Boondocking and Batteries

[Jstaud63]

Buying a 2019 Georgetown XL 377TS. It has 4 flooded coach batteries (2 under the stairs/2 in the compartment behind the stairwell).

Thinking they are 6V but not sure. Took a couple of pics to figure the wiring. Looks like they are in parallel to me but not sure.

Trying to figure the AMPs to draw from in this config. Any help would be appreciated.

Also, in this configuration, the batteries look like they are exposed to road debris and moisture being kicked up from under the chassis. Is that a concern for them being uncovered?

Thanks for your help.

[A32Deuce]

Second asking for this?

[formerFR]

if you're sure both sets are for the HOUSE, then yes, they are all 6v, though each set is wired in SERIES, making then 12v, then wired to the other set in PARALLEL, doubling the Amp Hours between the sets...

not sure, though, what you mean by 'amps to draw from...', you'll have to be more specific with your question.

as for the exposure to the road and weather, it's doubtful that it will impact them...

[sdowney717]

If you have model numbers on the battery then you likely can find their amp per hour rating they can supply x amps in x hours idea.
Do you have an amp meter that tells you the amps being drawn from them?
If they are 6 v, maybe they are deep cycle means they can provide more power longer without being damaged or destroyed. A few deep cycles on a non deep cycle battery will ruin it.

[SlowrideHD]

You need to know the voltage and amp capacity of each battery and then you can calculate what you have available. 6 volt batteries wired in series, you add all the volts together for a total but the amperage stays the same as one battery. Ex. You have a 6v, 115 amp battery. Two of them in series gives you 12v and 115 amps.
If you have another pair of these and they in turn are wired in parallel with the first pair, then you have 12v and 230 amps. Of this total you will have about half of the amp capacity available for use until you drop the voltage down to about 12.1v. You never want to discharge you battery bank below that number or you run the extreme risk of ruining your battery bank.

[richp]

Hi,


At the risk of looking foolish -- and it's aways possible I'm wrong -- I always believed that two six volt 115 amp hour batteries wired in series yielded 230 amp hours.


If it doesn't, my operational thinking has been wrong for years, even though my system seems to function as if I'm right.



FWIW.


Rich Phillips

[luker0]

Originally Posted by richp

Hi,


At the risk of looking foolish -- and it's aways possible I'm wrong -- I always believed that two six volt 115 amp hour batteries wired in series yielded 230 amp hours.


If it doesn't, my operational thinking has been wrong for years, even though my system seems to function as if I'm right.



FWIW.


Rich Phillips

Two 6v 115 amp batteries will yield
- 6v and 230 amp when wired in parallel
- 12v and 115 amp when wired in series

[richp]

Well duh, I totally forgot that my Trojan T105s are 225 AH 6 volts each, which was the starting point for my mistaken thinking about my 225 AH capacity.


Apologies for gumming up the works.


Rich

[TitanMike]

If you have four 6 V batteries, and assuming they are average in capacity (225 ah seems to be average) you will have a total amp hour capacity of 450 ah.

That's the total capacity but for best life you should only consider the total capacity to be 225 amp hours or 50%. Recharge when using 50% of the banks capacity and the batteries will last as long as the average lead acid battery. If you average about 50 amp hours per day with TV, Lights, Fans, furnace, etc, that means about 4 days on average.

My "guess" is based on my usage with a smaller trailer, not using the microwave with an inverter, of only 30-33 amp hours per day.

If you are running a residential type refrigerator cut my estimate in half.

A good Battery Monitor like a Victron BMV 712 would be a great investment to help manage your battery bank. It will give direct readout of load and indicate the State of Charge percentage without having to guess. Will also give an estimate of time left before hitting the 50% mark if you set the alarm for 50% State of Charge.

As for the dirt that accumulates on the batteries, I'd just wash the battery tops on a regular basis using a long bristle brush like a Milk Can Brush and a mix of Dawn and Water. Rinse with clean water. This will keep not only the dirt under control, it will also wash off any electrolyte that might have "sputtered" from the caps and minimize surface leakage of electricity as well as prevent corrosion of terminals.

Some old-timers will recommend using a mix of baking soda and water but I've found that just plain soap and water, used regularly, does a good job too.

If mounted in battery boxes, drain holes will need to be added to the bottom of the box.