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Isolating A Lipo.

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Dai Fledermaus07/03/2020 12:39:29
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Which method of switching off/on or isolating your Lipo do you use when it's in the aeroplane, apart, that is, from actually unplugging it.

Max 4 sell an XT-60 style plug on a "wall plate" , it's functional, but not the neatest of solutions I'd have thought.

Edited By Dai Fledermaus on 07/03/2020 12:52:47

Dickw07/03/2020 13:05:02
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For my Sebart Pitts I made my own "motor/ESC" isolator from 4mm bullet connectors. It is controlled by a push/pull linkage, and I can isolate the battery with a quick tap on the pushrod. In the OFF position you hardly notice it.

The small red wire powers the Rx even with the motor circuit isolated, so I can check out the controls etc. safely.

Dick

isolator off.jpgisolator in-situ on.jpg

ron evans07/03/2020 14:00:58
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Hi Dai, how are you/?

Dickw, that looks a fine solution to isolating a high power drive train in a larger model.

In my models I only use 3S lipos and the smaller ones just don't have the room for an isolator

Once the throttle travel and failsafe are set with the prop off, I rely on the TX throttle cut, keeping thumb on low throttle stick and treat a live model as if the prop was already rotating.

Ron

Dai Fledermaus07/03/2020 14:22:06
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Thanks Dick for your response. That's a very neat idea.

Hello Ron, you've finally won me over, I've crossed over to the Dark Side 😉 Is there any way back?. I'll be picking your brains the next time we meet up the field - if it ever stops raining. 😊

Dickw07/03/2020 14:22:27
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Ron

I only did it on the Pitts because it's a biplane with battery acces via the nose so you tend to work through the prop arc when connecting.

With all my other planes with a safer battery access I work in a similar way to you - but I do have a locking switch on my Tx for "throttle lock".

Dick

ron evans07/03/2020 14:48:23
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Dai, I'm sure you won't regret joining the spark side, and you can still play with the oily thing if you get withdrawal symptoms disgust

Dick, is your locking switch a home made affair?

Bob Cotsford07/03/2020 14:58:42
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8390 forum posts
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I do like the Dick trick unit for where battery access is poor. In the past when I used to use Deans plugs I glued a Deans socket in the side of the fuselage and used a mating plug with the contacts shorted, a home made version of the 4-Max XT60 unit. These days I set up a rotary switch on my Horus tx to disable throttle on all my models. I don't know whether I'd trust a toggle switch alone as they're too easy to switch on by accident.

Dai Fledermaus07/03/2020 15:47:18
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1057 forum posts
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I seem to remember reading about a removable blade type fuse, as used in cars, to isolate the battery, but the details escape me. It might have been in a old copy of RCM&E.

Dickw07/03/2020 15:57:37
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Posted by ron evans on 07/03/2020 14:48:23:

........

Dick, is your locking switch a home made affair?

Ron and Bob

The throttle safety lock on my Tx is a locking toggle switch similar to this one. You have to pull up the lever before you can operate the switch so it is almost impossible to move it accidently.

Dick

Andy4807/03/2020 16:57:26
1496 forum posts
8 photos
Posted by Dai Fledermaus on 07/03/2020 15:47:18:

I seem to remember reading about a removable blade type fuse, as used in cars, to isolate the battery, but the details escape me. It might have been in a old copy of RCM&E.

This used to be BMFA's solution, but it is horrible for 2 reasons. Firstly spade fuses are not meant to be removed repeatedly, and secondly what happens if the fuse blows?

Much simpler, glue an XT60 into a strongish part of the fuselage with epoxy. Much neater than the wall plate and very robust.

leccyflyer07/03/2020 18:56:34
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1424 forum posts
317 photos

Just the plugging in of the second 4mm bullet connector into the harness renders my models live. A very small number have a switch in the radio side. I see all of the extensions in the battery to ESC leads and wonder when we went away from the advice not to overextend those leads. A fuse in that linkage is a terrible idea and always was.

ron evans07/03/2020 19:38:40
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429 forum posts
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Fully agree, fuse is a no no.

I'm sure I read somewhere that modern speed controllers are much more tolerant of battery lead extensions.

Dickw07/03/2020 20:33:42
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668 forum posts
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Posted by leccyflyer on 07/03/2020 18:56:34:

Just the plugging in of the second 4mm bullet connector into the harness renders my models live. A very small number have a switch in the radio side. I see all of the extensions in the battery to ESC leads and wonder when we went away from the advice not to overextend those leads. A fuse in that linkage is a terrible idea and always was.

In the case of my Pitts, the telemetry sensor shunt adds perhaps 0.75 inch into the positive cable, and the isolator adds about an inch, so not extended by much at all. If I was worried I could esily shorten the battery cable a bit, but that plane is several years old and has so far completed about 45 hours "in the air" without problem.

However, extending the battery to ESC leads can still be a problem, particularly if near the ESC's current rating, so it is a good idea to plan the installation to minimise extra length and I would also consider shortening existing batterey and ESC leads to compensate if necessary.

Dick

Andy4808/03/2020 11:28:04
1496 forum posts
8 photos
Posted by ron evans on 07/03/2020 19:38:40:

Fully agree, fuse is a no no.

I'm sure I read somewhere that modern speed controllers are much more tolerant of battery lead extensions.

I've used quite long extensions -up to 30cm without adverse effect on a 5S 5000mAh system, and all my models have the leads extended to some extent. Never blown an ESC yet.

I think this is one of those things which may have been true years ago but is now consigned to the backet of old wives' tales.

Edited By Andy48 on 08/03/2020 11:30:26

John Lee08/03/2020 12:07:17
719 forum posts
62 photos

Simple 4mm plug into an embedded Jeti anti spark female, worked for several years with zero issues on my Sebart Angel.

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