mjp8081
100 W
I'm looking for an easy to read simple meter to gauge how much ride time/power I have left on my 8S/32-34v build. A cheap LCD or LED bar graph would be ideal. Any suggestions--Thanks
A simple inline meter to read 8S/32v power like gas gauge
- Thread starter mjp8081
- Start date
bandaro
10 kW
http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html
I got one of these. seems they may be replaced with a newer option now though. Doesn't show power remaining, just what's been used and current voltage so pretty easy to estimate how far you have left in it.
I got one of these. seems they may be replaced with a newer option now though. Doesn't show power remaining, just what's been used and current voltage so pretty easy to estimate how far you have left in it.
mjp8081
100 W
I forgot to specify--something that will not draw power and drain batteries, ideally, so I can leave it in the circuit.
There seem to be quite a few for LiFePO4 power denominations--24v,36v,48v., but not for LiPo
There seem to be quite a few for LiFePO4 power denominations--24v,36v,48v., but not for LiPo
torqueboards
1 MW
mjp8081 said:
A watt meter you can leave in the circuit when you turn it off your setup - it would also turn off the when you turn the main power off. It's not like the small balance connector alarms which draw power and drain batteries.
mjp8081
100 W
Something simple like this:
sl33py
10 kW
I like the idea!
I have tried a couple things myself. I have the balance plug alarms and those work for a "it's time to swap batteries", but not a "i'm at 50% i should turn around..."!
I got the HK Cell meter:
Likes/Dislikes - hard to read, would be impossible in bright light. Even indoors light you have to read it from "just-so" angle to make it easy to read. Not sure what "empty" or 0% equals voltage wise. I usually check when i return and i like the fuel gauge, but not super confident it's accurate until i run one fully down till it alarms.
Uses the balance connectors and it's pretty bulky. I think i could take it apart and have the screen somewhere with the "brain" buried elsewhere with an extension cable.
I absolutely love the Marbel "fuel gauge". LED's are bright and easy to see while riding (top front nose if you haven't seen it - 5 or 6 LED's) (EDIT - 8 total and here's a pic of it):
Wish there was a low-voltage e-ink option. Doing a bit of digging i saw this:
wonder if their "kit" would be easily integrated w/ arduino or similar for this function? So not my area of expertise...
Two alternatives i've thought of - the simple voltage meter someone linked on ebay. Run off your +/- so only shows voltage when powered on vs balance plugs. If you know your # of series batteries (6s, 8s, 12s) and what voltage is "full" and what is "empty" then you can guestimate what equals 50%, 75% etc.
Alternative 2 - off your balance plug run something up so it's visible. I got some 8s extensions to have the venom LCD on top so it's visible (not installed there yet).
It's alright. I plug in my batteries and connect the alarm at the same time. it's basically a nicer version of the basic alarm (in a case). Nothing fancy and i set the cutoff alarm voltage to 3.6/3.7. It constantly cycles through individual cell voltages and combined voltage which is a bit annoying.
HTH - GL!
I have tried a couple things myself. I have the balance plug alarms and those work for a "it's time to swap batteries", but not a "i'm at 50% i should turn around..."!
I got the HK Cell meter:
Likes/Dislikes - hard to read, would be impossible in bright light. Even indoors light you have to read it from "just-so" angle to make it easy to read. Not sure what "empty" or 0% equals voltage wise. I usually check when i return and i like the fuel gauge, but not super confident it's accurate until i run one fully down till it alarms.
Uses the balance connectors and it's pretty bulky. I think i could take it apart and have the screen somewhere with the "brain" buried elsewhere with an extension cable.
I absolutely love the Marbel "fuel gauge". LED's are bright and easy to see while riding (top front nose if you haven't seen it - 5 or 6 LED's) (EDIT - 8 total and here's a pic of it):
Wish there was a low-voltage e-ink option. Doing a bit of digging i saw this:
wonder if their "kit" would be easily integrated w/ arduino or similar for this function? So not my area of expertise...
Two alternatives i've thought of - the simple voltage meter someone linked on ebay. Run off your +/- so only shows voltage when powered on vs balance plugs. If you know your # of series batteries (6s, 8s, 12s) and what voltage is "full" and what is "empty" then you can guestimate what equals 50%, 75% etc.
Alternative 2 - off your balance plug run something up so it's visible. I got some 8s extensions to have the venom LCD on top so it's visible (not installed there yet).
It's alright. I plug in my batteries and connect the alarm at the same time. it's basically a nicer version of the basic alarm (in a case). Nothing fancy and i set the cutoff alarm voltage to 3.6/3.7. It constantly cycles through individual cell voltages and combined voltage which is a bit annoying.
