Battery monitor

[BRYAN ASTONParticipant @bryanaston57723]

[BRYAN ASTONParticipant @bryanaston57723]

Greetings all

Is there a simple alarm ,indicator , flashing light gizmo to show how much power is left in the battery which can be transfered from boat to boat ,this would save me waiting for the wind to blow my boat to the side of the pond.

Still plodding on with building the SY Medea

Yours in anticipation

Bryan

[ashley needhamParticipant @ashleyneedham69188]

Bryan. All Lipo boats should have the small and cheap battery voltage indicators as a matter of course. I dont know af anything for Nimh batts or SLA, however these are not so critical. In my experience the boat can be seen to slow noticeably with the latter types and so be easily turned back to base. WHat sorts of battery were you using?

In line power/voltage meters exist for general use are a great buy, see link…not suggesting this one specifically, but this is the sort of thing…doesnt have an alarm so would need to look at it in the boat. Would only give you voltage reading as a guage to how much energy the battery has left though. The beauty of this sort of thing is you can see how much current the boat uses at full power and so make an educated guess as to how much running time you might get

**LINK**

Ashley

[Dave MilbournParticipant @davemilbourn48782]

**LINK**

**LINK**

[BRYAN ASTONParticipant @bryanaston57723]

Ashley and Dave

The batteries I use are 7.2v NiMH which I always keep fully charged ,the boat that has recently been effected by the batteries suddenly going flat is the Sea Commander with a 700 series Jonhston motor, normally when the battery starts to lose power the boat obviously slows down giving me a warning, now it just stops dead, I rotate the batteries so it is not just one power pack , any ideas?

Dave

I will invest in a voltage indicator for the other boats.

Regards

Bryan

[ashley needhamParticipant @ashleyneedham69188]

Bryan. Are the batteries definately and actually flat when you recover the boat (ie if different batts are fitted does it all work ok?)

A meter will be the first step, show you power draw and if the batts are delivering a decent current, and if the voltage has dropped below what one would expect from a low (but not dead flat) battery. As you rotate the power packs it sound suspiciously like an ESC issue or something???

I have had a couple of batteries go in the past but they tend to simply not work properly at the start, or never seem to fully charge

Ashley

[Dave MilbournParticipant @davemilbourn48782]

Bryan

If you can push a pin through the sleeving on the packs to make contact with the metal tags then you can use a DVM to measure the voltage of each cell in turn. If there are any much below 1.0v then that cell is dead. If more than one pack is doing the same thing in this model then it is, as Ashley says, more likely to be an issue with either the ESC or the motor.

Using an on-board watt-meter would be a good idea; this would record and display the maximum current being used on each run. They aren't that pricey either – here's the one I have **LINK**

I'd forgotten it can also act as a low-voltage alarm, so it covers all of the problems you asked about. Shame I'm not on commission, isn't it?!

Dave M

Edited By Dave Milbourn on 15/09/2015 10:08:42

[BRYAN ASTONParticipant @bryanaston57723]

Ashley, Dave

It happens with whatever battery I use ,I have a few spare escs so I will change the one in the boat , this is the only . boat that it happens to ,I will buy one of the gizmos recommended by Dave

Dave and Ashley you will get your reward in heaven.

Thank You

Bryan

[Dave MilbournParticipant @davemilbourn48782]

I almost daren't ask, but what sort of ESC do you have in the model? I've already written down my guess and sealed it in an envelope……..

DM

[BRYAN ASTONParticipant @bryanaston57723]

From the people's Republic of China,I have never had any trouble with any of them. I will let you know if changing the esc solves the problem

Bryan

[Malcolm FraryParticipant @malcolmfrary95515]

The sudden die-off sounds like one cell in each pack tried has qualified for its' wrinkly ticket. When the pack shows fully charged, it will not be carrying the same charge as the others. As a result, it will empty sooner since in use they are all delivering the same current. When it does go empty, it tries to reverse charge, giving a drastic voltage reduction. The programming in the ESC might spot this and go into a "fail safe" or "panic" mode and basically switch off.

Using a SLA in my corvette, if I put the rudder hard left and gave a burst of full power I could judge the state of the battery by the height of the prop wash. If it was higher than the stern rail, all was well, if much lower, it was time to come in. Sort of a hydraulic voltmeter.

If using the pin trick to get to the connectors, remember to put a bit of sticky tape over the hole afterwards if the pack is still going to be used.

[BRYAN ASTONParticipant @bryanaston57723]

Greetings all

You may remember that I was having trouble with my Sea Commander suddenly losing all power, taking all your advice I changed the esc and tried the boat out again, same result a sudden complete loss of power, as I thought having two duff escs was unlikely I changed the batteries ,result perfect running, no sudden loss of power, the batteries were fully charged so the only conclusion must be that the pair of batteries must be NBG, and they are fairly new, only problem is that I cant remember where I bought them from, but is was not the Peoples Republic of China.

Regards

bryan

[harry smith 1Participant @harrysmith1]

Hi Lads

I bought a Turnigy Watt Meter(code TR-WATTMETER) about $32AU.

Reads Voltage and Amps.

Requires connectors.

Also Lipo Alarms are cheap(the black cased ones are better(reads battery voltage and cycles from cell to cell with a reading as well).

Harry

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