meter

[Alasdair AllanParticipant @alasdairallan37423]

[Alasdair AllanParticipant @alasdairallan37423]

More daft questions on electronics! I bought this overlander voltage capacity checker to check on batteries before i go to the lake. However, nothing I can find in the instructions or online gives me much clue about what kind of lead I need! I have stuck in a servo cable in this phot just because it fits, but it has three wires and the battery has two! All advice gratefuly received!  Thanks

[Colin BishopModerator @colinbishop34627]

Alasdair,

You need a conversion lead probably a Tamiya (Female) to Servo Adapter Cable like this one:

https://www.ebay.co.uk/itm/370442889910?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&_trkparms=ispr=1&amdata=enc:1i1jB064GRsmDASZeDuVaCA48&ff=11&customid=Cj0KCQjw2ZfABhDBARIsAHFTxGw67CSvGkwgaOMDuaGvTMAVi9PqhlICj5JDC1cURWihZaTTcU7YvgUaAsYXEALw_wcB&gclid=Cj0KCQjw2ZfABhDBARIsAHFTxGw67CSvGkwgaOMDuaGvTMAVi9PqhlICj5JDC1cURWihZaTTcU7YvgUaAsYXEALw_wcB

Check that your Tamiya connector is a male one.

There are plenty of other suppliers but Component Shop appears to be out of stock.

The smaller connector on the meter doubles as an input for checking NiMH batteries and servo/esc testing as explained in the instructions hence the servo size connector. The longer connector  on the meter is used for checking LiPo packs.

Colin

 

[Richard SimpsonParticipant @richardsimpson88330]

Just a word to put things into perspective.  The capacity of a battery is a measurement of its a ability to hold charge, i.e. current.

So a 5000mah battery can hold enough charge to supply 5a for an hour.  When you go to the pond in the morning you need to know how much charge is actually in the battery so you have enough for the day’s sailing. So if your 5000mah battery has only 2500ma charge in it it will only provide 5a for half an hour or 2.5a for an hour.

For the majority of the discharge process a battery should provide a reasonably constant voltage.  It will be slightly higher when fully charged and it will drop off as the battery discharges but mostly around the quoted voltage.  That constant voltage is important as it determines the speed the motor rotates at but not to be confused with capacity.

[Alasdair AllanParticipant @alasdairallan37423]

many thanks Colin and Richard – helpful advice as ever!

[Colin BishopModerator @colinbishop34627]

Richard is right in that you need a fully charged battery and an understanding of how many amp hours it can hold and consequently how long it can run the boat for. These meters can basically only measure the battery voltage to give an indication of the state of charge. This is critical when it comes to LiPos but the NiMH batteries have a very flat discharge profile so the meter will show whether it is fully charged or discharged from the voltage but are not much use in telling you anything in between. With NiMH cells, charge them up the night before and then if they are in good condition they will deliver most of their normal capacity.

Just out of interest, I recently replaced my car battery. It would still start the car OK but the stop start function was taking longer to kick in which suggested that it was getting a bit marginal. I did a resting voltage test which confirmed this as it was down to 12.4v as opposed to the recommended 12.7v. I have a holiday coming up where the car will spend a week at the airport. On my car, as on most modern ones, if the car doesn’t like the battery voltage it refuses to crank the engine unlike older vehicles when you used to be able to keep cranking until the battery was dead.

At nearly 8 years old, it is doubtful if the battery would have lasted through another winter, quite apart from the airport risk,  so the obvious solution was to replace it. £240, but better safe than sorry and I’ve had my money’s worth out of it as the usual battery life is quoted as 3-5 years.

Colin

 

 

[ashley needhamParticipant @ashleyneedham69188]

I think most of this sort of testers are for Lipos rather than Nimhs and then you just plug the monoitor lead of the lipo into the tester and it gives you a percentage charge reading, overall voltage and individual cell voltage reading.

The wattmeter I have only has leads to go the battery, and out to the esc , and will give a voltage reading of the entire pack but also current ‘through’ readings.

Does the usage leaflet tell you anything?

Ashley

[Colin BishopModerator @colinbishop34627]

I think this is the user leaflet:

https://www.overlander.co.uk/pub/media/downloads/Overlander_Design_Capacity_Meter_Manual.pdf?srsltid=AfmBOopdi0_YJv4LGp6C9b_DCbFdzrGyQW-04J7j3_5BL80ERcfkhI5R

Colin

[Alasdair AllanParticipant @alasdairallan37423]

Many thanks Colin, belatedly!  The link doesn’t seem to work am afraid, but have wired the meter up with a male lead. Unfortunately, nothing much seeems to happen when I connect the meter to a battery. nothing appears on screen.  sorry for the stupid questions!

[Alasdair AllanParticipant @alasdairallan37423]

[Alasdair AllanParticipant @alasdairallan37423]

As I post this occurs to me that the meter has been supplied with a lead that only fits into the bit for testing  lithium batteries, not for nimh nbatteries?  in which case what kind of lead do I need? sorry but the instructions provided were not much use! thanks

[Colin BishopModerator @colinbishop34627]

Usually the lead needed to plug in NiMH batteries is a standard RX connector. It will only give you a voltage which is of limited use though.

Colin

[Richard SimpsonParticipant @richardsimpson88330]

Have a watch through this, I know it is a different unit but I suspect it works in pretty much the same way as the Overlander.

From what I can see above you are connected into the Lithium socket when a Nicad or a Nimh should be connected into a dedicated socket somewhere else.

If you check out this page here:

Overlander 8S Battery Capacity Meter

You can see the line:

Please note: This capacity controller is optimised for use with Lithium batteries. Functions are limited to total voltage monitoring when used with NiMH/NiCd batteries. External power will be required for use with 1S lithium batteries and 1-3S NiMH/NiCd.

[Colin BishopModerator @colinbishop34627]

I think there is another socket next to the Lithium one which accepts an RX type lead. This is used to measure NiMH voltage as well as supplying power for analysing some Lithium battery parameters.

Colin

[Alasdair AllanParticipant @alasdairallan37423]

many thanks – will investigate!

[Chris FellowsParticipant @chrisfellows72943]

Whilst buying a smaller battery for my Faun I thought I’d get one of these as apart from testing the voltage etc. it has uses with ESC and servo testing.

Chris

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