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Why won't my battery charge?

osbourne one-nil

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osbourne one-nil

osbourne one-nil

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I've got a Mag 1 Portaball and it has a 12v , 0.8Amp Hr sealed battery inside it. It's brand new as the previous one died (or at least I thought it had). 

I've rewired it back in and it worked great last night (it seemed to be charged). However, I can't seem to charge it - the electrics work when the battery charger is plugged in to the scope, but as soon as I remove the charging cable - nothing. 

I have a 12v 500ma battery charger which connects to the telescope using a phono-plug type thing. From there three wires, a red, white and black run to mirror housing assembly and, I assume, up to the secondary cage. In the mirror housing, the two fan wires (red and black) connect and there's some funny switch wire in green...can't really explain it but to my mind, if it works when it's plugged in to the charger, why isn't the battery charging? Did I drain it too far last night and in the process kill it instantly?!

I'm probably asking the impossible?!

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osbourne one-nil

osbourne one-nil

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Thanks Louise - will try to get a voltage meter. Do you mean the voltage of the wires coming out of the battery? There aren't any terminals as such. No fuse either. The circuit's obviously ok (I assume) as it all works when plugged in!

Will check the voltage. 

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Thalestris24

Thalestris24

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Thanks Louise - will try to get a voltage meter. Do you mean the voltage of the wires coming out of the battery? There aren't any terminals as such. No fuse either. The circuit's obviously ok (I assume) as it all works when plugged in!

Will check the voltage. 

Yeah, the output wires will do - I take it they are colour coded re polarity? I imagine you wouldn't need to charge it much more than an hour and a half (based on the figures you gave). Can you tell what kind of battery it is? Do you have any info on battery use and charging provided by MAG?

Louise

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osbourne one-nil

osbourne one-nil

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I can't take it out without moving the primary mirror assembly, but I could connect it to the charger directly by uncoupling the lead. I'm using a 14.4v 1500ma charger as I remember reading somewhere that 12v wouldn't quite do it? 

I've been charging it all morning so far!

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Thalestris24

Thalestris24

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Hi

You said in your first post that it was a 12V 0.8 Ah battery and a 500mAh charger? Using a 1500mAh charger doesn't add up and might kill the battery especially if you leave it on for very long... There must be some supplier info to guide battery use and maintenance?

Louise

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osbourne one-nil

osbourne one-nil

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Ah, I've got two chargers - I always thought the battery would draw whatever current it needed and therefore you didn't have to worry too much about that? Live and learn!

In any case, my volt meter shows the battery's dishing out around 9v but the cable I thought was connecting the charger to the battery is providing the batter with 0v. I suspect that's the cause! Must have wired something wrong?

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Thalestris24

Thalestris24

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Ah, I've got two chargers - I always thought the battery would draw whatever current it needed and therefore you didn't have to worry too much about that? Live and learn!

In any case, my volt meter shows the battery's dishing out around 9v but the cable I thought was connecting the charger to the battery is providing the batter with 0v. I suspect that's the cause! Must have wired something wrong?

Not sure... Are you saying the battery charger isn't outputting a voltage?? I take it you've been connecting the charger's +ve to the battery +ve, likewise the -ve? Without being able to see it all, it's hard to tell what's going on... Presumably there is a built-in connector for connecting the charger to the battery?

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Zakalwe

Zakalwe

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Ah, I've got two chargers - I always thought the battery would draw whatever current it needed and therefore you didn't have to worry too much about that? Live and learn!

No, not at all. You can easily kill a lead-acid battery with too much charging current, or the wrong current at the wrong time in the charging cycle. You can warp the plates with too much current or cause a heavy build-up of sulphate on the plates.

Invest in a proper 12v smart charger. You can get them for motorcycle batteries. Something like this:

http://www.ebay.co.uk/itm/like/200766341586?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108

They'll supply the charge that the battery needs. You can also  keep them connected for weeks at a time and they will maintain the battery at the right level.

If your battery is giving out 9v, then it's needs charging NOW. Lead acid batteries do not like deep discharges (unless they are marine/leisure batteries) and deep discharging a lead acid battery will drastically shorten it's life and charging capacity.

