Cause of battery drain

[dwh]

But if you fully top off the batteries before storage and make sure all loads are turned off - a month is no big deal. Fully charged GC batteries self-discharge pretty slowly.

http://www.trojanbattery.com/wp-content/uploads/2014/01/GolfCarAdvisor_TrojanTips_2012SeptOct.pdf

 

[68camaro]

Better to do after your main system overhaul is complete, a minor detail and getting into the weeds would distract from the fundamentals of your overall design.

Is there any solar on the rig now?

It would also work if you leave the truck parked all day while off fishing. Especially if the truck is parked in the shade, being able to deploy a portable away from the truck sitting in the sun is handy. Again, as long as you can keep it from being stolen.

Lot of people around here use Renogy portables.

Rig was build in 2001 and has original fixed Siemens 45 watt panel on top. Not much room but I can get 14" x 8' up there. I can probably do better with newer technology.

While on trips I will be leaving rig during day so leaving portable Solar on ground or easiyily seen on roof will be problem as I have no way to prevent them from walking. My storage place is fine so I can leave on top of RV cover to keep topped off.

But if you fully top off the batteries before storage and make sure all loads are turned off - a month is no big deal. Fully charged GC batteries self-discharge pretty slowly.

http://www.trojanbattery.com/wp-content/uploads/2014/01/GolfCarAdvisor_TrojanTips_2012SeptOct.pdf

I have a storage mode that shuts off all electrical except for Mark 15 solar controller.

Doing analysis I think my max amp hour usage during dead of winter will be 117 amp hours over 3 days. I could reduce this if need be by watching less TV and/or reducing furnace usage. I will only be using RV early am and then back again at night. Then I will drive to new spot, usually. At 117 amp hour usage would 250 or 300 sized battery bank be sufficient?

I plan to have wiring looked at by Auto electrical installer company to make sure wiring is correct and not improperly sized. At same time I will check on how components are hooked up to make sure correct and try to see if anything would cause battery drain, plus see if GC batteries will fit.

 

[john61ct]

Doing analysis I think my max amp hour usage during dead of winter will be 117 amp hours over 3 days. I could reduce this if need be

If you have mains power available overnight before **and** after such a trip, that could just be one cycle, any extra energy inputs during the three days just gravy, "would be nice" not must have.

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

So two pairs $400, Bob's yer uncle

 

[john61ct]

flooded style or AGM style. There is essentially no difference other than the flooded will have a slightly longer lifespan

Scratch that "slightly".

Assume EoL is 70% SoH.

If perfectly coddled by an expert with top gear, maybe 30-50% longer.

Doing so is more difficult and take pricier infrastructure with AGM.

And in a normally "abusive" mobile context, the AGM can easily be murdered, only get say 2-3 years rather than FLA's 4-8.

The FLA is **much** more robust, much more likely to last in the hands of a normal end user who doesn't want to treat their electrickery as an interesting hobby.

 

[68camaro]

And in a normally "abusive" mobile context, the AGM can easily be murdered, only get say 2-3 years rather than FLA's 4-8.

The FLA is **much** more robust, much more likely to last in the hands of a normal end user who doesn't want to treat their electrickery as an interesting hobby.

I like the way you think....I want to think about batteries as little as possible when not using them, even then as little as possible.

 

[Steve_P]

Since I store RV in storage place with no electricity and I use a RV cover, would it be wise to put electrical system in storage mode and hook up movable solar panel to RV when stored to keep topped off and keep batteries charged?

RV 12 volt systems can have a lot of parasitic drain that might not be obvious. In my popup the LP leak detector can pull down the battery in a couple of weeks. In addition, if you have a house stereo with presets you'll have a constant draw from that. And some 2 and 3 way absorption refrigerators the circuit board remains hot even though the fridge is turned off. The 45 watt panel you have should offset these drains if it has enough available light but I would recommend that you remove the chassis ground strap from the house batteries when you put it in storage to make sure. Some use a battery switch on the ground wire. However, if you drive the RV with this ground disconnected the alternator will not charge your battery.

