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Keeping a 12v battery charged above 80%

Started by W. eWatson June 10, 2012
I had a fellow out to do some electrical work that involves one 12v 
marine battery. The battery will be used about 4-6 hours a night 
sporadically. Maybe 15-20% of the time. He offered that it should be 
recharged every day, and keeping it above 80% was important for the life 
of the battery.  Somehow that seems a bit high. Apparently, there's a 
charger of some sort that costs about $150 that will adhere to that 
schedule.  Comments?
On Sat, 09 Jun 2012 20:03:51 -0700, "W. eWatson" <wolftracks@invalid.com>
wrote:

>I had a fellow out to do some electrical work that involves one 12v >marine battery. The battery will be used about 4-6 hours a night >sporadically. Maybe 15-20% of the time. He offered that it should be >recharged every day, and keeping it above 80% was important for the life >of the battery. Somehow that seems a bit high. Apparently, there's a >charger of some sort that costs about $150 that will adhere to that >schedule. Comments?
Yes, lead-acid batteries should be kept fully charged. The proper charger shouldn't be that expensive. Just keep it charged. Put it on a timer, if it'll be months without use; charge an hour or three a day.
On 06/09/2012 08:03 PM, W. eWatson wrote:
> I had a fellow out to do some electrical work that involves one 12v > marine battery. The battery will be used about 4-6 hours a night > sporadically. Maybe 15-20% of the time. He offered that it should be > recharged every day, and keeping it above 80% was important for the life > of the battery. Somehow that seems a bit high. Apparently, there's a > charger of some sort that costs about $150 that will adhere to that > schedule. Comments?
I bought a Battery Tender Jr. for my motorcycle. A microprocessor-controlled marvel that usually did nothing at all, but sometimes it drained my battery below the level that it started at. Never once did it charge the battery. The "Lifetime" warranty required me to ship it back to Florida for repair, along with handling fees, diagnostic fees, return shipping fees, etc. that approached the retail cost of the charger. After a year, I smashed it with a sledgehammer and threw it in the trash.
On 6/9/2012 8:57 PM, Wrecker wrote:
> On 06/09/2012 08:03 PM, W. eWatson wrote: >> I had a fellow out to do some electrical work that involves one 12v >> marine battery. The battery will be used about 4-6 hours a night >> sporadically. Maybe 15-20% of the time. He offered that it should be >> recharged every day, and keeping it above 80% was important for the life >> of the battery. Somehow that seems a bit high. Apparently, there's a >> charger of some sort that costs about $150 that will adhere to that >> schedule. Comments? > > I bought a Battery Tender Jr. for my motorcycle. A > microprocessor-controlled marvel that usually did nothing at all, but > sometimes it drained my battery below the level that it started at. > Never once did it charge the battery. The "Lifetime" warranty required > me to ship it back to Florida for repair, along with handling fees, > diagnostic fees, return shipping fees, etc. that approached the retail > cost of the charger. After a year, I smashed it with a sledgehammer and > threw it in the trash.
I can certainly sympathize with that. I've had a few instances where I thought I might bring some faulty equipment into a mfger's office and drop it on the floor.
On 2012-06-10, W. eWatson <wolftracks@invalid.com> wrote:
> I had a fellow out to do some electrical work that involves one 12v > marine battery. The battery will be used about 4-6 hours a night > sporadically. Maybe 15-20% of the time. He offered that it should be > recharged every day, and keeping it above 80% was important for the life > of the battery. Somehow that seems a bit high. Apparently, there's a > charger of some sort that costs about $150 that will adhere to that > schedule. Comments?
I own a cheap 4A Arlec charger with electronic control (electronic control comprises a pcb with a pair of SCRs, a transistor, a zener diode, and some resistors) It charges to about 14V gradually reducing the charge rate. that would be stages 1 and 2 of the diagram here. http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery I use it for charging accidentally discharged car batteries, and for charging the sealed lead acid battery in childs electric trike. (it charges this smaller battery at 1A gradually tapering off) It sounds like you'd want one that also does stage 3 "float charge" for your application. $150 does sound quite expensive (about twice what I would expect) but I don't know of a more competively priced off-the-shelf solution. -- &#9858;&#9859; 100% natural --- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---
On Sat, 09 Jun 2012 20:03:51 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

