Sprinter house battery charging

[sandcastle]

The people who did my solar install do van conversions. I don't think many people ask them to do solar and those that do probably don't ask for my size system. I specified 4 panels and 4 AGM batteries with #4 welding wire with a junction box on the roof and they said fine. Then they asked if they could do 2 double-sized batteries instead and I said fine. I'm not sure I got as much battery as I asked for but someone has to crawl under the rig and drop the batteries from above to determine that. They did not buy the brand of panels they advertised so I know nothing about the panels they installed other than what it says in the picture they sent me of the label on the back of the panels. That's where I found out they are off-brand 95 watt panels instead of the brand name 110 watt I expected. And they decided not to use a junction box on the roof without telling me of the change. My guru no longer trusts them so doesn't want me going back to them.<br><br>They did not do an energy audit before installing the system and it didn't occur to me that they were selling me things my system wouldn't run. For instance they said one panel would generally run a fridge. They didn't say, what I now expect is true, that's the 3 cf fridge not the 7 cf one. The audit my guru and I did says I am likely underpowered for my demand even if everything is installed correctly.<br><br>The question I have for this group is what is the best way to make up that deficit. Thus, the question about charging using the alternator in idle. You have all assured me that's a bad idea. So, I either drive or plug in. For now I am plugged in.<br><br>Linda

 

[sandcastle]

The fridge is a Norcold 7 cf all electric with a compressor. It switches automatically from 12v to 120 volt except I have its circuit breaker turned off to keep it from going to 120 volt when using my inverter. The handles have a built in latch if you remember to push them in when closing the fridge which I usually do. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Linda

 

[peacetara]

AH! YAY for an Energy Audit!&nbsp; That's exactly what I wanted to do basically <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"> Glad you had it done already!<br><br>If you really are underpowered, that must be one giant Fridge load wise!!<br><br>Your options really fall back to, the original 2 things I mentioned, reduce/conserve electricity or add more capacity for power coming in.<br><br><ul><li>Trade your fridge out for one that uses less electricity, or one that will also let you use propane, and run propane when boondocked for long periods of time.</li><li>Plug in, like you are doing, or get a generator, to offset your deficit.</li><li>Add a wind generator (they are sort of a pain in the butt for the mobile lifestyle from what I understand -- I have no personal experience)</li><li>Replace the 95 watt panels for larger wattage panels.</li><li>Drive a lot <img src="/images/boards/smilies/tongue.gif" border="0" align="absmiddle"></li></ul><br>There are some small minor things you might possibly be able to do:<br><ul><li>Turn your inverter off when not in use (it uses a little bit of electricity just being plugged in and 'on').</li><li>Depending on the voltage/amperage of the panels, and your controller abilities, you might be able to wire a pair in series (2 pairs of series, tied in parallel or maybe all 4 in series), this will up the voltage, which is what MPPT controllers THRIVE for, and gets you closer to the 30% gain that MPPT controllers theoretically can give you).</li><li>Double check the wiring sizes, and increase them as needed (perhaps this isn't needed, but one has to check all the wiring and the power running thru them to be sure) there are online calculators that can help with wire sizing, you want to calculate for 1% drop if you can get away with it.&nbsp; Anyone that says just run X size always is just silly if you ask me, when the internet will do all the math for you, it's not even hard anymore to size properly.</li><li>Perhaps you can make your fridge more efficient, by giving it more insulation -- (but you have to make sure the compressor part has lots of air flow, when they get hot, they are way less efficient).</li><li>Full fridges are more efficient than empty ones, so keep it full if possible (containers of water work well if you don't have anything else needing to be cold)</li></ul><br>These are some of the tips I've come across or read about which are generally true.&nbsp; I don't actually have a fridge, so I'm sure people with fridges might have better ideas.&nbsp; I am thinking I may get one someday, mostly for hummus, because I'm addicted.&nbsp; I can't say enough good things about hummus! <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Hopefully we get magic electricity someday, that would be nice.&nbsp; I'd love it for sure, or Gadget powered: "go go gadget electricity!"<br><br>Anyways, I wish you lots of successes!<br><br>With Love,<br>Tara<br><br><br>

 

[StarEcho]

Yes, but it is not what I have. It says, in part, "<span style="color: #333333; font-family: Arial, Helvetica; font-size: 12px; background-color: #f1f4f8;">Mercedes Sprinter with BlueTEC technology and bio-diesel fuel capability"</span>&nbsp;whereas mine clearly says not to use more than 5% bio-diesel. If I'd known about this one when I was choosing mine I might have made a different decision. But probably not as Roadtreks are famous for their TINY black tanks. I like my customizations a lot!<br><br>Linda

