Batteries Charging:

[madrecpally]

I am trying to figure out how everything works in terms of charging batteries and going to post what iv found and would like feedback.  Im not sure if I am reading what I found correct and iv found contracting information.

A 100Ah Lithium Ion Battery ($900-$1000) can handle about 100 watts/hour for 10 hours in a perfect situation.  Best to plan on about 8 hours at this rate.  So simple math would mean if I wanted to use 400watts/hour a fully charged battery will last 2 hours.  600watts/hour would last 1 1/2 hours.

A 100Ah non lithium battery should not be discharged past 50%.  This means twice as many batteries are needed to perform the same duties as the Lithium which can be.

Charging batteries can be done a few different ways and the type of battery makes a difference.



Alternator:  Possible amps is determined by the size of the alternator.

• Isolator:  Basically connects your Vans battery to your battery packs to charge them with the alternator.  Can get more amps faster but it stresses the alternator more. 
• DC to DC charger:  Gives a set charge based on charger and alternator size.  Better for the alternator but pushes out less amps generally.

Overall an Alternator DC to DC charging system seems like it could be worth it but the Amps will be pretty low unless you run them in parallel which I would likely do depending on the vehicle.  My current truck has an [font=Roboto, Helvetica, sans-serif]220-amp alternator [/font]which I assume means I should have no issue with 60Amp DC to DC charger system.  The main concern I have with this is it was mention the wear and tear of the trucks alternator as an issue but no mention on how big an issue.  A quick google search shows a new alternator should be between $800-1000 plus the headache of it being in the shop.

Idling is not good for vehicles so I would only use this method when driving if i decided to use this method or as a backup.

Solar:  
Solar panels come in many different panel sizes but the most common is the 100 watt panel.  100 watts per hour is in ideal situation so iv read it is better to estimate 60-70 watts per hour when the sun is out on average instead of the full 100 watts.  Iv seen many sites claim the full 100 watts but these have been trying to push the panels they are reviewing.  The ones iv read that was not pushing a product mentions 60-80% on average.

This system requires other parts other than solar and it can get expensive.  Solar does seem to charge batteries better than other methods due to the type of energy and steady flow.  I have also read some good DC to DC charger systems can work with solar.

An 100 watt panel estimating 65watts/hour and 8 hours of sunlight will give 520 watts of energy.  I assume this means two 100 watt panels will be required to charge one 100Ah battery. 

Generator:  To charge a battery with a generator requires certain conditions to work.  Some batteries types will only charge up to 50% before slowing down to be basically pointless.  The battery type is important but if paired with a bad generator it could quickly destroy the battery.

I am having issues finding this information and all I can find is a battery charger is needed to be connect to the generator.


The above is a clear indicator that trying to get AC in a Van, Truck, or RV will be very costly but is still doable depending on set-up.  I am still confused on a few things though and here are some questions.

1. If a 5000BTU AC requires between between 500-650watts to operate does that mean per hour of continuous running or does it factor turning off/on to keep it a certain temp.  Iv also read that that turning on requires much more than stay on so how is this factored in.
2. Iv found 100Ah Lithium Batteries that mentions 3000 life cycles.  How much does being stored in a vehicle that could get hot during the day effect this.  Any first hand experience on how long they actually last?
3. My plan is not to us AC as much as possible.  Will it hurt the batteries if go times when I use them a lot and other times I rarely use them?

I know it will be expensive but if I can manage to get it done correctly I think I can add it to my business expenses to help offset the cost.  I have a monthly budget I have planned on so if I can get it to work I can take it out of it for the 12 month planned trip.

Any additional info and correcting any info I am mistaken is appreciated.

 

[bullfrog]

So are you saying you want enough battery power to run an air conditioner? Since you mentioned using your vehicles alternator to charge the batteries do you realize you would have to drive the vehicle several hours each day to fully charge the batteries? It would require a large solar array to get enough power to run an air conditioner and charge the batteries. Probably the best way to approach this is to list your power needs as in how many watts you need in a 24 hour period based on what you use and for how long. Then based on that determine the size of the system you need. Most likely you will find a generator or full hookup grid power is the most practical way. A system large enough for AC needs a lot of panel space and batteries which are very expensive.

 

[madrecpally]

It was more me rambling getting the information I had gathered together and hopefully not getting any of it terribly wrong.

