Won't be using my cars for the month of January. They will be in my unheated garage here in SE Pa. One has a brand new Deka 725 CCA battery and the other has a 4 yo 725 CCA Deka. Should I buy a couple Battery Tenders to keep them trickled-up? Thx.
Battery Tender
- Thread starter artbuc
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If you plan to do this more in the future, sure. If just this once, I'd buy one and move it every week.
A couple of cheap tenders could do the trick or you could disconnect them if they're fairly new batteries. I have an old SLA I've converted into a portable DC supply using a battery box and it may lose like .1v's sitting for a month unused (no load). I check it once a month and put it on a charger if and when it needs it, which is about every other month. Been doing/using this battery for about 2yrs now like this.
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You could connect the batteries in parallel with a jumper cable and use a single trickle charger to maintain both.
To join batteries in parallel, use a jumper wire to connect both the positive terminals, and another jumper wire to connect both the negative terminals of both batteries to each other. Negative to negative and positive to positive. You can connect the leads for the charger, red to battery 1 + and black to battery 2 -.
To join batteries in parallel, use a jumper wire to connect both the positive terminals, and another jumper wire to connect both the negative terminals of both batteries to each other. Negative to negative and positive to positive. You can connect the leads for the charger, red to battery 1 + and black to battery 2 -.
Originally Posted by 2010Civic
For only 1 month I would just disconnect the terminals and call it good. The battery will be fine. They sit at the store for several months before being sold.
Right. My portable one, which I've wired in a DVM, might drop to like 12.5v over 2 or 3 months just sitting on the shelf. An old or weak battery's a different story...
For only 1 month I would just disconnect the terminals and call it good. The battery will be fine. They sit at the store for several months before being sold.
Right. My portable one, which I've wired in a DVM, might drop to like 12.5v over 2 or 3 months just sitting on the shelf. An old or weak battery's a different story...
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JHZR2
Staff member
Depending upon the car, a month is probably ok. Not preferred practice to leave it like that, discharged, but not the end of the world.
If you don't have some sort of maintainer, IMO it's a worthy $50 investment for many reasons... so I'd say it's best practice and a smart buy.
If you don't have some sort of maintainer, IMO it's a worthy $50 investment for many reasons... so I'd say it's best practice and a smart buy.
Get one of these and switch between batteries every week. I have two of these and they work great.
https://www.costco.com/battery-tender-power-plus-3-amp-charger.product.100241973.html
https://www.costco.com/battery-tender-power-plus-3-amp-charger.product.100241973.html
Originally Posted by Mad_Hatter
Originally Posted by 2010Civic
For only 1 month I would just disconnect the terminals and call it good. The battery will be fine. They sit at the store for several months before being sold.
Right. My portable one, which I've wired in a DVM, might drop to like 12.5v over 2 or 3 months just sitting on the shelf. An old or weak battery's a different story...
One thing of note though... Flooded batteries lose 5-12 percent of charge per month.... Just sitting... So if one buys a battery that has sat uncharged for say 6+ months...that battery will have lost a lot of capacity and is likely sulfated... I believe a number of batteries purchased at AAP and AZ that have had short life is related to those batteries sitting for long periods of time with no charging being performed. A couple of years ago when we had a big cold spell that lasted awhile in late 2017 into early 2018... Many people had batteries fail and I bet a lot of that was due to those batteries sitting around a long time with zero charge added. Calcium AGMs are certainly better at having a lot less self discharge 1-3 percent per month... And the thin plate pure lead batteries are even lower at 0.1-.5 percent per month self discharge rate.
Originally Posted by 2010Civic
For only 1 month I would just disconnect the terminals and call it good. The battery will be fine. They sit at the store for several months before being sold.
Right. My portable one, which I've wired in a DVM, might drop to like 12.5v over 2 or 3 months just sitting on the shelf. An old or weak battery's a different story...
One thing of note though... Flooded batteries lose 5-12 percent of charge per month.... Just sitting... So if one buys a battery that has sat uncharged for say 6+ months...that battery will have lost a lot of capacity and is likely sulfated... I believe a number of batteries purchased at AAP and AZ that have had short life is related to those batteries sitting for long periods of time with no charging being performed. A couple of years ago when we had a big cold spell that lasted awhile in late 2017 into early 2018... Many people had batteries fail and I bet a lot of that was due to those batteries sitting around a long time with zero charge added. Calcium AGMs are certainly better at having a lot less self discharge 1-3 percent per month... And the thin plate pure lead batteries are even lower at 0.1-.5 percent per month self discharge rate.
Originally Posted by Mad_Hatter
An old or weak battery's a different story...
+1
The battery on my BMW needed a full two days of trickle charging to bring it back up to snuff from a summer of use.
Mind you, the BMW was only driven bi-weekly but still, you'd think that's enough to keep it charged up-clearly it wasn't.
Since then it only needs 10-20 minutes every few months to keep it topped off.
An old or weak battery's a different story...
+1
The battery on my BMW needed a full two days of trickle charging to bring it back up to snuff from a summer of use.
Mind you, the BMW was only driven bi-weekly but still, you'd think that's enough to keep it charged up-clearly it wasn't.
Since then it only needs 10-20 minutes every few months to keep it topped off.
Originally Posted by artbuc
Won't be using my cars for the month of January. They will be in my unheated garage here in SE Pa. One has a brand new Deka 725 CCA battery and the other has a 4 yo 725 CCA Deka. Should I buy a couple Battery Tenders to keep them trickled-up? Thx.
If you drive cars regularly then just disconnect it. Is garage insulated? If it is, it should be fine. Sometime ago I had often trips to Europe month or longer and I would leave vehicle in Alabama outside during winter for that period. Now, winter in AL is obviously much, much milder, but temperature during night drops below freezing for most January. I never had an issue with any vehicle except Mazda Millenia. I always had to jump start that one.
Won't be using my cars for the month of January. They will be in my unheated garage here in SE Pa. One has a brand new Deka 725 CCA battery and the other has a 4 yo 725 CCA Deka. Should I buy a couple Battery Tenders to keep them trickled-up? Thx.
If you drive cars regularly then just disconnect it. Is garage insulated? If it is, it should be fine. Sometime ago I had often trips to Europe month or longer and I would leave vehicle in Alabama outside during winter for that period. Now, winter in AL is obviously much, much milder, but temperature during night drops below freezing for most January. I never had an issue with any vehicle except Mazda Millenia. I always had to jump start that one.
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Thx. One thing I did not mention is I will not be here to switch a Tender from car to car. If I were here, we would be driving the cars as we normally do. Connecting the batteries in parallel and buying one Tender makes the most sense to me.
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