Power 3 ways???

[Scootr74]

Thoughts on additional regarging systems...

It is after my 1st 4 day trpi with my Grandby running on all DC power. I had thought that my addition of a battery isolator and wiring the camper battery to the vehicle charging system. Alas one cannot see the all pitfalls.

The Alternator goes out on the truck on the way to Baker. Truck has run from Menifee to Barstow at night on only the vehicle battery - or so I thought.... Next morning, the camper battery is apparently dead as a doornail - but starting to recharge - unfortunately the engle needed to run on the system.... Solor barely kept up but with the demand during the day, but after the night... I was back to where I started.

So what are my options?

Run Shore Power - although I don't know how involved or costly this will be. I think I'd need a converter of some kind + an additional penetration through the exterior for a hookup point.

Carry a portable generator.

Replace the Engle with a 3way??

Hmmmm......

 

[John D]

Liquid Energy

Liquid energy is very convenient stuff.

Optimally, the sun provides about one (1) kilowatt of energy per square meter at the earth’s surface. After the effect of lower seasonal declinations, reduction of the sun’s altitude with increased latitude, lower solar altitude in morning and evening, atmospheric degradation, and losses in the solar cells, the best that can be done is about half a kilowatt per square meter for only part of the day. In addition to those losses, weather may completely obscure the sun. Solar energy is not directly available at night. Thus, solar energy is unsatisfactory for powering anything with significant demand. Solar cells are less reliable than other sources, except wind. Solar energy is a neat trick barely worth the cost of acquisition and transport. However, solar energy is a religion. As such, it is satisfying to its practitioners. Because solar energy is a religion, it is never good to discuss it objectively because one is always stepping on toes.

Bottom line; for dry camping, liquid energy is better.

 

[chnlisle]

I'm way to old for power 3 ways. I can barely handle morning 2 ways

 

[lqhikers]

don't give up!

Scootr74,do not listen to anyone who tells you that solar will not run your engle and other uses (lights radios cell chargers etc).
Sounds like you still have problems with your system,keep with it till you figure it out or have some one trouble shoot it that knows what they are doing.
I have been using solar for many years,not one problem that was not fixable!
Proof of course just look me up anytime on the trail,we depend on our system all the time and it never lets us down.
Will report on two weeks of use when we get back from death valley area (leaving tomorrow!!!)
Drive slow and enjoy "its the journey"
Les,Lqhikers

 

[Jack]

I'll take a guess at what happened.

The battery separator, which is designed to connect your alternator to the camper battery only when the truck is running, has a very simple rule: if the voltage it sees is 13.5 Volts or above, it connects the alternator to the camper battery; if the voltage later falls below 12.4V to 12.9V, the separator disconnects (this is a hysteresis). Your alternator typically puts out about 14V, but this varies among manufacturers.

Most likely, the Engle is drawing enough current to either keep the voltage that the battery separator sees below 13.5V, or the voltage frequently drops below 12.4V to 12.9V and does not return to 13.5V very often. It's ohms law, realizing that the wire from the alternator to the battery separator has some resistance and the triggering voltage is close to the output of the alternator. If you are not familiar with ohms law, just realize that for a given total load (ie, Engle plus wires and other appliances), the current in the circuit is always the same, but the voltage will vary depending on where you measure.

What to do. Start the engine, turn on the Engle, and measure the voltage at the battery separator. If it's close to 13.5V, this is most likely the problem.

Ok, how to solve it. 1. Get a battery separator that has an adjustable set point and set it below the level you measured. 2, Replace the wire from the alternator to the battery separator with 6 gauge wire (FWC uses 10 gauge). This reduces the resistance between the alternator and the battery separator, which will increase the voltage at the battery separator. 3. Add a manual bypass switch that bypasses the battery separator and directly connects the alternator (and your truck battery) to the camper battery.

The problem with option 3 is that if you can drain both your camper AND the truck battery if you forget to return the switch to the battery separator when you stop driving. To protect against this, you can install a "Battery Brain" on the truck battery.

The same issue may arise if you run down your camper battery; the high recharging load results in a voltage at the battery separator that is less than 13.5V - it's for this reason that I installed a battery separator bypass switch. (I like to run the Norcold on 12V when I drive, and it has happened that I have forgotten to switch back to propane when stopped.)

Comments. Almost for sure, the charge controller for your solar panel trickle charges the camper battery - which means it will be a couple of days of full sun to recharge from the solar panel. I'm glad you posted. I've thought about ditching the pain in the derrier Norcold for an Engle, and I too will have to avoid this problem if I do it. We used to carry a 1KW generator before we added solar, but it takes up space and we (and fellow campers) hate the noise. You should be able to get your system to the point where it all works.

 

[John D]

Separate alternator just for the fridge

A dual alternator setup is another solution. One alternator charges the starting battery; the second charges the house battery. Brackets are available in the aftermarket for some vehicles to install and run two alternators. Mount both batteries under the hood for best results. It is no more expensive to install and run two alternators than the electronics, switches, and heavy wire cables needed for charging and using two batteries.

The real problem is the nature of lead acid batteries themselves. They behave in many ways like biological entities rather than mechanical devices. Batteries drive mechanical engineers nuts. They have memory and even an ability to heal themselves. A 12VDC lead acid battery is comprised by 6 batteries or cells, each with its own characteristics. A 12VDC lead acid battery is a complex system within itself. Two batteries used in two different types of service, such as one for starting and one to supply house power, become “accustomed” to different kinds of work and they don’t get along with each other very well when married together. It is better to keep them entirely separate.

 

[Scootr74]

Hmmm....

I never thought about the two different types of batteries being a problem. But now that it has been explained - I can see it being a potential problem...

I think I'm going to go with a cheap 1000w portable generator for now - I'm talking $159 from Harbor Freight or Kragen. I only have about 4 weeks until the next outing and I need to save most of my $ for gas/food/fun in between... You know the drill. Anyone have good results/recommendations using a cheapy genny? I'm only going to use it to charge the battery and double duty to run the fridge while the battery is charging.

I plan on getting a 1000W Honda or Yamaha genny when funding is a little more available.

 

[winter200]

Look at the bright side - had your system not tied the 2 batteries together, you may not have made your destination.

Looking through some of your other posts I found that you are using just a standard isolator and not one that senses voltage. I would guess that you have the switch wire hooked up to something on your truck that is only activated when the truck is running. It wouldn't care about the status of the truck system as long as it had power to the switch terminal. It used up the power from both batteries after your alternator went out.

My thoughts -

-The odds that your alternator would go out again this soon would/should be slim.
-Don't waste money on the cheap generator (it probably won't work when you need it) Save the money for the Honda or Yamaha.
-Buy a battery charger if you don't have one and carry that with. It would charge either battery from shore power or from your generator when you need it. The EU's from honda won't run 12vdc and 120vac at the same time. You would get the most benifit from a generator using the 120vac.
-Look into a voltage sensative isolator.
-The engel doesn't draw enough power to consider it a major load on the battery system.
-The main concern with the starter and deep cycle standing together was already mentioned. Seperate them when they are not charging and try to only use them for the purpose they were intended. Deep cycles don't like a fast rate of charge. A simple and easy way to slow down the rate of charge from the truck to the camper battery is to install a light bulb (variable resistor) in line on the charge wire. It will only allow a certain amount of power to go through, it will show you when it is charging and will dim when its done charging.

 

[John D]

Solar cells plus portable generator

A portable generator combined with solar panels should work. This gives you the option of keeping your two batteries separate should you need to do so.