HTH - GL!
CSN
100 W
- Joined
- Mar 4, 2015
- Messages
- 154
That Marbel guage is great.
Until something better comes along I just run an inexpensive voltage meter without the alarm speakers and connect with extension plug before I ride so it doesn't drain while storing.
One problem with gauges is seeing it in bright sunlight.
Sure if the sun is overhead can just move my hand to provide shade so it can be read.
My temp solution was to make a little hood out of plastic and tape so the gauge is easily readable as long as the sun is not directly overhead.
Not sure if I will make a hole in the board and place the LED below so it has a built in hood.
Also should point out if your connecting a voltage alarm and don't want to make piercing loud noise you can press your fingers over the speaker ports and nearly silence it.
Until something better comes along I just run an inexpensive voltage meter without the alarm speakers and connect with extension plug before I ride so it doesn't drain while storing.
One problem with gauges is seeing it in bright sunlight.
Sure if the sun is overhead can just move my hand to provide shade so it can be read.
My temp solution was to make a little hood out of plastic and tape so the gauge is easily readable as long as the sun is not directly overhead.
Not sure if I will make a hole in the board and place the LED below so it has a built in hood.
Also should point out if your connecting a voltage alarm and don't want to make piercing loud noise you can press your fingers over the speaker ports and nearly silence it.
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mjp8081
100 W
sl33py said:
Sounds like you have been thinking the same thing. Thanks
The ones that are perfect are simply for the wrong voltage, usually 12v
or, they need charging leads rather than read the combined output, so I would need a meter for each battery pack
I wonder if there was a way to tweak a 12v meter to read and display 8S-32v, dial down the input voltage to display the correct empty/full range of 8S.
Maybe a 36v would work fine, fully charged 8S is around 34v:
http://bit.ly/1K1CTch
Or I could just go old-school:
Depending on the meter you use and the fully charged to fully discharged range of teh pack, it could be as simple as a resistive divider, using high enough resistance that there is little current flowing thru it (because this is a constant drain on your pack). The resistor series set is wired directly from pack + to pack -, and the center connection of teh resistors goes to the input of the meter. Probably the lower value resistor goes on teh - side, and the higher on the plus, but that dpeends on your meter.mjp8081 said:
The ratio of resistor values can be the same as the ratio of pack voltage : meter voltage, if the meter's range is proportionally the same as the pack's range..
But let's say you have a pack that at full reads 32v (max of 4v/cell x 8s), but your meter only reads 0-12v full range. Then your meter has a 12V readout range. That's more complicated.
Or if your meter only has a 4V readout range...the pack's ~6v from 3v-4v charged range (though that probably isn't the charge range you'd actually want to use) could be scaled to that.
Another way to do it is with op-amps, which could also use less power depending on how it's setup, and perhaps allow adjustment easeir than with ressitive dividers.
mjp8081
100 W
I think I found the answer:
http://ebay.to/1IoAsQG
If I understand the instructions right, you can program it for 8S
http://ebay.to/1IoAsQG
If I understand the instructions right, you can program it for 8S
torqueboards
1 MW
mjp8081 said:
Yeah, those ones are pretty cool. More along what your looking for inline
sl33py
10 kW
mjp8081 said:
Ordered. Exactly what i was thinking of as well. Thanks man!
sl33py
10 kW
xdaass said:
Sweet! Thx xdaass - Please let us know what you think when you use it. Maybe add pics of how you install/use it?
MrDude_1
100 kW
mjp8081 said:
now you have me looking online for the LCD screen itself. I dont need the circuit, since I run 16s lipo anyway... but I can drive the LCD with a PIC or arduino or similar microcontroller. A little voltage divider circuit, and just tie it in to the on/off switch for the bike... instant power meter visible from across the room!
xdaass
10 mW
- Joined
- Feb 2, 2015
- Messages
- 25
tested two panels on the same battery pack (3SX2) = 21.6V/22V, results are not great but may be good enough for us:
First plate showed 98 %
second plate showed 87 %
i set them several times to be Li 6 (which is the setting for 6 cells = 22 V
on the other-hand while testing the pack with a fluke (volt meter) it shows = 23 V
i think I will use it anyway and see if its a good indicator for me.
some pictures :
First plate showed 98 %
second plate showed 87 %
i set them several times to be Li 6 (which is the setting for 6 cells = 22 V
on the other-hand while testing the pack with a fluke (volt meter) it shows = 23 V
i think I will use it anyway and see if its a good indicator for me.
some pictures :
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xdaass said:
11% is a rather big difference between the two panels.
