Battery tender

[bakalorz]

^^^^^ READ THIS, PEOPLE! ^^^^^
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I use a Shuhmacher battery maintainer myself. Also very high quality, and not as expensive as the Official Battery Tender Brand stuff.

As noted above, the cheapo wall-wart trickle charger from Harbor Freight is not controlled (and thus could overcharge your battery) and does not have a diode, so when the power is off, current reverses and slowly discharges your battery. Hook one up to your battery, turn off the lights, and unplug it from the wall -- you'll see its LED glowing weakly. Not good.

There's frugal, and then there's just plain cheap. If you can't afford anything better than the HF charger, pick up an extra lunch shift at McDonald's or something.

Umm, yes and no ...

The Harbor Freight cheapy is NOT a trickle charger. It IS a true controlled float charger. It will NOT over-charge your battery.
It will actually do a good job of keeping your battery up over the winter if you don't leave it attached to the battery but disconnected from A/C.
(which is not really something you "should" do with any charger ... although some are impervious to it)

The reason that the trickle chargers are diode isolated is because they are _SO_ simple. All they are is a transformer and a diode bridge.
The harbor freight charger has that, but then has additional circuitry to hold the voltage at float (and a current limiter and an antispark circuit of some type).
Connecting a battery but no A/C lets the battery power that extra circuitry.

So they CAN be an OK frugal choice.
That said, the voltage tolerance on them was pretty wide. If you buy one, the voltage may be set anywhere from about 12.8 to 13.2 volts. Any of that range would be OK for flooded and maintenance-free batteries (AGM batteries MUST be at the high end)(And I personally would prefer it at the higher end of that range for all of them)
So take a voltmeter along to harbor freight and make sure you get one set at 13.2

For a long thread on them read here.

[duaneage]

I use a solar powered battery tender on the roof of my shed. Works great and needs no power. And it has a diode built in for reverse protection.,

[dpep]

I use a solar powered battery tender on the roof of my shed. Works great and needs no power. And it has a diode built in for reverse protection.,

That sounds neat. Do you have a link to the product?

[Billy Ricks]

That sounds neat. Do you have a link to the product?

There are quite a few on Ebay Don. There's one with the diode for about $20. http://cgi.ebay.com/SOLAR-POWER-PANE...1%7C240%3A1318

[willie]

I know its been awhile since the last post on this topic but I thought I'd relate my experience at Harbor Freight over the weekend. I went there with the intent of buying one of their low budget trickle chargers that was mentioned here. I thought I was out of luck when the assistant mgr mentioned they were on sale but sold out. When asked when the next shipment was due he told me that the model I wanted didn't have a good rep with re: to longevity and advised against buying one. Instead, he recommended their on board charger which was heavier duty and more reliable. I told him that for the $20 price tag I'd rather invest in a Battery Tender. He marked it down to $9.99 and asked if that would change my mind. I bought 2.
Willie in TN
Ironically, I installed one in each of my skiboats and put my GK battery on a Battery Tender I'd been using for the boat. lol

[physics-teacher]

Harbor Freight Feedback

FWIW, I'm starting my second winter with HF cheapie battery tenders, $4.99 when they're actually in stock. I have four of them now and they did a great job on my rider mowers, etc. last winter.

[argonsagas]

FWIW, I've found a cheap trickle charger plugged into an appliance timer set to turn on for 1-2 hrs a day to be very inexpensive way to keep my battery charged during off seasons. It worked really well on the battery for my lawn tractor. I figured it should be the hot but cheap ticket for my bike batteries as well. I'd greatly appreciate the opinion of others.
Thanks
Willie in TN

You have my vote.

I use a one-amp charger and have a timer set to run 45 minutes a day with three parallel-wired batteries.