Battery Charger/Maintainer - What do you have/recommend?

You have conflicting requirements.

Typically, a charger with enough capacity to have a "start" function will NOT have the electronics
necessary to also serve as an automatic tender type charger.

IF.....you really need both functions, you probably need two different chargers.

NOTE: But if you get a tender with a capacity of say 4 amps, under most circumstances that should bring a weak battery back to life in an hour or so. If it is completely dead, it might take longer ........or not work at all.

I have and recommend the Battery Tender brand. 2 amp capacity or higher.
For starting a "dead" vehicle, I have jumper cables.

 

^ As both responders have said, you need two things.

What I’m using:

Jump starter: Clore JNC660 < It’s seen VERY limited use; never needed it for ours. It’s old-school, weighs close to 20 lbs.

Not sure I’d recommend though; the new light/compact lithium chargers look interesting. The quality varies though? All of them seem to have terrifically short cables.

Charger: CTEK 4.3 < It’s virtually always in use; we drive very infrequently, and I keep the battery on the charger ‘round the clock during the downtimes. I have it’s quick-connect wiring installed, so don’t need to use alligator clips.

It’s been quite dependable; I’d recommend. Current iteration is CTEK 5.0, pretty much the same thing.

NOCO is another good name. They have on-board chargers as well, intriguing.

 

As mentioned previously, you need two things. Three would be even better.

Need: I also recommend Battery Tender. I'd had mine for several decades. And when I took my part time job almost a year ago, I found that that shop uses the same brand and size as what I have.

For starting a car with a dead battery, the handiest thing is a lithium jump start battery because you always have it in the car with you and don't need to plug in. I have a Noco GB 40 that has always worked (even on a Ram 2500) except for one neighbor's car that was so dead I had to get out my plug in charger and let it charge for a few minutes.

Mine are just examples. I'm sure there are other good ones. The Schumacher isn't available anymore, but the 1300 looks pretty similar.

 

Jump Start:

(
NOCO Boost Sport GB20 500 Amp 12-Volt UltraSafe Lithium Jump Starter Box)

Lithium jump packs are all we use in the truck industry now. We use 10,000 Amp units that can easily be carried in one hand (by the handle) to jump 13-liter and 15-liter diesel trucks that rely on four large regular batteries to start them.

I bought that NOCO 500-Amp for my Prius after reading all the reports of the OEM batteries dying shortly after 2 years of use. Sure enough, that's about when my starter battery died. I was in the middle of nowhere, with no-one around, but then remembered that I had bought and stashed the NOCO unit in the car for just such an emergency. That was a good day that could have turned out very ugly.

Project Farm just did a video on testing jump packs, but for some reason he didn't level the playing field by buying/testing the same advertised-size jump packs. NOCO did come out on top, but it could be argued that it was because he bought a larger NOCO model than the others.

 

-Right now. Half price at $19.99 at Northern Tools. $5 off if you have the $5 off 20 coupon that Northern Tools regularly sens out.

https://www.northerntool.com/shop/tools/product_200332201_200332201

It still works after eight years and is still going strong.

BatteryMINDer Plus Battery Charger/Trickle Charger/Desulfator — 12 Volt, 1 Amp, Model# 12117TC

 

Haven gone that route yet, but I’m intrigued by on-board charger options. I see Toyota does offer “one” such accessory, for 4-Runner IIRC. For absurd price though.

I believe NOCO’s got one suitable. It’s been mentioned by @MSantos (fabled PriusChat and CleanMPG member, in same league as @Elektroingenieur and @ChapmanF for technical knowledge).

 

Was it the Comfort+ from Toyota Canada? If they offered it for Prius at a reasonable price I'd head across the border and get that installed. We regularly see -25F cold and the heat pump in my Prime can't preheat in that. But a block heater, battery tender and in cabin heaters? Sign me up.

Comfort+ Heating Accessories - Toyota Canada

 

It's really sad that a reputable company calls a unit like this a "Trickle Charger".......because it is NOT.

 

Yeah, that seems to be a package, block heater and battery charger. It’s VERY puzzling why Toyota USA and the US dealerships are so reluctant to stock such items, especially the block heater. You guys are taking a terrific winter hit right now, all the way down to Texas.

up here on the coast right now, we’re +8C, raining, snow melting fast, risk of flooding.

 

The dealer's web editor is labeling it as a trickle charger, the reputable manufacturer calls it a maintainer.

BatteryMINDer® Plus Charger Model 12117: 12V 1.33 AMP Charger-Maintainer-Desulfator

 

Find a local store in Wisconsin.

 

I think ship to store is FREE. They will email you when it's ready to pick up.

I'd give the local store a call.

 

I’m not that electrically bright, but suspect you could do better by spending more than $20 on a charger. How much better I don’t really know, but I like to play it safe: stay with a popular, full-feature brand around $100.

 

Well that explains it.
We all know that "dealers" are scoundrels and morons.

 

Curious why you think the $20 BatteryMinder is not popular and full featured, search VDC Electronics on PriusChat. You also mentioned Noco on board charger as intriguing, I have a BatteryMinder mounted as an onboard charger, just plug it in.

I have 4 BatteryMinders, a 1amp BatteryTender, a Ctek 7002, a B&D 15 amp charger starter desulfator, couple of no name 6 amp chargers, no name load tester, Clore BA6 load tester.

I also have a Noco GB70 Jump starter. I realize that it would be prudent to have a 4 amp charger maintainer if a person only had one battery to maintain, but I have upwards of 10 batteries to maintain.