External Battery Question

[jsac8]

I live in Norway and am faced with plenty of cold weather riding. This time of year all of my rides are in temperatures in the 40s and 50s. I was burning through batteries like crazy so I decided to build an external battery. I read the posts on the forum and decided to go with 2 AAA batteries and small copper strips over the connection points on the mount. I have a Gen3 iBike pro and am using the latest firmware. Now that the mount is built I have a couple of questions.

First, when the external battery is attached to the mount I used a volt meter to test the connection, which showed 3.21 volts. I then checked the voltage from the battery in the iBike, which was 2.90. When I place the iBike on the mount (with the external battery attached) the voltage shown from the iBike is 2.90, the same voltage as the iBike by itself. Is this correct? I assumed that the iBike would show a much higher voltage once connected to the external battery. Maybe it will only display the voltage of the internal battery..

Second, does the internal battery in the iIike need to be replaced if it falls below 2.7ish volts, even though an external battery is also connected? Shouldn't the external battery provide enough voltage for the iBike to function properly?

Thirdly, will the iBike function any differently once an external battery is connected? This question came up because the first day I rode with the external battery I had a huge problem with the wind scaling and thus the watts. I gave the unit ample time to acclimate and performed tilt and offset calculations prior to riding, as well as used a good profile.

Lastly, will I need to perform a new calc ride and coast downs with the external battery attached?

I would appreciate any feedback from other users with an external battery.

Thanks,
Josh

[rruff]

I don't understand why you picked 2x AAA batteries... lithium works better and it's what the iBike already uses. I've been using a CR123A with great results. Mine reads the voltage of the external when I hook it up... so maybe something is not connecting.

My wind scaling changed a lot (much higher) with the Gen3 and the external battery. I also have a Gen2, and oddly it doesn't change. I haven't a clue as to why... but you might need to redo your wind scaling. It's easy... I check it all the time.

[jsac8]

I chose 2xAAA because they were easier for me to use because I don't have soldering equipment and I couldnt find a holder for the c123a. Both the 2xAAA and the cr123a should provide 3 volts. I am pretty sure that I saw posts from other users saying they used 2xAAA too. But my iBike definitely does not read the voltage from the external battery. Do you know if there is an issue with using alkaline batteries instead of lithium? Could this be causing my ibike to not be picking up the voltage from the AAAs? Your help is much appreciated.
-Josh

[Steve_Davidson]

I chose 2xAAA because they were easier for me to use because I don't have soldering equipment and I couldnt find a holder for the c123a. Both the 2xAAA and the cr123a should provide 3 volts. I am pretty sure that I saw posts from other users saying they used 2xAAA too. But my iBike definitely does not read the voltage from the external battery. Do you know if there is an issue with using alkaline batteries instead of lithium? Could this be causing my ibike to not be picking up the voltage from the AAAs? Your help is much appreciated.
-Josh

I've used a cr123 and also 2 x AA but not AAA's. Take the battery out of the ibike and put it on the mount to check if the external battery is performing. Easy check. AAA's don't have high capacity so won't last long.
cheers


Steve

[rruff]

If they are alkaline batteries they should work, but they don't have as good performance at low temperatures. I'd check to make sure that everything is making contact... maybe take the battery out of your iBike and see.

[jsac8]

If they are alkaline batteries they should work, but they don't have as good performance at low temperatures. I'd check to make sure that everything is making contact... maybe take the battery out of your iBike and see.

i tried that and the ibike would not turn on. will your ibike turn on without the battery removed? i don't understand why there is a connection problem though, because when i test the copper strips with the voltmeter it reads 3.21 volts, but somehow the volts are not being received by the ibike. my only thought here is that the ibike is not compatible with alkaline batteries.?.? i am going to buy some lithium AAAs tomorrow to see if they work. if not i will rework the external battery to use a c123a...

[Russ]

jsac8,

Observe your iBike on the USB cable. If you see the voltage rise there then it means the voltage in is basically working. If you unhook the cable or the iBike from the cable while watching the voltage, you should see the voltage drop to the internal battery's normal level.

