It’s 2019 and we’re battery charger shopping

So we finally have had our fill of the battery chargers that came in the KoP…from my last time on 1293…which ended in 2006.

I know the ones from my old pals (and employer) at AndyMark are great. What other ones should I be looking at?

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We use this one.

Probably doesn’t need to be waterproof and it says it can cause cancer in California but it does charge batteries.

Qty. 4 (12 batteries worth)

Our old charger uses the AndyMark (Qty. 2) and is still in use on the practice field and is working fine.


Oh - I see that the 12A is 4A per bank, so it’s legal once you install SB connectors.

Apart from a manufacturing defect with one bank of one charger (did not switch properly to float; quickly and easily replaced under warranty), I haven’t had or heard of any problems with the ones from AndyMark.

We’ve had great experiences with the AutoMeter BusPro 660. It’s a 6 bank charger, AGM optimized, 5 Amps per channel. Each channel is a completely independent charging module. It’s on the expensive side (Amazon has it for $800, but it’s possible to find it cheaper sometimes, I think I got it for closer to $600). The team has two, and it’s been very robust over an 8+ year period; the only issue we’ve ever had with it was a bad generator spike at an event blowing the fuses, but a quick fuse swap and it was back up and running.

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I extensively researched chargers several years ago, and was not impressed with most of the selection out there. I specifically wanted something with no buttons or user interaction, and simple red/green indicators. There were very few chargers that met that criteria and are also in the range of 4-6 Amps per channel and multi channel. If you can afford it, the AutoMeter BusPro 660 has done well for us over the past three years or so. Aside from that, there’s the Dual-Pro RS3, which seems to do fine. Though, yesterday I put some very depleted batteries on it, and it seemed to go from red to green more quickly than I would consider reasonable for how dead they were. On the Autometer, we did have one resistor on the board of one of the chargers (one individual charging bank) fry itself which disabled the charger, and may have killed a battery in the process, but we repaired it and all has been well since.

Edit: sniped

We like the Schumacher SC1301 - no-buttons operation, rock solid reliability, $40/input pricing.

Lots of empty air in plastic cases by the time you’ve got a bunch of them hooked up on a bench, but did I mention $40/input pricing?

I’ll save @AllenGregoryIV the repost from when he answered my Facebook post with this:

$49.95 and small is really promising.

I would caution teams to pay a little more than they would like for a battery charger. The battery is the life blood of the robot. If the battery doesn’t work, literally nothing else will on the robot. Get a good charger!


548 tried some NOCO chargers a few years ago and we were not impressed. They seem to be too “gentle” on the batteries for our liking. They charged pretty slow and didn’t charge very much. We were used to our old chargers charging to 130% (measured on a battery beak) but the NOCOs hardly ever got to 100%. We bought the AndyMark chargers recently and they are pretty good. They always charge to 130%, but have a couple fixable issues. First, if you jostle them around too much, the potted electronics can fall out of the plastic case. We just duct taped ours in. Also, the yellow fuse/connector block things near the Anderson connectors are terrible. Many somehow got loose, resulting in an intermittent connection. We replaced the connection with a firm solder joint, which is probably less safe but the risk seems minimal.
After those repairs, they do their job quite well.

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I’ve been guilty of buying Walmart chargers in the past, generally in between-event desperation. It seems recommendations go anywhere from $40-100 per charging circuit, so price alone isn’t a perfect predictor. I think I know the answer to this these days, but I’ll ask for communal knowledge: What goes into a good charger?

For many years we’ve coped with a dozen partially working harbor freight chargers. After buying a set of new competition batteries this year and finding out they were AGM which didn’t really work with the chargers we had, we looked at replacing them last fall.

Instead of a set of individual chargers, we splurged and ended up with an excellent deal on a Schumacher DSR127 which is a pro level 8-bank recharger/reconditioner.

One of the freshman reworked the old battery cart to fit this and the whole things looks awesome. Even better, it worked great all year.

Not much, but a our testing soon showed that we would draw upwards of 1500 Watts for a minute or so if you quickly plugged in 8 dead batteries. We didn’t wish to blow the circuits at competition so we came up a procedure to plug them in one at a time and wait for the power to come down after its initial diagnosing phase. It usually will be around 150W per battery after the initial diagnosis tapering down as it gets close to filled.

