Long-term storage -- battery questions

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seattleclarity

New Member
Because of some upcoming travel, I will need to garage my Clarity for (in the first trip) 5 weeks, and (in the second trip) 3 months. A couple of questions:

(1) Should I put the 12V battery on a trickle charger? I have had experience with a Prius 12V battery running down over 3 months, and just getting back into the car and getting it started was a challenge.

(2) Should I leave the Clarity plugged in? On the one hand, it is a bit safer to leave it unplugged because of the slight chance of a lightning-caused power surge. On the other hand, if the traction battery keeps the 12V charged when plugged in (via the DC-DC converter) then I wouldn't need a trickle-charger on the 12V.

(3) Is there any feedback issue with having the 12V battery on a trickle charger and the car also plugged in?

Any advice welcome!
 
I'd leave the main traction battery unplugged and at about 50% charge state (no more than 80%, no less than 30%). I'd probably leave a trickle charger on the 12V battery, just so you don't have to worry with dealing with it when you get back. Others may weigh in on a more precise recommended charge state, but I'm pretty sure too much charge is bad and too little is also bad for the life of the battery (letting it sit for long in those states - high voltage at high state of charge and low voltage at low state). That's also why I wouldn't leave it plugged in.
 
I agree with @Robert_Alabama on the batteries. I would also recommend you take precautions against rodents if they are a threat in the storage location. There are other threads on long term storage, so if you want more ideas, run some searches.
 
Another option would be to disconnect the negative battery cable to the 12v battery, keeping it from discharging.
 
seattleclarity said:
Because of some upcoming travel, I will need to garage my Clarity for (in the first trip) 5 weeks, and (in the second trip) 3 months. A couple of questions:

(1) Should I put the 12V battery on a trickle charger? I have had experience with a Prius 12V battery running down over 3 months, and just getting back into the car and getting it started was a challenge.

(2) Should I leave the Clarity plugged in? On the one hand, it is a bit safer to leave it unplugged because of the slight chance of a lightning-caused power surge. On the other hand, if the traction battery keeps the 12V charged when plugged in (via the DC-DC converter) then I wouldn't need a trickle-charger on the 12V.

(3) Is there any feedback issue with having the 12V battery on a trickle charger and the car also plugged in?

Any advice welcome!
Click to expand...
Last winter I garaged my Clarity for 3 months. It was an unheated garage that got as cold as 20 F degrees, here in Michigan.

#1. Don't cover your car.

#2. I kept a battery tender on the 12v battery the entire time.
No problems. Don't expect to have your Hondalink app report you anything after about 7 days after leaving your car. The telemetrics turn off to save the charge on your 12v battery.

#3. Leave your car with a SOC of between 50-80%.

#4. Last winter I left the car plugged in. There are a couple of potential issues with leaving your car plugged in. First, if your electricity goes out, even for an instant, and then comes on, you will find that your car will start charging, to 100%. This happened to me last winter and I noticed my car, too late, was charged to 100%. I had my neighbor start the car and run the charge back down to 70%. I believe that it doesn't help your traction battery to be at 100% SOC (or even worse, near 0%) for more than a few days at a time. Second, if you leave the car plugged in you stand a remote chance of a power surge in an electrical storm (unless you have a sufficient surge protector).

#5. If you leave the car unplugged, which I intend to this winter, have a neighbor that can get to your car just in case. They can periodically check the car and SOC.

#6. Prior to my car accidentally charging to 100% after 2 months of inactivity, my neighbor checked my car for SOC after 7 weeks of inactivity. The traction battery only lost 2% SOC in those 7 weeks!

#7. Even with tires being better than ever before, I park my car on 1" of styrfoam sheathing to keep the tires from getting flat.

Hope these thoughts are helpful to you. Safe travels.

Sent from my SM-G955U using Inside EVs mobile app
 
+1 on all the above, especially @Richard_arch74 ’s advice. Nuff said.

IMHO, the best battery maintainer is a Deltran Battery Tender Plus. A perennial favorite that that always gets good reviews and has been around a long time. Very heavy duty with an all metal case, UL listed, and serialized. I’d steer clear of the cheap Chinese knock-offs.
If you’re going to store the Clarity more than once or twice, it’s a real time saver to attach a quick connect plug to the battery. It’s a quick and easy install and costs less than $5. Then you just plug in the polarized plug. I’ve got one on the riding lawnmower and one on my Clarity. Makes it a breeze and no worries about the clamps hitting the hood.
The quick connect is installed in just a few minutes since it has lugs that fit the accessory bolts on the + and - terminals and stores out of the way.
Here’s the posts you use. I’m holding the cover of the + terminal open
6BEF77DA-0EA5-4CD6-871B-29587A4CD077.webp


Here’s where the end neatly stores until needed
E19E9CC4-C9D7-4314-AE92-7B049415FE2C.webp


And here’s what you want. All metal and no cheap plastic. It comes w clamps and is ready to accept the quick connect also made by Deltran.
FF503B66-BD35-4A28-AD6C-AAD79E6FF10C.webp
 
seattleclarity

Along with Deltran...Prologic, Schumacher and several other notable companies make high quality equipment for batteries.

