Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: seagate on August 03, 2013, 01:32:28 am
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Hi,
I understand that SLA batteries need a top up charge every 3 months or so. Can anyone tell me how long to charge them for--is it a full charge, or is it just a percentage?
Also, after sailing, when the battery is only partially discharged, is it advisable to fully charge the battery, or would that result in overcharging?
The battery in question is a 6V 2.3Ah and my charger is a very basic type.
Thanks in advance
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the battery should be recharged after use, to avoid sulfating the plate's and ruining the battery...
standby , 6volt is ok ,the battery should be topped up at this point your looking for a voltage of 6.3 - 6.5 volt while the battery is left on the shelf. your charger should have an output of around 250-500 milliamp .. to much charger current will also destroy a battery. A good start is to charge it for 4 to 6 hours with a low current charger. using a charger that can develop 7.3 volt again at low current , no more than 500ma
A simple multimeter would serve you well. digital even better.
Just throwing this out there ,, I have 3 12v lawn tractor batteries that I use in two of my tug boats. I purchased a few battery tender/charger's ..just small 2/4/6 amp chargers.. I leave all my batteries on there ,, 5 years going and the batteries are still hanging in there..I also have a 6volt that's about 4 years old still doing fine with the casual bump from a 500ma wall wart charger
Hope this helps
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Also ..if you leave your batteries in the shed during the cold months as I do ,the battery will require more frequent charging for a longer period..again a multimeter is useful ,the tenders I use are microprocessor controlled and measure the ambient temperature to know where the battery charge state is, and to better regulate the charge state and current ..
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That's good advice, and the critical part is to charge your batteries after each use, don't store them partly charged. I have a couple of dedicated SLA chargers that automatically go to trickle charge once the battery has reached optimum charge, thus avoiding the risk of over charging.
Peter.
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IN the Fire Detection Units the SLA batteries are on constant trickle charge.
They are changed every 2 yrs and I have had many years use in my boats after this.
Bob
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A properly designed SLA charger will, among its other features, have voltage limiting built in, as well as current limiting. Once the limit has been reached, the charge current drops to near enough zero. The battery can be left connected indefinitely in that case.
A digital multimeter is a worthwhile investment - they are invaluable for measuring electric and much more difficult to break than analogue ones, their only downside is that once in a while they do need feeding with a new battery.
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I have one of these that we use to keep the battery on the jag charged over the winter
http://www.infinitymotorcycles.com/product/optimate-6-battery-charger/3522 (http://www.infinitymotorcycles.com/product/optimate-6-battery-charger/3522)
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Thanks for all your replies. I'll take your advice on board.
My charger states that it has "a built-in polyswitch for over-current protection" so following the above advice I assume it won't over charge if I leave it connected to the battery for any long period. I bought it from the Component Shop so it should be decent quality, if basic. This is the one: http://www.componentshop.co.uk/300ma-charger-for-6v-12v-sealed-lead-acid-batteries.html (http://www.componentshop.co.uk/300ma-charger-for-6v-12v-sealed-lead-acid-batteries.html)
Cheers,
John
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Be mindful of that//
The high current protection is normally to avoid a particularly low battery from sinking to much current and destroying itself , or to protect the charger from toasting itself.
Unless it the charger employs a trickle state please don't assume that it has such. 300ma trickle charge (24/7)on this battery will kill it, standby - trickle state at 300ma would eventually boil out the battery.. it should be around 30-75ma for this battery.
The advert states it will make a good trickle charge on larger batteries , were talking lawn tractor and automotive type batteries
so one a month let the battery go for a few hours, and check its charge state. after a awhile you will develop a feel,
I don't think this charger employs a diode to prevent discharging the battery while the charger is unpluged..if it does its a bonus ..a simple garden timer ..and you could set your battery charger to bump the battery a few hours once a week.. and it will be able to have your battery at the ready when ever you need it..
Hope this helps
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"polyswitch"
I do hate it when advertisers feel the need to create a made-up word that hitherto has meant nothing at all. And really, until a proper explanation without yet more made-up BS appears, still doesn't.
Polys = "belongs to parrot", witch = "does magic, usually malevolent"
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"polyswitch"
I do hate it when advertisers feel the need to create a made-up word that hitherto has meant nothing at all. And really, until a proper explanation without yet more made-up BS appears, still doesn't.
Polys = "belongs to parrot", witch = "does magic, usually malevolent"
Blowed if I can find that word on the link given, Doc. Maybe they killed the parrot (or the witch) when they moved to the new website?
