Solar trickle charging

[k0ua]

Well unhook one clamp off of each battery then put your digital volt meter leads on the 10 amp scale in series between the post and the lead and measure the current draw in amperes. Then you will know. You can get a rough idea even without a meter by unhooking a car battery's leads and hooking them back up in a darkened garage.. Little spark, small parasitic current draw.. Big spark, large parasitic current draw.. But of course an actual figure would be best.

 

[94BULLITT]

You need to wait 15-30 minutes for all of the modules to shut down. He may need to check on a lower setting than 10 amp depending on how bad the drain is.

 

[k0ua]

You need to wait 15-30 minutes for all of the modules to shut down. He may need to check on a lower setting than 10 amp depending on how bad the drain is.

Correct, but you always start on your largest scale when measuring currents to keep from burning out your meter shunt. You can also measure current by inserting a precision know value shunt in series from the battery to the load and measuring the voltage drop across the shunt with a voltmeter. For example, take a 1 ohm 5 watt resistor, and put it in series, and measure the voltage drop across it. calculate the current in amperes E=IR. or watch the smoke escape from it if the current draw is more than you expected. :shocked:

 

[Jkott]

I tried measuring the load on my duramax and it was "difficult".

When you first hook the battery back up through the ammeter, between the computer powering up and the courtesy lights all coming on, it's over 10 amps (60 watts) for a bit. And when things settle down, parasitic drain of 0.2a isn't perceivable on the 10 a scale and you have to break the circuit to switch to lower current, which reboots everything.

I never did get desperate enough to create jumper clamps to power things through a larger cable and then switching to the ammeter without losing continuity.

You will probably have to remove a few fuses if you want to measure real parasitic drain.

For me just put my gps on an ammeter and threw it in the freezer. **** thing never stopped charging the internal battery if it was in the freezer and was draining a half amp and hour. Why Chevy didn't put any switched cig lighter outlets in I will never understand. They are all always powered.

 

[k0ua]

I tried measuring the load on my duramax and it was "difficult".

When you first hook the battery back up through the ammeter, between the computer powering up and the courtesy lights all coming on, it's over 10 amps (60 watts) for a bit. And when things settle down, parasitic drain of 0.2a isn't perceivable on the 10 a scale and you have to break the circuit to switch to lower current, which reboots everything.

I never did get desperate enough to create jumper clamps to power things through a larger cable and then switching to the ammeter without losing continuity.

You will probably have to remove a few fuses if you want to measure real parasitic drain.

For me just put my gps on an ammeter and threw it in the freezer. **** thing never stopped charging the internal battery if it was in the freezer and was draining a half amp and hour. Why Chevy didn't put any switched cig lighter outlets in I will never understand. They are all always powered.

You bring up some good points about the variable nature of the loads in a modern vehicle with microprocessors booting up and dang courtesy lighting coming on briefly, again controlled by microprocessors. I hadn't thought about that.. Onstar radio's could be another drain I didn't think about.. The GPS sounds like a real problem. 500ma. is quite a bit of drain, especially in cold weather. In the old days when you turned the key off the car was dead, except for an electric clock winder once in a while.

 

[LindenBruce]

I don't have any GPS or Onstar or any of that stuff. It could still have a glove box bulb hanging on. My truck is on 06 model I bought in October 05. Had it since it was new. It's always had an issue of draining batteries if it sits to long. I guess I could get out in that cold 20something weather and run a draw test with my DVOM. Maybe I will try it tomorrow or Friday and report back. My 12v outlets are powered all the time also.

 

[Jkott]

I don't have any GPS or Onstar or any of that stuff. It could still have a glove box bulb hanging on. My truck is on 06 model I bought in October 05. Had it since it was new. It's always had an issue of draining batteries if it sits to long. I guess I could get out in that cold 20something weather and run a draw test with my DVOM. Maybe I will try it tomorrow or Friday and report back. My 12v outlets are powered all the time also.

Wireless key entry system? Alarm system?

Do you last days, or barely weeks? Might help narrow down the level of draw.

Dual batteries? Don't rule out one battery being possibly being bad at two years. One bad battery will actually charge from the other, draining both.

 

[Gordon Gould]

Sounds like you guys don't think having a controller or "minder" is worth the money to prevent over charging the battery or am I miss reading you.
I am thinking about getting a solar charger for my little dozer down in the woods. There is no parasitic drain because the master switch disconnects the battery (2 of them). I would want it to recharge even if it was slow. The temps here are 0* F and below on winter nights. I thought I would need the 15 watt model with the controller but from what I am reading here maybe I could do it cheaper. What do you think ??

 

[Soundguy]

You could still have something draining your battery, a radio, glove box light or a module.

them glove box lights will get you.

i had a 98 dodge i sold to work.. it developed a BAD parasitic drain. a 3 day weekend would make it a hard starter. tab in t e glove box broke, letting the ?? 168 or 194 bulb burn full time.....

 

[k0ua]

Gordon I think that since you don not have any parasitic loads on your dozer, you very may well get by with a small unregulated solar maintainer. Keep in mind these units wont really charge a discharged battery, or would take a very long time to do so, but are designed more to keep up with the inherent self discharge of the battery itself. A little harbor freight unit for 10 bucks might very well do what you need, if your needs are just to make sure the battery is kept up while it sits for weeks or months in the woods. But such a unit may very well not work for someone with a sophisticated pickup truck with a lot of parasitic drain parked at an airport for a month.

James K0UA

 

[Jkott]

I have Battery Tenders on every tractor, lawn mower, and atv. A full battery is a happy battery. Low batteries freeze, while a fully charged one will not.

