Oh sooooooooo much to learn😜

Hi cdfn.... I am afraid the answer is No. We all travel without the light of day and with eyes closed and fingers crossed. We work on the principle that the last time did not work so well so what about doing it this way?
This is the positive viewpoint others might cast the rhunes and offer a sage response but still hoping for the best.

The third way is to buy a meter study the stats of the motor fit a prop that gives the load that suits the battery, then of course there is the esc.

It is better to travel hopefully rather than to arrive and the true success is to labour. And speaking of traveling, look at the model and see what is the least power that will give a single wave from bow to stern and not produce a hump in the following water. This is too fast and that should be about right.

Actually Vic Smeed did produce a graph of type of boat v boat length to work out power in watts required. However there are expectations of performance now that have made most of it dated.

I expect you will be asked size type etc which is the key to it all.
Good luck
Roy

I know there will be a boat load of versions and factors here……. size of boat, weight, battery type # of cells, brushed motor ETC….

is there a chart of SUGGESTED performance from battery packs ?

Hi garyp
Is this the vintage Chris Craft type cabin cruiser that you were having water ingress problems with? If so the pics you posted showed a 550 type motor with a 3 blade brass prop. This model would require a 6 to 12 volt battery and probably had a SLA when built. If you are using 4 dry "C" cells then 10 mins sounds about right. You really need say a NiMh of about 5Ahr to give a reasonable run time. If you have a NiCd it's probably past its sell by date and need replacing.
As Roy says the wiring may need checking as on an older boat it could have deteriorated internally. High resistance in the wiring or internal battery resistance will prevent the battery from delivering its full potential as well as stop it fully charging.
Please make sure that the drive chain is free rotating as any resistance will add considerably to the battery drain and needs to be fixed. Your motor would be hot to the touch after running if this is the case.
Hope you find a solution
dave976

No just saying you had asked the questions that needed answers, a good summation of what was needed to get a useful response.
regards
Roy

Hi Roy.
Unless I’m reading it incorrectly are you thinking it’s me that has the battery problem?
If so it’s not me.🤞
I have replied to Gary asking for some more fact so we can help him.
Still awaiting answers from him.
Regards
Bill.

Do we assume AA cells?
Roy

What is the size of the pack in mAh ( milli Amp hours
For example a 950 mA pack drawing 2 to 3 Amps will be completely flat in approx15 to 20 mins

Hi, Scratchbuilder has the questions that need answers.
I have a lot of batteries and run my yachts on 4 cell AA battery packs. Lately 2500mAh or so, mine are relatively new and last for at least half a day.

If you have old batteries the capacity slowly reduces and the cells fail. One cell will fail first and it either goes open circuit or short circuit.
With the former there will be no charge current possible but if short circuit it will seem to charge but not last long running the receiver.

Are your batteries single cells in a battery holder or a 4 cell welded pack? Good quality cells last longer.

One of the frequent causes of failure is the black (negative), lead it changes colour from the copper metal colour to a black brittle wire. More often seen in transmitters. The wire needs replacing if that is something you can do.

But 4 cell packs are not that dear and it may not be worth the effort. I go for an average mAh capacity as they are usually cheaper.

This is on the basis that I know how long the battery needs to last, no point in paying for the extra capacity if you never use it! You will find if you buy say 4 packs then the postage per pack is less.

I favour the ones that retain their charge. I only buy from UK stockists that are well known for supplying batteries.
A year or so back I bought 8 cells from a well known supermarket as I used to get a discount. They were total rubbish and Which magazine had them as a 'don't buy.

It is worth having a cheap multimeter that can measure up to 10 amps, most checks can be done with this.
Regards
Roy

I have the same query. Have a four pack NiMh that should produce 6 volts at 2/3 amps. doesn't have the punch to drive a hi-tech winch. guidance from anyone?