Quite simply I'll just wait and see🤔

Roycv, very well said. I too take umbrage at the misuse of M versus m. Electrical units shud always be capitalized, they represent gentlemen's names...A=Ampere, V=Volta, W=James Watt, etc

I meant to add, recently I did buy some NiMh batteries from AliExpress and these were OK.
Roy

EdW and Roy. Thank you, both of you are right on.

I read articles like this with a great deal of interest, Roy sound like the voice of reason here. I qualified as an electrical engineer (light current) nearly half a century ago and have been in the game in some capacity or another all that time. It’s not only batteries that suffer from “Chinese Notation” but many electronic components as well. The rule is simple, if it is too good to be true, it probably is.😊

Hi all a quote from the Internet.

A lithium-ion (Li-ion) battery (LiPo 3.7 volt) differs from a lithium iron phosphate (LiFePO4) battery (LiFe 3.6 volt). The two batteries share some similarities but differ in performance, longevity, and chemical composition.

LiFePO4 batteries are known for their longer lifespan, increased thermal stability, and enhanced safety. (as used in cars)

Regards
Roy

Hi all I am getting a bit bothered with the posts about PP9 batteries.
First the descriptions. M a capital means Mega or 1 million. m, little m means milli or 1 thousandth.

As quoted 8800Mah for a PP 9 battery is just not possible otherwise electric cars would have the battery in the glove box.

The PP9 battery is quite a small battery and to have these numbers printed on them is just not true. I looked some up on ebay and found some I might just believe at 1.2 Ahrs (or 1200mAhrs).
Even this I find difficult for the volume of the battery.

I was told from a GB supplier that in China you can get anything you like printed on any battery you want.

About 7 or 8 years ago I bought a couple of 3800mAhr NiMh batteries. They did not seem to last very long and a while later I bought a piece of electronics which measured the i/p and o/p watt capacity of the batteries. My so called 3800mAh batteries were just over 1500 mAh each.

With Nimh batteries as the capacity goes up so does the weight of the battery.

Common sense once triggered can tell you that the numbers in the posts on this forum for this very small battery make them difficult to accept.

Has anyone tried to use a PP9 battery as a drive battery? With the numbers quoted you should be able to run a small boat at full speed all afternoon. We know this is just not going to happen!

I am not saying that members reporting this are mistaken, it is that what is printed is just not true!

Phone your specialist supplier for batteries and have a chat with them. When I last looked on the Components Shop web site they had LiFe cells (3.6 volts per cell) at 2600mAh.

The volume of the battery looks higher than the volume of a PP9 and the chemicals inside do all the work.

LiFe cells at 3.6 volts are used in car batteries and many units of 50 volt blocks are used in parallel to get the capacity needed for the claimed mileage.

Lipos that modellers use are a different combination of chemicals have 3.7 volts at the terminals.
As an aside I have a 1 cell electric torch the Lipo inside says 3450 mAh capacity. I weighed it and it just can't be it is not heavy enough more like 1500mAh.

As I said they will print anything you want on a battery out of China. Reliable countries are Japan and a lot of the far east and Europe and USA.

Regards
Roy

Like these but mine are 8800Mah

My PP9 batteries are rechargeable Lithium - ion

NickD.. the PP9 you refer to is Zinc Carbon?? (typically these are 5Ah battery)

https://uk.rs-online.com/web/p/9v-batteries/2282018

DG

My 2x 9v PP9 are rated at 8800Mah each battery.
My 2x 7.4v 2s 5500Mah each battery.

🤔😀😀

The 2x 9v will power the ESC and motor.
The 2cx 2s will provide 14.8v..3v..6v..12v possibly, any one see an issue with this set u please?

Hi Nick.
I use Buck converters (voltage regulator) with great success and have no issues.
I attach a picture of one in situe to step down from 7.5 to 4volts on a bilge pump.
Can’t help on those batteries I’m afraid.
Regards
Bill

I'll stick with Buck converter question...
They work well and are pretty efficient with very little loss. The only problem I have I can't find one that will allow for reversing polarity.
I have a RC crane that turns in both directions using the original RC trans/rec, and I need to reduce the speed.
Lew
Florida ⛱️, USA

Hi I use a Buck converter for a non-marine use. It drives an electric motor that operates some Mamod toys, used as a demo at our exhibitions.

Very good I can connect any battery to it and it delivers the exact voltage it is set up for. My one also has the voltage indicated and switches between i/p and o/p voltages.

PP9 batteries are such a small amp hour capacity they are only of use for very low currend consumption. Very often used in smoke alarms and meters.
So just 2 out of 3, I do not use Lipos etc.
Roy

What are the groups opinion of Buck converters up and Lipo batteries and PP9 batteries please?🤔

Thank you for all the good advice. I have to immerse my mind in the logic of all the connections to understand the functions assigned.
The drawings from Alessandro are helpful although I thought off something like it but unsure. What are the drawn in parts (capacitors or the like?) between battery, esc/bec and motor and their purpose?
Looking up Escs there are described with a variety of electrical terms, battery input voltage, ampere etc. What do I have to look for to be compatible with Receiver/Motor/Battery?

You're welcome Spence.

I'm very happy that the diagrams were useful to you.

In reality ColinH, Dgoss999 and Toradog had already explained the issue very well, but the human mind often needs to visualize.

I want to point out that these diagrams refer only to the simplest set-up which includes: forward gear, reverse gear, left turn and right turn. Nothing more.
In this case only two channels are sufficient.
The voltages indicated for the battery and motor are for example only.

