Charging house battery

[trasko]

So to start with, I'll say I've gained a lot of valuable information here. One thing is a reference to the book "Managing 12 Volts" which I have been reading.

I have some questions for the experts / experienced folks here. First, some background. I am primarily interested in powering a 12V fridge and estimate the daily amp hour usage to be around 40ah. It is an Edgestar 43qt. I am trying to figure out how to charge the house battery (Diehard Platinum g31 - 100ah @ 20h discharge).

I'd like to stay in the same place for 2, 3 or more days at a time. This seems to mean I don't have the capacity without something passive like solar to do the re-charging. This, however, has the very notable drawback of requiring sun. No parking in the shade and not much charging happening if it is overcast. Hmmph.

Another option is hooking it up to the car's electrical system and presumably using a charge controller. This requires running the vehicle every couple of days (or more often) which is definitely not ideal, but doable.

When I'm at home, I'd like to be able to top off the battery and be able to run a 120V input to the fridge to get it chilling while on shore power. I could just hook the 120V directly to the fridge, but if I want to charge the batt. while at home then I need yet ANOTHER form of a charge controller (inverter).


Am I crazy or does it seem you want 3 types of charge controllers for this simple system?

Questions:
1) Given the above comments, what do ya'll recommend?

2) HOW do you even wire up a system with multiple chargers? I haven't gotten there in the book yet if it is ever covered.

3) What is the simplest and/or cheapest solution to charging (aside from simply hooking it up to the car's alternator -- I believe in using a charge controller of some type is worthwhile).


That'll do for now. I am confused but definitely learning a lot. Right now I am leaning towards a solar setup with some sort of manual backup in which the truck could be used to charge the battery.

 

[Barko1]

Solar can be pretty simple and you get some charging even with clouds. A simple 7amp charge controller is good for 105 watts of solar and costs about $20 on Amazon. A 60w panel for $160 http://www.solarblvd.com/Solar-Panels-&-Systems-Individual-Solar-Panels-55---95-Watt-(7)/c1_25_41/p260/Solar-Cynergy-60-Watt-12-Volt-Solar-Panel/product_info.html
Then a connection to the vehicle for back up and I guess if you want to charge when parked you could buy a simple little charger like a battery tender and connect it to your house battery so that if you plug into AC you can charge that way. I think the solar would do it, driving would top it off, I never bother with the AC charge, I have 75 w.

 

[pods8]

What are you starting out with, a shell?

The 120V deal can go 2.5 ways in my head.
1) When the 120V power comes into your camper you have the fridge plugged into on plug and a shore power charger plugged/wired into the 120V as well which will charge up your battery and the fridge runs off 120V.
1.5) Just power a shore charger off the 120V to charge/maintain your battery and run the fridge off the battery still
2) If you're starting from scratch you can get a combination charger AC/DC distribution panel. The way these work is there is 120V input, a charger, and an AC distribution block and DC distribution block. The DC distribution block is tied into the battery and when there isn't 120V present current flows from the battery into the block and powers the circuits. When 120V is present the block receives current from the charger so it flows into the circuits and into the battery. Additionally when the 120V is present the AC distribution portion is live as well and would power your fridge if it was plugged in.

Multiple chargers:
Each respective charger gets tied into the battery posts, chargers are usually back flow protected.

Solar:
Your call on whether you think you'll have enough sun.

Truck alternator:
When you say charge controller do you mean you want stage charging or just something to isolate the battery? They make DC-DC stage chargers. I have one but it's only 7.5amps so it is much more suited for maintaining the batteries while driving as opposed to trying to quickly dump a charge into the batteries by running the truck for a bit. They make larger ones like 40amps but they are spendy. If you're just looking for isolation there are lots of options there.

Generator:
If you're toying with needing to run your truck to charge up your batteries you could also consider a small generator for those times since you'd already be making noise anyways.


Anyways clear up what you're starting with and what ideas interest you and we can roll from there.

 

[Barko1]

Generator:
If you're toying with needing to run your truck to charge up your batteries you could also consider a small generator for those times since you'd already be making noise anyways.


