Power Meter - Rechargeable or replaceable battery?

Hi there,

I am in the middle of making a decision between Power2Max and Quarq PM and one thing makes me thinkinh, is battery types.

While Quarq offers PM with 2032 replaceable battery, Power2Max comes with rechargeable one. I am not a big fun of rechargeable batteries but Power2Max look like a solid PM.

Appreciated if you can share your thoughts and experiences?

Thanks

My P2M uses a coin type battery, not rechargeable. Which model are you looking at?

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Thanks for the reply.

Check out DC Rainmakers review of the P2M eco which is the one with the coin battery vs the more expensive rechargeable model. Bottom line, no good reason to buy the more expensive one. FWIW I have the eco and totally happy with it.

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After 2,5 years I have only very good experience with NG ECO and batteries - I just need to change it 3-4 times a year. Mostly before it is actually needed, just in case so technically you can do it even less often. The only pain is CR2045 battery is not as common as for example CR2032 so it is more difficult to buy one if you need it NOW :slight_smile:

In my other bike with Quarq dzero power meter after 6 months I still have an original battery inside, but this bike is used rather rarely. This is CR2032 battery so you can but it literally everywhere.

On the other hand, I have rechargeable battery for my Di2 and it is also completely flawless. Just recharge it every 2-3-4 months and thats it.

I’m generally a coin-cell over cable kinda guy, but merely because I have zero organizational skillz and 10,000 cables.

So, trying to figure out a month or two later where I put the always-unique charging cable for that given power meter is a pain in the butt. Or, remembering to take it travelling. Or, when I do ignore the low battery message one too many times and then want to ride and have to A) Find the damn cable, B) Plug it in to charge

That said, many other people are more organized than I. Or, don’t ignore the messages.

I’d love to see a re-chargeable power meter with a simple twist battery cover over a USB-C port. That’d I’d be happy with. I get why companies do non-standard ports (waterproofing is better), but why can’t someone do a battery cap style design that opens up to a USB-C port?

Hmm…maybe I’ll ask Quarq.

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My 4iiii left only crank is charged via a micro usb cable. It’s a bit fiddly but works just fine. It’s the same cable I use for my lights and wahoo so that’s actually pretty handy.

I try not to use disposable batteries for environmental reasons, that’s the reason I went for a rechargeable power meter. But I can understand people who prefer to have some spare batteries handy instead of remembering to charge every once in a while. If the iq2 pedals ever get here I’ll try and find some rechargeable coin cells, if those even exist.

I use my Quarq PM 5-6 times a week every week of the year. I’ve only needed to change the battery once a year.

Just to understand, is this rechargeable also replaceable? I was confused with BBs and now batteries :smile::smile::smile:

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Same here with the Ng Eco and the coin cell battery. Such a hustle free little thing. You change it like once every few months and that’s it. The PM (and the head unit if it has such a feature) will give you ample time for changing the battery if it will be running out.

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I don’t see a case for the NG over the Eco. The NG is +400ish, HAS THE SAME MECHANICALS (just passed the test at a higher spec), rechargeable battery, and some useless/non-trust worthy features. The L/R balance isn’t good, the torque isn’t useful (it’s roughly your power at 90rpm cadence / 10 = torque ft/lb), and the coin cell batteries are better.

I had the Gen1.5 and the current NGeco. Coins are the s***. It’ll last 1/2 year on my 4000mi season. Coins are a downside for crankarm PMs because of chainstay clearance, but here that’s not an issue. I can carry a nickle sized spare in my flat kit in a space normally occupied by an air pocket. Only downside is that if you’re doing something like CX, you can knock out the cover with the right move. It is a low low low risk though, and I’ve never done it. P2M is top notch in terms of reliability.

On the crank- That ALDHU24 is expensive ($690w/ crank / $490 w/o). It’s nice that you can move it to a 30mm crank as it’s modular. The selling point on the Rotor is the flexibility for TT big rings through adventure MTB rings, and oval ring clockability. You lose the ability to go sub-34t here if you’re thinking 110bcd and adventure bikes. (+$200 for the crank is a good deal here BTW).
The $590 Rotor for P2M is the way to fly with just a 25gr penalty. I think it is just an Aldhu minus some machining on the crankarms - https://power2max.cc/collections/ngeco-road-powermeter/products/ngeco-rotor-power2max-edition-24mm-with-cranks.
It might be worth considering SRAM based cranks if you want to use this on a few different bikes. SRAM/Quarq carbon arms (of the same performance as the Rotor) as just cheaper and everywhere. You can pick up a set of SRAM or Quarq carbon GXP arms for $75 on ebay - https://www.ebay.com/itm/SRAM-Force-1-Carbon-Crankset-172-5mm-42t-51175/124095870959?hash=item1ce4b0b7ef:g:ZGgAAOSwG11eVEF6.
The BB30 and GXP use the same interface for the PM to the crank (same store with the Rotor Aldhu line), so the PM will transfer if you want - you’d just need a 3-bolt SRAM crank. For the GXP, you’d need to replace the non-drive side bearing in your bottom bracket or put a spacer in (worst case $100 part and labor). This only makes sense if you don’t want to transfer the whole crank for some reason - maybe you’ve got a beater CX crankset or you’ve got 110 MTB rings.

I had a similar dilemma. Garmin Vector 3s or Assioma Duos.
I ended up going with the Assiomas because the battery life is more than I ride in a month and their test was for 5,000 cycles meaning this thing will last me more than 10 years.

Sort of on topic but wondered if anyone had experience with using rechargeable lithium batteries for Powertap P1 pedals instead of non-chargable batteries?

Here’s an option on Amazon that I would like to try.

https://www.amazon.com/Rechargeable-Batteries-Charger-Charging-Indicator/dp/B08267BBJT/ref=sr_1_26?crid=2D7PNUV5331GF&dchild=1&keywords=aaa+rechargeable+lithium+batteries&qid=1590076978&sprefix=aaa+rechargable+lit%2Caps%2C181&sr=8-26