Smart Charger question

[Rzrbrn]

I need to keep a car battery connected to a battery maintainer while in storage at home during the time we are on the road, for about 4 to 5 months. I have been using a Battery Tender(s) for years, but one just died and will not light up. I need to replace it.

I also have a Duralast DL-50D, 50/10/6<>2 amp, automatically selects charging rate for charging & maintaining (took this info from the front of the unit). The instruction manual says this is a multi stage charger and will maintain a car battery for an extended period of time. I bought this in 2018 while on the road when the converter in my Casita died. It does not state that it is a smart charger.

Can I keep the car battery hooked up to this unit like I had the battery connected to the Battery Tender? I expect to be away from the house about 4 to 5 months.

Does anyone have the Duralast DL-50D and use it in this fashion?

[gordon2]

I cant find a manual online for that unit. It does say it maintains a float, but looks like the minimum is 2 amp which is more than I consider a trickle charge. It looks kinda cheap.

4-5 months is not that long for a battery in storage. If you just disconnect the negative battery post connector then the battery should maintain plenty of charge. And IMHO thats safer then leaving a charger of questionable quality active and unattended.

[Rzrbrn]

Thanks Gordon. Normally I do research before buying but in this instance it was an emergency while on the road with the trailer, and far from home. It was the best Autozone had and it did what was needed, that is, charge and maintain the trailer battery for a couple of months until we got home.

If no one else chimes in, I may just buy a Battery Minder 1215C.

[Jim Bennett]

I have used CTEK chargers for a bunch of years now, and really like them.They have many that do float charging.

I was wondering why the need for any charging. A fully charged battery isolated from a load will last 4 to 5 months no problem.

[GOB]

You said you want to keep a car battery up. Will it still be in the car? If so, just disconnect the neg cable. If you don't want to do that then you will need to put it on a charger.

[Darral T.]

Rzr I own the BatteryMINDER 12248 and love it! It will kick up to 8A if needed (good for a ran-down battery). My BM has a "desulfating" feature on it as well.

I also have many BT Jr's in use both at home AND at work. Wouldnt be without them.

My opinion is, whether stored with load or no load, keeping them on a smart charger will NOT hurt the battery but at least you'll know you have it covered either way!

Originally Posted by Rzrbrn

Thanks Gordon. Normally I do research before buying but in this instance it was an emergency while on the road with the trailer, and far from home. It was the best Autozone had and it did what was needed, that is, charge and maintain the trailer battery for a couple of months until we got home.

If no one else chimes in, I may just buy a Battery Minder 1215C.

[Rzrbrn]

Jim, I just got in the habit of using battery maintainers when I had a tractor and a diesel lawn mower, neither of which I used during the long winter months. The tractor battery had to be replaced yearly until I started using the Battery minder and Battery Tender. Once I started using these I never replaced a battery again. Also I notice that when I don't drive one of my cars for a couple of weeks or so the batter connectors will become corroded with sulfate: I think it is zinc sulfate, but not sure, white powdery stuff. When I use the maintainers, so more sulfate.

So now I use this all the time. I have some installed permanently on the vehicle and just plug in every time we park the vehicle.

[minke]

I have not done this myself:


It would seem that any charger could both keep your battery charged and not harm it if the charger ran e.g. one hour a day. Set a timer such as https://www.homedepot.com/p/Defiant-...6378/205517336 to one hour.

[Rzrbrn]

Thanks Alan. Interesting thought. Not sure I would want to trust this device to work for 4 or 5 months. Better to have a charging device designed to be left alone for an extended period.

[Dave Fish]

I'm not familiar with the Duralast, but I have 2 chargers that I use all the time successfully. Both are 3amp. One is a Diehard that came with my trailer. I do not have a converter, so I use it to maintain the battery when the trailer is in in the carport and the solar panel is covered. The other is a Battery Tender that I use to keep the mower battery charged between uses and over the winter.

As far as keeping a car battery up, I think it's a great idea. A few years ago, my wife's CRV did not get used for a few months and the battery died. The cost of the battery tender is far less than the cost of a new battery.

