Eight volt battery

Phil-mar Farms · Oct 15, 2021

I want to charge a 8 volt battery. I heard you could put a light bulb In series and cut 12 volt to 8 volt. What I need to know what size bulb and if it makes a difference if its on the positive side or the negative side

centash · Oct 15, 2021

Most 6 volt generators on tractors will charge an 8 volt battery if they are in good condition. I would think most battery charges set to 6 volts would also charge an 8 volt battery.

Ben

Steve@Advance · Oct 15, 2021

I've never tried using a lamp as a resistor. It would not matter which post, as long as it was in series.

But using a resistor (a lamp) would slow the charging process, but would not stop overcharging if left too long unless it was a very small lamp or high resistance resistor.

If the battery is seriously discharged, I would put it on 6v and let it charge. If a low amp setting or low amp charger, say 2 amp, is used, leave it a good while, probably overnight. If a higher amp, 10 amp or so, maybe a couple hours if it's really low.

Then start checking the voltage. Fully charged will be 9.2 volts off the charger. If it stops coming up before 9.2v, try it, see if it will start the engine.

Unless the regulator has been set up for 8 volts (9.2v), it will never operate as a fully charged 8v battery. If it has been adjusted up, it will finish safely charging the battery, that is if you can get it started!

Something that might work for you, a very low amp 12v solar charger. They put out a relatively high no load voltage, but the amperage is so low it won't overcharge. It should work as a maintainer.

gene bender · Oct 15, 2021

just put it on 6v and take cell readings with a hydrometer to soo what condition the batt is after on charge for a time.

Russ from MN · Oct 15, 2021

Yes, my 12 volt solar panel puts out 18 volts with no load, but it charges a 12 volt batter just fine. it's small enough it doesn't overcharge.

John T · Oct 16, 2021

I always used a 12 volt charger SET ON LOW CHARGE then monitored the cells using a hydrometer and kept an eye on it to avoid OVERcharging and any excess outgassing and boiling over. SURE it will work just DO NOT let it overcharge by carefully and frequent monitoring

John T

jimg.allentown · Oct 16, 2021

Batteries are normally charged at a voltage that is higher than their nominal voltage. A 12 volt battery will be charged at 14 or 15 volts. A 6 volt battery would be charged at around 8 volts. The rate of charge is determined by the actual charging voltage. Low setting on a charger will produce a lower voltage than the high setting.

So, to charge an 8 volt battery, I would want a voltage higher than 8 volts. That leaves the 12 volt low setting as the closest to ideal setting. I may be mistaken, but I would think that using 8 volts to charge an 8 volt battery would take a long time if it charged at all. An ammeter in series with the charger would tell how much current is actually getting into the battery.

I wouldn't bother with a light bulb. I would just use the lowest 12 volt setting and an ammeter. Then I would monitor charging time carefully. That would be my opinion.

ArleninOr · Oct 16, 2021

So, does that mean you canput 8 gals of gas in a 6 gal can? Like to see that one.

rustyfarmall · Oct 16, 2021

(quoted from post at 08:17:39 10/16/21) So, does that mean you canput 8 gals of gas in a 6 gal can? Like to see that one.

Don't know about that, but I do know you can put 6 gallons of gas into a 5 gallon can.

centash · Oct 16, 2021

I put an 8 volt battery in all my old 6 volt tractors. Works fine. Helps them start a bit better. Only had to adjust the regulator on one.

Ben

Eight volt battery

Phil-mar Farms

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centash

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Steve@Advance

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gene bender

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Russ from MN

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John T

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jimg.allentown

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ArleninOr

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rustyfarmall

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centash

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