Hello CD!
My team and I are currently assessing battery options for our robot this season, and we’re curious about the best brand to choose or whether the brand makes a significant difference.
Specifically, we are considering purchasing PowerSonic batteries. Does anyone have previous experience with this brand?
Thanks!
In my experience, Brand does make a difference in battery performance, though it’s not the only differentiator (even within a brand you can get variations between batches of batteries).
I have heard of PowerSonic though I have no experience with them. In general, they don’t seem to be considered a “preferred” option for FRC as far as I know, that would generally go to Interstate Batteries, MK, and Duracell.
Personally, due to recent bad experiences with Interstate, and underwhelming performance by MK, my team will likely go all-Duracell for future battery purchases, as those have been rock-solid for us (though they are a bit more expensive).
I know that my team is committing to a full switch to MK Batteries starting this year. I’m not on electrical so I couldn’t get into detail on it but I’ve been told they are the best ones. I could ask one of my coaches tomorrow and get more details about this if you’d like!
MK batteries can now be purchased for $46/ea + shipping. Call 800-372-9253 and ask for FRC batteries. they’re generally regarded as one of the more available and higher quality options than a handful of other brands. Duracell is very expensive comparatively, and harder to source in my experience.
We’ve had pretty good luck with PowerSonic Batteries. We ran them in 2019-2022.
We switched to MK batteries last season, thinking they were more “premium” didn’t see much difference. They weren’t bad persay, but we didn’t see any advantage
Considering all of that, we decided to move back to PowerSonic for 2023. The price is great on amazon (with prime shipping). YMMV, but we’ve at least been happy with them.
Echoing what @lexeo said. We’ve been using PowerSonic for the last couple of years for all the competition events and they have been solid so far. All were purchased via Amazon.
We purchased a set of these for Worlds 2023. So far we like the performance. We did notice they were marginally larger in size compared to our MK batteries and were not an exact swap. Our battery compartment was very very snug on the robot. (intentionally due to violent driving, but this felt way more snug)
Anecdotal, but we use a mix of PowerSonic and MK, and I’ve never been able to tell a difference.
I wonder if there is any team who has done a pseudo-statistical comparison of battery brands. Obviously hard because no single team is likely to actually get enough statistics. I am not sure what would be the measure of battery quality (or maybe 2); maybe general Ah in the load tester, and a some measure of lifetime.
For what I would love to see, it would be something in the vein of the Backblaze long term monitoring of hard drive and SSD lifetimes, but again, would be really hard to get that level of statistics for FRC batteries.
Our team used a mix of duraacell and MK last year. By the end of the season, two of our duracells were completely unusable, and two others were completely dead when we got them (we purchased from a local batteries+, and we’re looking at other options). Our MK batteries, on the other hand, still have over 16 ah after an entire season of driving. We did run our batteries pretty agressively, and we have also had duracell batteries work very well in the past. We’re looking at other vendors for duracell, or just buying MK.
I think the problem with this is that standard battery measurement tools aren’t really designed to mimic the kinds of load conditions FRCFIRST Robotics Competition robots put on batteries, nor do they do a good job of tracking battery health over time. We’ve used a number of tools including the battery analyzer from AndyMark and most of the time the battery “quality” rankings we would give based on these tools were not reflected in actual on-robot performance, leading us to throw out the rankings and base them instead on observed performance (how fast they die).
The one method I’ve considered would be some sort of on-robot battery logging that tracks the total draw on the battery over time and the battery voltage over time (to track voltage drop) during robot operation and somehow compile that into a battery health tracker. That said, I’m also not a programmer, so I can’t really speak to the specifics of how that would work.
Anecdotally, all of the batteries seem to have gotten worse since ~2017.
Earlier this year, I set up a battery analysis rig with my big electronic load (0-600A) and collected some data on two of our Interstates (one of which had failed), four new PowerSonics, one or two of our MKs, and one Duracell. This was mostly for my own curiosity, and my process evolved during the testing. I purchased and tested the Duracell to see if it was significantly better, but I need a bigger sample size.
My main conclusion was that the chargers I used produced inconsistent results (they were not smart AGM chargers) and that I should really repeat it with proper chargers. I’m figuring on picking up one of the Noco ones that AndyMark sells.
I’m interested in doing more testing after this season. I’m especially interested (and could be persuaded to start earlier) if anyone can help me work out a decent methodology, and possibly a better battery model.
Last summer I purchased one Powersonic PS-12180NB just to test it because at that time it was $36 delivered to my house. The discharge curve I got sat right on top of the curves for the six new MK batteries we bought at the beginning of last season.
Being that I’m on team 1712, using anything other than the MK17-12 would just feel wrong. It certainly helps that they’ve also had the best performance of any battery we’ve tried.
Team 2619 has done something close to this and published their testing data in a whitepaper in 2018 (See page 20). Their conclusion was that Duracell branded batteries seemed to be the best at the time.
This Fall offseason we bought 7 new MK batteries during the summer, 7 more in October, and 7 more now for 2024 season.
For the 1st item ever, we experienced issues with 4 of our batteries from both the 1st batch and 2nd batches we got. They leak bad.
We’ve bought them from the same local supplier for years. They did mention that MK is now produced by another country (manufacturer). Cant confirm, but it probably has a lot to do with what we are finding now.
Thanks Joe for navigating the previous responses.
I do recall our supplier saying that they are now made in Vietnam. Ours have leaked the same way described by 111/112. Ours would leak after just a few uses each time for the defective ones.
At our last event at Beach Blitz, we had our 4th battery leak. 5199 allowed us to leave it there and they said they would dispose of it.
The 1st 3 we were back on island, so I got replacements from our supplier free of charge.
I’ve never had the ambition to do a real formal-type comparison of battery brands, so have always defaulted to MK.
This year I took a chance on four Powersonics via Amazon - to avoid the shipping costs from MK (its a 200 mile round trip to the nearest MK distro center for us)
Anyway - all 4 Powersonic batteries got through CBA testing, although 2 of them ended up in the 12 Ah range.
Anecdotally - our drive team claims that the Powersonics brownout more than the older MKs we have - with our non-optimized/non-current limited Kraken based MK4i swerve.
(The logs don’t seem to completely support that claim though)
So - I’ll bite the bullet and stay with MKs from now on - again, based mostly on drive team feedback …happy drive team means happy overall team