I have a small generator, maybe 1300w, with a 12v outlet for charging a battery but it seems like it would take forever to get a good charge. I think I might do better by plugging a 10 amp charger into the generator and hooking it to the batteries? The gen is a pain in the ass to haul around so I don't but it does provide some insurance if all batteries crap out miles from no where.

 

[UglyScout]

I have about 75% of your solution in my setup.

I have the Edgestar, no factory battery, no factory 120v/12v converter, no solar, etc...

So my solution was to:
A) Add a good battery
B ) Add a battery seperator with a feed line from my truck to charge while driving. I did not add any type of charge controller.
C) Added a 120v battery maintainer/trickle charger that is tied into the factory 120v system, so when I plug the camper in it feeds the battery maintainer. I did not add any type of controller as the trickle charge is 'smart' and does it's own thing.
D) I do not plug my edgestar into 120v when it is in the camper - if I have 120v's avaliable I just plug the camper in and let the 12v system do it's thing.


I do not have solar - but if I did I would add a controller that tied right to the battery and leave all my other systems as is. They shouldn't fight each other and the way it is setup they won't back feed into each other either.

The ultimate solution would be to just buy it all setup from the factory with the converter and solar controller....


I have not done any duration testing to see how long the fridge runs without a charge - but it will run at least 24 hours.

 

[pods8]

I have a small generator, maybe 1300w, with a 12v outlet for charging a battery but it seems like it would take forever to get a good charge. I think I might do better by plugging a 10 amp charger into the generator and hooking it to the batteries? The gen is a pain in the ass to haul around so I don't but it does provide some insurance if all batteries crap out miles from no where.


Depends what the 12V output is set at in terms of voltage and amps. 1300watts at 14V is over 90amps for instance which is a hell of a lot (not that I particularly suspect that outlet is actually rated to put that out).

If was going with a generator I'd look at the little honda ones, but I'd rather avoid that outright by just making sure I have enough battery capacity and drive often enough. I was just making the generator suggestion if idling the truck of a long time was going to come up often.

 

[trasko]

Solar can be pretty simple and you get some charging even with clouds. A simple 7amp charge controller is good for 105 watts of solar and costs about $20 on Amazon. A 60w panel for $160 http://www.solarblvd.com/Solar-Panels-&-Systems-Individual-Solar-Panels-55---95-Watt-(7)/c1_25_41/p260/Solar-Cynergy-60-Watt-12-Volt-Solar-Panel/product_info.html
Then a connection to the vehicle for back up and I guess if you want to charge when parked you could buy a simple little charger like a battery tender and connect it to your house battery so that if you plug into AC you can charge that way. I think the solar would do it, driving would top it off, I never bother with the AC charge, I have 75 w.


Whoa, this is less expensive than I thought. I think I would go bigger for the panel and the charge controller so perhaps the price goes way up, but that is more affordable than I thought. I already have a trickle-charger for the motorcycles that I could hook up occasionally but... if the solar panel was hooked up permanently then there doesn't seem much point in it.

What are you starting out with, a shell?

The 120V deal can go 2.5 ways in my head.
1) When the 120V power comes into your camper you have the fridge plugged into on plug and a shore power charger plugged/wired into the 120V as well which will charge up your battery and the fridge runs off 120V.
1.5) Just power a shore charger off the 120V to charge/maintain your battery and run the fridge off the battery still
2) If you're starting from scratch you can get a combination charger AC/DC distribution panel. The way these work is there is 120V input, a charger, and an AC distribution block and DC distribution block. The DC distribution block is tied into the battery and when there isn't 120V present current flows from the battery into the block and powers the circuits. When 120V is present the block receives current from the charger so it flows into the circuits and into the battery. Additionally when the 120V is present the AC distribution portion is live as well and would power your fridge if it was plugged in.

Multiple chargers:
Each respective charger gets tied into the battery posts, chargers are usually back flow protected.

Solar:
Your call on whether you think you'll have enough sun.

Truck alternator:
When you say charge controller do you mean you want stage charging or just something to isolate the battery? They make DC-DC stage chargers. I have one but it's only 7.5amps so it is much more suited for maintaining the batteries while driving as opposed to trying to quickly dump a charge into the batteries by running the truck for a bit. They make larger ones like 40amps but they are spendy. If you're just looking for isolation there are lots of options there.