But yes, you do not want to over charge. That's why I do use the Deltran battery tenders. They are all 0.800 to 1.25 amps and lower the current and voltage as it approaches 100%. That rate is between 10 and 15 watts max.

I would think that 15 watts, even with only about 8 hours of daylight this time of the year could keep a battery maintained, but it will not charge it.

With a 10 watt charger, 8 hours of daylight, and probably not 100% efficiency from snow or ice covered windshield or array, and you are probably looking at closer to a realistic average of 1-2 watts usable.

That should still be enough to maintain your disconnected battery, but it may not be enough if you have modern vehicle computer draw.

 

[LindenBruce]

Wireless key entry system? Alarm system?

Do you last days, or barely weeks? Might help narrow down the level of draw.

Dual batteries? Don't rule out one battery being possibly being bad at two years. One bad battery will actually charge from the other, draining both.

Three weeks without a start up and the engine barely turns over, not fast enough to start so I need to jump it. No alarm system, no aftermarket stereo equipment like amp's, but it does have factory wireless entry of course. Do any of the manufacturers these make cars without a wireless remote entry?

I have a load tester so I can also check the batteries. But I will need to charge then first. Or it will not be an accurate load test. B.

 

[94BULLITT]

I checked the battery on my BX today. I have a 5 watt solar panel on it. The tractor has been sitting since Monday. It was up to 13.27 volts. I guess the solar panel is doing it some good.

Sent from my GT-P3113 using TractorByNet

 

[Soundguy]

a quality digital autometer.. especially most any autoranger.. should show a 200ma draw even on a 10a setting.

a trick to use a low setting and not reboot is to thouch the cable end to the post.. have your meter leads clipepd to post and cable end. let the high current cycle exhaust witht he direct cable to post connection.. then pull the cable from the post, leaving the meter shunt inbetween to measure...

I tried measuring the load on my duramax and it was "difficult".

When you first hook the battery back up through the ammeter, between the computer powering up and the courtesy lights all coming on, it's over 10 amps (60 watts) for a bit. And when things settle down, parasitic drain of 0.2a isn't perceivable on the 10 a scale and you have to break the circuit to switch to lower current, which reboots everything.

I never did get desperate enough to create jumper clamps to power things through a larger cable and then switching to the ammeter without losing continuity.

You will probably have to remove a few fuses if you want to measure real parasitic drain.

For me just put my gps on an ammeter and threw it in the freezer. **** thing never stopped charging the internal battery if it was in the freezer and was draining a half amp and hour. Why Chevy didn't put any switched cig lighter outlets in I will never understand. They are all always powered.

 

[Soundguy]

I don't have any GPS or Onstar or any of that stuff. It could still have a glove box bulb hanging on. My truck is on 06 model I bought in October 05. Had it since it was new. It's always had an issue of draining batteries if it sits to long. I guess I could get out in that cold 20something weather and run a draw test with my DVOM. Maybe I will try it tomorrow or Friday and report back. My 12v outlets are powered all the time also.

check any lamp issues.. courtesy.. etc.

do you have a electronic brake controller?

at least one instance I have seen a bad one pull juice always.. good draw too.

lastly. you can leave a meter in line and pull a fuse at a time and see what it does to draw.. leaving ecm for last.

sometimes relays hang too.

 

[Gordon Gould]

a trick to use a low setting and not reboot is to thouch the cable end to the post.. have your meter leads clipepd to post and cable end. let the high current cycle exhaust witht he direct cable to post connection.. then pull the cable from the post, leaving the meter shunt inbetween to measure...

That is clever Soundguy

 

[Gary Fowler]

I pulled a couple of solar panels (really small 6volt) from some kind of HF gizmo that never worked right, I hooked them in series to get 12 volts of power. I have them mounted to a plywood board and am thinking I can put them on my trailer to keep the brake battery charged up. I cant figure out how to measure the watts with my el-cheapo multi-meter but it should keep the little battery up since there is not any drain on it.
As for my truck (2007 Chevy) it has some parasitic drain from the alarm but that isn't much as I have left it set for up to 8 months and it still cranks abeit a little weak in the battery. I don't have any drain on my tractors that I can tell. The LS has set for 8months at a time and still has a hot battery. I think the most my Kubota has set is 3 months and still cranks normally.
I have a 12 volt 14 watt solar panel that I used to use on my JD mower as it set for 6 months at a time and it never harmed the battery and kept it fully charged. I have a bunch of battery tenders for all the other vehicles that don't see at least weekly use. My GPS and radar detector left on will pull a good battery down in a couple of weeks, not enough to need a jump start but I can tell the battery is weak.

 

[Jkott]

P=I*V

Watts = amps * volts

Measure the voltage. Should be above 12.6 and around 14 if charging. Then if your meter can measure current, out it inline to measure the amps generated.

 

[LindenBruce]

It does have a trailer brake controller. But it is Ford's integrated unit. So I have no idea if that could be drawing current. And yes, I have done the "pull one fuse at a time" trick in the past when trouble shooting electrical gremlins. I always hated tracing electrical shorts. They can be a real pain at times.

I am currently running a trickle charge on each battery and have the batteries isolated while I am doing this. Then I will let them sit a day before I tie them back in. Then I will let them sit another day before I isolate them for a current draw test with my DVOM. If that test is normal I will load test each one to see how they respond. If the current draw test shows high draw then it's off to the races pulling fuses to see which circuit is the "red headed step child". And on and on and on. Oh what fun it is, aye? B.

 

[JRobyn]

I saw that Northern is running a sale on a 20w polycrystalline panel right now (I think today is the last day) for only $59. Very cheap for the wattage!

- Jay