 

[68camaro]

So based on my usage which will typically be 2 - 3 day weekend trips, mostly under tree canopy except when driving I am estimating using at most 135 ah per winter trip (if I was an energy hog I would be at 159 ah over 3 days with furnance blasting all night) , summer would be much less. I recently bought 2 Full River DC220-6 batteris rated at 110ah at 20 hours, these are 6v deep cycle AGM type batteries.
http://www.fullriverbattery.com/product/batteries/DC220-6

I am thinking of buying two more to give me 440 ah or 220 ah at 50% DOD, but in talking to Full River and looking at below chart, do I really need four since I can get draw down to 62% DOD (135/220ah) and still get 1000+ Life Cycles. I would only use the RV 18 times a year max, realistically less even, so at 18 life cycles a year and 1000 life cycles if I target 60% DOD, wouldn't the batteries last me well beyond the 5-7 years I am looking to get out of them if I recharged properly? I understand batteries degrade naturally over time but on paper at 18 life cycles per year these batteries should last like 55 years (I know they won't) at 60% DOD (1,000 life cycles/18 life cycles per year), even at 80% DOD and massive natural degradation these batteries should last decades If I only have 18 life cycles per year? And this assumes no regarging from solar, generator or alternator while out.

Am I missing something, or drawing down well below 50% I can still easily get 5-7 or more years out of these?

 

[luthj]

some reading here if it hasn't been posted already.

https://marinehowto.com/what-is-a-deep-cycle-battery/

AGM’s & GEL’s are arguably a bit temperamental in how they are cared for, and charged, and these batteries really need to be installed as a “system“. The charging system upgrade costs can far exceed the cost of the batteries. These batteries are simply too expensive to not install correctly. Done correctly AGM can often approach & some can exceed 6V GC2 life and GEL’s often exceed it.

Those cycle life charts are for lab testing only. And should be treated as best case. In reality you will get only 1/3 to maybe 1/2 of those cycles in real life. Batteries age, even if they are not being used. Deficit cycles which are not to a true 100% before discharge will accelerate sulfation. The AGM batteries are also more sensitive to sulfation as they cannot tolerate equalize charge cycles. If you put the batteries on a good shore charger (meets mfgs specs) after each outing, you can expect 3-6 years in my estimation. Maybe longer if the ambient temps are low in your region. Ideally you would keep them on a float charger or some solar when not in use.

For the 700$ those batteries will cost, I would find a way to fit some GC2s for 250$. Replace every 3-4 years.

 

[68camaro]

some reading here if it hasn't been posted already.

https://marinehowto.com/what-is-a-deep-cycle-battery/



Those cycle life charts are for lab testing only. And should be treated as best case. In reality you will get only 1/3 to maybe 1/2 of those cycles in real life. Batteries age, even if they are not being used. Deficit cycles which are not to a true 100% before discharge will accelerate sulfation. The AGM batteries are also more sensitive to sulfation as they cannot tolerate equalize charge cycles. If you put the batteries on a good shore charger (meets mfgs specs) after each outing, you can expect 3-6 years in my estimation. Maybe longer if the ambient temps are low in your region. Ideally you would keep them on a float charger or some solar when not in use.

For the 700$ those batteries will cost, I would find a way to fit some GC2s for 250$. Replace every 3-4 years.

The GC were elimated due to space issues and difiiculty reaching them to fill with water, the 6v AGM seemed like best compromise since they are identical to Group 27 size which my compartment/slide was designed for and for my circumstances. I can see going to Lithium in 4 - 5 years and if these batteries last or I keep for 5 years my yearly ownership for two is $120 so I am happy with that.

I read the Marine How To several times and used it in my decision, it was very helpful. When not in use I do plan to get a movable solar when in storage but here in central VA we get a lot of overcast days it seems like. I also bought Boonedocker 4 stage 45 amp power center/charger which can be dialed in for battery many specs.