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Author Topic: Find positive on solar charger  (Read 503 times)

Johndoh

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Find positive on solar charger
« on: August 27, 2018, 10:20:38 PM »
Hi guys I got a solar trickle charger the idea being it will keep the generator battery topped up. the crocodile chips are missing and both wires are black, is there an easy (ish) way to find the positive wire. Many thanks
It is better to light a candle than to curse the darkness

glort

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Re: Find positive on solar charger
« Reply #1 on: August 27, 2018, 10:34:51 PM »

Get a multi meter on the voltage setting and put it on the wires. It will indicate that the polarity is.

Other way is just put it on the battery.  Little sparks indicate correct polarity, Big sparks indicate wrong polarity, no sparks means you now need another controller.   :0)
The Chinese Cheapies I have all have reverse polarity protection.

Johndoh

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Re: Find positive on solar charger
« Reply #2 on: August 27, 2018, 11:40:20 PM »
Mercy Bucket Glort!
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mike90045

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Re: Find positive on solar charger
« Reply #3 on: August 28, 2018, 03:45:34 AM »
Sometimes there is a slight "rib" molded into the cable insulation.  That helps the mfg, but I have no idea if they call it - or +

BruceM

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Re: Find positive on solar charger
« Reply #4 on: August 28, 2018, 05:37:50 AM »
+1 for Glort's suggestion.  A Volt-Ohm meter comes right after screwdriver, or was that before wire strippers?

glort

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Re: Find positive on solar charger
« Reply #5 on: August 28, 2018, 08:06:05 AM »

I have a Multimeter Fetish.
They are so cheap from fleabay now.  I remember the first decent on I bought not long after I started working. $90 which was more than the weeks wage I was getting then. Be about $1000 in todays money.   I still have it and it still works fine even though it is nothing more than a cheap  chinese meter now.
The cheap Chinese meters I buy now for $10 delivered have far more features in fact.

I think it's because I remember how much they were I love to buy the things so cheap.  People rubbish the low end meters but their accuracy is very good in my experience. I did but a better one the other week, (over $20!!)  and the voltage is off by about 3. Dissapointing as it's a nice looking and well featured meter. 

One tip with Multi meters...
When You are checking the amps on a 5Kw solar array at lunchtime, DO remember to set the leads back in the correct position when you go to measure the voltage.
Otherwise you might have the thing connected and say, Oh, I have the wrong setting still, turn the selector dial and then hear the welding sound inside and see the magic Smoke disappearing before you can remove the connection.  You can watch a Whole $7.99 go up in smoke before your eyes.
Not that I would ever do anything silly and amateurish like that of course.... just something I have heard other people might do and passing on the tip!   :embarassed:   ::)    :angel:

Reminds me, I never replaced that meter..... errr, that errr, Fell out my pocket when I was on the roof that is.....   ;D
Have to go have a look at what fun new offerings are on fleabay this Month!


glort

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Re: Find positive on solar charger
« Reply #6 on: August 28, 2018, 12:55:11 PM »

JD I think you gave me a brainwave idea that will save me considerable  bucks.... for which I greatly thank you!

The Mrs has been complaining the Kitchen is too dark without the lights on. Probably spoiled her with the powerful LEDS I put in a couple of months back.
Changed the main Fitting for something a bit more decorative and appropriate rather than the stained glass horror that was there and then she complained the stove was dark ( which it  was) so I had another Led in the roof and working in 5 Min flat.  Brownie points for me.

Thing is now I have spoiled her, she wants more. She has been talking about putting in a skylight which I don't want to do for several reasons.
They are not cheap,
I can't / don't want to do it which means I have to get some pelican tradie in which is out of my comfort zone for fear of what else they will stuff up,
Skylights disturb the roof "seal" and can leak or be broken,
And I have panels up there and that will disturb my array layout. 

This thread made me think of the controllers I have  ( which have screw terminals and are all marked) which I have been wanting to have a play with again.  Lead me to think of a setup I have up the back with a light I use in my seed raising incubator ( AKA, old fridge) .
Solar panel powers that and it is also connected to a transformer.
The solar panel puts out higher voltage than the transformer so during the day, the panels are supplying the grow light and as the sun goes down and night falls, the tranny takes over. Sun comes up, panel voltage goes higher than tranny, free light all day.
And before anyone asks, why not open the door during the day? Because then the plants are subject to hot/ cold/ dry/ instead of the much more constant environment the fridge provides.

