Parallel batteries and a question regarding reserve capacity

There are those of us who use large inverters and load them heavily. In that instance 12 volt jars may offer better service than 6 volt units.

It is important to wire any battery bank in a balanced manner. See the link for directions.

Reserve capacity, just like the more familiar amp-hours may more than double because of the Peukert effect.

http://www.smartgauge.co.uk/batt_con.html

macscac wrote:
Matt_colie, what battery specifically would you recommend?

Costco sells Interstate, Sams sells Duracell (made by East Penn/Deka). Both are good and cost less than $100 a piece.

These are "flooded cell" (wet) batteries, so you do need to check the fluid level regularly.

Trojan does make an AGM golf cart battery, but it is probably twice the cost (if not more) !

Thank you all for the quick responses..

Matt_colie, what battery specifically would you recommend?

Well Mac,

The golf cart batteries are the hot set up... They are designed to survive that sort of abuse. They are typically in the range of 220+/- ampere hour and can be depleted to 50% without damage. Lifeline AGM say that they can do this 80 cycles with no loss of capacity.

What you are trying to figure out is the rating given because car battery manufactures did not want to be held to a 20 hour rate for Ampere-Hour capacity. What reserve means (kind of) is "How long can I leave the headlights (~25amp) and still start an engine" that doesn't need a lot of cranking (because it won't be there). That measure goes from 12.8V starting at 25amps until the terminal gets to 10.5V (iirc). At 10.5 most Lead Acid batteries have been harmed. You get to do this about three times before that jar is toast.

Go with the golf cart pair in series.

Matt

The battery is rated at 100Ah which is the rating you want to use for house batteries. So 200Ah total in parallel. Best to limit the drain to 50% or 100Ah.

You didn't specify 2A AC or DC for the TV. Assuming AC then the inverter would draw 20A+ and your run time is 100Ah/20A = 5 hr. If DC then it's 50 hr. That's for a 100% charged battery.

However RVs have other drains like refer, smoke detector, lights etc.

Plus I would not use a battery rated for both starting and house. Instead I'd use 2 6V deep cycle batteries in series. Typically they are about 220Ah but designed for more cycling.

macscac wrote:
2 Interstate 31m-agm's.

They aren't what you should be getting. From what I see those appear to be engine starting batteries.

Solar is an easy and quiet way to recharge RV batteries...which should be fully recharged daily for maximum life.

Take how many amp hours you have and double it for two batteries. Then never let it go below 50% charge.

I have 430 ah which would power a 2 amp tv forever with my solar recharging it.