I have a super microprocessor-controlled mains-powered SLA charger for 6v batteries which I bought from Craplins about a thousand years ago. Wishing I'd bought the 12v version now. Maplins being what they are these days (a glorified toyshop and Chinese junk emporium) the thing is discontinued. Shame.
DM
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Maplins being what they are these days (a glorified toyshop and Chinese junk emporium) the thing is discontinued. Shame.
Even back when they were a proper electronics outfit (with a catalogue having a Sc-=Fi themed front) they had the unfortunate habit of looking at what I was buying and discontinuing it immediately. I recall one occasion back then when the new book showed a really useful combined optical isolator and op-amp, I only got to a Maplin on Sept 2nd that year, it was already discontinued. The book was dated to start Sept 1st.
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I have one of those small 'top up' solar panels that I leave connected to a 12v sla, just to keep it topped up.
Grendel
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How did it perform during the 'Heat wave'. :}
ken
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its only 1.5W so will never replace the charger, but will keep the battery topped up
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How did it perform during the 'Heat wave'. :}
ken
dunno, but the battery was still charged when I needed it yesterday
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When I mentioned "polyswitch" I was quoting what was stated on the box the charger came in.
I take it I really need a better charger, one that has a trickle charge of 30ma-75ma, and to leave the battery on charge after and when not in use?
How about this one: http://www.ebay.co.uk/itm/Charger-For-2V-6V-12V-Sealed-Lead-Acid-Batteries-600Ma-/260729506759?pt=UK_Sound_Vision_Battery_Chargers&hash=item3cb4b08bc7 (http://www.ebay.co.uk/itm/Charger-For-2V-6V-12V-Sealed-Lead-Acid-Batteries-600Ma-/260729506759?pt=UK_Sound_Vision_Battery_Chargers&hash=item3cb4b08bc7)
Or this one: http://www.ebay.co.uk/itm/6V-SLA-SEALED-LEAD-ACID-UK-MAINS-BATTERY-CHARGER-5Ah-/400544587076?pt=UK_Sound_Vision_Battery_Chargers&hash=item5d42515d44 (http://www.ebay.co.uk/itm/6V-SLA-SEALED-LEAD-ACID-UK-MAINS-BATTERY-CHARGER-5Ah-/400544587076?pt=UK_Sound_Vision_Battery_Chargers&hash=item5d42515d44)
Would it be safe to do so with the battery in the boat--it won't be very accessible for frequent removal and I intended to fit a charging socket?
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This is the current version of the one I wish I'd bought from Maplin. CPC are also doing free delivery this month.
http://cpc.farnell.com/yuasa/ypc2a12/charger-12v-2a-lead-acid-battery/dp/BT05336?in_merch=Products%20From%20This%20Range (http://cpc.farnell.com/yuasa/ypc2a12/charger-12v-2a-lead-acid-battery/dp/BT05336?in_merch=Products%20From%20This%20Range)
DM
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Would it be safe to do so with the battery in the boat--it won't be very accessible for frequent removal and I intended to fit a charging socket?
Provided that the boat ventilates well, just in case. There was a story a few years back concerning a submariner who got a good collection of unvented fumes and detonated his sub when something sparked. Careful charging helps a lot, but good practice regarding ventilation helps more.
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This is the current version of the one I wish I'd bought from Maplin. CPC are also doing free delivery this month.
http://cpc.farnell.com/yuasa/ypc2a12/charger-12v-2a-lead-acid-battery/dp/BT05336?in_merch=Products%20From%20This%20Range (http://cpc.farnell.com/yuasa/ypc2a12/charger-12v-2a-lead-acid-battery/dp/BT05336?in_merch=Products%20From%20This%20Range)
DM
Thanks, but that's a 12V charger. My battery's 6V.
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Provided that the boat ventilates well, just in case. There was a story a few years back concerning a submariner who got a good collection of unvented fumes and detonated his sub when something sparked. Careful charging helps a lot, but good practice regarding ventilation helps more.
I'll take heed, thanks.
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Thanks, but that's a 12V charger. My battery's 6V.
http://cpc.farnell.com/yuasa/ypc2a6/charger-6v-2a-lead-acid-battery/dp/BT05335?ref=lookahead (http://cpc.farnell.com/yuasa/ypc2a6/charger-6v-2a-lead-acid-battery/dp/BT05335?ref=lookahead)
Wasn't hard to find.
