vosper mtb

[Andy HustlerParticipant @andyhustler32076]

Dave Abbot , how do i create an access hatch to the batteries without carving up 1/2 the deck ???

[Andy HustlerParticipant @andyhustler32076]

[Colin BishopModerator @colinbishop34627]

Andy,

Dave does not look at this Forum and appears to have taken a break from modelling at the moment.

Colin

[Andy HustlerParticipant @andyhustler32076]

I spoke to a very helpful guy in Antics Cardiff today and he suggested putting bulkheads in the boat to stop water damage and put a spur off off the battery pack so the battery can be left in place and charged in place .What do you think on this idea and as i am no sparky can anyone supply me with a diagram in plain English

[Charles OatesParticipant @charlesoates31738]

Personal opinion, I don’t like charging batteries in the boat. Too many things to go wrong, one failed conection or switch and you have a fire hazard. Also, some esc makers recomend disconecting the battery when not in use. So you might as well charge it then.

[Andy HustlerParticipant @andyhustler32076]

oK I would like to take the battery out but back to square one how do i take the battery out without ripping the superstructure to bits ??

[Dave MilbournParticipant @davemilbourn48782]

Andy

As long as all joints are properly made and the cable used is adequate in size there will be no more risks of fire than there would be under normal running conditions. You can arrange for on-board charging by using a changeover switch and on-board charging socket like this:

Dave M

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Dave,

I assume that Andy is going to use a LiPo as DA used. Will there be any difference in your set up a) because its a LiPo and b) because the connections will be different?

I'm doing a PT boat 1/35 and will make a deck access point just for the battery, a small flat LiPo, as I never charge any batteries inside any equipment. Even theTx batteries are removed for charging, I've had my on board near fire/heat damage and my assessment is now to charge outside the boat/equipment in my designated charging zone.

Aye, Kim

[Dave MilbournParticipant @davemilbourn48782]

Kim/Andy

The conventional approach to charging LiPo batteries is different to NiMH and NiCAD cells. Here is Component Shop.co.UK's "Do's and Dont's". **LINK** while here is my approach.
CompShop recommend that LiPo packs should always be charged and stored inside a fire-safe container, such as a purpose-made sealed bag. I do use one of these for storage (because Iain Lewis gave me one to try!) but not for charging, mainly because the battery leads are so short.
I use a little voltage/battery state indicator to tell me the voltage of each individual cell in the pack. This allows me to see if the cells are balanced (unbalanced cells in a pack is a potentially dangerous state of affairs). It also gives me a good idea of the charge remaining in a pack http://www.componentshop.co.uk/7-segment-display-battery-status-indicator-for-2s-to-6s-7-4-22-2v-with-hard-case.html
I have an X200 charger which monitors just about everything and stops the charge if anything goes remotely awry. If you use a mains (slow) balanced charger then there's precious little which could go wrong at the low currents involved.
I always remove the pack from the model and I NEVER leave packs unattended while charging them. I should say that my models all have easy access to the radio and battery compartments so there's no reason to leave the battery in situ.
I always restrict the charge rate of my LiPo packs to 1C – which is pretty quick anyway if you're charging during the previous day. The packs never get hotter than 30°C at this rate.
I ALWAYS use a balanced charge – there's no reason why not to do so.
I think that with sensible handling there's no reason why these batteries shouldn't be left in a model while charging, as long as you don't do anything daft like fast-charging them at 5C and that you keep an eye on the charging process all the time. I would say, however, that the battery ought to be removable for the occasional physical examination (for "puffing" or dents in the cells).
Finally bear in mind that even with the best charging and maintenance you'll only get about a hundred charges from a LiPo pack before it's exhausted, whereas a NiMH pack will give you thousands. If you're in any doubt then use a NiMH pack instead of a LiPo.
The layout in the diagram above is a movable feast. For example, you could fit the Deans connector between the battery pack and the switch instead, and you might sensibly incorporate a fuse in the positive line from the switch to the ESC.
I hope that's clarified a few things; we're all still learning about these new things but the overarching consideration should be safety. I've seen videos of these battery packs blowing up and I wouldn't want to be anywhere near one if it did.

Dave M

Edited By Dave Milbourn on 07/03/2015 11:02:30

Edited By Dave Milbourn on 07/03/2015 11:14:11

[Andy HustlerParticipant @andyhustler32076]

Hi guys I'm using either a 1900 mah 7.2v ni-cd battery pack , nice and flat or 5 Tornado 3800 batteries in a row from West borne models .The only difference is that the tornados have a spur coming off to connect to the receiver.So folks which ones do i use ????

On another subject how do i determine where the shaft comes out in the hull without chopping up half the underside ??

[Dave MilbournParticipant @davemilbourn48782]

Andy
Connecting 7.2v directly to the receiver is risky because your receiver may not be equipped to accept such a high voltage. There's no reason why you shouldn't use the pack to power the main motors, however. You'll likely find that your speed controller has battery eliminator circuitry (BEC) so the receiver will take its power that way i.e. through its normal connection to the speed controller.

I can't help you with the shaft question as I'm not familiar with the model.

Dave M

[Paul TParticipant @pault84577]

Hello Andy

Most of the answers to your questions can be surmised by reading Daves article and looking at the build photos, for example access to the motors / batteries is achieved by removing the entire deck and superstructure.

If you look carefully at the image showing the open hull (with fitted equipment) you will see small screw location sockets and the corresponding screw holes in the deck. It is therefore logical to conclude that Dave built his version with a fully removable deck.

You can also see how he fitted the shafts.

Paul

Edited By Paul T on 09/03/2015 10:21:01

[Author]

Posts