Author Topic: Battery Polarity  (Read 1002 times)

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Shadow

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Battery Polarity
« on: March 22, 2006, 01:55:55 AM »
From a Battery's point of view, Does it care which is used for ground,positive or negative?I was hooking up one of the large recitifiers that phone companys use on a 48 volt battery bank.After finally getting the 110 volt input mastered,instead of 220,(theres no wiring diagram).I'm getting strange readings from float to equalize its as if they are backwards. Then it dawned on me I remember hearing they use a positive ground.Sooo, I can switch the leads around for positive ground, and also switch leads around on my wind turbine for positive ground? But somewhere down the line I gotta go with negative ground would I not?I was just gonna use this rectifier to float/equalize these batteries for a day or so then back to the wind turbine.
« Last Edit: March 22, 2006, 01:55:55 AM by (unknown) »

willib

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Re: Battery Polarity
« Reply #1 on: March 21, 2006, 07:21:03 PM »
shadow , you have to be much more specific if you want a reliable answer.

first off , wireing diagram on what?

what is Float to equalize

what are you trying to do, and what do you have ?

« Last Edit: March 21, 2006, 07:21:03 PM by (unknown) »
Carpe Ventum (Seize the Wind)

Nando

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Re: Battery Polarity
« Reply #2 on: March 21, 2006, 07:23:50 PM »
Shadow:


You are not very clear.


BUT you may ground either polarity as needed BUT once, which means you can not down the line to ground the opposite polarity, a short will occur and current limited by the ground impedance.


Wind mills, many times are not polarity ground, specially when one may have a high voltage and this voltage is used to produce AC voltages by doing electronic polarity switching thusly generating the desired AC, like in a Transformerless DC/AC inverter.


Floating supplies ( or Wind mills) require special circuit to protect the system from lighting hits.


If you are just charging and equalizing a bank, just ground the supply and not the battery bank though make sure that you do not have equipment attached to the battery bank that may be grounded down line with the wrong polarity.


Nando

« Last Edit: March 21, 2006, 07:23:50 PM by (unknown) »

Shadow

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Re: Battery Polarity
« Reply #3 on: March 21, 2006, 08:09:21 PM »
Sorry guys, A pictures worth a thousand words.I'm hooking up oneof these,

, 110 volt AC input, 48-57 volt DC/30 amp out put. It does a variety of things if wired accordingly. Auto float, manual float, auto equalize, manual equalize, low and high voltage alarms, temp compensations, etc. But.. Its designed for postive ground so if I hooked it to my battery bank using negative ground, I get fault readings and switches working backwards. (Float boosts the power to 57 volts).Now my Wind turbine was hooked to the bank using negative ground, So My question is if I unhook the wind turbine completely,(keep in mind nothing is hooked up to this battery bank, just 8 batteries in series to make 48 volts)I should be able to hook this rectifier up with postive ground? Then float and equalize for a day or so,then unhook this rectifier and hook turbine back up using negative ground? Will it matter to the battery bank it just got equalized and floated with postive ground, then put back to work using negative ground? As long as the two are never combined? Anyone follow me now? I just couldnt imagine rewiring this rectifier for negative ground, which brings up another question, Why do some things use positive ground? Some of the old tractors used that configuration.

« Last Edit: March 21, 2006, 08:09:21 PM by (unknown) »

commanda

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Re: Battery Polarity
« Reply #4 on: March 21, 2006, 10:36:06 PM »
I think I know what is confusing you, so I'll try & explain.


Motor cars use the chassis ground as the circuit return . This halves their wiring.

Originally,they used positive ground. But this caused problems with electrolysis (rust). So modern cars use negative ground.


That charger is ex telephone exchange (very nice, by the way (can I have one??)). Telephone exchanges run positive ground.


Us humans are used to considering ground as being negative, simply from our motor cars.


It really doesn't matter. As long as the positive lead from the charger goes to the positive battery terminal, and negative to negative, it should just work. Just be aware that the metal case of the battery charger is connected to the positive battery terminal. This can probably be fixed, by the way. There's probably a heavy lead bolted to the inside of the case and connected to postive which can be removed. Otherwise, don't sit your inverter on top of the charger. The inverter probably has negative connected to the case.


Clear as mud, I know.


Amanda

« Last Edit: March 21, 2006, 10:36:06 PM by (unknown) »

kell

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Re: Battery Polarity
« Reply #5 on: March 23, 2006, 05:50:44 AM »
"if I unhook the wind turbine completely,(keep in mind nothing is hooked up to this battery bank, just 8 batteries in series to make 48 volts)I should be able to hook this rectifier up with postive ground? Then float and equalize for a day or so,then unhook this rectifier and hook turbine back up using negative ground?"


Yes you can do that, the batteries will never know the difference.


On another note --

if you can isolate the rectifier from ground, maybe you can use it full time.

Might not be feasible, or might be unwise from a safety standpoint, but worth looking into.

« Last Edit: March 23, 2006, 05:50:44 AM by (unknown) »