Unconventional and limited budget builder has some questions

[nature lover]

I am building my second van as my beloved GMC now resides in a junk yard.  I have a 1998 Dodge conversion van with 110 K. I have been driving it for 5 weeks and it seems to be good mechanically (doing some work any how).  I really wanted an in and out fantastic fan but I am thinking of saving $ by installing a cheap standard vent and rigging a 10 in fan run by rechargeable batteries to hang under it.  The rig would allow me to pull the fan down to change batteries and allow me to turn it upside down to blow in and out.  Noise would be an issue but I think with padding and a clamping rig it could be done - what do you think?  In my old rig I had a regular vent and used the battery powered fan in the living area but I was not full time so now to have it on the vent would be better.         ====  also like my last van everything I need will run on rechargeable batteries AA, AAA, C, and D except now I need to keep meds cool so I want to add a house battery(s) charged by the alternator to power a small 12 volt fridge.  Trying to save $ by not adding solar panels and  12 to 110 converter.  Only fridge on battery and maybe another small 12 volt appliance in the future ???   I know to isolate the batteries with c o solenoid or switch.  But what kind of battery / charge controller do I need to keep battery from discharging too far or charging too much?  Make your answers simple because I am the stupid in the old saying "keep it simple stupid".

 

[highdesertranger]

simple answer,

it literally takes hours and hours of driving at highspeed to recharge a lead acid battery.
you need to recharge the battery back up to 100% everyday. that means driving hours everyday.
if you don't recharge daily to 100% you will greatly shorten the life of the battery.

highdesertranger

 

[Trebor English]

Unless you drive a lot every day using the van alternator only to charge your house battery will leave it hungry running a tiny 12 volt efficient fridge. 

The switch or solenoid to isolate is really all the charge controller you need.  Charging too much won't happen.  Little fridges come with a built in low voltage cut off to protect your battery but all the ones I've looked at stay on to a very low voltage.  There's not much battery protecting.  A low voltage disconnect is tricky because the voltage drops when the compressor starting surge happens triggering the disconnect.

 

[user 423]

My cheap Alpicool fridge has a battery protection feature. It has 3 different settings/levels you can choose from.

It protects your battery by turning off power to the fridge when the voltage gets too low. The very basic user manual doesn't specify what the voltage points are.

How much you drive will dictate how much your house battery gets charged. Do you plan to drive a lot?

And it will depend on how big the battery is and how much power whatever fridge you have uses.

 

[flying kurbmaster]

Aa or aaa batteries are not cheap if you are adding a house battery and a fridge spend a bit more and buy a 100 watt solar panel and a charge controller. I don’t have a roof vent, as long as I can get a cross draft I manage fine it is not a priority.

 

[nature lover]

I am trying to understand this all and am thankful for the input. I will not be driving a lot every day because of gas budget. I did not know that the cycle had to be everyday. I thought that a small alpicool fridge would be good for several days on say like a 400 amp bank. I understand that if I go with lead acid I can not discharge more than 50 % but that AGM can discharge up to 80 % without damage. I would eventually like to put solar on the system but I am trying to spread out my spending a little. So the iceco 20 draws 5 amps per hour and say it runs half of the time that's 12 hours x 5 amps or 60 amps per day so if I have 2 200 amp agm batteries wouldn't that be good for 5 days. Of course that is an expensive battery bank. but can't I turn the refer off on the cooler nights and with some extra insulation it might hold cold till am sun starts to warm van again. As I said I am stupid so tell me where I am wrong. For one thing I may be better to go with one 200 agm and what money I save on batteries I put into a panel. And am I right in calculating that if it was on for 24 hours it would really only run about 1/2 the time to keep temp cool enough (outside temp not excessive.) At this point all I have is one of those cheap 12 volt coolers I don't know what they draw (I heard they are next to worthless) but could run off van when driving and then get ice for when I am camping. I am considering all options and will not be able to make a decision until I see how the money holds out on the rest of the build but I am out of this place and in the van no later than May 31. THANK YOU FOLKS!

 

[nature lover]

kurbmaster I use rechargeable batteries. saves a lot of $ and desposal of batteries.

 

[MotorVation]

Agm, flooded lead acid and gel can only be discharged to 50% on a regular basis. Lithium (lifepo4) can be discharged to 80%, even 100%, although I wouldn't do that purposely, without damage.