This check being completed ok, I would suspect that the copper strips may need cleaning or the like as meter leads, being somewhat sharp to sharp on the ends put considerable more pressure per sq inch than the iBike contacts and might give a good reading when the iBike doesn't. Also the meter draws less current (microamps) to take it's reading so a little resistance won't do much to that reading.

I think (try it) that you can power up the iBike on the USB with no internal battery.

Russ

[racerfern]

Some notes from another happy external battery user.

I use a CR123 in the handlebar end with a wire up to the head. You don't need a holder, just put a few layers of electrical tape around it and shove it in. Go buy a cheap soldering iron. It's easy.

The battery voltage as shown on the iBike is almost always around 2.8v even though the external is at 3.03v.

I've only used 3 batteries in the iBike over the last 5 months although I don't have bitter cold weather.

And yes, even a battery that shows as bad upon startup will rise to the occasion as soon as you put it on the mount with the external battery hookup.

[jsac8]

Some notes from another happy external battery user.

I use a CR123 in the handlebar end with a wire up to the head. You don't need a holder, just put a few layers of electrical tape around it and shove it in. Go buy a cheap soldering iron. It's easy.

The battery voltage as shown on the iBike is almost always around 2.8v even though the external is at 3.03v.

I've only used 3 batteries in the iBike over the last 5 months although I don't have bitter cold weather.

And yes, even a battery that shows as bad upon startup will rise to the occasion as soon as you put it on the mount with the external battery hookup.

How often and what will cause you to decide to change the internal battery in the iBike unit? Did you also find a difference with the wind scaling after hooking up the external battery?

It is no fun going through so many batteries here so I appreciate all of your responses.

[racerfern]

Like I said, 3 internal batteries in the iBike over a 5 month period. I change them when I finally get a "BAD BATT" message turning on the iBike when it's not on the mount. I don't think I would ever get a BAD BATT message if I left the iBike on the mount all the time.

Even though I can take a bad battery and put it on the wireless head at which point the voltage goes up to where it's good, I'm not going to push my luck.

Wind scaling does not change. However, the effects of wind offset because of voltage changes are eliminated. IOW, wind offset will not change during your ride because the battery voltage is constant. Wind offset will still change if there are significant temperature changes, but at least one of the two things that affects wind offset is now under control.

[jsac8]

thanks to all for your input.

[rruff]

Mine works with the battery out... so I'd advise checking to see if you are applying voltage to the right terminals. If so, then the terminals are not making contact. Your batteries are not the issue.

[rruff]

Wind scaling does not change.

I wonder why mine does... and this is with two different Gen3 units, BTW. I'm talking about the wind scaling nearly tripling... currently at 3.6.

[rruff]

I've only used 3 batteries in the iBike over the last 5 months although I don't have bitter cold weather.

Come on... it's hardly even *cool* in the winter in Santa Barbara! But I've had a similar experience riding in temps generally ~40F this winter. The external battery has been in there about a year now too... I think... and still has good voltage.

[racerfern]

Wind scaling does not change.

I wonder why mine does... and this is with two different Gen3 units, BTW. I'm talking about the wind scaling nearly tripling... currently at 3.6.

Nope, my wind scaling number has been at .462 since I last moved the iBike to its latest position. Come to think of it that was after the external battery was installed. However the wind scaling previously was .473 IIRC so with a slight change in the location of the iBike I would have to say wind scaling has not changed.

[racerfern]

I've only used 3 batteries in the iBike over the last 5 months although I don't have bitter cold weather.

Come on... it's hardly even *cool* in the winter in Santa Barbara! But I've had a similar experience riding in temps generally ~40F this winter. The external battery has been in there about a year now too... I think... and still has good voltage.

Santa Barbara??? It gets cold that far north. I live in Newport Beach and had to endure sub 40F temps quite a few times. Although it never went below 33F. All kidding aside, battery life take a big hit even below 45, so the external battery has certainly help tremendously. Even at 45-55 degrees, the external increases the battery life of the CR2032 significantly.

[rruff]

Sorry... don't know why I had SB in my head. I lived for several years in the LA area, and it *can* be cold... briefly... when you get out at the crack of dawn in winter.

