Battery power question

Kminor28 · 10-18-2020, 04:06 AM

I have a Tuscany 34ST equipped with 4 Lifeline AGM batteries. Each is rated at 220 amp hours. Two are connected in series, 2 pairs in parallel. It is a 12v system. If I understand it I should have approx 440 amp hours. When dry camping; I charge my batteries for 2-3 hours ending at approx 8 pm. At 9 pm, my Magnum meter shows inverting DC 12.5v - 2a (can be up to 7a if the electric refrigerator is running). I have everything turned off (that I can turn off). No lites used, no heater, no water pump left on. By 0700 the next morning it is displaying Inverting DC 11.5v -2a. By 9 am my AGS system is auto starting the generator. How long should my batteries be lasting at a 2-5a rate? The dealer tells me I should be able to watch TV and use lites with no problem- Not. I also have 3 solar panels that charge quickly during the day, however by 5 or 6 pm (depending on how long the sun hits the panels, usually until around 3 pm) I am back to the low voltage. Any ideas?? Thanks in advance

**16ACE27** · 10-18-2020, 05:20 AM

You have 440 Ah, only 220 Ah are usable.
2 - 3 hours is probably not long enough to fully charge your batteries.
I suspect your inverter is reading DC volts and AC amps, 5 AC amps is 50+ DC amps, or 4 hours of use from your available 220 Ah ay that rate/ At the 2 amp AC (20+ DC amp) rate you would have 10 hours.

With the unknown solar input in the mix you really need a good battery monitoring system to keep track of current in and current out so you have a better idea of the real SOC of your batteries.

lwmcguire · 10-18-2020, 10:27 AM

I have a similar battery bank with 4 T105 AGM batteries

Amp draw sounds similar for 120v and we run the heat plus fridge easily overnight

I would keep investigating to determine what else is drawing amps

We typically run the generator 2 hours in the morning and the Magnum indicates 105-110 amps charge rate

If the temperature is expected to drop again overnight and require heat the generator is operated again prior to quiet time for two hours

DavidEM · 10-18-2020, 11:08 AM

Yes, I also think your inverter is reporting 120V AC amps and the DC required is about ten times the AC value.

If you have a residential type AC fridge running on the inverter, these can draw a lot of DC current to power the inverter and is probably what is running down your batteries.

David

galOnTheGo · 10-18-2020, 01:54 PM

connected in series means you have 24v. connected in parallel means you have 440 amp hours. repeating what has been posted, only good for 50% means 220 ah. if all 4 batteries are connected together you have a 24v 440 ah with useable 220ah.

Bob Denman · 10-18-2020, 02:03 PM

Quote:

Originally Posted by galOnTheGo

connected in series means you have 24v. connected in parallel means you have 440 amp hours. repeating what has been posted, only good for 50% means 220 ah. if all 4 batteries are connected together you have a 24v 440 ah with useable 220ah.

I don't think that the OP stated this; but I believe that he has 6-volt batteries...

Kminor28 · 10-18-2020, 03:51 PM

Bob is correct, I have 6 volt batteries. Can anyone recommend how to become knowledgable on this subject? I don't understand the benefit of a 4 battery system if all I am getting is 220ah, listed as the output of one battery. I understand a series connection giving me 12v, what about the other 2 batteries, also connected in series, then hooked up in parallel, or so it appears. Any suggestions on where to look for a better battery monitoring system? We do a great deal of dry camping.. thank you all for your responses. The more I learn the more I realize how little I know!

Hugh.vines@att.net · 10-18-2020, 04:01 PM

Look up will prowes on line or you tube. He is an expert and has a great book at amazon. Straight arrow no bs. He has a website too. If you look him up on you tube you can watch videos that start for people that know nothing. You will enjoy his videos not boring

Bob Denman · 10-18-2020, 04:04 PM

We also have a lot of really smart folks in here. They've got AC/DC Power figured out!

But not me: I just like the Band...

**16ACE27** · 10-18-2020, 04:53 PM

Quote:

Originally Posted by Kminor28

Bob is correct, I have 6 volt batteries. Can anyone recommend how to become knowledgable on this subject? I don't understand the benefit of a 4 battery system if all I am getting is 220ah, listed as the output of one battery. I understand a series connection giving me 12v, what about the other 2 batteries, also connected in series, then hooked up in parallel, or so it appears. Any suggestions on where to look for a better battery monitoring system? We do a great deal of dry camping.. thank you all for your responses. The more I learn the more I realize how little I know!

As I stated above you actually have 440 AH of capacity but since drawing Flooded Lead Acid (FLA) batteries down below 50% can cause damage to the batteries the usable capacity is 220 AH.

Batteries in series add voltage but the AH don't change so it takes two of your 6 volt batteries in series to give you 220 AH at 12 VDC.

Batteries in Parallel add capacity but the voltage doesn't change, so your two series strings in parallel doubles your capacity to 440 AH at 12 VDC.

A lot of people swear by the Victron battery monitor:

https://www.amazon.com/Victron-Energ...dp/B075RTSTKS/

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