battery tender (maintainer), completely off NOT FLOAT.

[rphillips]

I'd like to find a tender, or maintainer, that turns completely off when batt. is completely charged. All I'm finding are the ones that have the float mode, they constantly charge, just at a very low amp, that shouldn't harm the batt. Both my home charger & boat's, on board charger, turn completely off when batt. is fully charged, then if, when, batt. loses a slight amount of voltage, it will turn back on till fully charged, then to off again. Has anybody seen or heard of such an animal? I'd just feel better knowing it's not trying to charge a batt. that is already at full capacity. Just seems good.

[posplayr]

People that build charges are usually pretty expert at battery charging. Buy a quality charger. If you are really worried about it get a mechanical timer to shut off the charger.

A 24 charger will probably work OK then it is only on a short period (your choice) of time a day.

https://www.amazon.com/GE-Mechanical-Programing-Polarized-15076/dp/B002HEY300

[rphillips]

Didn't mean to insinuate I was worried, Just knowing the technology is in use for other chargers, If I find or hear of something like it in the tender, maintainer category, I'll be interested.

[Steve]

I have a few Schumacher Battery Maintainers around here. I got some at Wal-Mart several years ago for about $20. Before they closed, Sears had a Die Hard version of the same thing. It looked identical, I think Schumacher made it for them.

The link above is for one that is available for about $23, but it's also available on Amazon for $29.

I have had no problems with my units here, I would not hesitate to buy another one, if needed.

.

[rphillips]

Thanks, but after a little searching, found the SC1355 is on a float system also. I thought I'd found one a while back, Tusk (or Task) makes a little tender size, 1 amp, & when batt. is fully charged it will automatically shut off, but reading farther, it won't turn back on when batt. drops a little, kind'f useless, to get it back on, you need to unplug it then plug it in again. Just thought, as this technology has been around a few yrs. now, someone would have introduced it in the tender, maintainer mkt. Oh well, maybe not, or I maybe I just haven't found it yet.

[Rob S.]

People that build charges are usually pretty expert at battery charging. Buy a quality charger.

Yes and yes.

Sears had a Die Hard...

Bought one about six years ago. Extremely satisfied with it.

[fbody_mike]

How about putting a battery tender on a smart plug. Set the smart plug schedule for once a week for a few hours that way it can't float.

[bwringer]

That's exactly how, um, y'know, Battery Tender brand battery tenders work.

I guess I'm not seeing why you have any trouble finding such devices. Old-school float or trickle chargers are pretty rare nowadays.

Ack, phooey, I was wrong about this. Battery Tenders do indeed apply continuous voltage and will nuke your motorcycle batteries. Sorry 'bout that.

[Rob S.]

That's exactly how, um, y'know, Battery Tender brand battery tenders work.

I guess I'm not seeing why you have any trouble finding such devices. Old-school float or trickle chargers are pretty rare nowadays.

The original poster doesn't want to charge, or even "maintain" a fully charged battery. But consider this: the moment you disconnect it from the charger, the battery is discharging. It's only fully charged for an instant. Unless it's on a maintainer.

[rphillips]

That's odd, I've read most everything there is to read about the Battery Tender, & all I see says go into a float mode. Now, I've just got off the phone to Deltran U.S.A., (the Battery Tender folks) & talked with Loretta in Tech. Support. She advised they have no Tenders, maintainers, that switch off, All theirs constantly float, keep charging, forever. I asked how much it charged when in float mode & she said appx. 100mA., or 1/10th of an amp. She also explained the newer AGM & maintenance free batteries actually needed a constant charge going in all the time. I didn't question her a lot, It's gets over my head pretty quickly, but wondered why. I think all, On board chargers shut completely off when batteries are completely charged, & I know mine are, & I know many batteries in the boating world are maintenance free. I always see the simple side of things, adding current to a batt. that is completely at full charge, seems like putting gas in a can that is already full, just don't see an advantage.

[Rob S.]

That's odd, I've read most everything there is to read about the Battery Tender, & all I see says go into a float mode. Now, I've just got off the phone to Deltran U.S.A., (the Battery Tender folks) & talked with Loretta in Tech. Support. She advised they have no Tenders, maintainers, that switch off, All theirs constantly float, keep charging, forever. I asked how much it charged when in float mode & she said appx. 100mA., or 1/10th of an amp. She also explained the newer AGM & maintenance free batteries actually needed a constant charge going in all the time. I didn't question her a lot, It's gets over my head pretty quickly, but wondered why. I think all, On board chargers shut completely off when batteries are completely charged, & I know mine are, & I know many batteries in the boating world are maintenance free. I always see the simple side of things, adding current to a batt. that is completely at full charge, seems like putting gas in a can that is already full, just don't see an advantage.

Look at it this way: the gas can is full, but the gas is evaporating.

[dorkburger]

The first winter I had a Battery Tender, I though I was smart leaving it plugged in most of winter. That Spring after a couple of rides, I had a weak battery. Upon checking I found that the water in the battery had evaporated. I topped it off and it lasted a couple of seasons. After that I only used the tender ocassionly and unplugged it when it indicated full charge. No issues after that.

[rphillips]

My point, being on a fixed income, I sure hate losing that gas.

[rphillips]

You got it dork, that's the point!!!

[posplayr]

My point, being on a fixed income, I sure hate losing that gas.

Batteries self discharge when left unattended. You can't do anything about that.

https://batteryuniversity.com/learn/article/elevating_self_discharge

In theory the battery tenders simply is overcoming the self-discharge or other parasitic loads in your bike.

If that is boiling your battery , then I would suspect a different problem of the battery is already bad.

As I mentioned before use a mechanical timer for say 50% duty cycle (e.g. 12 hours on and 12 hours off or some other 1 hour on/ one hour off)

Looking at this figure, self discharge is dramatically affected by storage temperature. In this case cold is good meaning low self discharge. It suggests that if you live in a cold climate 0 degC, that you shoudl be able to leave your bike off tender for 3 full months with no problem; there is little discharge even after 18 months.

On the other hand storage at 40 degC will require a recharge well within only 6 months.

Figure 6 illustrates the self-discharge of a lead acid battery at different ambient temperatures At a room temperature of 20°C (68°F), the self-discharge is roughly 3% per month and the battery can theoretically be stored of 12 months without recharge. With a warm temperature of 30°C (86°F), the self-discharge increases and a recharge will be needed after 6 months. Letting the battery drop below 60 percent SoC for some time causes sulfation. (See also BU-702: How to Store Batteries.)