I find the whole issue of wind scaling pretty curious... why it varies so much depending on the unit, in addition to why my external battery mount seems to be the only one that results in a huge change. My wind scaling is 8 times bigger than yours! My unit is mounted right next to the stem, so it isn't obstructed in any way.

[racerfern]

Anything other than dead center will affect the wind scaling significantly, but then again you know that. Each iBike is different in regards to wind scaling. If you were stem mounted previously you might have had a huge change in readings.

My friend with whom I ride regularly had his wind scaling drop from 3.3 to .75 by moving from next to the stem to the stem itself so it's not an unreasonable number change.

[jsac8]

Anything other than dead center will affect the wind scaling significantly, but then again you know that. Each iBike is different in regards to wind scaling. If you were stem mounted previously you might have had a huge change in readings.

My friend with whom I ride regularly had his wind scaling drop from 3.3 to .75 by moving from next to the stem to the stem itself so it's not an unreasonable number change.

racerfern - out of curiosity, will your ibike function without an internal battery?

[racerfern]

racerfern - out of curiosity, will your ibike function without an internal battery?

Yes it will, I just tried for the first time. However the iBike only shows a voltage of 2.63v without an internal and 2.88 with the external. That's in the house at 72 degrees this morning. So I have to assume that without the internal battery I would get a BAD BATT message. I'll check that next time the unit is off for more than four hours.

One more thing, I turn my unit on and set it outside to acclimate. When I'm ready to ride I put it on the ibike mount and do a wind offset, otherwise just putting on the mount will change the wind offset simply because of the possible change in voltage. As the day progresses, if there are significant temp changes I will do an occasional wind offset. However, assuming pretty constant conditions I don't do another wind offset for that ride.

[rruff]

Anything other than dead center will affect the wind scaling significantly, but then again you know that.

Actually I don't.

My friend with whom I ride regularly had his wind scaling drop from 3.3 to .75 by moving from next to the stem to the stem itself so it's not an unreasonable number change.

Think about that for a moment... both have a clear unobstructed view to the front, so why the huge reduction with the stem mount? Unless the stem mount puts the sensor in a spot where the airflow is accelerated (ie behind the bar)... resulting in a lower scaling factor. The problem with that IMO, is that this effected airstream will probably be variable if the wind fluctuates. But I doubt that accelerated flow could account for that big of a change anyway.

Mine was running ~1.1-1.2 next to the stem until I got the external battery. I tried adjusting tilt to see if that mattered and it didn't.

[lorduintah]

My most recent iPro is mounted as close to the stem on the handlebar as I can get. The wind scaling is about 2.5 - and is a little different between the three sets of wheels I have - Mavic Ksyrium, Mavic Cosmic Cabone and Corima Aero. I had my previous iPro go from 0.7 to 3.x in the matter of 4 days - while not doing anything to it or the position of the mount and nothing to the battery. - I think this was an electrical belch that shifted something substantially - maybe even a diode popped on the circuit board?

I would think that the stability and reproducibility of the electrical circuits would be a little more robust, as well as the sensor to sensor variability. But then I also do not have knowledge of what was done in designing this circuit.

I want to make a point that this has gotten off the original topic and am sorry that we (a few of us, anyway) twist the path away from the original topic. There does seem to be some conflicting information on battery voltage levels and the wind offset and or scaling - which can be a lead in to more than just cold temps needing a bigger equivalent battery (i.e., external). It is curious about the relative range of wind scaling and how this could affect aerodynamic sensitivity as far as watts - is the wind scaling a measure of the sensors linear response to wind velocity more than a deviation from "zero"? These two concepts could be in conflict and indeed the response of the sensor may not be linear over the range of typical wind speeds - say up to maybe 40 mph or so? What is the design expectation?

Tom

[racerfern]

We're certainly off topic, however I wonder if some people haven't gotten a bug or something caught deep inside the bowels of the wind port (if there is such a place). This would significantly affect wind scaling although the chances of this happening are rather small.

[lorduintah]

Fernando -

That thought came to me not long ago. The bike path I ride has gnats - clouds of them - and the big shift I recently had with the previous unit could have been just that - assuming a high scaling factor means less sensitivity due to a blocked air path to the sensor. But that does not explain the brand new unit I now have and the 2.5 (approx.) factor - right out of the box.