I would love to get an AC powered but the system will depend on how feasible it would be.  I would likely also use a combination of all three:  Alternator, Solar, and generator if I went with my truck instead of a hybrid.

Something like this:
400Ah of Lithium Batteries ($4k)
Trucks alternator that charges 80Ah/hour driving.  ($800)
Generator:  ($1k)
Solar:  System I can bring out when needed.

Plan would be something like this:
In morning I wake up and turn on generator and begin charging the batteries.  I will stop at a % of charge depending on how much I plan on driving that day.
Drive and top off the batteries.
Solar for backup and when I do not plan on driving much or at all to top off the batteries.

My plans is to go to events and between them explore.  I love driving and normally drive 40k miles a year while working from home.  On the road and more places to explore I foresee that increasing to 60k miles for the year I plan on doing this.  During the events themselves I will likely stay at a hotel if needed.  Currently when I do this I only do it for about a month at a time and always stay at hotels and its over $2400 just for the hotels.  If the system will last long enough it will be worth it just in savings.

Im also still leaning towards just getting a Rav4 Hybrid but still considering my options.  My current truck is a Diesel off road and during my exploring iv gotten near 30mpg so its not bad.

 

[JDub]

It's been my experience that an AC is infeasible to run off pure solar without a VERY large panel array. It can be run separately off a generator or by the alternator of your vehicle operating your on board vehicle AC. IMHO, if you really have to have AC, invest in a (at least) 2000W inverter type generator. The open frame ones make too much noise to use in proximity to other campers for long. One place you COULD run them without risking complaints. I see campers parked in the far reaches of the local WM parking lot all the time running gennies without anyone complaining.

Cheers!

 

[Freelander]

I'm not so sure the DC to DC charger is the way to, I have a Isolation module in mine, and it cycles on and off to charge the batteries. 15 minutes on and 20 minutes off, and it will allow charging both way, alt to DC batteries, and solar to start batteries.

Also I watched a video on YouTube where a guy lost 2 alts because of his DC to DC charger. With the ac running, and everything to power the engine, it just wouldn't keep up.

 

[bullfrog]

The most important thing is to first determine how much power you need then see how much or what kind of system will work best for you. A Kill-A-Watt is a simple in line meter that may help. Basically we need to know how many watts for how long in a 24 hour period.

 

[madrecpally]

I would never use the DC to DC charger and alternator with the AC running. It would only be when driving from point A to point B and using the trucks built in AC. So no idling the engine either.

With DC to DC charger iv read that it is not as bad on the alternator as long as you are not idling the vehicle or using power from the battery at the same time. Some of the things iv read contradicted this but for the most part that was the general opinion on it. Not sure if there is better information out there from it.

 

[Camper]

You can read any thing you want on the internet, but if your alternator burns up on a trip.... you are grounded until you find another one. I learned my lesson the hard way many years ago.

 

[vanstu]

vanstu here--1st post--
briefly I have been installing photovoltaic power and various electrical systems for over 20 years (Dad is an electrical engineer and I grew up doing this type of stuff) A couple of thoughts on this thread-- 1) when connecting your alternator to the house batteries (mine are in the garage in back) make sure that the output voltage (alternator) matches what the house batteries want-- for example if you have a regular lead acid starter battery under the hood and AGMs in the back allow for that-- they are close to the same voltage (regular lead acid voltage is higher) but over time you will overheat the AGMs and reduce lifespan! 2) Lithiums are totally different as well as other types-- I use a DC to DC converter to compensate for this... 4) I upgraded my alternator to a heavier duty one but SAVE the old one in the van to prevent getting stranded-- change it out on the side of the road and down road you go!  Just my 2 cents worth....

 

[user 37446]

Vanstu, good idea to save the old working alternator and yes a dc to dc charger (which will current limit) is a must! Correct wiring gauge and fuzing is important as well.

 

[madrecpally]

Iv been trying to read more about the dc to dc charger for alternators and I get mixed messages. 

I am wondering how much of this is due to how people are using them and not having the most optimized builds for it.  From what iv read if I had a normal older van with its original alternator or a generic one then I would avoid using them with a DC to DC charger or isolators.  Most of the horror stories are about this type of set-up and it is the most commonly used method until they begin wearing out their alternators.
 


