Can I replace a 12V 7Ah battery with a 12V 12Ah battery ?

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Old 12-19-17, 05:25 AM
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Can I replace a 12V 7Ah battery with a 12V 12Ah battery ?

We have a Vista 20P. It works fine but our power goes out a lot lately and the current battery only powers the system for about 30 minutes or so. Can I replace it with a 12Ah battery ? Would that have a longer lifetime ?

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Old 12-19-17, 05:49 AM
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The 12 ah battery is physically larger than the 7 ah so it might not fit in the enclosure, but otherwise, sure. It will last maybe 40% longer than the smaller battery.

The bigger question is...do you have that large a system (or that many current using options) that the 7 ah is not large enough? Or is it that the current battery is just plain worn out. I don't remember the UL requirements but the battery should hold at least 24 hour in a standby condition. I think mine can go 48 hours.
 
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Old 12-19-17, 06:20 AM
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Thanks for pointing that out. We started with a 4Ah battery and pretty much the 7Ah battery was just longer (and fit in the box no problem). But - the 12Ah battery is 1.3" wider and that will not fit in the box.

I guess I'll stick with the 7Ah and just add replacing it to the things I do every January 1st.

We needed the larger battery because of the 748 siren. I do have the extra panel/parts to power the siren independently but have never gotten around to installing it.
 
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Old 12-22-17, 05:03 AM
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An alternative is to connect two 5 Ah batteries in parallel, this would give you a 10 Ah reserve that would fit in the box.
 
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Old 12-22-17, 05:21 AM
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Hi MrRon - Happy Holidays !

So today I have 2 X 4ah batteries and 1 X 7ah battery. Can I mix and match them or do the two batteries have to be the same type ?

Also - what would you call the cable that would connect the batteries. I had a quick look on ebay for "cable batteries in parallel" and I don't see anything that looks like it would work.

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Old 12-22-17, 05:21 AM
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Have you looked at Motorcycle Batteries; they seem to come in an almost endless variety of dimension sizes (including height) and Ampere Hours.
 
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Old 12-22-17, 06:00 AM
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Generally, on the rare occasion that I need to double up batteries, I either use a "Y" connector to let me jump from battery to battery (https://www.gordonelectricsupply.com...saAolJEALw_wcB), or I just cut off the existing end and crimp new connectors on to make up the parallel connections.
 
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Old 12-22-17, 08:56 AM
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If you use batteries in parallel they really should all be of the same ampere-hour capacity. Otherwise they may not fully charge and have a much reduced lifespan. This is especially true of lead-acid batteries, regardless of whether they are sealed, AGM or wet configurations.
 
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Old 12-23-17, 09:16 AM
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In addition to what Furd wrote, rechargeable batteries used in parallel should also be of pretty much equal age (preferably new). Otherwise, the unequal ability to accept and deliver a charge will lead to shorter battery life.
 
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Old 12-23-17, 10:23 AM
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Exactly, the dissimilar size/age can lead to what I call a "push-me/pull-you" effect, where the weaker battery damages the stronger. Basic good engineering practices still need to apply.
 
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Old 12-23-17, 01:24 PM
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Thank you all for your replies. I'm glad I asked what I thought was an obvious question.

In general I understand the Y connector - but for the life of my I do not see on ebay/amazon etc what would seem to work out of the box without modifications. On the humorous side - I was reminded of my first programming position, 30+ years ago, where they handed me a spool of wire and a box of pins etc and told me to wire my terminal back to the computer room. And that was a decent sized company...

Anyway - we have a chain here called Steren which is similar to Radio Shak. It is where I would buy the batteries anyway and they are somewhat intelligent so I'll see what I can do.

Feliz Navidad !
 
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Old 01-03-18, 06:57 PM
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Having similar concerns re: battery life, something I did with my panel when I first installed it was replace the standard siren with a low current model. It cut the siren current draw in half, approximately doubling run time on batteries.

Looks like the standard 748 draws 1.2 amps but the 748LC only draws 550 mA.
 
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