Running out of water...

[vvviivvv]

I need to recharge my battery's to 3,85 volt per cell and by the time i get back from school (5) its pitch black and every weekend from now till i break up i busy so the soonest i can decharge the batts to storage voltage is the 18th... the batts havent been used in about a month anyway, can i run the boat at low rpm for a long period of time to lower the battery ? out of water that it...

or can anyone post some suggestions to lower the battery voltage, i would try a bulb but it would take so long that i would probs forget and it would de-charge right down

[NativePaul]

If your strut has leadteflon bearings running it out of the water will knacker the bearings in seconds even at low RPM, if its ballraced it should be OK and for brass bushings I'll defer to someone else as I have never used them. I used to use a headlight bulb to discharge with back when I was cycling NiCads.

[Simon.O.]

I need to recharge my battery's to 3,85 volt per cell
or can anyone post some suggestions to lower the battery voltage, i would try a bulb but it would take so long that i would probs forget and it would de-charge right down

A few things here.
Recharge to 3.85v/cell ?? Why, when a full cell is 4.2 or there abouts.

I know that discharging with a lightbulb can be time consuming and distractions can occur. You must stay on the job when you are doing this kind of work. I usually take the time to clear and clean my work space so that I can monitor my battery charging.

Another option is to go and check your packs at say 5 min intervals, it is easy to set a kitchen timer or your mobile ph to do this. I use a good old wind up kitchen timer that has a fairly loud ring to it.

Just a few ideas. :tiphat:

[vvviivvv]

I don't think there are any bearings in the strut...

[Simon.O.]

Don't use your boat to discharge batteries.
There are better ways.

[vvviivvv]

I was told to store lipos at 3.85 volt...?


Won't be using again till late January

[NativePaul]

Sorry I forgot to mention flexshafts as I haven't used one in a while, if you run a teflon liner on a flexshaft dry you may melt the teflon seizing up the flex and if that happens kiss goodbye to your ESC.

A single 55w headlamp bulb should draw about 4.5A taking around 30 mins to get your battery half empty assuming 5000mah 4s packs if you run 2s packs a motorbike bulb will work the same if you know a friendly biker, if your boat pulls more current than that at low throttle out of the water yo have some binding in the drivetrain that needs sorting, and you can always use 2 bulbs in parallel to halve the discharge time. Quickest way to discharge if you have lots of packs is to buy a prop adapter and aero prop from your model shop take your motor/esc out of the boat fit the prop adapter and hold the motor in a workbench you can then run your motor at similar currents to your boat with air cooling, cost would likely be around £10 for adapter and prop, if you want to do it this way let me know what motor you have, cell count and what current you want to discharge at and I will say what size prop you need.