Investing in a proper setup can greatly reduce the wear and tear of the alternator and make it much more efficient.  The issue then becomes is this worth it.  There is still risk as there is an additional moving part added to operate the Van/truck which means the possibility of it breaking down and requiring it to be towed or the alternator being replaced on scene.  The risk can be minimized but only so far and the cost to do so can be higher than most are willing to spend.  Not to mention being without a home while it is being worked on.

Alternator charging can work but the risk need to be considered.

• The batteries can be degraded if problems occurs doing charging.  Batteries are expensive and this can destroy them.
• Alternators can break with the increased wear and tear forcing the vehicle to be in the shop.
• It can add heat to the engine compartment which can add wear and tear to other nearby components.

Ways to reduce the above risk:

• Have a good DC to DC charger that has protections built in to prevent bad charging.  This can help protect the batteries.
• The charging system: alternator, batteries, and dc to dc charger all need to be sized correctly and optimized to work together.  One size does not fit all and incongruencies can have a major impact of the system.
• Good heavy duty alternator.  These come with better heat sinks to reduce the wear and tear and are overall built better.
• Know the limits and most optimized levels to charge the batteries.  This can depend on the alternator, batteries, and charger.
• Only charge while driving and avoid doing it while idling.  Idling is placing a ton more wear and tear on the vehicle that it would not have had otherwise.

I am not a fan of idling the vehicle to charge the batteries and it can even be illegal in some states.  Once I figure out my vehicle of choice I will still keep alternator charging as a viable option but will take the increase cost to do so effectively into consideration.

 

[LargeMarge]

[edited for brevity]

...in a perfect situation... simple math would mean...
Alternator...search shows a new alternator should be between $800-1000 plus the headach...
[Photovoltaic]... common is the 100 [W]att panel. 100 [W]atts per hour is in ideal situation...expensive...
Generator...Some batteries types will only charge up to 50% before slowing down to be...pointless....very costly... Any first hand experience on how long they...last?...expensive...

.
Here is our Real-World experience based on a half-century of Real-World rigs, plus nearly two decades Real-World full-time live-aboard in our Real-World ExpeditionVehicle
.
*****
.
Photovoltaic:
Our photovoltaic was added after about a decade of full-time live-aboard.
This's our only genset.
Prior, we generally eliminated draws instead of attempting to duplicate a stand-still house through brute force.
.
We have six 305-Watt panels, a total of 1,830-Watts.
The only time we have a slow charge is in Alaska, the sun on the horizon.
.
We helped dismantle an array on an office building.
Everybody in our caravan received all the panels they needed, and sold the rest.
Cost -- less than zero-zero-zero, a few hours labor, plus the income from selling the spares.
.
*****
.
Bank:
Our ancient AGM batteries are reasonably strong after nearly two decades full-time live-aboard.
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We are waiting for the LiFePo4 industry to mature before considering a change.
That may take a while...
.
*****
.
Alternator on the Cummins:
About a half-decade ago, I saw a massive 220-amp 'big-house' alternator at a semi-truck dealer.
A few measurings with a tape indicated it would easily fit our 505ci.
This alternator is rated 'continuous-duty', an indication of its durability and reliability.
us$199 out the door, about twenty (20) minutes to swap, and we keep the original as a spare.
Cost -- a couple hundred fedbux divided by five years equals a whole lot of fun.
.
*****
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Costs:
Nearly two decades full-time live-aboard in our ExpeditionVehicle, our cost-per-use passed zero-zero-zero a long time ago.
How anybody pays their mortgage -- or the landlady's mortgage through rent -- is one of those baffling mysteries...
... utterly beyond our comprehension.
.
People ask about our fuel mileage.
We rarely travel more than a hundred miles a month.
Fuel is a very minor part of our budget.
.
People ask about costs for resorts, parks, and campgrounds.
No idea.
Our rig was engineered from the get-go for boondocking exclusively.

 

[AmargosaWayne]

Old thread, over a year since the previous last post. OP hasn't "been seen" for over a year.

 

[Ozybstd]

A year ago i bought an alternator on Ebay for about $170. A mechanic installed it for about $200. It is really powerful too. I have hooked my 40amp DC to DC charger to it and I haven't missed a beat. It is powerful enough to run a bigger one but 40 was big enough.