Convince me to get a Watt Meter & Power Analyzer

[kmxtornado]

Specifically, the Watt's Up one b/c it's cheaper and I'm not sure I really "need" this. For those that have been following my build thread, I'm a bit of a newb but love anything that's cool looking that I can modify and when I'm done, it moves me around town. The Cyclist Analyst some of you hardcore guys use I understand has a lot of capabilities 'n all, but the price is beyond my budget (yes, an e-biker w/ a budget). Let's focus on the lower priced RC power analyzer here: http://www.amazon.com/Watts-Meter-Analyzer-WU100-Version/dp/B001B6N2WK

Here's your chance to show off your analyzer! Share pics, talk to me like a newb. Come on techies. Let me have it.

What exactly does this do other than look cool on my handlebar?
What are the features exactly and how will my life be better b/c of it?
Does it give me the range I have left on my battery?
I know it shows me the amps I'm using in real-time during my ride, but why do I care? (not trying to be a jerk. I'm seriously just ignorant to this stuff and curious why having one of these gadgets is helpful for ebikers).

So far I've read up that it can inform me if/when my cells are out of balance. What else. Sell me on this guys. Tell me how cool it is and why you have one. Perhaps your checking different setups. That wouldn't help me, but maybe there's other benefits to this gizmo.

Enlighten me. Thanks fellas.

 

[Russell]

When I first started e-biking I mounted a WU meter on my handlebars on top of the controller. The information it gave during a ride was very interesting. It showed me when I was drawing max current, it allowed me to ride more efficiently (important with a small pack), and of course it indicated when I was getting low on juice (important w/no BMS). Keeping track of data like "Vmin" also can alert the rider if something is amiss with the pack if for example on one ride the minimum voltage is significantly lower for a given Ah used.




I also use the WU meter when charging a battery. If you watch it you'll see that each battery chemistry charge profile is different.

After a while I moved the controller but had a light with an LED voltage display which was enough to tell me the SOC of the battery. That light broke so nowadays I run with no real-time display though I still connect the WU meter to the pack in the trunk bag so I can see my power use after a ride.

The WU meter is terrrific and versatile and I can't recommend it enough. Putting Anderson connectors on it and all power leads makes it more useful.

-R

 

[Alan B]

From Memory,

Watts-Up:

60 volts max (my watts-up would die on my 18S ebike)
Displays Volts, Amps, Amp-Hours, Watts, Watt-hours, voltage sag (min V), max amps, max watts
Display switches between readings which is dangerous while riding
Requires running long high current wires to handlebars which increases losses and inductance to the controller
Display not back-lit
Display is small
No mounting system
Is not waterproof
Loses data when powered off so must keep on/waste power or keep track of amp-hours somehow when off
Knowing amp-hours in battery and seeing amp-hours consumed one can subtract and estimate remaining range

Cycle Analyst:

in addition to the above it knows speed and distance so it can do many more things
such as watt hours per mile, speed, distance traveled this charge, max speed, average speed, etc
it saves readings when powered off so it doesn't lose info or waste power
has a much larger display (large screen model)
can do active limiting of speed, current, etc
can be configured in miles or kilometers
most displays are static for greater safety while riding
keeps long term statistics such as total mileage, number of charge cycles, etc
uses shunt in controller which lowers losses and eliminates long heavy wiring
will handle higher voltage
has backlight for low light visibility
has a competent mounting system
is waterproof

 

[dogman dan]

A Wattmeter is mandatory or not, depending on your battery monitoring or bms. I rode years with no CA, and could calculate ah used close enough by noting the time recharging took. I also rode off with a half charged battery a few times, resulting in long pedals home. That could have been prevented with a simple volt meter though. 42v? wtf? full charged is 45. This was with a ping pack, so I trusted the cutoff to work. It always did, till about cyle 750 three and a half years later. You always knew the cutoff was coming, in the last half mile. You'd feel the cells go off the cliff by the slowing of the bike.

I consider the CA a mandatory peice of equipment if I'm riding with no other kind of monitoring or bms at all, And, you are riding a route that is not routine. You get the start out voltage, and knowing your pack a bit, can easily predict a good time to turn for the corral based on the wh/mi you are getting on that trail. But on a routine ride, like a commute or familiar trail, again, just knowing you have a full charge could be all you really need. You know for sure you'll make it as long as you have a full charge when you leave.

Where having a wattmeter really shines is when you are riding a new route, and really need to know your status. Setting out to ride a 70 mile route or longer, you may really need that real time watt number to make it at all. When hypermiling, that watt data real time is pure gold.

