Battery Tender

[JCH13]

Hey you! Take your silly common sense elsewhere!

Yeah... I know... I'm sorry guys... I know common sense has no place on the internet.

I agree with this but most people would forget about that battery and let months go by which is why the tender is an appealing option.

Then they get to pick between wasting $10-30 every year in electricity to run the tender, or buying a new battery every 3-4 years instead of every 5-6. Or, if they can bring themselves to spend 3 minutes checking battery states every month, they can have a battery that lasts 5-6 years while only spending $5 a year in electricity.

 

[WilliamM2]

On my motorcycle I never even took the battery out. It required removing bodywork and the gas tank to get it out. Not worth the time. I atached pigtails to the battery so I could just leave it in. I used a 1 amp charger bought for $10 back in the 80's. Every 2 to 3 weeks I would charge the battey for 3 hours.

OEM Yausa battery lasted 11 years, if fact is still worked fine when I replaced it, I was just getting paranoid. Second battery was still going strong after 8 years when I sold the bike in 2012. Bike was stored at least 5 months a year, sometimes a little longer due to weather.

I still use that cheap charger on my cars when needed. It will charge one up overnight. I was always taught that the lower/slower you charge a battery, the longer it will last. I usually get 7 or 8 years out of car batteries too, but I use those year round.

 

[LTC8K6]

I actually have digital 7 day timers on my two small chargers. They charge the battery for 1 hour twice a week. Every once in a while I check on them.

 

[tortillasoup]

I actually have digital 7 day timers on my two small chargers. They charge the battery for 1 hour twice a week. Every once in a while I check on them.

it would be a good idea to measure the power consumption of those timers. Some timers use as much electricity as a battery tender, effectively using the same/more electricity as leaving the tender plugged in w/o timer!

 

[jagec]

Also, bear in mind that a tender costs money to run, perhaps between $10 and $30/year depending on how long a battery is stored, assuming the tender is run continuously.

Where do you get that number?

I just measured the draw on my battery tender (hooked to a 24V bank, mind you), and even at my $0.13/kWh rate, it's only costing me $3.50 a year.

 

[LTC8K6]

it would be a good idea to measure the power consumption of those timers. Some timers use as much electricity as a battery tender, effectively using the same/more electricity as leaving the tender plugged in w/o timer!

Oh no! Not an extra $5 a year!

Besides, I don't have a Battery Minder, and my batteries will be destroyed by my inferior chargers without the timers.

 

[tortillasoup]

Oh no! Not an extra $5 a year!

Besides, I don't have a Battery Minder, and my batteries will be destroyed by my inferior chargers without the timers.

Then what is the point of having a timer? Or is your argument that you have the timer on there because you know your charger is a piece of shit?

 

[LTC8K6]

The point was sarcasm about your obsession with the minutiae of trickle/float chargers and batteries...

 

[JCH13]

Where do you get that number?

I just measured the draw on my battery tender (hooked to a 24V bank, mind you), and even at my $0.13/kWh rate, it's only costing me $3.50 a year.

I made some pretty general assumptions:

1.5A*12V = 18W

18W * 5mo * 30day/mo * 24hr/day = 65 kWh

65kWh*$0.15/kwh = $10

And rounded way up for areas where electricity gets pricey and to account for the charger's inefficiency. This month in NH we're seeing a ~50% spike in electricity costs, I think most of the state is around $0.22-$0.30/kWh now.

 

[Zenmervolt]

I made some pretty general assumptions:

1.5A*12V = 18W

18W * 5mo * 30day/mo * 24hr/day = 65 kWh

65kWh*$0.15/kwh = $10

And rounded way up for areas where electricity gets pricey and to account for the charger's inefficiency. This month in NH we're seeing a ~50% spike in electricity costs, I think most of the state is around $0.22-$0.30/kWh now.

The rated amperage for a float charger is always the bulk charge amperage, not the maintenance/float amperage.

Typical maintenance/float amperage is around 300 milliamps.

So you end up with only 3.6 watts, which comes out to 13 kWh. Even at an inflated $0.30/kWh, you're realistically looking at less than $4.00 per year (assuming 5 months of storage per year).

ZV

 

[JCH13]

The rated amperage for a float charger is always the bulk charge amperage, not the maintenance/float amperage.

Typical maintenance/float amperage is around 300 milliamps.

So you end up with only 3.6 watts, which comes out to 13 kWh. Even at an inflated $0.30/kWh, you're realistically looking at less than $4.00 per year (assuming 5 months of storage per year).

ZV

:thumbsup:

Good to know.

 

[tortillasoup]

:thumbsup:

Good to know.

He's mostly right but his assumption is with 100% efficiency... Most tenders use around 5w at a minimum. This isn't that big of a deal if you live in an area with cheap electricity but when you live in California or Hawaii, then it can become a problem if you don't like wasting money.

 

[Zenmervolt]

He's mostly right but his assumption is with 100% efficiency... Most tenders use around 5w at a minimum. This isn't that big of a deal if you live in an area with cheap electricity but when you live in California or Hawaii, then it can become a problem if you don't like wasting money.

Even at 5 watts, that's a lot less than JCH's estimated 18 watts, which was the point.

At 5 watts, the total cost per year is well under $5.50 assuming a cost per kWh of $0.30.

In terms of "wasting money" I probably lose that much in dropped change over the course of a year.

ZV