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What is a battery balancer.

John.

If the batteries are permanently connected, the voltage has to be the same in each battery.  Like water, it finds its own level.

Jim

Quote: Originally posted by Greendemon315 on 28/4/2010

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If the batteries are permanently connected, the voltage has to be the same in each battery.  Like water, it finds its own level.

Jim

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Jim

Two batteries connected together do not equalise like water in two connecting tanks does. You cannot transfer power from one to the other which is what you are alluding to.

If two batteries are not identical and do not perform exactly the same you can have a problem with one discharging more than the other. When it comes to recharging, unless you re-charge each seperately, the charger can overcharge one as it brings the other up to capacity. This could damage batteries if you charge your batteries regularly. A balancer prevents this.

Yes they do.  I have used multiple battery banks, particularly in boats, over the last 40 years or so and, unless a battery is defective, every battery in the parallel bank (usually 4 in my case) will show the same voltage.  Of course, you need to disconnect them to check, but you will find that is the case.

If a battery is on the way out, you may get a different result.

What you are talking about is usually a device for shunting power into weak cells, not between batteries. 

http://en.wikipedia.org/wiki/Battery_balancer

I have seen them between batteries, but really it's a waste of money.  If one battery is consistently low, replace it.  As a matter of principle, I don't ever replace a single battery.  I always replace the entire bank.  Same age, same capacity.  Then you don't need battery monitors or balancers.

Jim

Quote: Originally posted by Greendemon315 on 28/4/2010

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Yes they do.  I have used multiple battery banks, particularly in boats, over the last 40 years or so and, unless a battery is defective, every battery in the parallel bank (usually 4 in my case) will show the same voltage.  Of course, you need to disconnect them to check, but you will find that is the case.

If a battery is on the way out, you may get a different result.

What you are talking about is usually a device for shunting power into weak cells, not between batteries. 

http://en.wikipedia.org/wiki/Battery_balancer

I have seen them between batteries, but really it's a waste of money.  If one battery is consistently low, replace it.  As a matter of principle, I don't ever replace a single battery.  I always replace the entire bank.  Same age, same capacity.  Then you don't need battery monitors or balancers.

Jim

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Waste of money? If you had a balancer or equaliser you may not have to replace the entire bank Jim.

I wouldn't dream of replacing a single battery in a bank, unless one had failed prematurely after only a few months.  However, I've always had good service from batteries, because I never let them discharge too far, and always have more than I need, so nothing is ever stressed.

In the same way, I never buy one tyre, always at least in pairs, and I have a car larger than I need, again so nothing is stressed.  I don't tend to have too many problems, and all I can say is, it works for me, and has done over literally hundreds of batteries.

I wouldn't dream of trying to dissuade you from what you want to do, and I wish you every success.  Just not the way I would do it, that's all.

Jim

Quote: Originally posted by Greendemon315 on 28/4/2010

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I wouldn't dream of replacing a single battery in a bank, unless one had failed prematurely after only a few months.  However, I've always had good service from batteries, because I never let them discharge too far, and always have more than I need, so nothing is ever stressed.

In the same way, I never buy one tyre, always at least in pairs, and I have a car larger than I need, again so nothing is stressed.  I don't tend to have too many problems, and all I can say is, it works for me, and has done over literally hundreds of batteries.

I wouldn't dream of trying to dissuade you from what you want to do, and I wish you every success.  Just not the way I would do it, that's all.

Jim

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Thanks Jim

I bow to your greater practical experience on multi battery use and am happy enough now to use my two batteries without the need for a balancer.

Cheers.

I certainly didn't mean to influence you so much.  Please do take the opinion of others on the subject.  I won't be offended in the slightest.  I do know people in the boating world who have had all sorts of battery monitoring systems, and they have been nothing but trouble.  I'm sure there are also success stories out there.

Trucks, buses and coaches all run multiple batteries, and don't usually have any fancy systems.  Just as an aside, these may have come in recently, because I've been out of the mainstream recently, but I do know that I've managed on all of those without anything extra.

Main thing is, don't connect a new battery to an old one.  If you have to do this, disconnect them periodically just to test for failure of the old battery.  You're far better off putting them in as a pair.

All just my opinion, but it is based on many years of buying batteries.  As far as boats are concerned, I usually have between two and four x 110 A/H for the domestic side, and an 85 A/H for engine starting.  I do like to keep them separate so I never get stuck with a flat engine battery (very hard to get a push start on the water). To achieve this, I use a four position master switch, so I can use or charge them independently. (The domestic batteries stay connected in parallel).  The switch allows 1 engine, 2 domestic, 3 both, 4 off.

Just remember, if you're changing the switch, say between 1 and 2 while the engine is running, you MUST go through the "both" position, not "off".  Otherwise you will damage your alternator.

Works for me, but do get others to comment if you can.  If I can help any further, just ask.

Jim