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Battery Tender options

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Was nosing around online and came across these.  Not too pricey, and solar.

 

https://www.etrailer.com/Battery-Chargers/Performance-Tool/PTW2997.html

 

I'm a big fan of battery maintainers.  I have about a dozen of them scattered around the house/shop.  With as many seldom used vehicles and tractors around, constantly buying batteries can be really expensive, and tenders tend to make my batteries last a LOT longer.

 

So my question is, 2.5 watts all the time going to hurt the battery?  If not, these could be handy for my mowers and a couple of the Jeeps that are parked where I don't have electricity handy. 

 

Anyone know of an alternative solar unit that is decent and not too pricey? 

 

For regular tenders I do have one "Battery Tender Jr" that works fine, and the rest of mine are the Schumacher units like this one.  https://www.amazon.com/Schumacher-SC1319-Automatic-Battery-Maintainer/dp/B0756Q88J5/ref=asc_df_B0756Q88J5/?tag=bingshoppinga-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4584345016155877&psc=1

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Regulated output voltage (13.4-13.5 volts constant) is required for any DC power supply to be used to maintain a battery. Current needs are usually quite low in that usage case, so those 2.5 watts max panels might work fine on a small battery... provided the output voltage is actually regulated. China crap are usually not regulated at all so its a crap shoot.... you'd have to buy one, then measure the output voltage to learn whether or not it is fit for use as a battery maintainer or not.

 

If I were in need of a solar maintainer I would buy a small, decent quality 18 volts panel, then make my own adjustable voltage regulator, which would cost me less than $5 to make one having 5 amps (enough current to trickle charge and maintain 3 large batteries at once) total current capacity.  I don't trust china to make a better device than I can.

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I think 2.5 watts is too much. My Battery Tender brand is .75 amps.........750 milli amps. As you know it keeps six batteries simultaniously.

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1 hour ago, retro said:

Regulated output voltage (13.4-13.5 volts constant) is required for any DC power supply to be used to maintain a battery. Current needs are usually quite low in that usage case, so those 2.5 watts max panels might work fine on a small battery... provided the output voltage is actually regulated. China crap are usually not regulated at all so its a crap shoot.... you'd have to buy one, then measure the output voltage to learn whether or not it is fit for use as a battery maintainer or not.

 

If I were in need of a solar maintainer I would buy a small, decent quality 18 volts panel, then make my own adjustable voltage regulator, which would cost me less than $5 to make one having 5 amps (enough current to trickle charge and maintain 3 large batteries at once) total current capacity.  I don't trust china to make a better device than I can.

LOL, well you have to remember that most of us can't make little McGuyver gadgets!

 

I have a couple of tractors that take a full sized 12V battery, and a lot of smaller things like riding mowers (3) and ATV's (6-8 at the moment that should have good batteries on them). 

 

For something like this I don't need to do more than one at a time, simply because the goal is to find something I can stick on the machine so I don't have to pull the batteries when they're going to be sitting for awhile.

 

I have tenders in my shop along the wall, with holes drilled through to run the pigtail off the tender.  Then I have the harnesses permanantly attached to the battery terminals, so I can just plug the pigtail in when I part the ATV.

 

Unfortunately, I only have room for 4 ATV's along the shop under the overhang.  Mowers, tractors, and 2 of the three Jeeps are parked elsehwere, where there is no power source for a plug-in charger.

 

There are these things that look interesting.  Guy on a Jeep board bought one and was using it.

 

 

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I have a solar charger and it regulates the charge and shuts down when the battery is charged. I don't remember the brand or size of it. I bought it about 5 years ago to charge the camper battery when primitive camping so we had some light at night. I have used it many times on various machines sitting around to maintain the batteries without dragging cords around.

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Sounds like what I'm looking for.  I'm not in any hurry, but next time you're around it will you get the make and model off of it?

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The maintainers that are shown in the video are regulated and use the same type of linear voltage regulator that I use, so those are useful maintainers, although the panels look pretty small. How much do they cost?

 

But the first gadget linked is china garbage. Lets assume that their 2.5 watts rating is actual and that the full 2.5 watts are available in the output AND that the output is regulated to provide a constant 13.5 volts. All of which are probably false.... but we are idealizing here, so lets play along with the chinaman... After doing the math we learn that device would supply 0.185 amps, or only 18.5 milliamps at 13.5 volts.

https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html

 

18.5 milliamps might be enough current to maintain a mower battery, or an ATV battery in excellent condition in a warm climate. That device isn't worth 50 cents though.