Thinking of this setup lead me to realise I can do the same with the lights in the Kitchen.  I'll just throw another panel up on a relative flat part of the roof and run a wire back in teh ceiling to supply the LED down lights.  Even a crappy 175W panel which I have a heap of up the back will run a heap of led's  @ 13W ea and may even provide more light on a dull day than the skylight would.  I
Ordered some buck and boost  regulators to give me the right voltage from the panels so all should be sweet.
Might just have to rewire the Lights from individual transformers  to a parallel arrangement to make the Solar input easier and then gang all the trannys together on the same feed wire. Maybe put in a Diode on the tranny feed, haven't checked the trannys as yet, all I know is the voltage and they are the little electronic ones.  Bought a heap of 10A diodes a while back so have them if I need them.

Solar powering the Downlights saves a lot of expense, penetrations in the roof and ceiling I don't want and I suspect may provide more light than the skylight anyway.  Can always put another panel up in parallel to make sure of that.  :laugh:

Thanks for the round about inspiration and reminder of the solution to the problem.  ;)





BruceM

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Re: Find positive on solar charger
« Reply #7 on: August 28, 2018, 03:27:31 PM »
I use the cheap multimeters myself, though now I've had to spring for a bit more for true RMS meters.  Dropping things is unavoidable when you often can't feel much of anything with your fingers and frying meters in the Amps, oops, Volts game is also a specialty.  I only risk my good meters when I must and find the $7 meters of very good utility.

My workhorse is an old analog needle type Radio Shack meter I've had for 40 years. Piece of crap, terribly inaccurate, but does the job without the EMI of the digital ones which do me in after a while.  With a homemade active probe via op amp voltage follower, I can use it for troubleshooting my most sensitive low power analog circuits, where the load of normal meters affects the circuit too much.  The RS meter is totally fuse protected, and I still pop those regularly with the volts-oops-amps snafu.

If I ever get a windfall, I'd replace the Radio Shack meter with a Simpson analog.  Their meter movements are much better calibrated.








Johndoh

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Re: Find positive on solar charger
« Reply #8 on: August 28, 2018, 11:11:30 PM »
My multimeter cost 7.00 off a well known auction site. I dont know why the battery is losing charge its almost new could there be something causing it to discharge on the generator when its switched off. here is the multimeter
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BruceM

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Re: Find positive on solar charger
« Reply #9 on: August 29, 2018, 01:46:15 AM »
So hook it up and mark the positive lead with some red tape or something.


glort

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Re: Find positive on solar charger
« Reply #10 on: August 29, 2018, 03:48:26 AM »

I bought 2 of those meters last night.
I only paid $7 odd delivered which I thought was great for what they are and do.  I had 4 but I have cooked a couple in recent months so in the absence of anything more exciting for the price or a fairly wide variation of it, I bought those.  I have found them in the past to be good meters.  I also bought 3 of the super Cheapies @ under $4 ea. also found them to be good meters just I have become a multi meter snob and they look cheap and amateurish.  Can't fault their performance though.
When you get a few of them, line them up and they all read  within 2/100ths of a volt the same, you know they are accurate enough.

I have to laugh at the price variation for the same thing. I see there are now about 8 Colour schemes for the same  meter. I have a couple in black and green, one in yellow but last night I got a couple in a fashionable Blue and white.  The prices varied from low $7 to $40 for the same meter and all from Chinese Sellers. Many of the local merchants were cheaper than a lot of the OS sellers.  Same with all of them. Same with some voltage probes listed from anything from $1 to $30.  pays to be a tightarse like me and do your home work.  Price is rarely indicative of quality with cheap electronics especially from china.

When you say Discharged on the generator, are you indicating you have it hooked up all the time?  I would not think that would cause a problem but then again I have never left one attached  to anything.  There are separate Volt meters available for that which are cheaper if you want constant monitoring.
You could make up a board with the back lit Digital meters showing Volts, amps and frequency and then make it super impressive and add similar gauges to a board with engine and genny temps.

I bought a bag of Indicator lights a while back as well. Cheap as Chips, well under a Buck as I recall. Red, green yellow and orange.
Handy to know something is actually connected and a visual warning when something is live.

