mainlandboy Reader
2/10/22 12:34 a.m.

Hi all,

My project is car is just about complete and should be ready for the road this summer. I bought a new battery for it a couple years ago, but because the car sits in the garage un-driven for long periods, the battery could barely turn the engine over the last time I tried to start it. I'd like to buy a charger that can also be left connected as trickle charger while it sits in the garage. My local parts store has a pretty good selection, but I'm not sure what things I should look for when buying one. Is there one of these that you would recommend?:

obsolete GRM+ Memberand HalfDork
2/10/22 1:30 a.m.

It won't charge up a dead battery, but just as a trickle charger/maintainer, this one has always worked well for me:

Berck Reader
2/10/22 5:55 a.m.

I'm a fan of this one.

I've suffered through several terrible chargers, and I think this one is well worth the price. It'll charge reasonably quickly, but you can leave it connected forever and it'll trickle.  It will also desulfate, has modes for AGM and lithium and will be a 12v supply when needed.

JShaawbaru New Reader
2/10/22 6:16 a.m.

In reply to Berck :

I bought the NOCO Genius 2x2 (can charge/maintain 2 batteries), and although I just bought it for this winter storage season, I feel more confident about it than any other maintainer I've ever used. The AGM mode was important for me, and the Prius forum that I checked for maintainer advice recommended one with desulfation ability, and this has it.

Unfortunately since I just started using it in early January, I don't have any long-term use information to offer.

Real big fan the the noco genius series. Got 3 noco genius 1s and have no problem leaving them plugged in when I'm not home. 

David S. Wallens
David S. Wallens Editorial Director
2/10/22 11:21 a.m.

Some chatter on the subject that might help:


rslifkin UberDork
2/10/22 11:32 a.m.

For long term maintenance, I like the Battery Minder 1510 units.  Only a 1.5 amp charger, so pretty much just for long term maintenance.  They've been reliable, have a good charging profile to be nice to the battery and they're temperature compensated, so they charge well in a garage with varying temperatures. 

californiamilleghia UltraDork
2/10/22 11:34 a.m.

I have heard of a couple of these maintainers catching on fire and burning the car down , 

is there one brand that was having problems ?

not sure they need to be plugged in  24/7 365 days a year  if you do not have a draw on the battery.

Thoughts ?

Professor_Brap (Forum Supporter)
Professor_Brap (Forum Supporter) GRM+ Memberand UberDork
2/10/22 12:36 p.m.

In reply to californiamilleghia :

I personally only ever use them in winter in Ohio, and do one month on one month off on stuff that doesn't get touched all winter. 

maschinenbau GRM+ Memberand UltraDork
2/10/22 12:52 p.m.

I have the Autometer one. It's pricey but I'm done buying off-brand crap electronics. I wired it to the battery and put the SAE connector up under a fender so it's really easy to use. I also like that you can wall-mount it. 

I also have a Battery Tender brand lithium-compatible one for my motorcycle. I recommend that brand too.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/10/22 1:12 p.m.

Times eleventy on the Noco Genius stuff.

For my motorcycle I have the cheapest of the cheap Battery Tender brand maintainers.  They won't charge, but they will maintain.  They are a plug-in box (meaning that the plug is on the box itself) with a switching power supply inside and a chip that tells it what to do.  Assuming your battery was put away with 11.7v or more (I think that's the number in the spec) it will charge/maintain it.  I finally replaced the battery in my bike this last season after getting 8 years out of the old one, so I give it my thumbs up.

I bought a handful of the same maintainer in the HF version and I use them on the boat, tractor, and my LeMans as well.  The nice part is that they come with a quick connector so you can leave a pigtail on the battery and just plug it in.

Like this.  I leave the pigtail bolted to the battery and leave the box plugged into an outlet.  Pull the bike in the garage for the winter and plug in the connector tucked under the seat.

WirthCo 20026 Junior 12 volt .75 amp battery charger

Brett_Murphy (Agent of Chaos)
Brett_Murphy (Agent of Chaos) GRM+ Memberand MegaDork
2/10/22 1:31 p.m.

I'd love to get a solar powered solution set up for this. Is anybody getting good results with solar?

I know some of the camping/overlander folks were using them

clutchsmoke UltraDork
2/10/22 1:52 p.m.

I've been happy with my NOCO and CTEK.

P5Racer (formerly BMWGeoff)
P5Racer (formerly BMWGeoff) GRM+ Memberand Reader
2/10/22 2:54 p.m.

Check this out, Not the cheapest, but I high quality option:


Full disclosure, I work for the company.

mainlandboy Reader
2/10/22 9:44 p.m.

Thanks for all the feedback!

Sounds the NOCO Genius is well recommended, but I noticed that some other chargers have a high-amp engine start setting that you can jump start the car from:

This seems like it would be quite useful, and I don't think that the NOCO Genius chargers can do this. 



Slippery GRM+ Memberand UberDork
2/10/22 10:04 p.m.

In reply to mainlandboy :

They have jump starters. I have a NOCO that can jump start a car. Its a separate product tough; mine, at least, will not charge a battery. 

Berck Reader
2/11/22 12:23 a.m.

I'd suggest you don't actually want the jump start feature.  It's terrible for your batteries, and most of the chargers I've used that theoretically implement it aren't very good.

hybridmomentspass HalfDork
2/11/22 9:50 a.m.

I have Battery Tender and love them

I grew up with them, that's what dad has, so I got my own later in life and moving out etc

I like the quick connect pigtails you can buy, every now and then catch them on sale for about 5 or 7 bucks and put them on, dang-near, everything.

They also make USB ports (to charge a phone or something) that will plug into the quick connects, though Ive not used one yet.


I have another, older charger that I got from my dad, but it's more of a jumping off box, not trickle charger. 

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) SuperDork
2/11/22 10:46 a.m.

X however many on the battery tender. I have the pigtail hardwired on my race car and leave it in the trailer all winter plugged in.

JShaawbaru New Reader
2/11/22 11:19 a.m.

In reply to Brett_Murphy (Agent of Chaos) :

I have 2 Paladin brand solar charger/maintainers from Amazon, one is on my trailer winch battery, and seems to be working. The other was on my Saab 9-2x, and as far as I can tell, it somehow *drained* the battery. It sat fine from September to mid-November without a maintainer at all, started up no problem when I went to put it on ramps to do an oil change, but when I went to move it again, 3 week to a month after putting the solar charger on it, the battery was completely gone. I could get it running with a jump pack, just barely, but wouldn't hold a charge as soon as the car was shut off. That was with a battery that was only a year old.

I also bought a Renogy charger, and I have that one hooked up to my truck, since it only gets driven a couple times a month at most, and sometimes sits for months at a time. That one, installed at the same time as the one on the 9-2x, seems to be working great. I hadn't driven it at all this year, and when my roommate went to borrow it last week, it started up no problem.

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