Automating multiple battery tenders - how often to turn them on/off?

[lhfarm]

I run a half dozen battery tenders in my unheated barn. Three tractors, my ZTR, and two old Jeeps. I hate the idea of running them 24/7 all winter long. I already have home automation running in the barn, so I can turn individual outlets on/off remotely and on a schedule. I've mainly used it for turning on the block heaters.

I haven't found anything here or online about what makes a good schedule so that the batteries are ready if I need them. I'm thinking about a once a week for 24 hours as a starting point. I know there are lots of variables - battery age/state etc - and I could program each one. But just trying to not overthink this.

Does anyone have their tenders on a schedule?

Barry T

 

[fatjay]

Battery tenders generally do that, tend the batteries. When they detect the battery is topped up, they shut off until the battery drops below a certain voltage. This way, the battery isn't overcharged. It's not like the old style trickle chargers that charge at a constant rate all the time. So it's safe to leave them on.

I have a variety of chargers, but I think my favorite is the noco genius 2.

 

[Peter 315]

I just leave my 5 battery minders on all the time..

 

[oosik]

I have three battery tenders. They will shut down until they sense a need to "top up" a battery. I mainly keep them on my "vehicles" only in the winter. The idea being - keep the battery topped up so it won't freeze.

 

[Oaktree]

Most of mine are "dumb" trickle chargers. I've just got them on a timer...usually 3-4 hr/day. I would imagine it's safe to leave a smart charger connected 24/7.

 

[BigBlue1]

That's what a battery tender is designed to do... automatically alternate between charge and no charge depending on the state of the battery. I run many of these in my shed in the winter, 6-8 at any given time, and I just leave them do their thing. I have great results with batteries. The battery in my Honda VTX 1800C cycle lasted 13 years.

Now if what you have is a 'trickle charger' that's an entirely different thing. If so, buy battery tenders. They can be had for about $25 each. Completely worth it.

 

[Tinhack]

My experience with battery tenders would be to NEVER turn them off unless you remove them from the battery. If you lose/cut power to them they will render a battery stone-cold dead in about a week. This is the type that tell you to connect the battery first then plug the tender into AC. Without AC, they constantly draw power. I lost three batteries when I lost power and nearly a fourth. The fourth was less than three months and a larger battery. I'm glad of that because it was one of the $250 batteries. I was able to put a real charger on it and bring it back to life.

They are tenders. Leave them on or remove them.

 

[kozal01]

My advise after using tenders for years at the expense of battery life is to not waste time with them. Make sure the battery is fully charged then disconnect it. If you're really worried about the cold bring them inside. Once I stopped with tenders my batteries lasted years longer and Ive never had a dead battery in the spring.

 

[4570Man]

My experience with battery tenders would be to NEVER turn them off unless you remove them from the battery. If you lose/cut power to them they will render a battery stone-cold dead in about a week. This is the type that tell you to connect the battery first then plug the tender into AC. Without AC, they constantly draw power. I lost three batteries when I lost power and nearly a fourth. The fourth was less than three months and a larger battery. I'm glad of that because it was one of the $250 batteries. I was able to put a real charger on it and bring it back to life.

They are tenders. Leave them on or remove them.

That’s not been my experience. I have one on my dump trailer and one on a truck that doesn’t get used everyday. I never bothered plugging the truck one up unless it’s sitting a couple weeks and the trailer sits on jobs for a dumpster. I usually don’t plug it up more than a couple days before I plan on dumping it. Neither one ever killed the batteries.

 

[BigBlue1]

My advise after using tenders for years at the expense of battery life is to not waste time with them. Make sure the battery is fully charged then disconnect it. If you're really worried about the cold bring them inside. Once I stopped with tenders my batteries lasted years longer and Ive never had a dead battery in the spring.

That's 180 degrees from my experience. I have a lot of equipment and vehicles with batteries and battery issues are very rare for me. Over the last decade I've probably had, on average, a dozen vehicles or pieces of equipment with a 12V battery (not including power tools, obviously) stored or in use over each winter. I've purchased two replacement batteries in that time: one was for a 2015 Highlander that is used all the time and never on a tender; the other was a 10 year old original battery in my 2012 Victory Cross Country cycle replaced in 2021. This is everything from small batteries in my trailer's brake control to motorcycles to full size truck and tractor batteries. I also live in MN where in the winter these batteries in non-heated storage shed can get down to -20*F sometimes and below freezing most of the winter. You don't just let them sit without a tender unless that vehicle is used at least weekly.

I find battery tenders to be fantastic.