is this wattmeter ok and how to fit

[footpump]

hello all have kudos vita uno 3 years old 4k covered battery is now wanning.

power seems ok on flat but under load display drops to 1 out of 4 battery level.

if I do fit a wattmeter will it tell me what is left in the battery as regards watts/ah
whats in the battery when fully charged from its original (10.4 ah)

and idiots guide on http://www.ebay.co.uk/itm/New-FT08-RC-150A-Hight-Precision-Watt-Meter-Power-Analyzer-Backlight-LCD-UK-K1O7/162083199831?_trksid=p2054502.c100227.m3827&_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20160908103841&meid=b3d70559c3884d479b88d8e0a5e6eaf5&pid=100227&rk=2&rkt=12&sd=391310516149how to fit the meter, this is the one I have purchased

 

[Deleted member 4366]

All you need to do is find the two wires from the battery to the controller. Cut or disconnect them. Join the two on the load side of the wattmeter to the two on the controller and the other two to the battery.

If you want to mount it remotely, do the same but use 14g wire to run up to the wattmeter and back. Leave the red wire joined as it was before, but splice in a thin wire and run it up to the battery side red of the wattmeter. Leave the load side red disconnected, but insulated.

The red wire is only used to power the wattmeter. The measuring is done on the black wire, so the full current goes through it to the wattmeter, which is why you need a thick black, but only a thin red. The thick red from the battery must be joined to the thick red from the controller though.

 

[footpump]

thanks d8veh whats the best method for joining the wires ,as I might want to revert to standard at av later date

 

[Deleted member 4366]

I use Deans connectors, or you can solder the wires together, which is quicker and cheaper. When you've finished with the wattmeter, unsolder it and solder the original wires back together. That's easier than soldering on connectors.Use heatshrink sleeve to insulate them.

 

[D8ve]

Perhaps it might be easier to run the battery flat then time how long it takes to charge.
A 10 ah battery should charge in 5 hours at 2 amps.

 

[awol]

if I do fit a wattmeter will it tell me what is left in the battery as regards watts/ah
whats in the battery when fully charged from its original (10.4 ah)

Ideally, when you've fitted it you would charge the battery up to full, then in one go - run the bike until the battery cut's off and take the wh/ah readings for future referance, but the watt meter will also cut off and loose the readings so you would have to keep an eye on it when the battery is getting very low down to about 30v ish under load.
There is also an aux socket on the side which can apparently be used to connect external power, anyone know what the tiny plug is to use that?

 

[Deleted member 4366]

This is the best watt meter. It has a remote shunt and it remembers it's reading:

http://www.ebay.co.uk/itm/DC-50A-LCD-Voltage-Current-KWh-Watt-Car-Battery-Panel-Power-Monitor-Combo-Meter/181814316903?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=2&asc=20140122125356&meid=abfb62cdf5de4035900cee73c6164a71&pid=100005&rk=1&rkt=6&sd=171870530730

 

[Andy Bluenoes]

I cant get the search function to find what Im looking for and I know its here somewhere...
Its related to using this meter.

My battery is a 48v, and shows 55v when fully charged. It has usally dropped to a touch under 50 after my commute....memory tells me that the voltage drops by 1 volt for every 10% is that correct? If so, Im actually only using 50% of my battery, which would explain why its fully charged after 2 hours or so.

Do these meters show the voltage as it drops so you can more accurately estimate fuel left?

 

[Nealh]

Do these meters show the voltage as it drops so you can more accurately estimate fuel left?

Yes if you verify the voltage reading when initially connected.
Some are better then others you need to verify any voltage reading with a dvm or other meter source. I had a 150a GT one but it over read so when I used it I had to allow for the voltage over read, the Gt 130a and the blue 100a ones I have had have all been pretty much bang on.
I use them for checking all my lion battery voltages and when bulk charging lipos. I now have one wired up in line and it lives in the panniers. For Tueday's ride I paralleled some lipos to my Oxydrive battery as the controller is integrated with the battery fitting, the finished voltage reading was 37.25v, another independent reading with a lithium lipo/lion multi checker showed the lion was 37.25v and the lipos at or about 37.02v. I paralleled at about 41.5/6v so all in all the batteries discharged quite evenly as did the readings.

 

[Andy Bluenoes]

Thanks for that

Are they waterproof so you could mount them on the handlebars?

 

[Nealh]

Not really.
The blue 100a aren't one of mine got wet I and now only shows volts and amps ok for the pannier now as a fuel gauge. The GT's are better though still need a bit of sealing at the ends where the wiring exits, there is an air vent on the back.

 

[Deleted member 4366]

Some of them don't work with 48v, even though they're supposed to. IIRC, it was the GT meters. The display goes blank. You have to change a resistor somewhere to get it to work.

There's a new one now with a remote shunt, so easier to install. It's panel mount, so you need a box or panel to mount it:

http://www.ebay.co.uk/itm/New-DC-0-90V-0-30A-Voltage-Current-Energy-Power-Watt-Meter-HHO-EV-car-Solar-Wind-/142041096071

 

[Andy Bluenoes]

Thanks for the tips...I'll probably leave it as its not going to be straightforward then. The bike wont be long term so not worth going to too much trouble to add one to.

 

[Deleted member 4366]

A wattmeter teaches you so much about how your motor works. I'd recommend everybody should have one for a while. They're not difficult to fit, especially the ones with remote shunts. You just cut the battery negative wire and fix the ends to each side of the shunt, then connect three thin wires: one to the battery side; one to the controller side; and one to any battery positive. Run those wires up to the display.