Generator:
If you're toying with needing to run your truck to charge up your batteries you could also consider a small generator for those times since you'd already be making noise anyways.

Lots of good info 'pods8' -- I expected I might hear from you. I've learned a lot from your previous posts. I used to have an old Grandby but I got rid of it. For now I am working with a standard camper shell and adding in some features (such as a house batt + fridge). I'm doing my best to retain a configuration that allows use of the truck bed for standard "dirty" truck tasks. I've got a good place on the frame-rail setup to mount the house batt. with lots more room for other stuff down there.

My goal is to have a battery system built in such a way that I don't have to charge it externally. I've never used "shore power" nor really plan to. I drive enough that relying on the truck running isn't out of the question but solar is the most attractive to me. 98% of this trucks life is going to be parked on the street and not being used for camping. I am hoping solar + smart charge controller will keep the battery topped off without cooking it.

After y'alls feedback, I can also say:
- 120V is lowest priority; I'll use the motorcycle trickle-charger if I must; hopefully I won't need it.
- I don't want a generator.
- I *do* want it tied to the truck's charging system as a backup to solar

I have about 75% of your solution in my setup.

I have the Edgestar, no factory battery, no factory 120v/12v converter, no solar, etc...

So my solution was to:
A) Add a good battery
B ) Add a battery seperator with a feed line from my truck to charge while driving. I did not add any type of charge controller.
C) Added a 120v battery maintainer/trickle charger that is tied into the factory 120v system, so when I plug the camper in it feeds the battery maintainer. I did not add any type of controller as the trickle charge is 'smart' and does it's own thing.
D) I do not plug my edgestar into 120v when it is in the camper - if I have 120v's avaliable I just plug the camper in and let the 12v system do it's thing. <snip>

I like the simplicity. I am curious about the battery separator and charging while driving. Is the separator automatic (like a relay off the ignition hot line?) or is it manual?



My revised thoughts so far:
- primary recharging will come from solar
- backup (and faster) charging will be from vehicle while it's running
- long-term, I may install an inverter/charger/shore-power system so I can pre-cool the fridge on 120v while topping off the battery prior to leaving. This is a pretty low priority, though.

With these revised thoughts, I do have 2 main questions:
- what sort of solar charge controller should I use
- is it worth using a 12v-12v charge controller or is it fine to depend upon the vehicles alternator? Is it common to put a manual switch for this so the house battery isn't always connected to the vehicle's electrical system so it doesn't get cooked by the alternator? I am thinking the only time I'll use the vehicle's charging system is when I am out camping long enough that the solar can't keep up and the battery needs a boost. Charge-rate in this case does seem important.

 

[pods8]

This panel has caught my eye personally: http://www.solarblvd.com/Solar-Panels-&-Systems-Individual-Solar-Panels-100---170-Watt-%288%29/c1_25_42/p2489/Solar-Cynergy-155-Watt-12-Volt-Solar-Panel/product_info.html
MPPT are definately the best controllers but you also pay a premium so a good PWM controller can be attractive. If you aren't looking for a meter on your controller, etc. then a basic sunsaver like this might be worth a look: http://www.solarblvd.com/Charge-Controllers-PWM-Charge-Controllers-Morningstar-Charge-Controllers/c6_48_100/p191/Morningstar-Sunsaver-SS-10-10A,-12V-Pwm-Charge-Controller/product_info.html
If you're looking for MPPT, display, etc. then maybe read up on this unit (definitely a few more pennies):http://www.roguepowertech.com/products/mpt3024.htm

The connection to the truck mainly depends on what you want to get out of it, battery type, etc. Just know you'll only get one kind of charge from it without a DC-DC charger. However given you're interested in solar my personal take would be to use a relay/solenoid powered off an ignition hot line with a switch in it. Thus the only way it would connect is with the truck on AND the switch flipped. You can use the truck when you need a dump of charge into the battery and solar isn't cutting it. Then the rest of the time the solar panel will do the conditioning work.