Lastly, if you plan on making a contribution to the review section, you look like an idiot without a wattmeter. I did. I did my best to get a solid number for range at a certain speed for a 20 ah 36v pack. But it was lame not to be talking in wh/mi by then. The Ca had been on the market a couple years by then, and I looked stupid. Once I could afford it, I got the CA.

 

[Rassy]

Initially I just had my Watts Up attached near the battery and used it to check how many AH's had been used, basically as a fuel gauge, and to estimate how long the charger would take.

At some point I ran wires to the front of the trike to see just what the amp draw was under various speed and hill climbing conditions. This was going to be a temporary install, but has now been made permanent. It also allows me to see what the voltage sag is with different battery sizes and chemistry.

With the mid-drive giving a choice of gears that the motor uses, knowing the real time amp draw allows me to select a gear and speed for maximum efficiency when needed on longer rides.

 

[dogman dan]

That makes a lot of sense. I think a lot of cyclone bike riders have fried stuff, by not being in the right gear. Tending to ride too tall a gear and pulling more amps than they would in a lower gear.

Watching a wattmeter, you coulld see what gear worked best at what speed, and what gear climbs a hill drawing the least.

 

[neptronix]

Hobbyking sells their watt meter for under $30..
Works up to 60v..
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080

The question is, why would you NOT want one? would you drive a car without a fuel gauge and tachometer?

 

[dogman dan]

Sure, but not without the odometer too. Had 4x4 truck that showed empty with 15 gallons left. So when it was empty, you had 100 miles range.

For sure get a wattmeter if you don't have a reliable bms to back you up.

 

[kmxtornado]

Thank you everyone! Lots of helpful info. So far I got:

- Using it as a fuel gauge.
- Did I read correctly that it can help me gauge how long I can expect the battery to charge.
- Real-time view of my stats so I can learn to ride more efficiently (determining proper gear vs amount of throttle).

This is good stuff. Keep 'em coming folks.

INSTALLATION?
Again, I'm new to this stuff. Looks like there's 4 wires coming out of this thing. How does it hook up? I'm assuming I need to splice this somewhere, throttle wire? Dunno. Don't be afraid to explain it to me like I'm in 5th grade. Elementary terms would help.

Hobbyking sells their watt meter for under $30..
Works up to 60v..
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080

The question is, why would you NOT want one? would you drive a car without a fuel gauge and tachometer?

Wow! That price can't be beat and it even looks cooler! Black with blue lights. That's awesome! Perfect for my blue bike. I really appreciate the recommendation.

 

[Alan B]

The Watts-up splices into the battery lines going to the controller. Battery to Watts-up to all loads. 2 heavy wires in, 2 heavy wires out.

The Direct Plug CA goes to the controller. One cable, small conductors, Done. Low current, just gets a sample of shunt voltage from shunt that's already in the controller.

 

[Rassy]

The Watts-up splices into the battery lines going to the controller. Battery to Watts-up to all loads. 2 heavy wires in, 2 heavy wires out.

Actually, you only have to run a small positive lead to the Watts-Up, but the negative does require a heavy wire in and out. I.e., the main positive supply from your battery to your controller does not have to pass through the meter.

 

[kmxtornado]

Thank you both. Do either of you or anyone else know how the Turnigy one is installed? My battery and controller are both on the opposite end of the bike from where I'd want to mount the watt meter. Is it correct that I would need to splice wires from the controller-to-battery wire up my top tube to the handlebar. I'm guessing the wires that come with the Turnigy and/or most watt meters are fairly short.

 

[neptronix]

Installation kit provided by home depot. This is a pipe clamp with shrinkwrap around it + zip ties to secure the watt meter to the bike. Runs inline with the battery.

 

[kmxtornado]

Your picture answered my question above as I was typing it. Boy you're fast! Thanks for taking the time to load the pic. I think my biggest challenge (since I'm such a stealthy) is figuring out how to best hide all the wires. I'm sure I'll think of something creative. Or since you guys answered my question so quickly, maybe we can turn this thread into a....

HOW DID YOU MOUNT YOUR WATT METER?
Please post pics (not you Neptronix! You've done a great job already! Thanks! You too Russell. I haven't forgotten you).

 

[neptronix]

I think my biggest challenge (since I'm such a stealthy) is figuring out how to best hide all the wires. I'm sure I'll think of something creative.

If we're talking about an upright bike, i've came up with 2 different ways:

All wires inside falconEV bag. Only wires visible are throttle cable, turnigy watt meter breakout, and rear phase cable.

All wiring in rear topeak bag.. and yes i know i should clean up those throttle + ebrake wires..

OK i'll shut up now

 

[kmxtornado]

Don't shut up. You're helpful. Thanks for the pics, but the last one doesn't seem to be working. Your method's great for diamond frame battery mounting, but I don't plan to change out my current setup with the batteries in the rear. Maybe that's the sacrifice.