 

How many solar maintainers do you need @jeepwm69? You can buy china panels cheap. Here are 25 watt (panel only) models priced at $22.50 each shipped:

https://www.ebay.com/itm/25W-Power-Solar-Panel-12V-Off-Grid-Kit-Battery-Charge-Controller-for-Car-RV-Boat/254454530208

 

So what if they only produce 15 watts actual, thats enough current to maintain any good battery. I can make the regulators inside a sealed box for less than $10 each, probably closer to $7 each with waterproof connectors soldered onto long enough leads to be useful. So estimated cost would be about $30 each. What say I build ya one and send it to ya for testing? If you can buy a complete comparable unit cheaper than $30 fine.... but I betcha ya can't. 🙂

 

EDIT: 15 watts @ 13.5 volts = 1.11 amps. Thats enough current to maintain two or three Jeep batteries simultaneously.

 

EDIT AGAIN: That 25 watt panel I linked above is actually only a 10 watt panel. chinamen lie. This one is the same brand, is twice the size (16" x 11") and is being sold as a 50 watt panel, Its actual output is just 20 watts tho... chinamen lie.

https://www.ebay.com/itm/18V-50W-Solar-Panel-USB-Battery-Charger-10-20-30A-PWM-Solar-Controller-ELINK/193039617557

 

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found this on amazon. Schumacher SP-200 2.4W 12V Solar Battery Maintainer $21.53

 

 

412fZNyKsWL__AC_.jpg

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17 hours ago, retro said:

The maintainers that are shown in the video are regulated and use the same type of linear voltage regulator that I use, so those are useful maintainers, although the panels look pretty small. How much do they cost?

 

But the first gadget linked is china garbage. Lets assume that their 2.5 watts rating is actual and that the full 2.5 watts are available in the output AND that the output is regulated to provide a constant 13.5 volts. All of which are probably false.... but we are idealizing here, so lets play along with the chinaman... After doing the math we learn that device would supply 0.185 amps, or only 18.5 milliamps at 13.5 volts.

https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html

 

18.5 milliamps might be enough current to maintain a mower battery, or an ATV battery in excellent condition in a warm climate. That device isn't worth 50 cents though.

 

How many solar maintainers do you need @jeepwm69? You can buy china panels cheap. Here are 25 watt (panel only) models priced at $22.50 each shipped:

https://www.ebay.com/itm/25W-Power-Solar-Panel-12V-Off-Grid-Kit-Battery-Charge-Controller-for-Car-RV-Boat/254454530208

 

So what if they only produce 15 watts actual, thats enough current to maintain any good battery. I can make the regulators inside a sealed box for less than $10 each, probably closer to $7 each with waterproof connectors soldered onto long enough leads to be useful. So estimated cost would be about $30 each. What say I build ya one and send it to ya for testing? If you can buy a complete comparable unit cheaper than $30 fine.... but I betcha ya can't. 🙂

 

EDIT: 15 watts @ 13.5 volts = 1.11 amps. Thats enough current to maintain two or three Jeep batteries simultaneously.

 

EDIT AGAIN: That 25 watt panel I linked above is actually only a 10 watt panel. chinamen lie. This one is the same brand, is twice the size (16" x 11") and is being sold as a 50 watt panel, Its actual output is just 20 watts tho... chinamen lie.

https://www.ebay.com/itm/18V-50W-Solar-Panel-USB-Battery-Charger-10-20-30A-PWM-Solar-Controller-ELINK/193039617557

 

 LOL.  They would never overstate the specs Retro!

 

Most of my 110 maintainers are Schumacher, but that solar charger got some pretty shoddy reviews.  https://www.amazon.com/product-reviews/B004ZC3TFC/ref=acr_dp_hist_1?ie=UTF8&filterByStar=one_star&reviewerType=all_reviews#reviews-filter-bar

 

@retro I appreciate the offer, but I feel like I'm turning you into my personal gadget maker lately LOL.  Those VW solar jobs usually go for $25-50 on ebay.  That might be the way to go.  I wouldn't think VW would supply absolute junk with their cars, although they are made you know where.

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