 

[trasko]

This panel has caught my eye personally: http://www.solarblvd.com/Solar-Panels-&-Systems-Individual-Solar-Panels-100---170-Watt-%288%29/c1_25_42/p2489/Solar-Cynergy-155-Watt-12-Volt-Solar-Panel/product_info.html
MPPT are definately the best controllers but you also pay a premium so a good PWM controller can be attractive. If you aren't looking for a meter on your controller, etc. then a basic sunsaver like this might be worth a look: http://www.solarblvd.com/Charge-Controllers-PWM-Charge-Controllers-Morningstar-Charge-Controllers/c6_48_100/p191/Morningstar-Sunsaver-SS-10-10A,-12V-Pwm-Charge-Controller/product_info.html
If you're looking for MPPT, display, etc. then maybe read up on this unit (definitely a few more pennies):http://www.roguepowertech.com/products/mpt3024.htm

I think this is what you were linking to: Morningstar Sunsaver SS-10 10A, 12V Pwm Charge Controller.

Wow I really like both of those suggestions (the panel and the PWM controller). It seems the PWM controller -- for the price -- is the clear choice. The vast majority of the time I will be sitting in my office or cutting the dang grass and only occasionally will I be camping. The PWM charge controller will keep the batts topped off (safely, right?) and they will do a good job of replacing lost amp-hours when out camping, just not as good as a MPPT controller would do.

I'm ready to buy that panel and controller right now. Any reason I shouldn't? Would you get the controller above or the same one that also has LVM? (Morningstar Sunsaver SS-10L 10A, 12V Charge Controller). This is a question of $44 vs $56. The Edgestar also has a cutoff but I think it is too low at something like 10.6V.

The connection to the truck mainly depends on what you want to get out of it, battery type, etc. Just know you'll only get one kind of charge from it without a DC-DC charger. However given you're interested in solar my personal take would be to use a relay/solenoid powered off an ignition hot line with a switch in it. Thus the only way it would connect is with the truck on AND the switch flipped. You can use the truck when you need a dump of charge into the battery and solar isn't cutting it. Then the rest of the time the solar panel will do the conditioning work.

This is exactly what I'm thinking. A kind of "double-safe" setup that, at worst, means I leave my house batteries connected to the vehicles electrical system and only then when the ignition is on. Any products you'd recommend for this job? I'm thinking as simple as possible is best. I dunno if it is a factor but if I ever want to jump the truck from the house batt. I'll just run jumper cables -- the ones I have are long enough.

 

[pods8]

The sun savers only do one voltage setting (14.1V for sealed and 14.4V for flooded) which isn't ideal for a sealed battery, not so bad for a flooded battery that has caps you can refill.

You'd need to set up to a prostar controller to get a float setting (data sheet http://www.morningstarcorp.com/en/support/library/ProStarENG2_11.pdf): Link 1 They also make it with a display on it for another $50: Link 2

Low voltage disconnect: It all depends if you want to run something off it. I don't think I'd bother to set up a system like that and instead keep track of my battery status.

MPPT: Is for trying to get peak performance out of your panel. Many "12V" panels put out their rated wattage at 17V. So if that 155watt panel was putting out that at 17V it would be putting out 9.11amps. A PWM controller just chops the voltage down to the desired voltage and its still at 9.11amps. A MPPT controller theoretically will convert the 155watts down to the desired voltage and recovering the amps so 14.4V and 10.76amps. Not necessarily a huge gain on smaller panel systems.

Relay/solenoid: Cheap route would be to just get a continuous duty solenoid.

 

[HIKEMT]

In case it is helpful for comparison, we are using a hellroaring battery isolator for alternator charging, 120 Watt Solar Blvd house brand solar panel (solar cynergy), Morningstar SS-10 pwm charge controller, dual interstate 100 amp batts. This system seems to be powering our Edgestar just fine, plus some light use of water pump, roof fan, phone charging, camper lights while parked. Last time was 4 days without starting the truck, in partially shady conditions, temps not over 75 degrees. Plan is to add an MPPT controller and/or 120v charger later as needed.