Is there maybe a trimpot somewhere to adjust it? (other than the buttons to select modes)
Would be interesting to hook it up to a variable voltage power supply and see what it reads compared to a set cell count, like what voltage is 0,10,20% and so on...
mjp8081
100 W
Ordered mine as well. For the price, if you just want the LCD display, you could just Frankenstein it out.
As far as the discrepancies in % readings, when I was looking at the various settings you can program in, relative to your battery setup (on one of the auction pages for the same item) some of those don't match up. Luckily the chart gives you the voltage range too, so it may be a matter of setting the gauge for 9S rather than the actual 8S it is reading.
I just tried to find the original chart I saw, but I can't find it--I assume it comes with the manual
It's so cheap ($6), I'm willing to mess with it--Also, even with cheap stuff on eBay from China like this, I've never had a problem getting a refund, usually without having to return it either.
As far as the discrepancies in % readings, when I was looking at the various settings you can program in, relative to your battery setup (on one of the auction pages for the same item) some of those don't match up. Luckily the chart gives you the voltage range too, so it may be a matter of setting the gauge for 9S rather than the actual 8S it is reading.
I just tried to find the original chart I saw, but I can't find it--I assume it comes with the manual
It's so cheap ($6), I'm willing to mess with it--Also, even with cheap stuff on eBay from China like this, I've never had a problem getting a refund, usually without having to return it either.
If you want to build your own
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=22675&hilit=gauge
or
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=29049&hilit=gauge
a search that shows a number of topics on the subject (also others that arent')
http://www.endless-sphere.com/forums/search.php?keywords=gauge&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=22675&hilit=gauge
or
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=29049&hilit=gauge
a search that shows a number of topics on the subject (also others that arent')
http://www.endless-sphere.com/forums/search.php?keywords=gauge&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
mjp8081
100 W
I just got mine, sans instructions/manual. This eBay listing includes the best instructions, including the battery setting codes AND f1-f6 display modes:
http://www.ebay.com/itm/12v-48v-Dig...ester-Lead-acid-Lithium-Battery-/181662987310
Also, it retains its voltage/battery settings without the need of any power. It's important to know the "f" functions (I had to search a bit), so you can minimize power draw and get display mode with more precise "nn.n V" reading along side the simple battery graphic. If this thing ends up being an accurate gauge, I would say for the price and features its a "must have" for your eBoard--really cool little gadget.
http://www.ebay.com/itm/12v-48v-Dig...ester-Lead-acid-Lithium-Battery-/181662987310
Also, it retains its voltage/battery settings without the need of any power. It's important to know the "f" functions (I had to search a bit), so you can minimize power draw and get display mode with more precise "nn.n V" reading along side the simple battery graphic. If this thing ends up being an accurate gauge, I would say for the price and features its a "must have" for your eBoard--really cool little gadget.
My gauge arrived today and I couldn't wait to install it and try it out. Works ok, easy to read even during the day. Don't know how accurate it is. Need to use up the batteries to 3.7v and see what percentage I get. The only complaint is when the percentage displayed goes up and down with corresponding throttle use. Only when you are off the throttle that the display figure stays steady Giving you a "true" percentage of remaining battery level.
Will build a mini matching enclosure to protect device. For the price and being compact enough, I think it serves its purpose.
Will build a mini matching enclosure to protect device. For the price and being compact enough, I think it serves its purpose.
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sl33py
10 kW
Thanks mjp8081 - exactly what i needed to configure mine!
cdn - that looks sweet! I'd be a bit worried about water with the back fully exposed - maybe some plasti-dip or similar to waterproof it? I'm hoping to do something similar on my next build and it's really great to hear it's readable in direct light!!
Random q - anyone turned on the low voltage beep on these? I don't see a speaker for it to alarm. I plan on still using a cell alarm on the balance plugs, but hey an extra warning doesn't sound like a bad idea.
cdn - that looks sweet! I'd be a bit worried about water with the back fully exposed - maybe some plasti-dip or similar to waterproof it? I'm hoping to do something similar on my next build and it's really great to hear it's readable in direct light!!
Random q - anyone turned on the low voltage beep on these? I don't see a speaker for it to alarm. I plan on still using a cell alarm on the balance plugs, but hey an extra warning doesn't sound like a bad idea.
mccloed
100 W
What about one of these:
http://www.batteryspace.com/fuelgaugeforpcbof296vli-ionbatterypack.aspx
http://www.batteryspace.com/fuelgaugeforpcbof296vli-ionbatterypack.aspx
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