Upgrading batteries and adding battery monitor

[quicky06]

I have a 2018 Coachman 283RKS that I am trying to get setup for boondocking several days at a time. I plan on using for deer season this year ( archery and rifle so it will be several trips at 4-5 days a trip).

The trailer came with a dual purpose 24 series POS battery. I am planning on redoing the battery setup with 2 6 volt Costco golf kart batteries in order to keep cost in check, don't know what I will be using for battery boxes yet because I may mount them on the frame under the camper to cur down cable length and tongue weight. I also will be adding a disconnect switch at that time.

Anyway I am looking for some info on a simple battery monitor that will give me a percentage of battery capacity left. I'm not well versed on deep cylce batteries, charging, monitoring, and maintain them. IM after a simple way to monitor the charge so I know when I need to hook up the generator and recharge them.

Also I am wondering if the converter that came with the trailer is adequate to charge them, I have not pulled it out yet to se what model it is.

any help would be appreciated. the Wiring and mechanical side of it is not an issue to me, I'm just trying to get pointed in the correct direction.

[HONDAMAN174]

I use a battery meter that plugs into a 12v socket.

Here is a chart to show you state of charge

I picked up Trojan t125's in may and really like them since most of our summer camping is boondocking.

I also replaced my WFCO 4655 over a year ago with the progressive dynamics "upgrade" unit and it charges way better than what I had. Could never get WFCO into hi output mode.

Hope this helps.

[Navaner]

I put 2 12 volts 31ah deep cycle bateries on my hitch in parallel.
I use the stock guage indicator in my vibe 268rks to monitor them
It last 2-3 days tops before I turn the geny on.
Mind you i could get more if i unplug the beer fridge outside... but who wants warm beer!
The stock charger does a good job replenishing my batteries.
I can send you a picture of my set up if you want

[babock]

Originally Posted by Navaner

I put 2 12 volts 31ah deep cycle bateries on my hitch in parallel

Sure hope they are more than 31AH batteries.

[boondocking]

This is an excellent monitor that will not break the bank.

[John McClain]

Why Two 6 volt ? if one goes bad your down ! They make true deep cycle 12 volt batts now .

[babock]

Originally Posted by John McClain

Why Two 6 volt ? if one goes bad your down ! They make true deep cycle 12 volt batts now .

And if one 12V goes down, it will pull down the good battery until you realize what is happening. Then when you replace the failed 12V, you will now have 2 batteries with unequal capacity.

[John McClain]

Originally Posted by babock

And if one 12V goes down, it will pull down the good battery until you realize what is happening. Then when you replace the failed 12V, you will now have 2 batteries with unequal capacity.

Not the case at all you can disconnect the bad batt and recharge the good one !
But what the heck do I know just because I worked for a battery manufacture for 10 years. But anything is better than trying to run a 12 volt system on 6 volts

[babock]

Originally Posted by John McClain

Not the case at all you can disconnect the bad batt and recharge the good one !
But what the heck do I know just because I worked for a battery manufacture for 10 years. But anything is better than trying to run a 12 volt system on 6 volts

What the heck do I know...Electrical engineer on the GM EV1 program for the motor controller that used lead acid batteries.

There are pros and cons for each way. I am going with the 2 6V in series myself.

[Navaner]

Originally Posted by babock

Sure hope they are more than 31AH batteries.

It works fine.
I don't see what you are worried about

[babock]

Originally Posted by Navaner

It works fine.
I don't see what you are worried about

LOL...look at the specs of your batteries. No way they are 31AH batteries. Are they actually size 31 batteries?

[Navaner]

Tge are a dc31dt marine master.
Actual spec is 105 amp hours
Works great for my 2 friges

Originally Posted by babock

LOL...look at the specs of your batteries. No way they are 31AH batteries. Are they actually size 31 batteries?

[Less is More]

Before all you experts get too wrapped around the axle, I would like to point out that Costco is no longer stocking the golf cart batteries. I have no opinion whether two 6 V or two 12 volt is a better choice.

[babock]

Originally Posted by Less is More

Before all you experts get too wrapped around the axle, I would like to point out that Costco is no longer stocking the golf cart batteries. I have no opinion whether two 6 V or two 12 volt is a better choice.

Guess they need to update their website. BTW, not all Costcos carry them.

[UT_Grandpa]

The only real measurement or reported specification that matters is Amp-Hour rating. It can be specified at rates from 5-20 Amps. When you run two 6V batteries in series you get the capacity of the weaker of the two batteries. When you run two 12V batteries in parallel you get the total of the two batteries. In many cases you may get more battery capacity with two 12V batteries than with two 6V batteries.

A couple of other points:
1. 6V batteries tend to have thicker plates and should run through more DEEP discharge cycles than the dual purpose or deep cycle 12V batteries. BUT thick plates means longer life not more capacity. They tend to make batteries bigger and heavier.
2. Two 12V batteries in parallel won't necessarily run themselves down due to them not being exact matches. My Dodge Cummins truck has two 12V batteries in it and they do just fine. If the batteries sit for long periods of time with neither a discharge or charge going on they could "run each other down" with a small current flow between them. Lead acid batteries self discharge at a rate of 5% per month so if you let them sit for a couple of months they will be down a bunch.
3. I found this from rv.net:
"Battery rules:

If you have two Gr 24 12-volt batteries at 85 amp-hours each, in parallel you will have 170 amp-hours.

If you have two Gr 27 12-volt batteries at 105 amp-hours each, in parallel you will have 210 amp-hours.

If you have two Gr 27 12-volt batteries at 115 amp-hours each, in parallel you will have 230 amp-hours.

If you have two 6-volt batteries at 220 amp-hours each, in series you will have 220 amp-hours.

That explains why, when going from two 12-volt batteries to two 6-volt batteries, some people get more amp-hours and some don't.

If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity.

You can save money by using the good batteries you have rather than buying new ones. When they wear out, then buy new batteries. "

[CJ2]

What do I know. I taught Voltaire how to stack dissimilar metals with an electrolyte, then lent Franklin the string for his kite, and I'm not going to give my opinion unless someone asks in private at a campground.

[babock]

If you compare 2 Trojan T-105 6V batteries with 2 Trojan 27TMX 12V batteries, the cost per battery is similar with the 12V slightly higher.

When you compare capacity specs:
The t-105 will have a 5 hour reserve capacity of 185 and 2 of the 12V will have a reserve capacity of 2 x 85 = 170.

For the same amount of money you can generally get better capacity for the same amount of money. Also, depending on location, the 6V T-105s are very easy to find.

[boondocking]

Actually for the size footprint with (2) 12V compared to (2) T-105 you get 140 AH with the 12v not 170 AH.

[Dano1955]

two of these type 24 12v will give you 150AH for less than $150, free 12 month replacement.

10% discount for pu in storee.

https://www.batteriesplus.com/batter...p-24m/sli24mdc

[babock]

Originally Posted by Dano1955

two of these type 24 12v will give you 150AH for less than $150, free 12 month replacement.

10% discount for pu in storee.

https://www.batteriesplus.com/batter...p-24m/sli24mdc

Or go to the same place and spend $20 more and get 215AH with the same brand battery in 6V

https://www.batteriesplus.com/productdetails/sligc110