 

[trasko]

In case it is helpful for comparison, we are using a hellroaring battery isolator for alternator charging, 120 Watt Solar Blvd house brand solar panel (solar cynergy), Morningstar SS-10 pwm charge controller, dual interstate 100 amp batts. This system seems to be powering our Edgestar just fine, plus some light use of water pump, roof fan, phone charging, camper lights while parked. Last time was 4 days without starting the truck, in partially shady conditions, temps not over 75 degrees. Plan is to add an MPPT controller and/or 120v charger later as needed.


That's helpful. I'll look up the "hellroaring" isolator. 4 days sounds great to me. I've got only 100 ah but I think that'll be fine with a setup like you are describing.

 

[trasko]

Relay/solenoid: Cheap route would be to just get a continuous duty solenoid.

I'll sleep on the panel / charger you mentioned. I like the looks of them. In fact it'll be 2 nights sleep since I'm headed out camping for one night...

I went ahead and ordered a random continuous duty solenoid I found. Looks like 65A continuous and 100 or 200 amp surge rating. That should be plenty for this application.

I'm thinking this:

Put SPST switch on dash for "house batt" that is illuminated when "on." I'll use a tap off the ignition wire to go to the switch and then the switch to the solenoid trigger. The solenoid will run from... what to what? The house batt. positive to starting batt positive? And have the negatives of the batts connected all the time? Is there anything special to do in a dual-starting-batt arrangement?

 

[ntsqd]

For simple systems I prefer Automatic Charge Relays or Voltage Sensing Relays for charging off of the engine's alternator. They both work the same way (diff. mfg's names) in that they allow the starting battery to come up to full charge after starting before switching in the house bank for charging. When the alternator quits charging they switch off. Put one in parallel with a marine battery switch if you want self jump-start capability and/or some redundancy in case of a failure.

Take care that you don't try to start with the continuous duty solenoid switched on. If the starting battery is low enough the starter will try to pull power from the house bank, which the solenoid really isn't up to doing. A breaker next to the solenoid to protect it and the wiring would be a good idea if you're forgetful like myself.

 

[pods8]

Put SPST switch on dash for "house batt" that is illuminated when "on." I'll use a tap off the ignition wire to go to the switch and then the switch to the solenoid trigger. The solenoid will run from... what to what? The house batt. positive to starting batt positive? And have the negatives of the batts connected all the time? Is there anything special to do in a dual-starting-batt arrangement?


My take:
Main battery positive -> Autoreseting breaker (located close to the main battery) -> Solenoid -> Autoreseting breaker (located close to the axillary battery) -> Aux battery positive

Yes connect up the negatives.

 

[EdoHart]

So to start with, I'll say I've gained a lot of valuable information here. One thing is a reference to the book "Managing 12 Volts" which I have been reading.

I have some questions for the experts / experienced folks here. First, some background. I am primarily interested in powering a 12V fridge and estimate the daily amp hour usage to be around 40ah. It is an Edgestar 43qt. I am trying to figure out how to charge the house battery (Diehard Platinum g31 - 100ah @ 20h discharge).

I'd like to stay in the same place for 2, 3 or more days at a time. This seems to mean I don't have the capacity without something passive like solar to do the re-charging. This, however, has the very notable drawback of requiring sun. No parking in the shade and not much charging happening if it is overcast. Hmmph.

Another option is hooking it up to the car's electrical system and presumably using a charge controller. This requires running the vehicle every couple of days (or more often) which is definitely not ideal, but doable.

When I'm at home, I'd like to be able to top off the battery and be able to run a 120V input to the fridge to get it chilling while on shore power. I could just hook the 120V directly to the fridge, but if I want to charge the batt. while at home then I need yet ANOTHER form of a charge controller (inverter).


Am I crazy or does it seem you want 3 types of charge controllers for this simple system?

Questions:
1) Given the above comments, what do ya'll recommend?

2) HOW do you even wire up a system with multiple chargers? I haven't gotten there in the book yet if it is ever covered.

3) What is the simplest and/or cheapest solution to charging (aside from simply hooking it up to the car's alternator -- I believe in using a charge controller of some type is worthwhile).


That'll do for now. I am confused but definitely learning a lot. Right now I am leaning towards a solar setup with some sort of manual backup in which the truck could be used to charge the battery.