[Glenn Baglo]

From Trojan Batteries FAQ:
1. What is the shelf life of my battery?
The limiting factor of battery’s shelf life is the rate of self-discharge which itself is temperature dependent. VRLA batteries will self-discharge less than 3% per month at 77º F (25º C). Flooded batteries will self-discharge up to 15% per month at 77º F (25º C). VRLA batteries should not be stored for more than 6 months at 77º F (25º C) without recharged. The specific gravity or voltage of flooded batteries should be monitored every 4 – 6 weeks and should be given a boost charge when they are at 70% stat of charge (SOC). When batteries are taken out of long storage, it is recommended to recharge before use.

[Rzrbrn]

Darral T. I am with you on this. I have ordered the Battery Minder 1215C. I went to the BM company website and cannot distinguish between many of the models, so I just picked the cheapest that seemed like it would do the job. I prefer a bench top to a plug in. For instance, what is the difference between a BM 1215C and the 12248? Unfortunately the BM1215C is not listed on the BatteryMINDer® Non-Aviation Comparison Chart so I could not compare it to the ones on the chart. Not sure why it is not listed. But the 1215C does state that it can be used for both AGM (Optima, for example) and flooded batteries.

I have both Optima and flooded batteries. The Optima seem to last longer, are sealed, and work better, so when I replace a battery usually it will be with an Optima when they are available. I use both the BM and BT plus smart chargers. The BT Plus is the second BT to self destruct over about a 20 year period, so I have ordered the BM this time.

[Rzrbrn]

Thanks for the info Glenn. Discharge rates are even greater during the winter months, as you probably well know.

[gordon2]

Originally Posted by Glenn Baglo

From Trojan Batteries FAQ:
1. What is the shelf life of my battery?.....

This of course is for a battery in storage (disconnected) and not one installed a vehicle. Even when parked there are typically some small loads on a car battery, so 4-5 months in a vehicle likely calls for a trickle charger or disconnection. A battery tender might be more convenient than disconnecting the cable (and losing your radio presets perhaps) but it does have the benefit of being slightly safer and just a little less expensive.

[minke]

Originally Posted by Rzrbrn

Thanks for the info Glenn. Discharge rates are even greater during the winter months, as you probably well know.

My understanding is that chemical reactions are faster at higher temperatures. Self-discharge will be slower when cold.

[Raz]

Originally Posted by gordon2

If you just disconnect the negative battery post connector then the battery should maintain plenty of charge. And IMHO thats safer then leaving a charger of questionable quality active and unattended.

I agree. At least one member has reported leaving a battery connected to a battery minder unattended for a winter, only to find the electrolyte boiled off and things very hot. I would disconnect the negative cable, clean the top of the battery with water and baking soda and when you return check the terminal voltage and charge. I'd rather lose a battery than my house.

[John in Santa Cruz]

for vehicles parked outside that are rarely used, I connect a 10W solar panel. I put a pigtail on the batteries of my diesel truck with an SAE connector right near the lower left corner of the windshield, and put the panel on the roof of the cab, being sure to drape the wire down the windshield in front of the driver so I don't drive off with it up there, hah hah.

my 10W solar panel is BatteryTender brand.

[Rzrbrn]

Originally Posted by minke

My understanding is that chemical reactions are faster at higher temperatures. Self-discharge will be slower when cold.

Alan you are right: Battery drain caused by leakage is slowed. However, the chemical reactions are slowed, less energy is produced and the power output is lowered; with a lower output, the battery cannot keep up with the demand and can go dead, producing no current.

[Rzrbrn]

John, I used that same sit up, that is, the BT 10W solar panel. I don't think mine supplied enough electricity and the battery sulfated. So I discontinued using it. I thought about hooking up 2 of these 10 watt panels but never did.

It did ok the first year or two, then about year two or three it just did not produce the electricity, even after I cleaned the face of the panel.

[John in Santa Cruz]

btw, someone mentioned CTek, and I agree, they are excellent, another good one is NOCO. both these companies make a wide range of smart chargers, most all of which go to maintenance mode once the battery is fully charged.