I like making up control boards. My main solar array board is total overkill but allows me to manipulate things in ways that I will never need to and makes me look like I have a clue about this stuff.  :0)  Meters and breakers look  great when all set out on a board on the shed wall.
Would be Illegal as all get out even though the level of protection it provides is way beyond what anything to regulations would be which here with solar, is a dogs breakfast and known to CAUSE significant problems in what  the rules require.  Yeah, Putting the disconnect on the roof next to the panels is a effing great idea!    :o  So much better than mine at ground level where everyone and anyone can reach it.   ::)

Apart from that, I'm not a licensed, accredited solar Sparky. Can't have the amateurs who spend time and money to ensure their house don't burn down showing up the  professionals who take every shortcut possible to save money and time so they can get to the next job ASAP!

Things I have already found here that were clearly done when the house was built are enough to undermine and faith I have in sparkys I don't know and the so called professional standards of the industry.

Johndoh

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Re: Find positive on solar charger
« Reply #11 on: August 29, 2018, 08:26:16 AM »
My local spark said you need a Fluke multimeter costing about 400.00 which seems a lot for what I do with it. The rectifier on the generator produces almost 14 volts when its running which should keep the battery charged, it's a small car battery starting a single pot engine with no other loads on it. It would be useful for the missus if it were electric start and I wasn't around during a (rare) power outage. The little solar panel is making 18 volts in the rare sunlight here so I'm hoping it will keep the battery charged. It was in the boot of an old car I bought.

The Chinese really do make some things very cheaply I ordered these https://www.ebay.ie/itm/10PCS-Crocodile-Alligator-Clips-Connectors-for-Test-Leads-Red-and-Black-42-5mm/263719665526?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
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glort

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Re: Find positive on solar charger
« Reply #12 on: August 29, 2018, 01:33:58 PM »
My local spark said you need a Fluke multimeter costing about 400.00

My mate has top of the line Fluke meters. They are worth a fortune. He has a set of them. Multi meter, thermometer, phase angle meter, air flow and pressure, clamp meter... You name it. Worth the same as an up market car all together.  He has his Multimeter Calibrated every year or so.  I calibrate my cheapie meters against his.  Usually all I have to do is test one to make sure it's right and can compare my others. He's amazed how accurate the Chinese cheapies are.  They are pretty much always within 1/10th of a volt  which is close enough or anything I do.  If they are out, I get a texta and write on the back with a + or - and the difference from true if I really need to worry.

I can guarantee you that 98 out of 100 cheapie meters will be well and truly accurate enough for what you need.

Your battery going flat has to be one of 3 reasons.
1. It's stuffed and internally discharging,
2. There is a phantom load from the genny/ starter that is draining it, and related,
3. Battery is not being properly re charged.

If it's a non sealed type it could also be low on electrolyte..... which would probably mean it's stuffed now anyway through wither being or getting in that condition.

Easy to check.
Set your Multimeter to AMPs ( A) on the highest setting, usually 10A.  Take one lead off the battery and put one probe on that lead and the other on the battery terminal with the battery and everything else switched off. Make sure the meter is set to DC if it  needs to be, the leads are in the right socket and no need to worry about the polarity.
IF you get a reading  of anything more than a few Milliamps ( MA)  something is wrong. If you don't get anything in the 10A setting, go down one, usually 200Ma and re test.  You shouldn't see much at all if anything. I'd guess you'd want to see less than 20 Ma.  Least I'd be wondering why if there was more drain than that.

If there is, then you have a problem  ( what a clever diagnosis I made!   :angel: ) which you can start to look for.  Or not.

Other method to find the problem is simply disconnect the battery.
I would take a volt reading when you do and note it. I'd take another 24 hours later and see if it had dropped.  I'd wait probably 4 Hours ( or longer) to let the battery stabilize after a run and then measure for a few days.  You could measure every few hours initially. If you see more than a volt drop you probably found the issue. It will drop maybe 10ths for a couple of days but if it's dropping a volt a day, it's cactus and you need another because it will be technically flat ( under 11V) in a few days anyhow. 

You Might also want to check the charge rate of the alternator or charging circuit on your genny.   Put your leads on the battery terminal and on the battery lead in such a way you can remove the lead from the battery but keep the meter connected.  An easy way of doing this may be to use a car Jumper lead with the battery lead off the battery.  Take the jumper lead off the battery and the meter remains connected.
The idea is to have the only connection through the meter without loosing contact.