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Skipper Billy

Skipper Billy

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I've got a Mag 1 Portaball and it has a 12v , 0.8Amp Hr sealed battery inside it. It's brand new as the previous one died (or at least I thought it had). 

I've rewired it back in and it worked great last night (it seemed to be charged). However, I can't seem to charge it - the electrics work when the battery charger is plugged in to the scope, but as soon as I remove the charging cable - nothing. 

I have a 12v 500ma battery charger which connects to the telescope using a phono-plug type thing. From there three wires, a red, white and black run to mirror housing assembly and, I assume, up to the secondary cage. In the mirror housing, the two fan wires (red and black) connect and there's some funny switch wire in green...can't really explain it but to my mind, if it works when it's plugged in to the charger, why isn't the battery charging? Did I drain it too far last night and in the process kill it instantly?!

I'm probably asking the impossible?!

If it's a 0.8 Ah battery a 500 mAh charger will charge it from dead flat to 100% in about an hour and a half.  The 1500 mAh charger you mention would charge it in 20 mins but in reality would probably overheat it and destroy it.

If you are testing with a multi-meter be very careful not to short the central pin to the out shell of the power socket with the tip of the multi-meter probe or you will definitely have a problem !!

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Starlight 1

Starlight 1

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They are dead now. You can get some capacity back into them with a smart charger, but they'll never recover fully.

I can just about kick start  any battery back to life ,but you can not  do any thing with sealed lead acid once gone under 3v.

My charger will do gell/lead-acid/nicd/nimh/li-po from 0.01 to 5.0A.

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Mick J

Mick J

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Interesting looking scope (I have been on google),  so fan under mirror, heater for secondary and finder, bigger 12" (american measurement  :smiley:) has 2 batteries. wonder what controls the heaters - circuit board or something?   Cannot be much help, just be careful not to short anything while using the tester, you seem to be getting somewhere.

A circuit diagram from Mag 1 may help you trace it out.

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osbourne one-nil

osbourne one-nil

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Thanks - don't think anything will have happened in terms of damaging the battery due to overcharging as the battery doesn't appear to be receiving any current!

In photo 1, you can see the charging cable (and I've connected things up with the right cable going to the right cable) attaching to the telescope. 

In photo 2, the connection between the cable coming from photo 1 to the primary mirror cell can be seen (it also runs up to the secondary housing to power a dew heater and a red dot finder.  There's a red cable, white cable and red cable connecting. When I connect the volt meter to the red and black cables, it reads around 11.5v. 

Those cables then run under the primary, connect to the fan and connect to the battery, as seen in photo 3. It's at this point, on the charger-side of that connection where there's no voltage - the battery is giving out about 9v. 

I'm wondering why, near the battery, I'm connecting a white cable to the red, but I'm sure I'm copying how it was before?!

Any help to anyone? Wish my mum was still alive - she was a physics teacher and this would have been child's play to her!

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osbourne one-nil

osbourne one-nil

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Interesting looking scope (I have been on google),  so fan under mirror, heater for secondary and finder, bigger 12" (american measurement  :smiley:) has 2 batteries. wonder what controls the heaters - circuit board or something?   Cannot be much help, just be careful not to short anything while using the tester, you seem to be getting somewhere.

A circuit diagram from Mag 1 may help you trace it out.

I don't think they're still going - I know the original owner died, and I've never had any luck getting in touch with the person who took over. 

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Thalestris24

Thalestris24

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I don't like where there are bare wires! Anyway, it looks like a lithium battery. With the battery connected, but not being charged, the voltage between the red and black wires is 9V? It probably shouldn't be allowed to get any lower as 9V indicates it's fully discharged. Does that voltage go up to 12 - 12.5V with the charger connected? If not, there's either a problem with the charger or there's an open circuit there somewhere (bad connection or broken wire).

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osbourne one-nil

osbourne one-nil

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Thanks all - I think I'll strip it down again and this time check to see there's something at the point where there currently isn't anything....if that's not too technical. 

I agree about the bare wires btw, but it's very protected down there in the base of its fibre-glass home!

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