#12313  by Mark
 Sat Jan 23, 2010 8:06 pm
Thanks Geof I think it would be useful to add that to our Links page.
I'll try to remember to that on our first wet day.
 #12314  by Nut17
 Sun Jan 24, 2010 4:28 am
Genesis wrote:Mark,

This link may be useful for you, if you haven't already seen it.

http://www.windsun.com/Batteries/Batter ... tm#Battery Voltages
Hi Geof,

That is certainly a very informative link. I am keen to double up my solar capacity and will need to replace my controller. This site has certainly given me the info I need to make the right decisions.


Cheers Chris
 #12316  by Gay'zin
 Sun Jan 24, 2010 7:59 am
Hi Geof,

I double what Chris says, I have actually saved this link to my favorites, it is definatly something that needs to be absorbed gradually into my brain. I have read a couple of other blerbs about the batterys and set up, but nothing this usefull.

 #12331  by John&Helen
 Sun Jan 24, 2010 5:02 pm
Very good and readable link.

A postscript to my earlier entry in this post.

It appears my dropping voltage is the result of a non working - off position, in my 12V compressor fridge, not a decaying battery as I suspected.

I caught the culprit starting up, whilst cleaning the MH this afternoon. Ive pulled the fuse and will need to check the voltage again every 24hrs for the next few days to confirm.

Posting to let other know, OFF, isint always off when applied to an ( admitedly 12yr old ) fridge.
 #13153  by Van Campa
 Mon Mar 08, 2010 9:52 am
I have a few digital multimeters being an electronics technician.

I have been thinking that they are pretty accurate despite of the battery voltage of the power supply.

Recently I bought a cheap Uni-T UT208 DVM for making a current meter for my solar panel. It worked pretty well until the 12 V battery inside the meter went low.

I tested agains my better DVM and sure enough it was showing far too high reading.

When the better DVM was showing 12.5 V the cheap UNI-T was showing 16 point something. After replacing the little 12V battery inside the measurements were pretty much identical.

12V lead acid battery on its own can not put out 16 volts.

Now I have wired another Uni-T UT 208, $13 at Jaycar, with a ciggy lighter plug so it is easy to check the battery voltage. I might hardwire it later.

To save on battery I need to fit in a momentarily ON push switch and leave the dial on 20 Volt setting. This switch would prevent draining the battery.
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