The parroted Mantra is you can't disconnect an alternator from a battery while it's running or you ll blow the regulator / diodes in it.   I have found that to be absolute horse hockey with any car alternator I have ever played with. And there have been a few going back a while.
That said, I'm not sure if your charging system is a field off the Generator itself or a separate alt but I suspect the first so I'm erring on the side of caution. If you keep the connection, no damage can be done.

After a minute or so from starting, separate the battery and the lead from a direct connection so all the power is going through the multimeter ( WITH ) correct polarity and see which way the power is going.  You should be getting a charge INTO the battery not out of it.  If that's not happening, that could be your problem.  No charge for the battery will eventually deplete it naturally enough. You don't want to measure straight after charging because if the charging is working the current is more than likley more than the 10A your meter can handle and you'll blow it or the fuse if it has one... which a lot now don't seem to sacrificing the tracks on the board instead!  ::)  After a minute the major current should have stopped ( providing the battery was not discharged to start with) and the battery will have just a few amps being fed into it.

Don't know how often you use your genny but keeping batteries on float charge is always a good idea.  If the charging circuit is not working, you can either look at fixing it or don't worry. If you start it infrequently, the solar charger may be enough to keep it where it needs to be. It shouldn't need a lot of amperage  if the thing starts easy say once a day. That being said, Battery's also have a charge curve.  This means when they are say 50% charged you could pump -say- 50 amps into a battery. Once that same battery ( any lead battery and lipos and others) hit 80%, things change. You must put that last 20% much more slowly and the more charged the battery is, the less current you can feed it.  When it's 95% charged, said battery may only be able to safely take -say- 10A.  Varies on battery size and type but the principal is universal.

Now what all this means is if you are starting your genny and it needs a bit of cranking and then you only run it an hour, the battery may never get fully charged.  That last little bit can take a very long time relatively.
Having your solar charger on the thing will give it the hours it needs to bring the voltage right where it should be.
Where that is becomes one of those endless opinionated electrical discussions but for a car battery, a float voltage of 14 to 14.8V would be good.  If your controller has settable cutoffs, 14.5 would be a happy medium. The battery may have cycle and float voltages on a sticker you can follow.

A lot of people make mistakes with the flat battery problem. Usually people blame the battery and get a new one only to find their car won't start again 2-3 days later.  That's because the alt is on the Fritz but most people first time round assume the battery and never test the alt.  Can't tell you how many people I had come back when I ran a parts shop complaining the new battery they purchased 3 days ago was no good because the car wouldn't start again.  Get them to bring their bucket of bolts round, test the alt and it's dead as a door nail. NO, you can't have a replacement or refund!!  >:(

By the same token, you may find a problem with the alt and fix that only to still have troubles because now the battery is stuffed from being over discharged.  A normal  car type battery only needs to be run flat a dozen times and it will fail even if it's brand new.  Repeated deep discharge dramatically shortens life expectancy.

Any lead battery ( and a lot of the newer types as well) all do better with a little discharge rather than a lot. For a normal, non deep cycle car/ marine battery, a discharge of no more than 20% will give the battery its best life.

Again, 
1, Check Battery itself,
2 Check for discharging when the genny is off,
3, Check battery is being charged properly.

You are going to think that 7 quid was money real well spent on that meter when you find the problem.  :laugh:

Johndoh

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Re: Find positive on solar charger
« Reply #13 on: August 29, 2018, 05:50:27 PM »
Thanks mate theres a few little jobs lined up for me this evening. There are little coils behind the flywheel making ac on the generator it goes into a little rectifier and 14v dc comes out. I already checked the battery all the plates are covered. These generators are started with a motorbike battery maybe its not producing enough power to charge a car battery?
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glort

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Re: Find positive on solar charger
« Reply #14 on: August 29, 2018, 11:06:12 PM »

If the generator is getting a decent run time i would think it shouldn't make any difference.
I have been playing with my china Vertical Cyl Diesels this week and they put out a very decent 13A on the charging circuit. Plenty to keep even an N200 battery topped off. The air cooled Ruggerini I bought a couple of months back does similar, about 16 A and that thing Definately needs a car or a truck battery to start it!

Lots of cheap car battery chargers only do 4A but they will still charge a car battery albeit may take 24 hrs.