johnt
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Post by johnt on Nov 2, 2021 9:11:20 GMT
I know its not advisable to charge a sealed gel battery with the old fashioned 6/12 volt battery charger but is there a way of limiting the amperage output to say 0.5 amps or there about's? Can I charge a 12 volt battery at the 6 volt setting?
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Post by davwat on Nov 2, 2021 12:23:53 GMT
Can I charge a 12 volt battery at the 6 volt setting? Yes to being an electrician (retired) but it's a long while since I was at school 
No to charging 12v from a 6V charger. A 6V charger may pump out 7-8 volts: but as they are connected in parallel the battery will never go higher than the charger voltage.
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johnt
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Post by johnt on Nov 2, 2021 13:06:08 GMT
Thanks for that. is there any way of restricting the Amperage out put at 12 volts?
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Post by oxfordshirejohn on Nov 2, 2021 16:24:27 GMT
is there any way of restricting the Amperage out put at 12 volts?
The short easy answer is yes, but the long complicated answer needs a bit more explanation. Amperage is proportional to the voltage and inversely proportional to resistance, thus the higher the output voltage of you charger the more current will flow given a fixed resistance of the load. Conversely the higher the resistance given a fixed voltage the less current. Some types of chargers have the means to to vary the output voltage but most of the simpler types sold for DIY use won't. In order to reduce the current flow you will need to add extra resistance in series with the charger and the battery, the old style rheostats would do the trick but you probably don't have one of those so an alternative would be to use a light bulb in series instead. The voltage and/or wattage of the light may take some juggling as the required size will be dependent on amongst other thing on the output voltage of you charger plus the type and state of your battery. Also you will need an ammeter wired in series as well if your charger doesn't have one.
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johnt
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Post by johnt on Nov 2, 2021 18:32:50 GMT
Thanks for the reply. The charger is 50 years old but does have an ammeter. The battery is a good one and when I connected it to the charger it showed a 2 amp charge but the battery became warm quite quickly. I will try one or two 12 volt bulbs in series and see what happens. I believe 0,5 amps is a suitable charge rate.
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Post by davwat on Nov 2, 2021 19:25:30 GMT
Thanks for the reply. The charger is 50 years old but does have an ammeter. The battery is a good one and when I connected it to the charger it showed a 2 amp charge but the battery became warm quite quickly. I will try one or two 12 volt bulbs in series and see what happens. I believe 0,5 amps is a suitable charge rate. If you just want to keep an unused battery fully charged could you not try something like this. |
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johnt
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Post by johnt on Nov 3, 2021 7:37:05 GMT
Thanks Dave. Yes that would do, will consult Ebay.
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