Solar battery charger for 6 volt Farmall H

Sounds like I am playing, I am.
The tractor only runs for about 20 minites every other day to haul wood to the house.
Most of the time we dont know if the battery is full or half dead. Sometimes I think that old girl would run off penlight batteries.

Also, 6 volt panels are not common. Even 12 volt panels are getting a bit scarce, as 24, 48, and 72 volts become more common. You might need a controller if you buy certain panels - and with a controller - you have more loss.

Take tha 2.5 watts - and you've got less then 1/2 amp at 6 volts - which isn't much.

I live in a poor sunshine area of New York, and I have several solar battery maintainers for tractors that spend most of their lives sitting. I use 15 watt panels and they work well enough to maintain batteries that are already charged. Not to charge run down batteries.

You can buy some pretty good 15 watt panels with battery cables for $60 if you shop around.

Here in New York, I use several - and a 15 watt panel works well, all winter, with no controller.

As you probably aleady know, Volkswagen was giving them away (with new cars) and they plugged into the cigarette lighter. They sell outright for around $50 for a 2 watt model, and $100 for a 6 watt. The larger 6 watt is needed unless you live in a very bright area.

Small panels are very expensive with the price per watt and - they are also not as good quality as larger panels. I can buy 120 watt panels at $3 per watt. The small panels often cost $15 - $20 per watt.

You also need a way to charge a 6 volt battery, and you won't find many 6 volt panels.

Where can you buy 120w PV's for $3/w? I just bought two more US64(64w) Friday night as that was the best bang for the buck I could find at $4.83w. I would have jumped on two 120w for a little more.

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Hi Frankiee,

If your going to go with a trickle charger, Wally World has Schmuacher 1.5a, PWM, 6/12v chargers for $18. PWM chargers have a bulk charge, finish charge and a float charge mode for keeping the battery maintained in top condition without ever overcharging. It would take aprrox 24hrs to recharge a dead battery with this recharger.

T_Bone

Sun sells several brands - but their store-brand, that they market as SUN brand, are usually Evergreen panels made in Massachusetts with cosmetic blemishes. Full performance, and full warranty - they just don't look perfect if you look real close - slight waves in some of the foil inside. I will also add, that sometimes they have some deals even cheaper - but those get advertised as "outside the USA only." Don't worry about it - they don't mean it and will sell and ship to anyone. Link

A 3w PV won't charge a dead battery or serrious depleted battery in a acceptable amount of time. For solar charging I found that 15v is a realistic number on 12v systems for calculating PV wattage requirements. A 12v PV will produce more than 15v, more like 21v open voltage but that's just not a useable number to use as it will cause you to under size the actual PV wattage requirement.

So that would be 7.5v on a 6v system. At 3w/7.5v=0.4ahr(amps per hour) that the PV will charge at. That's enough to maintain the state of charge in a fully charged battery without a CC(charge controller) and without overcharging the battery. A CC is nothing more than a voltage regulator. You'll need a CC on any PV greater than 5w or the battery will over charge if given enough recharging time.

At 0.4ahr then with a PV tracking the sun (move the PV once at 1pm to face west and once at dusk to face east) then we can plan on 8 solar collecting hours in full sun, cloudy then about 1/2 of the rated amp/hr, or about 3.2amps/day output on a 3w rated PV.

If you have a typical 6v starting battery at a 100ahr capiticy, then 100ahr/(3.2a/day)=31days/2= 16days to recharge a battery that's 50% discharged with a 3w rated PV.

And yes, you would need to put a 5a diode in one leg of the PV wire to keep the battery from discharging at night.

If you run a battery much past a 50% discharge rate then it will severely shorten the battery life.

T_Bone