 

[John in CR]

"Convince me to get a Watt Meter & Power Analyzer"...Why? I manage to get along fine without one, and I have CA's that I haven't bothered to install. Focus should be on the road, not some display. Spend the $ on more batteries, because the easy way to ride is to have a conservative maximum range target, and then all you need is a $5 bike computer. The one CA we have mounted on a bike my son uses only as a voltmeter and never even bothered to calibrate it.

If you're into getting all the data and tracking usage etc., then just get a CA and be done with it. At maybe 10 cents a day in electricity used, I can't imagine a bigger waste of time, and anything distracting you from focus on the road puts your life at far greater risk.

That's my 2 pesos anyway.

John

 

[neptronix]

fixed pics. my bad.

 

[Alan B]

If I was going to use a watts-up I would mount it at the battery and forget trying to look at it on the road. The display switches around and can lead to a crash. Stop and check it when you need to see how much battery you have left. You don't need to check your gas gauge every 5 seconds. This also allows keeping the wires short and mounting it under some precipitation protection.

One other thing I forgot to mention about the CA is you can set the voltage shutdown easily. For example you could set it at the 70% drained point and then it would give you a low warning, and you could reset it and use your reserve.

 

[kmxtornado]

"Convince me to get a Watt Meter & Power Analyzer"...Why? I manage to get along fine without one, and I have CA's that I haven't bothered to install. Focus should be on the road, not some display. Spend the $ on more batteries, because the easy way to ride is to have a conservative maximum range target, and then all you need is a $5 bike computer. The one CA we have mounted on a bike my son uses only as a voltmeter and never even bothered to calibrate it.

If you're into getting all the data and tracking usage etc., then just get a CA and be done with it. At maybe 10 cents a day in electricity used, I can't imagine a bigger waste of time, and anything distracting you from focus on the road puts your life at far greater risk.

That's my 2 pesos anyway.

John

Thanks for your response. It's always good to hear the "other side." Otherwise, what's the use of a forum, right? I realize you're comment is more for the group. But personally, I do have a computer and am an avid rider of my recumbent tadpole trike (not motorized). I'm well aware of the safety issues particularly being so low to the ground and riding in the crazy cities. The watt meter for me would be:

1. A cool factor b/c I can't stop myself from adding more and more stuff. I'm just a modaholic.
2. It would be nice to get all the info provided by one and once I understand it, I won't really need it much. Paying attention to the road is number 1. No argument there.
3. Fuel gauge

If I don't get one, the $30 + shipping saved would most likely not going into helping pay for additional batteries as it would to mod up my mini bike which I have yet to do.

fixed pics. my bad.

Thanks. I'll have a look. You are soooo fast.

If I was going to use a watts-up I would mount it at the battery and forget trying to look at it on the road. The display switches around and can lead to a crash. Stop and check it when you need to see how much battery you have left. You don't need to check your gas gauge every 5 seconds. This also allows keeping the wires short and mounting it under some precipitation protection.

One other thing I forgot to mention about the CA is you can set the voltage shutdown easily. For example you could set it at the 70% drained point and then it would give you a low warning, and you could reset it and use your reserve.

For the full stealth look and for simplicity, I was considering mounting it near the battery as you suggested. However, then I'd miss out on the live real time feed of the info when I'm climbing hills. That's probably the most attractive part. I pedal the whole time up hills and pretty much 90% of the time overall. So I'm less concerned, but out of curiosity, I'd still like to know how "efficient" I'm being. For now, my butt dyno just says that if I'm pedaling quite a bit and I don't feel the motor doing much, then that's good enough for me. Seeing some numbers would be nice though.

 

[Alan B]

Another option is to take the watts-up apart and separate the display from the CPU board. There are generally only six small wires to the display. I believe others have done this already. This would also allow you to waterproof both parts of the unit, and the CPU part could be incorporated into your battery.

 

[tuxman]

I considered getting a Watt Meter. Asked myself what will I do with the data recorded? So I didn't get one.

I also crossed dynamometer off my list, too.

 

[Alan B]

The primary use of these meters is to help you manage your battery pack - get good life, avoid ruining it early and avoid having to pedal home with no power. Other ways of doing this are often more expensive and may involve ruining a few sets of batteries as so many have done here already. At the cost of good batteries the meter is a reasonable insurance policy. But it is entirely up to you.

 

[John in CR]

With batteries other than nickle based or Lifepo4, voltage works just fine as a fuel gauge. If the OP likes gadgets then go for it of course. I'm at the other end, and once I get dual motors running with regen I'll just have a single mechanical brake, a throttle and a small voltage display, but that's me. I like simplicity.

 

[Alan B]

John, your controller is not simple. You'll hafta go back to brushed.