Tom

[racerfern]

racerfern - out of curiosity, will your ibike function without an internal battery?

Yes it will, I just tried for the first time. However the iBike only shows a voltage of 2.63v without an internal and 2.88 with the external. That's in the house at 72 degrees this morning. So I have to assume that without the internal battery I would get a BAD BATT message. I'll check that next time the unit is off for more than four hours.

One more thing, I turn my unit on and set it outside to acclimate. When I'm ready to ride I put it on the ibike mount and do a wind offset, otherwise just putting on the mount will change the wind offset simply because of the possible change in voltage. As the day progresses, if there are significant temp changes I will do an occasional wind offset. However, assuming pretty constant conditions I don't do another wind offset for that ride.

As a follow up, this morning I removed the battery before turning on the iBike, then I put it on the mount and hit the button. The BATT TEST showed bad battery because the voltage was only 2.63v. So, I think you should keep a battery in the unit even though the external battery powers it.

Next, I installed a rechargeable lithium LiR2032 battery that was at 2.21v and placed it on the wireless head. I left it there for about 20 minutes and then turned on the iBike. The BATT TEST showed good at 2.85v. So, it appears you can use rechargeable batteries in the iBike and maybe change out the external battery once a year. I'll try a couple of rides with the rechargeable and report back.

[racerfern]

OK, this is my last posting on this subject; I hope. I can't see using a LIR2032 battery as the main battery in the iBike and relying on the external battery. Although the voltage of a basically discharged LIR2032 did go from 2.2 to 2.9 as soon as I turned on the iBike the voltage gradually started to drop. I threw in the towel at 2.61v.

So, I'm back to regular CR2032 batteries in the iBike and wireless head and the external CR123 battery in the handlebar. I've held 2.75 volts during cold weather and 2.85 with temps over 60F. I only used 3 coin batteries in the iBike all winter and expect to only use one or two the entire summer. I'm happy.

[texmurphy]

...Next, I installed a rechargeable lithium LiR2032 battery that was at 2.21v and placed it on the wireless head. I left it there for about 20 minutes and then turned on the iBike. The BATT TEST showed good at 2.85v. So, it appears you can use rechargeable batteries in the iBike and maybe change out the external battery once a year. I'll try a couple of rides with the rechargeable and report back.

I used rechargeable LiR2032's in my iAero and wireless mount getting about 6-7 hours per charge when temperatures were in the low 30F's this past winter. Easier solution when I found that copper strips just wouldn't stay put.

[ludlaw]

The LiR 2032's that I see are 3.6v. Is there any problem with using a 3.6v battery in the iBike?

[jparker]

OK I've tested the rechargeable batteries but only in the wireless mount not in the unit because I didn't want to take a chance on frying the computer! The voltage is higher at 3.6v (actually 3.7 to 3.8 when fully charged) for the 2032 rechargeable batteries you can buy online,as I had been told by others on the forum so that's why I used them only in the mount. The reason being is that you get some voltage from the battery in the wireless mount which helps support the voltage in the battery of the computer. When I use the rechargeable battery fully charged in the mount with a new battery in the computer the most voltage I have seen is 340 with no side effects or damage to the computer. I'm not saying it couldn't in some way damage a computer but I have been using this combination for almost a month with no issues. The rechargeable batteries don't last long 4-6 hrs. but that's ok because I can just charge them up in a couple hrs.and they're like new. I will only do this for cold weather riding because warmer weather won't eat the batteries like the cold does and it seems like a great alternative to buying alot of new batteries or having the cold weather wired battery rig just so I can go ride in the cold which is a good bit. (This is from a previous post I wrote over a year ago). Since then I've used this set up for the past 2 winters and still have had no problems with using the LiR 2032 in the mount(wireless). Since I could recharge them I saw no reason to take the chance of using it it the computer but from what Texmurphy states that it can be used in the computer and mount but it's good to know because if yours is not wireless then you could use them in your unit, I just didn't want to take a chance on trashing my unit since this had not really been tested. Anyway I hope this helps to answers your question

[FelicianoVASA]

Hello,

Anyone can help with a photo or a tutorial for a external battery.

Many thanks