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happyantix
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Joined: 20/07/2010
Location: Australia
Posts: 8

Posted: 08:41am 20 Jul 2010

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Hi everyone!

Have read this site for a while, but just realised it is Australian, and has forums!

I currently have a small hydro setup producing around 7amps@12v, running my house offgrid as well as solar.

The problem is when the sun's out, and the batteries are full, they continue to charge from the hydro, i usually turn appliances on to use the excess, but it is a pain to monitor constantly.

The house batteries are 15years old at least, seem to charge up quick but also drop in voltage (and fluctuate voltage) quickly, i think they are on their way out.

I need a diversion load controller for the hydro...

was considering this

http://cgi.ebay.com.au/40A-Wind-Solar-Charge-Controller-Dive rsion-Regulator-/150361554773?cmd=ViewItem&pt=LH_DefaultDoma in_0&hash=item23023f3f55#ht_6003wt_934

with a few of these

http://cgi.ebay.com.au/2-OHM-100-WATT-POWER-RESISTOR-DIVERSI ON-DUMP-LOAD-12V-/180400648576?cmd=ViewItem&pt=LH_DefaultDom ain_0&hash=item2a00b77180#ht_3782wt_934

What do you think?

Thanks in advance!

JJ

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 02:24pm 20 Jul 2010

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Hi Happy

Your batteries need a desulphator to revive them a bit.

There is a dump load controller Glenn has designed on the electronics section on the front page nice simple little unit to build.

I use a few coils of nichrome wire wired in parallel submerged in a drum of water, not high tech but it only cost $20 for the nichrome at Jaycar. I wound them on some old ceramic formers I had in the junk box. A piece of cement sheet with holes drilled in it works well also. Also if you have a boost element in the HWS it will absorb a couple of amps, old headlight globes from the wrecker are good too,

All the best

Bob

Foolin Around

happyantix
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Joined: 20/07/2010
Location: Australia
Posts: 8

Posted: 02:53am 21 Jul 2010

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Thanks for the reply, i will check it out.

What type of battery desulphator would be suitable?

I have one of these types that i had on there for a few weeks but did not appear to help: http://www.1xpressstore.com/media/catalog/product/cache/1/im age/5e06319eda06f020e43594a9c230972d/b/a/battery_desulfator_ b_1.jpg

Also the positive battery terminal gets extremely hot, is this normal? thinking it could be due to the high resistance in an old battery.

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 03:07am 21 Jul 2010

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Hi Happy

The hot terminal sounds like a bad connection in the cable end or the contact to the terminal, as if it was the battery, that cell would boil out the electrolyte quickly.

The desulphator I use is supplied by www.infinitystore.com in Malaysia, I have tried several brands and this one has been the best and I haven't killed it so must be tough.

All the best

Bob

Foolin Around

happyantix
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Joined: 20/07/2010
Location: Australia
Posts: 8

Posted: 04:44am 21 Jul 2010

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Battery terminal is hot as well as the wire going into it, would that still be caused by a bad connection to the terminal contact? I might take it off and scrub it up with a wire brush,it has some corrosion coming off it.
Would a fluctuating voltage be a sign of battery failure? would it be worth letting the hydro run and charge it up to 16volts or so, to try and give it a decent equalisation charge?

also the site you linked appears to be down..

Thanks again

Edited by happyantix 2010-07-22

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 06:14am 21 Jul 2010

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Hi Happy

Sounds like a resistance problem as that will cause the fluctuating voltage you mention, when you clean the terminal give it a good wash with hot water 1 liter with a table spoon of washing soda to clean the pores of the metal then rinse with boiling water several times. Smear with petroleum jelly or GP grease to keep the corrosion at bay.

Examine the cable end as it may have corroded inside the lug and give you a high resistance connection to the cable. Give it the same treatment with washing soda and re solder the lug to assure a good contact, if it's to bad it may be best to remove the lug and fit a new one.

http://www.infinitumstore.com correct spelling now sorry about that.

All the best

Bob

Foolin Around

happyantix
Newbie

Joined: 20/07/2010
Location: Australia
Posts: 8

Posted: 07:38am 21 Jul 2010

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Thanks that is great info, i will do all that in the morning.

I turned off the hydro to give the batteries sort of a load test, within an hour they dropped down to 11.5volt with estimated under 100watt draw..

The desuphator i have is exactly the same as the one on that site, just rebranded.. i might hook it back up, may take a long time to work as i have 6x 2v cells and they are quite huge (not sure of total AH as they are in a metal box, privately renting here).

Thanks for all the help will let you know how i go

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 10:34am 21 Jul 2010

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Hi Happy

These desulphators are slow on big batteries and meant to be left on, so don,t expect miracles in the first week, but my experience with them is that they will slowly increase the capacity, sometimes back to nearly new levels, I put one on a battery a week ago that had been flat for three years, just a mass of white crystals on the plates and 0 volts measured, one week on it is showing 12.7 volts at rest and increasing capacity to 25% and still improving, just an experiment but it demonstrates the use of a desulphator.

All the best

Bob

Foolin Around

happyantix
Newbie

Joined: 20/07/2010
Location: Australia
Posts: 8

Posted: 10:41am 21 Jul 2010

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It was probably more like a month or more had the unit connected if i think about it, i am going away for 3 months on holiday so will connect it before i go.

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