DM
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Seagate.
either of the two you mentioned will do fine.
However like any piece of new equipment double check it frequently with a multimeter..just to be sure your not over charging the battery.. and you're good to go.
pay particular attention to the charger to see if it will discharge a connected battery while the unit is unplugged. if it dosent your good to go..its good to know ,a completely drained battery for the most part is ruined, often it can be resurrected with a desulfation cycle built into a charger..but rarely does the battery reach its previous potential
Most cheap digital meters also employ an amp meter/ammeter ..often up to 10 amp.. when connected in series you will know if the battery charger has switched to trickle mode..
Its a long drawn out process I know ,but the little you learn here will help you preserve and maintain larger more expensive batteries should you ever need to get one. Theres no reason you shouldn't be able to get 5yrs out of your battery with proper maintenance ..
hope this helps
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http://cpc.farnell.com/yuasa/ypc2a6/charger-6v-2a-lead-acid-battery/dp/BT05335?ref=lookahead (http://cpc.farnell.com/yuasa/ypc2a6/charger-6v-2a-lead-acid-battery/dp/BT05335?ref=lookahead)
Wasn't hard to find.
DM
[size=78%]
Nope, but it's out of stock and I need one soon. Also, I'm concerned about the stated output current of 2A. If that's the charge current, then I was warned earlier not to go above 500mA. It also states for batteries with capacities of 6 - 20 Ah, whereas my battery's only 2.3Ah.[/size]
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Seagate.
either of the two you mentioned will do fine.
However like any piece of new equipment double check it frequently with a multimeter..just to be sure your not over charging the battery.. and you're good to go.
pay particular attention to the charger to see if it will discharge a connected battery while the unit is unplugged. if it dosent your good to go..its good to know ,a completely drained battery for the most part is ruined, often it can be resurrected with a desulfation cycle built into a charger..but rarely does the battery reach its previous potential
Most cheap digital meters also employ an amp meter/ammeter ..often up to 10 amp.. when connected in series you will know if the battery charger has switched to trickle mode..
Its a long drawn out process I know ,but the little you learn here will help you preserve and maintain larger more expensive batteries should you ever need to get one. Theres no reason you shouldn't be able to get 5yrs out of your battery with proper maintenance ..
hope this helps
Thanks for that, I'll do as you suggest.
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https://en.wikipedia.org/wiki/Resettable_fuse (https://en.wikipedia.org/wiki/Resettable_fuse)
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I personally don't use continuous trickle on my SLAs. I recharge after use (with a charger that goes to trickle at the end so it doesn't matter if I forget it for a day or few). Then I take them off charge and check the voltage occasionally with a meter. When it gets down to about 12.6V (for a 12V nominal battery), which I believe is about 70% capacity, I give it a recharge.
Two reasons:
1/ I don't like leaving that kind of stuff live all the time - it's in the house where I and my family sleep.
2/ Cost. Most of these chargers are quite warm in use. I've not measured any but as an example if you say it's dissipating 5 Watts then you can do some math. 365 days, 24 hours/day x 5W = 43,800 Wh. Nearly 44kWh. At current UK prices of around 14p/unit that's over £6 per year. (And it's not very 'green' either :-) (which is also why new telly's, etc, now have to use <1W in standby))
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which is why mine sits on a 1.5w solar panel and stays topped up for free. (plus those panels are at £10 each at maplins at the moment).
Grendel
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which is why mine sits on a 1.5w solar panel and stays topped up for free. (plus those panels are at £10 each at maplins at the moment).
Now this may be just luck but i had a dead 12v 17ah sla that wouldn't take a charge from anything , I tried various voltage/ currents,so I connected it to a solar charger (Maplin 1.5w) in the greenhouse, this was at the beginning of May, in mid July I took it out discharged it ( hi amps ) by use of an inverter, then recharged as normal.This battery has been in normal use since, at normal capacity :-)) , I wonder if a hot humid greenhouse had any effect combined with a slow trickle charge?.
Tony
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I have heard that the slow cyclic charge provided by a small solar charger can bring back a sla from dead, and even had it bring one back from a 6.5V condition (12v battery 10Ah) but couldnt repeat on another battery with a similar voltage, so it may just have been luck.
Grendel
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Its pretty much hit or miss bringing a battery back to life from stone cold dead.
Desulfation cycles help but often the battery dosent respond..
I give the sla's a shake before even bothering with them, if anything rattles around its a good sign its not worth bothering to try, its dried out and burnt.