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Old 09-21-2016, 11:25 AM   #15
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Originally Posted by trekerboy View Post
...the 12v system is drawn down to the 10v range which triggers low-voltage alarms ...?
Are you measuring the 10V at the battery posts or on the display monitor? The voltage drop might be thru the wiring.

I know that one of my circuits has multiple high current loads AND the tank/battery monitor display. If I turn on all of the devices, the tank display shows 10.5V...BUT the Trimetric that is wired directly to the batteries shows 11.8 V

Wiring voltage drop.

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Old 09-21-2016, 11:36 AM   #16
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Originally Posted by HiHoAgRV View Post
Are you measuring the 10V at the battery posts or on the display monitor?
It's being measured from the BMS, but the BMS is effectively wired directly to the battery bank, so I don't think there'd be much of a voltage drop from the wiring...

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Old 09-21-2016, 12:21 PM   #17
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Originally Posted by trekerboy View Post
QUESTION: Can I somehow "regulate" a 24v battery bank to produce constant 12v (while keeping the bank in a 24v configuration) even under load?
There are switching power supplies available that will do that, yes. Commercial products are sold for that for a couple of related applications. One us the use of 12 volt accessories (such as car audio) with the 24 volt electrical systems used in some military surplus vehicles. There are similar applications in aviation, and in marine systems.


BACKGROUND: In in our renovated AS we have a 4x6v battery bank wired in series-parallel for 12v. I am finding that the components I have on the 12v system are too much of a draw. For example, with 3 Fantastic Ceiling Fans going at the same time (and maybe a few other things like LED lights) the 12v system is drawn down to the 10v range which triggers low-voltage alarms on the fridge, inverter and other devices. I would just ignore the low voltage alarms but the beeping drives me crazy and I can't turn it off!
That is because there is something wrong with your setup.

The battery bank itself, if sufficiently charged and working properly, should be able to deliver several hundred amps without dropping below 12v.

There are any number of possible causes. It isn't possible to diagnose them accurately or safely over the internet.

Is this a bad idea for some reason?
It's relatively easy for someone with an electrical engineering background to put together a device that will turn a 24 volt input into a 12 volt output. It takes some work (and parts cost) to make a device that will do it efficiently across a wide range of power draws. In round numbers these devices end up being around 90% efficient in the real world. They are also expensive to build, with costs similar to a 120v inverter of similar watt capacity.

You still have the problem of charging the battery, of course, so you would have to replace your 12v converter-charger with a 24v one.

What you suggest is a bad idea because it will not solve your problem, unless by happy circumstance you end up replacing whatever component is failing. A 12v system that isn't working still won't work if it's reconfigured for 24 volts.
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Old 09-21-2016, 02:05 PM   #18
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There are such devices but it won't solve your problem. Your problem is most likely not enough amp-hours of storage capacity and that will be the same at 24V as it is at 12V. Then you would have some loss in the 24V to 12V converter so you would have even less usable storage. As lead acid batteries age they lose storage capacity and behave like smaller batteries and this might be your problem. Good luck with finding a solution and let the forum know what works!
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Old 09-21-2016, 02:05 PM   #19
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In addition, if you hook up four 6V batteries in series to get 24V and one goes bad, you're going to have no power.

If you instead hook those four 6V batteries in series/parallel to get 12V and one goes bad, you can limp along on the good pair. Same if you use a pair of 12V batteries connected in parallel. A bit more flexibility, no voltage converter to build/buy, and so on.

Life's better at 12V when everything around the batteries is built on the assumption of 12V.
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Old 09-26-2016, 04:59 PM   #20
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Does not your battery monitor measure energy? The units would likely be in Whr. You can convert the energy delivered into how much stored energy is in you battery bank. That will tell you how many AH your battery bank can deliver.

To me that kind of voltage drop sounds like a bad electrical connection, those commonly occur at the battery, but could also be at your fuse box. You can search with your volt meter to find a voltage drop across the bad connection.

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