Seeking some small battery charging advise

[Mike Delisser]

A mate gave me a several small batteries to run my camping lights but not sure if any of my chargers would be suitable for them - CTek 15,000 - a basic Arlec 10A - Projector 2.5A trickle. I use these on my 130AH Trojens.
The new batteries are all - Vision CP12170 & Exide Powersafe EP1229W - small alarm system types.
I hooked one of the Visions up to the 2.5 charger and the charger's light started flashing after a few mins (never done that before) normaly the light is either on when it's charging or off when the battery is full. Is a special charger required for either of these model batteries? if so what type? Thanks

Cheers
Mike D

[cormorant]

Hi

They are both batteries designed for UPS so when power goes off the UPS switches on and high discharge batteries through a inverter create 240 v. They are designed to spend 99% of their life on a trickle and then bang down to 15% of capacity when the power goes off then a solid charge back up to capacity. Great for camping lights but try not to run them down more than about 70% of capacity

http://www.vision-batt.com/products/manual/CP.pdf Describes what the best charging is.
http://www.vision-batt.com/newpdf/CP/CP12170.pdf

They charge at a higher rate than 12v lead acid wet and hold a higher charge than a normal lead acid so the little charger may be recognising it as fully charged or overcharged ( although it isn't)


In the UPS racks they run 3 stage chargers with a sulphatesation stage as well.

That number didn't come up for the exide. Double check it as a lot of stuff can be anywhere from 2v to 6 to 12v. for different applications.

The ctek is a good charger and just set it to the correct settings for VRLA Constant voltage charging and keep a eye on battery temperature as high temp will kill it.

The projecta etc a will get em mostly charged if it puts out 14.4 but is a low quality charger so use the good one and they will last longer.

A lot of UPS batteries have a pretty fixed life being on constant trickle and depending where they have come from may be at the end of their life. They regularly get audited , changed out so the UPS are relaible. . They will have a date stamp or circle clock date stamp on them. Different qualities anywhere from 2 years to 10 and XX cycles.

17ah will run leds for a long tme.

[Roughasguts]

You just need to charge more than one at a time! get some little aligator clips and jump the pos and neg to another same type battery and it will charge.

I have been doing this for me 12 volt 7 Ah/20hr battery for years.

As you say put one one charge and the full charge light comes on almost straight away.

Cheers.

[cormorant]

Other reason for a charger to throw up odd lights is that there is a direct short in the battery. Ie battery stuffed in a couple of cells .

Check with a multimeter

[oldboot]

You do need to take note of the maximum charge rate of these smaller batteries.....try charging them with a big beefy charger and they will get very hot very quicly and that is not good.

consider 10% of the AH capaity as a reasonable charge rate..they can be pushed a bit harder than that ( some maybe as high as 20%)..... but putting a 7AH SLA battery on a 10 amp charger with no specific low current function is not a good idea.

If one of your chargers has a small battery function, use that...it may be depicted as a morotcycle function.

Otherwise there are plenty of small chargers available out there at pretty low prices.

Also if they are shagged or nearly shagged, they may not accept any charge at all.

Some batteries that have got to a low state of charge will confise the new funky chargers and they may either read charged when they are not or simply refuse to charge.

If you have this problem, an old style dumb charger or a DC powersupply may wake them up and get the charging started.

cheers

[Mike Delisser]

Thanks 4 the help guys. I got them up by linking 3 of them. It wouldn't work with 2 that were pretty full but it would when I added a 3rd that was a little run down (that's a pain cause I only want to keep 2). I'll try draining 2 of them down a bit then charge them linked on my 2.5 trickle and see how it goes.

Also I don't understand what you mean by VRLA constant voltage on the CTek as I can't find the book and I can't see a button for a that mode on my 15000. And I checked the code on the little Exide 7AH and it's correct.
Thank again for the help fellas, cheers.
MD

[cormorant]

PDF of the manual which is probably the same model?

http://www.ctek.com/files/manual/Multi-XS-15000_au.pdf

Referred to as the "supply" setting I think. The ctek is designed for batteries above 30 ah .

VRLA Is valve regulated lead acid. It referrs to battery construction and basically means that the gas produced from charging is recombined to make water inside the case for no maintainance and if you overcharge them they have a pressure release valve. They are generally glass matt and gel technology batteries in sealed cases and have no liquid in them. Overcharge them and they get hot and buckle cases and then pressure release. Often see them with bulging sides when they have been overcharged/ charged too fast. Should never be warmer than luke warm as gel seperated away from plates and they lose capacity and then get hotter next time etc etc until they go bang or fail.

Some chargers have a setting that ensures the correct voltage for max fast charging is fed in and staged so they don't get hot / gas. Can refer to constant voltage per cell but smaller current as they get fully charged so they don't overheat - XX stage chargers . Some chargers have a thermometer probe in the leads or seperate to measure both air and battery temp. So many batteries are combinations of technology these days that the charger companies are having a bit of trouble in giving all the options without 20 buttons / menus and lights on em.

Smaller cheaper low tech chargers are normaly meant for normal wet lead acid batteries and won't 100% charge a gel battery ( not that that really matters a lot for domestic use) The gel batteries have a higher standing charge and the "dumb" battery chargers assume that that means it is fully charged and turn to a float mode or off or won't begin to charge at all. 2.3 v per cell times 6 has them at 13.8v

[oldboot]

Sorry but there are few things that must be corrected.
VLRA refeers to a varitey of batteries...almost anything that is semi sealed (there is no such thing as completely sealed), and this includes, gell batteries( by far the minority), sealed wet, starved electrolite and agm batteries.

Quite a lot of VLRAbatteries do have wet runny acid in them........the major problem is that if they are overheated or overcharged, the gass recombination system can not cope with the gassing generated, and thus they vent.

If the vent system is in good condition that is sort of fine but some gass and liquid may be lost, this can not be replaced.

These batteries if they have some age under them especially if they have been run in warm places ( like in UPS units) the rubber in the valves degrades and sticks and the safety valves often do not work.....I have seen batteries blown up like balloons...I have not encountered one that has exploded (it does happen) but I have seen them split at the seams.

Also if you run too much charge current, they heat up and the heat alone damages the battery.

Almost every sealed battery (VLRA) I have ever seen has a maximum charge current printed on the side..mostly with recommended charge voltages......these should be adhered to.......ya might push you luch a littel but doubel or more the charge current and expect a real problem.

As far as the "standing charge"......almost evey sealed battery I have encountered float charges at 13.8 volts..which is more or less standard for most lead acid batteries.

So for charging your VRLA battery you need a charger that
1/ either specificaly controls its current or has a maximum current less than the specified maximum charging current of the battery.
2/ is voltage regulated within the specs for that battery.

7 AH sealed batteries as commonly found in UPS and allarm systems are commonly charged at arround 1 amp ant 13.8 volts.

cheers
The big issue with the older dumb chargers is they have a high charge voltage, very poor voltage regulation and no form of current controll.......best not to try charging a sealed batter with and old style dumb automotive battery charger