That is what the colorful thing is in the corner – a volt/amp/watt meter that cost about $12. Not only does it tell us what we are using, but its perfect for showing inquisitive LRIs how much current we are drawing.

Also list price is really expensive. I’ll say that we paid a whole lot less.


That’s the 64 million dollar question.

I would say a charger that seems to have some intelligence. It’s should be able to figure out when to stop charging. Some of the cheap chargers are just low current transformers ran through a rectifier. If you put a scope on the output, it looks like unfiltered, rectified AC. They count on the battery voltage to come up to the charger output voltage to stop the charge.

A red/green indicator is a sign that there might be some intelligence but isn’t a guarantee.

Research said charger and see if they make claims that they can be plugged in indefinitely.

I’ll bet most of the chargers folks recommend here are good chargers especially the expensive ones.

jnicho15 mentioned the NOCO chargers seem to be a bit gentle on the batteries and I tend to agree. We recently put Volt/Amp meters on them and found when they think the battery is charged they put ZERO current into the battery so there’s no trickle/maintenance current. Sometimes smart chargers are too smart for their own good.

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This looks pretty cool, how do you make sure you meet the current requirements in R42, I was looking at the product page and I don’t see a way to limit max current to 6 amps. Is there a switch or setting somewhere?

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The NOCO charger does 4 Amps per battery. They say 12 Amps then later say that they really mean 4 Amps per bank. No switch.

R42 says
“Any battery charger used to charge a ROBOT battery may not be used such that it exceeds 6-Amp peak charge current.”

They mean per battery so the NOCO falls under this.

If you’re thinking “man I really want that extra 2 Amps” I can’t blame you but we run a 12 battery rotation and these keep up with the demand.

Sorry Mark, I meant to reply to @KelleyCook but clicked the wrong button. I apologize I know how the NOCO chargers work, I was referring to the Schumacher DSR127

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Judging on how this weekend went on CD, I really enjoyed responding anyway…:slight_smile:


Before buying, we were concerned about this too (even though other teams we respect use similar systems). Then we saw this post by the ever helpful @Al_SkierkiewiczBattery Cart

Basically, as he mentioned with the McMaster-Carr 8-bank model, this Schumacher smart charger quickly figures out the battery type and charges them correctly.

The sales blurb says each back can adjust between 5-12A, but If you look at the DSR127 specs it states each bank is rated for a continuous output of 12V/7A which is more reasonable expectation.

Battery Type: Standard, AGM, Gel, Deep-Cycle, Lithium Ion
Input Voltage: 120V AC
Input Current: 12A
Output Voltage: 6/12V
Output Current: 12V, 7A cont; 4/12A int
Dimensions: 23.75 × 17 × 15.25 in
Weight: 40.11 lb
Safety Certifications: UL ULC
Warranty Period: 1 year

After getting it, we implemented “Trust but Verify” by watching the draw meter and except for a very short testing phase, the smart charger stays well under 6 amps for both the Lead Acid (now our practice batteries) and the AGMs we purchased for last year. For topping off batteries it usually significantly less, like <2A.

Its also another reason for the AC Amp/Watt meter on the side. One of the electrical mentors felt we could demonstrate this at a competition if it was inquired, though no one has ever asked us too.

The McMaster we bought is this one…

The data sheet is written my marketing people but it is really good at checking first what battery type you have connected. In a lot of testing, with our AGM batteries, these never went over 6 amps charge current. The downside is you have to press the button to start charging and the fan is kind of noisy. It gives the battery terminal voltage on one display and percent charge on the alternate display. In spite of the way the description reads, this is not a trickle charger. Instead it periodically tests the battery and charges when needed. We choose not let batteries sit on charge as I don’t want to have an unsupervised charger in a school setting.

Team 4926 has also had the connections fail on the AndyMark 3 channel charger near the yellow block. Gone… and replaced with a robust connector. Otherwise those things appear solid to us.

Are you referring to the inline fuse holders? Yeah, they are terrible. We’ve cyanoacrylated their housings shut in moments of desperation.

It would be good to replace them with ATC style inline fuse holders.

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