battery getting hot

[Ding123]

I have been unhooking the battery by hand whenever it gets warm, but it can be such a drag. I can't afford a charge controller and there is alot of comments about relays.Could someone tell me where to get a relay and even more ,how to hook it up.

I know it hooks to a dump load but that 's all I know.Thanks.

[whatsnext]

I'm pretty sure if you search the web for DIY or homemade charge controller you will find what you seek.

John

[phil b]

http://www.digikey.com/ has about any relay you might want. Read the manufacter's data sheets for hookup instructions.

Used ones are available on about any auto.

[kitno455]

you did not say how much power you are making, but assuming that you are putting the relay on the dc side, and you dont mind your power source going open circuit, you could look at a ford starter solenoid, usually easily accessible on the firewall, 4 good connectors, and a mounting bracket.

you need a temperature sensor to close the relay when the battery is cool. that could be bimetallic mercury switch from an old home thermostat. those old round, brown honeywells are getting tossed out everywhere. just dont spill the mercury.

allan

[Ungrounded Lightning Rod]

How hot is the battery getting?  Batteries normally warm up when accepting a charge, not just when overcharged.

What kind of battery is this?  A lithium cell?  NiMH?  NiCad?  A flooded lead-acid?  A jell-cell lead-acid?  You have to watch the temperature on some of these, but it's not all that big a deal on lead-acids unless they're getting REALLY hot rather than just warm.  (In the latter case I'd wonder if something other than overcharging is wrong.)

Get an inexpensive digital voltmeter from Radio Shack or the like and measure the battery voltage.  Don't unhook it or turn on extra loads until it reaches full charge voltage.  Exact voltage for full charge and for a good point to stop dumping / rehook to your power source varies with battery type.  When you start making that dump load controller you'll need the digital voltmeter to adjust its settings, so you're not wasting the 20 bux or so it will cost now.

Why are you unhooking the battery?  Try turning on all your loads, instead.  Or hook up some suitable power dumps (like a bunch of automotive headlights) and turn them on when you're approaching full charge.  You can probably get one-beam-dead headlights at your local auto shop for the asking.

What is your charging device?  If it's solar panels and you have a blocking diode near the battery you can just short them upstream of the blocking diode.  They will only produce a few amps so an ordinary switch or relay will do the job.  If it's a mill you can also short it upstream of the rectifiers (provided the alternator is sized so it will bring the blades to a near stop) but this will take a more powerful switch, such as the starter relays mentioned by another poster.  (Though I'd worry about starter relays being used for continuous duty.  Be sure to fuse them.)

If you know how to solder you can make a dump load controller from circuit diagrams posted elsewhere on this board using WELL under $100 worth of radio-shack parts.  Use it to control a low-current automotive relay (pick on up at a junkyard) that turns on your headlights - or turns on a bigger relay such as the starter relay.)

[Ungrounded Lightning Rod]

If you have a mill, a dump load is MUCH preferred to disconnecting the load.  A dump load also has advantages even for solar.

With an adequate automatic dump load you don't need any other charge controller, and can merrily hook up more panels, one or more mills, and mix-and-match (just as long as your dump load pulls more power than all your sources combined.)  (Then the only advantage you'd get from a solar controller is if it is an expensive max-power-point device, squeezing more watts out of your panels.)

[ghurd]

How much power are you making?

Not sure I would consider a relay as reliable, over the long term.

G-

[Ding123]

It is a wind genny, putting out anywhere from 350 to 400 . I only have a lead acid battery.about 90 cranks.It is a Cat battery. I just want to know what the pioneers of wind gennies used before regulators, if anything...I've heard of people using 12 volt relays. If this can be done, the relay would click in at about 13 volts to a dump load such as a heating element. I don't know if this has been done , but I would like to be able to do it.Thanks.

I posted this seperately by mistake. I am sorry about that,Wolfhounder

[RogerAS]

Hi,

I suspect something else is going on than overcharging. What type of turbine are you running? PM alternator, DC motor or what? It almost sounds like the battery may be bad, like a dead cell. We need some real detail for any suggestions.

I had a battery BLOW UP in my '65 Mustang as the result of a dead short in a middle cell. Carefully check with your volt meter and an amp meter, look into each cell as it's being charged, maybe with goggles on!

Please be as specific as possible. If a DC motor turbine have you a blocking diode in-line and attached correctly? See, we have to guess. 300 or 400 what? Amps, volts, watts??? If watts how are you getting that number? 90 cranks??? See what I mean?

RogerAS

[dinges]

'I can't afford a charge controller'

This sounds like bad economics to me. You can afford (or scrounge) batteries but not invest the few $$ to make sure they're properly cared for. That way they won't last long.

There's plenty of simple circuits around for DIY construction (e.g. at homepower, or search this board or google). If you can't build yourself, they can be bought too.

Much cheaper in the (not so) long run that ruining good batteries. Even when you managed to get those batteries for free.

'The most important part of the battery system is not the battery but the charger'

Just made that up myself and it sounds good

Peter.

[whatsnext]

I'm going to guess it's just overcharging. A 400 watt mill would be putting 33A into the battery so unless he has a 240Ah battery I could easily see it getting hot when the wind blows.

John..