Skywatcher PowerTank 7Ah

[stargazerkelly]

Hi guys this is going to be so silly of me to post, but i bought one of these but i have lost the charger where can i buy one from

stargazerkelly

[rowan46]

maplins will do one

[nightfisher]

yes, maplins, but make sure its right for the job

[Gerontius]

The charger that came with my 7Ah Power Tank is 15V DC out @ 500mA

Make sure that the polarity is correct on the output plug - centre contact is positive.

[Matt2011]

I have charged my Skywatcher 7AH power tank since Saturday and its Wednesday and its still on RED charging and is it normal for it to take so long to charge up!

[Nexus 6]

Matt, you may find this useful

Power tank question, anyone understand electricity? [Archive] - Stargazers Lounge

when did you last charge it up?

[Matt2011]

Hiya, I charged it up on Saturday and its still charging and for all I know its probably charged but you normally get the green light saying "FULLY CHARGED". When I flick the switch on the Skywatcher 7AH Power Tank to ON it says "Ready To Use" but its been a few weeks since I used the power tank so its been 5 days and all I see is the RED light on saying "CHARGING". Thanks

[Matt2011]

Is it normal for a Skywatcher 7AH POWER TANK while charging show a red light and a green light also at the same time. Many Thanks

[brantuk]

Dunno why but I've never found those charging indicator lights very reliable - sometimes they apear to work - other times not. But the unit usually gets charged if I leave it on for 8-12 hours overnight.

The supplied chargers are only trickle chargers - if it's been run flat you may find you need a deep cycle charger to revive it. If it's been left too long you may not get it back at all. Best thing is to use a voltmeter and check what it's delivering after a charge.

[Matt2011]

I agree and at the moment the RED charging light is on along with the GREEN fully charged light and I charged this Skywatcher 7AH PowerTank up at 8pm last night so maybe its fine and nearly charged but I wonder if anyone else on SGL has had this as well. Thanks

[glowjet]

These type of batteries should be charged at one quarter of the output rating, so for your 7Ah you should have at least a 1.5 amp to 2.0 amp charger, if its well bellow this, it will take a long time. My batteries are Power-Sonic 17Ah and 7Ah and if you look up the company they do very informative pdf`s concerning this type of dry cell battery and one interesting piece of information is that they have a long shelf life and do not need charging every few weeks, well theirs don`t other makes might, as for chargers try the company Battery Masters they have a big range of chargers suitable for dry cell batteries

[Matt2011]

Thanks Glowjet, Yeah looking at the powertank its a Skywatcher 7AH 12 Volt D.C and the input on the charger is AC 100-240V-50/60HZ-0.5A. Output is D.C 15V 500 mA. Its a BI switching power supply. Hope this info helps as I am not to knowledgable myself. Thanks

[glowjet]

SLA batteries sometimes, if they are charged and discharged for the same period over a long length of time can form a memory or get stuck, one way to avoid this is to give the battery a complete discharge at reasonable intervals, by using such as 3 or 4 x 21 Watt 12V car bulbs soldered to a length of a wire and connected across the terminals, wait till the bulbs glow dim, but under no circumstances let them go out as this will flatten the battery, which you do not want, you can then carry out a full recharge. You can also check to see if your battery is ok, if you calculate the the amperage of the bulbs you use, watts divided by volts, say you use 4 x 21 watts = 84 watts will give you, divided by 12,= 7 amps, if your battery is 7Ah this theoretically should give 7 hours use at a discharge rate of 1 amp, so our working example should give 1 hours use at 7 amps discharge or thereabouts, if you loose virtually all power within 30 mins or so then this tells you that you have a faulty cell or two and the unit is no longer good for long periods of discharge. A little long winded but hope this helps to resolve your problem