>I had a fellow out to do some electrical work that involves one 12v >marine battery. The battery will be used about 4-6 hours a night >sporadically. Maybe 15-20% of the time. He offered that it should be >recharged every day, and keeping it above 80% was important for the life >of the battery. Somehow that seems a bit high. Apparently, there's a >charger of some sort that costs about $150 that will adhere to that >schedule. Comments?
There must be dozens of good schematics for battery chargers on the web if you want to roll your own. Schedule? there is no schedule, but a fully charged battery will live longer. I had a Marine battery on my boat that lasted 12 years (through two boats). I put a Heathkit charger on it about once a month when I remembered to do it. Another on my sailboat that went 10 years on a solar panel and shunt regulated charger I built. It started the motor, kept the anchor light going, and cabin lights when I was on board I only checked the electrolyte level religiously and looked at the charger once in awhile to see that it was limiting current when I first got on board (every weekend) --
On Sat, 09 Jun 2012 20:03:51 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

>I had a fellow out to do some electrical work that involves one 12v >marine battery. The battery will be used about 4-6 hours a night >sporadically. Maybe 15-20% of the time. He offered that it should be >recharged every day, and keeping it above 80% was important for the life >of the battery. Somehow that seems a bit high. Apparently, there's a >charger of some sort that costs about $150 that will adhere to that >schedule. Comments?
Black and Decker used to have a selectable 1 and 2 amp charger. It turned off when the battery was fully charged. I've been using one of them for a number of years to keep the grandkids' battery-powered vehicles charged (beats using the "battery burner" that comes with the vehicles). The charger was about $30. I think they still have a similar one that only has the 2 amp output. That would be OK foryour application, but the small SLA batteries in the kiddie cars live longer if the charge is limited to 1 amp. Ideally, a lead acid battery is never discharged below 50% - that's the standard used in designing the battery system for solar or other alternate energy. The less a lead acid battery is discharged, the longer it lasts - the electrochemical reactions (charge/discharge) are reversible, but there is a limit.
On Sat, 09 Jun 2012 20:03:51 -0700, W. eWatson wrote:

> I had a fellow out to do some electrical work that involves one 12v > marine battery. The battery will be used about 4-6 hours a night > sporadically. Maybe 15-20% of the time. He offered that it should be > recharged every day, and keeping it above 80% was important for the life > of the battery. Somehow that seems a bit high. Apparently, there's a > charger of some sort that costs about $150 that will adhere to that > schedule. Comments?
I repeat a conversation I heard recently between an ace mechanic and regular trailer camper, and a new trailer camper with a dead battery: Go to a place that sells RV stuff and get a float charger. Figure on spending $20 to $25 bucks. A "plain old" charger for lead-acid batteries will boil the electrolyte dry (well, it'll electrolyze it into hydrogen and oxygen, but it's the same difference to you). Go for the float charger. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
news@jecarter.us wrote:
> ... > Ideally, a lead acid battery is never discharged below 50% - ...
How is charge measured? Voltage? Does 50% mean a 12v battery at 6v? That doesn't sound right.
Bob Engelhardt <bobengelhardt@comcast.net> wrote in news:jr8d6d01ej8
@news3.newsguy.com:

> news@jecarter.us wrote: >> ... >> Ideally, a lead acid battery is never discharged below 50% - ... > > How is charge measured? Voltage? Does 50% mean a 12v battery at 6v? > That doesn't sound right. >
That is because the talk was about the charge, not the voltage. 8-10 volt means almost empty. Below that you are trying to kill the battery.