If you take your batteries down to 50%, I don't think it matters whether it's one day or several days to take them down but once they reach that, they should be charged fully up to 100%.
Each cycle that they're not charged back up to 100% will result in damage to the batteries.

 

[maki2]

I think you should save up to purchase a very simple solar system to help ensure you have enough power for the fridge for your medications. It could be a portable panel you set out on the roof or ground while you are parked. You are not going to want to be driving long distances everyday due to the cost of fuel. Watch the videos that are on the Cheaprvliving youtube channel that review the portable panels. You can connect leads to your house battery so that you can plug the cord from the portable panel into that battery without a lot of fuss whenever you are in a position to do so. You can buy those leads already pre-made to put onto your battery. Beginner friendly.

 

[becida]

Solar is magic!

 

[Trebor English]

now I need to keep meds cool so I want to add a house battery(s) charged by the alternator to power a small 12 volt fridge.  Trying to save $ by not adding solar panels

Medications that require refrigeration vary in price and they vary in the speed they degrade when the temperature is too high and they vary in what temperature is necessary.  If you have $1000 worth of medication that degrades quickly above 45 degrees that's different from $100 for a tiny bottle of eye drops that degrade slowly over 60 degrees. 

A battery protecting low voltage disconnect to make a $100 battery last longer might be a bad idea if you lose half a month's worth of kilobuck meds.

 

[DannyB1954]

Those cheap 12 volt refrigerators are very inefficient. They use a thermo conductor device to cool, On a hot day they will not even cool down to 60. You are much better off with a very good cooler like Yetti. You can usually also add insulation for better effect. One method is to get a larger cooler to put a smaller cooler in. The space between can be used for non perishables like broad, crackers, noodles etc.

Another great method for keeping medication cool is to get a small wide mouth thermos bottle. Put the meds in there with a small bag of ice. The vacuum bottles are much better insulators than even the best cooler.

 

[StitchExperiment626]

FYI
Just providing information.

I have a 12vdc fridge from Ausranvik from China and Amazon I put it on a save list and got a notice to buy it for $200 so I took a chance. It has 3 settings hi, medium, low for voltage cutoff (I have it on medium.) I live in a van the fridge runs day and night. It runs at less than 50 watts.
Just from reading on the internet 33% duty cycle in summertime seems an answer.

AGM batteries charge 5 times faster. AGM 100 ah can charge at 25 amps. I have 60 amps into 440 ah AGM 12vdc, 4x 6vdc.
If you parallel connect you need to wire correctly.
I think you need to condition a new AGM battery but I don't know how and am trying to find out.

 

[becida]

AGM batteries charge 5 times faster. AGM 100 ah can charge at 25 amps. I have 60 amps into 440 ah AGM 12vdc, 4x 6vdc.

How do you do 60 amps into a battery?

 

[StitchExperiment626]

I had limited information to go on at the time and later found about Sterling but even then it cost $500 for 100 amps. I did a search of DC to DC battery charger and got Renogy a new product 60 amps @$260 12vdc. The only problem is if you need to run long lenghts from the start battery to the DC to DC battery charger you might need welding cable. I used 1

 

[StitchExperiment626]

I used 1/0 welders cable.

See my post under StitchExperiment626

 

[nature lover]

DanyB - I like the thermos Idea - I have a real good stanley. might be big enough for a months supply. My problem is $. I guess I was trying to get the system I need in cheaper segments. I have a garage appointment for the van tomorrow and depending on how bad the bill is I will know better what I can spend. I have been putting off full timing for years. Now I got the new (to me) van and gave notice to the landlord for the end of May. I had to draw a line in the sand or I would have never moved on. So maybe the thermos will get me through to another months ss check. Did anyone think about my fan idea?

 

[MotorVation]

Nature Lover, are you aware of HOWA? (Homes on wheels alliance)

Here's a link to their website. I encourage you to take a look around. 

HOWA

 

[highdesertranger]

I don't know where all this misinformation about batteries is coming from.

AGM batteries still take hours and hours to charge back to 100%
you can not(or shouldn't) take an AGM battery down to 20%
"condition a new battery". someone on another thread said "break in a new battery" big question mark here, where is this info coming from?

highdesertranger

 

[StitchExperiment626]

Condition a new AGM battery I think was on a Canadian manufacturer web site possibly. My AGM only charges to like 12.9 with rest a AGM chart says 13 volts 100 percent charge.