I started a system similar to what you describe, but it got side tracked about 4 months ago (just after I ordered all the parts). Today I finally put the camper back onto the truck. I realize that many of your questions have been answered, so I'll address just 2 areas.

1) Connecting multiple chargers: As long as the charge controllers you're thinking of using are "smart" chargers for an AGM battery, then you should be able to wire them in parallel (that's what I just finished doing, but I haven't field tested it yet).

2) Charging from your alternator: If your house battery is heavily discharged, when you start to charge it from your alternator it will draw a large current, which means you will need large guage wires to connect it to your alrternator/battery isolator. Also, an alternator/voltage requlator in a car is designed to bring an SLA battery to about 80% charge capacity; they aren't designed to fully charge an AGM deep cycle battery.

During the 4 months that my truck was sitting idle, I would connect a simple 12v battery charger to the truck's batteries, and the camper's house battery about once a month to help maintain them.

 

[trasko]

To update:

I returned the Sears Platinum G31 AGM batt and found a couple of 6V golf cart batteries for roughly the same price, except they give me 220ah vs the 100ah from the single AGM.

For my upcoming trip I'll be running the fridge for maybe 60 hrs (real time) with an estimated 120ah usage. I'm just gonna let that happen rather than rush the wiring by this Thursday. That'll take me < 50% but I'm not going to worry about it for just one time. I already have the solenoid and the wire is on it's way. I'll just need to arrange some of those breakers, some terminals and a switch for inside the cab and I'll be good to go.

I am still interested in that panel linked by pods8 and may go for it for when doing extended camping, however for my normal outings (2 nights) I should be fine w/ just the batt. and then charging on the way there and on the way home with the occasional trickle-charge overnight. If I do go for the panel, I already have a friends unused PWM solar charge controller. I'll also probably not permanently mount it and just put it out during those (unfortunately) rare long camping trips.

 

[pods8]

I am still interested in that panel linked by pods8 and may go for it for when doing extended camping, however for my normal outings (2 nights) I should be fine w/ just the batt. and then charging on the way there and on the way home with the occasional trickle-charge overnight.


I'm basically in the same boat. I like the wattage/size/weight of that panel but since I also am running two 6V batteries (AGM's though) I've got 220ah and really don't need a panel for 90% of what I do at this point. I've held off because solar is constantly improving and coming down in cost so no reason to rush to buy.

 

[UglyScout]

For my upcoming trip I'll be running the fridge for maybe 60 hrs (real time) with an estimated 120ah usage. I'm just gonna let that happen rather than rush the wiring by this Thursday.


This past weekend I ran my edgestar for about 50 hours set at 38 degrees (outside temps of 80 degrees during the day), plus 2 nights of my heater (temps were in the high 30's/low 40's over night) the heater was set at +/- 55, degrees before it tripped the low voltage shut off on the fridge. My battery was not charging correctly - so I have no idea where the battery was at when I started the weekend.

In testing to find the root of my battery problem I tested the edgestar at full load and it pulled a steady 4.20 amps. Peak at start up was 5.10 amps, but in under a minute it was at 4.2.

Good luck and let us know how it does.

 

[trasko]

This past weekend I ran my edgestar for about 50 hours (80 degrees high during the day), plus 2 nights of my heater (temps were in the high 30's/low 40's over night) set at +/- 55 degrees before it tripped the low voltage warning. My battery was not charging correctly - so I have no idea where the battery was at when I started the weekend.

In testing to find the root of my battery problem I tested the edgestar at full load and it pulled a steady 4.20 amps. Peak at start up was 5.10 amps, but in under a minute it was at 4.2.

Good luck and let us know how it does.


I'll let y'all know. Should be good to go for this 2-day trip but I'm doing a 4 day trip the following week. I love summer!

After lots of reading here and at ExPo on the Edgestar I've decided to use a value of 2ah as the average consumption of that fridge (43qt). It starts at 5+ then runs around 4 but then of course it cycles on and off. I think 2ah is conservative (aka a high estimate) which leads to 48ah usage per day. I expect it to be more in the neighborhood of 35-40 ah/day.