12volt vs 6 volt house battery bank

[Jeff753]

I have a 2000 watt Trace inverter with 4 house batteries. I don't know why but these batteries are 12 volt 85 amp hours for a total of 340 amp hours.
The manual says it should have four 6 volt 225 amp hour batteries for a total of 450 amp hours.It says I can use 12 volts but it calls for five 255 amp hour batteries for a massive total of 1275 amp hours. Presumably for an all electric operation.


So two questions. Can I run my Norcold 1200 on the inverter? Or a coffee maker (but not both).


My 12 volts only have two years on them and hold 100% State of Charge. 4 new 6 volt T105 Trojans would cost 500-600 bucks.
Any benefit?

[K7JV]

I posted this note on another item, recently, but it applies to some of your questions. One thing to note when putting loads on inverters, is that the current draw on the coach batteries is approximately 10 times what it is on 120VAC. That is because of the voltage ratio of 12 volts to 120 volts. On purely resistive loads, the kVA demand is the same as the watts demand. On motors, or other reactive loads, the ratio goes up due to the reactive load VARs. So on things like heat pumps, A/C's, motor driven tools, the factor can be considerably higher than 10 to 1. So just remember, when you put, let's say, an 8 amp load on your inverter, you are putting at least an 80 amp load on your battery bank. That's a lot!

Also know that even a 450 amp-hour battery bank can't begin to deliver that many amp-hours if the current draw rate is high. Something like a space heater, a convection oven can use up a lot of your dry-camping energy in a hurry. Check the ampere ratings of the devices you want to operate on the inverter, and go from there. And remember that the amp-hours available from your batteries is inversely proportional to the rate at which you "spend" them.

Inverters, when off of shore power or generator power, can take batteries down in a real hurry. They're still an awesome addition to our RV's. We just need to know not to expect them to replace the energy capabilities of shore power connections or on-board generators.

As for battery choices? Ten RV'ers, ten answers. I did just replace the lead-acid batteries in our '06 Dynasty with four, 6 volt Lifeline AGM batteries. So far, I love them! My mess in the battery compartment is gone, and they have performed well, so far. I've not demanded much from them by dry camping or leaving them off-charge for an extended period, though, so it's a case of so far, so good. Time will tell if it was a good choice.

Looking at your situation, if your 340 AH bank is clean, kept well watered, and is working for you, I probably wouldn't go looking for replacements until the batteries start letting you down. Good luck in your decision making.

[Jeff753]

Originally Posted by K7JV

I posted this note on another item, recently, but it applies to some of your questions. One thing to note when putting loads on inverters, is that the current draw on the coach batteries is approximately 10 times what it is on 120VAC. That is because of the voltage ratio of 12 volts to 120 volts. On purely resistive loads, the kVA demand is the same as the watts demand. On motors, or other reactive loads, the ratio goes up due to the reactive load VARs. So on things like heat pumps, A/C's, motor driven tools, the factor can be considerably higher than 10 to 1. So just remember, when you put, let's say, an 8 amp load on your inverter, you are putting at least an 80 amp load on your battery bank. That's a lot!

Also know that even a 450 amp-hour battery bank can't begin to deliver that many amp-hours if the current draw rate is high. Something like a space heater, a convection oven can use up a lot of your dry-camping energy in a hurry. Check the ampere ratings of the devices you want to operate on the inverter, and go from there. And remember that the amp-hours available from your batteries is inversely proportional to the rate at which you "spend" them.

Inverters, when off of shore power or generator power, can take batteries down in a real hurry. They're still an awesome addition to our RV's. We just need to know not to expect them to replace the energy capabilities of shore power connections or on-board generators.

As for battery choices? Ten RV'ers, ten answers. I did just replace the lead-acid batteries in our '06 Dynasty with four, 6 volt Lifeline AGM batteries. So far, I love them! My mess in the battery compartment is gone, and they have performed well, so far. I've not demanded much from them by dry camping or leaving them off-charge for an extended period, though, so it's a case of so far, so good. Time will tell if it was a good choice.

Looking at your situation, if your 340 AH bank is clean, kept well watered, and is working for you, I probably wouldn't go looking for replacements until the batteries start letting you down. Good luck in your decision making.

I read your post on the inverter/norcold post. Thx. Where did you get your lifelines. I saw the at the brooksville FMCA rally.

[K7JV]

I actually ordered them directly from Lifeline, in Azusa, CA. Their number is (626)969-6886, and their website is Lifeline Batteries - Marine & RV Deep Cycle AGM Batteries. They appear to be pretty nice units, but there is some sticker-shock involved. I was particularly impressed that Lifeline is a family owned and operated company, that truly seems to care about their employees and their customers, and the actual president of the company was willing to give me his personal cell phone number to use, if I had any problem with their batteries.

One other nice thing is that since they aren't a conventional lead-acid type battery, they can be shipped via UPS, to your home. I don't know if there are any measurable difference between their AGM batteries and anybody else's, but I have observed that the prices are pretty consistent from brand to brand. Interestingly, my coach owners manual shows the AGM option, and they list the Lifeline as being their AGM choice.

Again, I'm not sure I would look to invest in a new bank of batteries until I either started getting failure or performance warnings, or I knew I was going to be making heavy demands on an aging bank of questionable integrity. Assuming I don't have problems with my new batteries, the next time I'm looking for a new, quality, minimal maintenance bank, knowing what I know now, I will surely give Lifeline a call.

[K7JV]

Interesting. I put the true website address in my reply, but when it posted, it converted it to their corporate description. I suspect the link will still work, though. If it doesn't, try putting the www in front of, and the dot-com after, lifelinebatteries.