For JockScott the choices may be more thoughtful because he is building a model weighing around 33 kg (we still have to discover the precise displacement), a beast.
He will have to start from the correct choice of a propeller and then an engine and gradually go back to the other pieces of the electronic puzzle.
As Colin says, he can count on the forum of enthusiasts.
I would rely heavily on the advice of the admirals of this forum.
The positive side is that JockScott can put whatever he wants with such a high displacement.

Without dwelling on the description of the diagrams, I would like to point out, for any novices, that the signal cable is the one dotted and indicated with the letter S. In the receiver the positives are in electrical continuity with each other and the negatives are in electrical continuity with each other.

Shortly:
in the first diagram the power supply of the receiver and servo is foreseen thanks to the BEC (Battery Eliminator Circuit) integrated in the same electronic apparatus as the ESC (Electronic Speed Controller).
In the second scheme the receiver and servo are powered by an external BEC which can be connected to the same battery or to a separate one.
In the third scheme the receiver is powered by a battery of adequate voltage, in itself, and without any use of BEC.
In the second and third diagrams the BEC inside the ESC device is unused, as the positive is disconnected, only the negative cable and the signal cable remain to control the ESC.

My (entirely personal) preference is for the third scheme.
I prefer to have a separate battery (or more) for the servos (especially if there are also winches or other loads) and not use a BEC, neither internal nor external, neither linear nor switching.

We all are still learning, even us oldies don't know everything.
So don't be afraid to ask, and I'm sure someone will have the answer.
Cheers Colin.

Thanks Colin and all you guys for the very detailed explanations. I particularly appreciated the diagrams from AlessandroSPQR but all you guys are so helpful. What would I do without you all? Cheers Spence.

Thanks Colin.

I made them in a hurry on paper without double checking.
If you've checked them again, I'm sure they're fine.

Yes, you're right, it's impossible with a cell phone (at least for me).
I could have done them on the PC but only tomorrow and I was afraid I would forget to do them.

A diagram can be more useful than a long description, maybe we will do it anyway if necessary.

That's very clear Alessandro, I would have done the same diagrams, but not easy on my phone.
Cheers Colin.

Hi JockScott.

Perhaps these three diagrams can help you understand. Look at them carefully (I hope there are no mistakes because I made them quickly).

If you still have doubts, don't worry, we can make a detailed explanation, first speaking in general and then adapting to the specific case of your tanker.

Jock,

With a Modern ESC/BEC device you don't need a receiver battery.

The 12v supply you have goes to the ESC and then to the motor. ESC also supplies a stabilised supply for the Receiver and generally 5-6volt via the throttle lead. Typically all the +ve and -ve pins on the receiver are connected in parallel (signal pins are unique to each port), so the BEC function powers all the Receiver ports..

The Throttle channel controls the voltage the ESC supplies to the motor.

Some people choose not to use the BEC (5-6v supply) function from the ESC and cut out the centre wire in the throttle lead and plug in a Battery to the Battery port on the receiver.

A modern ESC is NEVER powered by the receiver battery!

DG

I am not sure if I understand this correctly. Isn't the ESC control supplied from the receivers battery which is 6V. The ESC control regulates the power to the motor. Can that not be separate from one another? And if, what parameter are required from the ESC?
I am a total novice in this area looking for suitable tutorial material.

Jock,

You need to look at this from another other perspective.. Your 12volt battery supplies to the ESC which in turn drives the motor. The ESC can also supply the receiver with a 5 - 6volt stabilised supply via the Throttle lead. If you are powering the the receiver from a separate supply/battery, you can cut this power lead out from the ESC feed (the centre lead in the receiver plug) to the receiver. This will allow just the Throttle signal into the receiver.

DG

I would like to use a 12V lead/acid Batterie for running the motor. What do I have to look for in the ESC if it is supplied by a 6v receiver?

Another option is to use a stand alone BEC. There are many available and quite a few of which convert 12 volts or greater to a selected voltage for the receiver.
A draw back of using a BEC, whether stand alone or ESC equipped, operating on a supply voltage of 6 volts, is that when the battery voltage drops, the BEC become less efficient and is not able to supply a steady voltage to your radio.
The greater the difference between the input voltage and the demand(output) voltage of the BEC, the more stable the output voltage remain. Kinda mumbled, but i hope that helps.😌

Hi it is unusual for modern esc's not to have a BEC built in. Most esc's have a switch on a wire for turning BEC on or off.
Roy

Like Colin said, the receiver supplies power to the servos.

Best to check the voltage limit on the ESC. Many will go up to 12V input, with two outputs:
1. Supply power to the receiver (which in turn powers the servos).
2. Supply variable power to the motor(s) which varies the speed (and direction) with voltage up to the input voltage.

If you use the standard hobby battery pack usually based on 6 - C cells, you can increase the voltage with more cells. Available packs are usually:
7.2V - 6 pack
8.4V - 7 pack
9.6V - 8 pack
10.8V - 9 pack
You also have the option to build your own battery pack by putting multiple batteries in series. Keep in mind what you will need as a charger.
Lew
Florida ⛱️, USA

Spence, most of my models are powered by 12v 7ah sla batteries .
The power to the servos is via the reciever which in turn is supplied via rth esc ubec output which is normally at 6v.
Just check the esc details to ascertain the output voltages.
Cheers Colin.