Each brand offer multiple units...distinguished by the features offered...basic to advanced. Price points are the ~same for similar features when compare brand to brand.

Figure out what features mean the most to you and then search online for those specs. On any given Sunday...you will find a unit produced by reputable company that is "on sale" and save $20 versus just buying one brand.

Take away is...buy a unit from a reputable company with the features you want and pay less if you take a few minutes to see who has what on sale.

Good luck.
 
I’m more in the “buy once cry once” camp myself. If I’m going to attach a battery-minder to a $30,000+ techno-marvel of a car, I’m not about to quibble over 20 or 30 bucks. Not knocking other companies, but the Deltran is arguably the best battery minder in a crowded market. Ask any gearhead car collector or RVer.
 
@KentuckyKen -
I would like to purchase one of these units, and was surprised to find that Deltran has so many choices:
http://products.batterytender.com/Chargers/

The one in your picture looks like it could be their legacy product. They also have a "brick" style that seems virtually identical:
http://products.batterytender.com/Chargers/Battery-Tender-Plus-High-Efficiency.html

No real discernable difference in the performance numbers, and essentially the same price on Amazon, etc...
The only thing I see that tips the scales is the fact that the 'legacy' metal chassis unit has a 10 year warranty vs. 5 years for the 'brick'.

Do you think the 'brick' may fall into the cheap Chinese knock-offs category (even though branded as Deltran)?
 
FWIW: I’ve been using a Battery Tender Jr that was Hecho en Chine for the past 10 years on a truck that has been stored for up to 6 months at a time. Truck starts every time.

I’ve also used solar panel maintainers, no doubt made, you know where, with success on cars, yard maintenance equipment and a motorhome.

These are simple devices that provide ~1A of current to a 12V lead acid battery. Same principle whether used on a $2,000 clunker or a $1M super car.
 
Last edited:
Richard_arch74 said:
...
#4. Last winter I left the car plugged in. There are a couple of potential issues with leaving your car plugged in. First, if your electricity goes out, even for an instant, and then comes on, you will find that your car will start charging, to 100%. This happened to me last winter and I noticed my car, too late, was charged to 100%. I had my neighbor start the car and run the charge back down to 70%. I believe that it doesn't help your traction battery to be at 100% SOC (or even worse, near 0%) for more than a few days at a time. Second, if you leave the car plugged in you stand a remote chance of a power surge in an electrical storm (unless you have a sufficient surge protector).
...
Click to expand...

You mentioned leaving the car plugged in, but not charging. The only way I know how to do this is to plug it in, then use the app to "stop charging". Is there another way?
 
MrFixit said:
@KentuckyKen -
I would like to purchase one of these units, and was surprised to find that Deltran has so many choices:
http://products.batterytender.com/Chargers/

The one in your picture looks like it could be their legacy product. They also have a "brick" style that seems virtually identical:
http://products.batterytender.com/Chargers/Battery-Tender-Plus-High-Efficiency.html

No real discernable difference in the performance numbers, and essentially the same price on Amazon, etc...
The only thing I see that tips the scales is the fact that the 'legacy' metal chassis unit has a 10 year warranty vs. 5 years for the 'brick'.

Do you think the 'brick' may fall into the cheap Chinese knock-offs category (even though branded as Deltran)?
Click to expand...
I don’t know for sure. It’s certainly getting harder and harder to find quality products these days. It seems every mfg is going cheaper and cheaper and this is probably being driven by the fact that most people shop just on price and not on quality.

Mine is most definitely a legacy model since I bought it earlier this year from HD who was discontinuing it. Got a great price on a dusty package. I’m old school and like the heft of a metal unit.
I’d say the longer 10 yr warranty speaks well to the quality issue. Have you tried eBay for a new, old stock item?
 
I didn't mean to imply that the 'Legacy' unit was not available. It seems to be a current product too.
Easy to find on Amazon, etc. It's just odd that they are still producing both (for essentially the same price, around $44).
Maybe the metal style will be phased out, but not yet.
 
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