Kyle,

I am not familiar with the U47 hull as I run the Engel boats and a Moebius SkipJack class boat.

All of these boats are static divers. (They have piston tanks) My 1:96 scale Lafayette class (Boone)
and Engel George Washington Class (Abe Lincoln) hulls are 12V systems using 540 brushed motors
for both the ballast tanks and prop motors. My 1:72 Shipjack class boat runs off of 6V and uses
a 380 motor on the modified Engel pump and a 380 motor for the prop motor.

I use 2 12V 3 A hr NiMh sub C packs in parallel for the Boone, giving me a total of 6 A hr
of battery capacity. It is a great running boat and has alot of speed also.
My run time is approx 1 hr minimum.

MY comment is you need to decide how you want to run the boat.

Typically I use the ballast tank to get me to the depth I like then run the boat and patrol the pond.
The ballast tank should only draw battery current when you are setting the depth.
(Either surfacing or submerging)

As far as running a 6V system as compared to a 12V System, that would depend on how
much room you have in your hull. Granted a 540 size motor will give you more
speed if that is what you want.

For the 6V system in the Skipjack, the speed control has a built in BEC, and has enough
power capability to reliably run both the motor for the modified Engel ballast tank
and the prop drive motor.

Not being familiar with how much room you have for your tech rack or the size of your hull,
My opinion is to just keep it simple and figure out first how you want to run the boat.

Don

[nelix6030]

Don, thanks for all the advice. speed is not my thing, but I do think that I will move towards 12v then just step down to run the 6v motors and esc. While the hull of the Robbe U47 is pretty roomy, its also limited because of the rear access. The batteries are not a huge cost and I can use my 6v's in a future sub. Thanks again for the knowledge share.

Kyle

[bob the builder]

Remember that wattage (workload) is Amps times Volts. If your workload remains constant (IE: the speed you want your boat to go, or the cycle time of your ballast system), then doubling the voltage means you halve the amps you're drawing. Lower amperage also means you can get away with smaller wiring. Lots of benefits of going with higher volts.

[feet wet]

No, what you are suggesting is not a hybrid thing. It is a parallel/serial circuit. It is easy to do, take two six volt batteries, wired in series+12 volts. Meanwhile also tap 6 volts off each 6 volt battery and parallel connect them to load.As Bob points out, if you increase the voltage the amperage halves,BUT that will still give you the same relative speed of taking in or pushing out ballast. To increase the rate will increase the amp load at 12 volts. Another thought occurs to me. You have an Engel boat and the ballast controllers are set up for 6 volts yes? It may cause real headaches to change over.
KISS principle....RIP Skip.