<br><br>Sorry Linda if I confused you. &nbsp;I wasn't saying anything about getting a Roadtrek! &nbsp;Or that I thought you had this Roadtrek (they are VERY new and not many people have them) <br><br>I was referring to the fact that this new all electric Roadtrek which is based off a MB Sprinter Diesel specifically states that those who own one charge their batteries by idling (for 30 min I think it said)....which others have said is a no-no...but if they are specifically saying that's how to charge them, then I wonder why that would not be true for your MB Sprinter Diesel. &nbsp;Of course it wouldn't be the first time that marketing claimed something that just wasn't true, but still....<br><br>Now if you're saying that having a bio-diesel fuel "capability" makes it safe to idle to charge whereas not having that capability makes it a no-no...then that would be a different story. &nbsp;But it's good to know that for future reference if you do know that to be true. &nbsp;I couldn't find any info that connected bio-diesel fuel vs regular diesel fuel with idling to charge batteries, but that doesn't necessarily mean much. &nbsp;I'm probably not using the correct search keywords.

 

[Van Tripper]

You know the dangers, won't repeat them.<br><br>Truck Stops have a simple idle devise that hooks under the steering-wheel, and adjust to push on the accelerator pedal.<br><br>Getting depressed from lack of light: &nbsp;This condition has been recognized for a long time, mainly in winter in high north/south latitudes, have seen where doctors recommend getting a full spectrum fluorescent light system and sitting for a time in it's light&nbsp;(reading, hobby), could help.&nbsp;I would try a small 12v system.

 

[bee]

While people are giving your really good tips in this thread you need to start at the beginning.&nbsp; The first thing to do is make sure all your new equipment is right for your build and that everything is working properly.&nbsp; For example 99% of installers do not change the settings in the solar controller for optimum charging, or you may have the wrong kind of fridge.<br><br>First step is to find all your electrical loads and record how much they are drawing.<br>Second step, verify that all your charging sources are working properly.<br>Third step use the information you have gathered to most efficiently address the issues.<br><br>Okay so lets focus on step one.<br>You can use your trimetric meter for this.&nbsp; There are 3 basic readouts it gives, and it cycles through them when you press the main button.<br>They are:<br> % charged<br> volts<br>amps or watts (depending on how it was programmed)<br><br>1.&nbsp; Set it to amps/watts, (it doesn't matter which)<br>2.&nbsp; turn off everything in your rv that draws power from the batteries.&nbsp; Turn off anything that is charging the batteries like the solar panels.&nbsp; The meter should read zero or really really close.&nbsp; If it doesn't then something is still on.<br>3.&nbsp; Now go through and turn on each load seperatly and record the readings from the trimetric in a list.<br><span style="text-decoration: underline;">example list</span><br>No electric loads &nbsp; &nbsp; -0.2 amps<br>lights &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; -2.5amps<br>laptop charging while surfing the web-4amps<br>tv&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; ?<br>radio&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ?<br><br>4.&nbsp; Post this list up in this thread so we can tell you if the numbers look right.&nbsp; This is will also show you what is worth conserving and what isn't.&nbsp; For example no point sitting in the dark to save electricity if you could accomplish the same thing by just turning the coffee pot off after it is done brewing instead of leaving it on for 5 minutes after it brewed.<br><br><br><br><span style="text-decoration: underline;">Fridge.<br></span>The size of your fridge while on the large side should not be a problem, <strong>if</strong> you have an efficient compressor.&nbsp; As wrcsixeight mentioned this is the likely culprit to your issues so you have to find out how much energy it draws.<br><br><strong>best way</strong><br>If you can access the 120v plug use a watt meter like this one<br> http://www.amazon.com/P3-Internatio...1356339543&amp;sr=8-1&amp;keywords=watt+meter<br>Plug the meter in and run the fridge off of 120v for about 24hrs.&nbsp; Make sure you use the fridge normally, opening and closing the doors to get food to create a realistic work load.<br>The reasoning for this is, the compressor will cycle on and off and the watt meter will automatically average the draw for you.<br><strong>2nd way</strong><br>If you can't use a watt meter you can tell us what the reading from the trimetric is when the compressor is on and then give an estimate of its duty cycle.<br><br><br>In addition you should find out what kind of compressor your fridge is equipped with.&nbsp; I think norcold uses a rare compressor, and I have no idea if it is efficient.&nbsp; Hopefully it is a danfross which is well known.<br><br><br>Hope all that made sense, looking forward to seeing your results.<br id="tinymce" class="mceContentBody "><br>

 

[VanLifeCrisis]

Are the panels hooked up right?&nbsp;&nbsp; How much power is making it to the batteries?

 

[wrcsixeight]

My previous fridge was a 1.7 cubic foot Norcold compressor fridge. &nbsp;It was over 5 years old when it failed. &nbsp;It was over three times smaller than your fridge, and averaged about .9 amps per hour. Yours likely consumes 3 times as much at a minimum.<br><br>Norcold uses passive condensers. &nbsp;Condensers remove heat from the refrigerant which removed it from the fridge box. &nbsp;If the condenser is not properly ventilated the fridge will consume much much more electricity. &nbsp;If your fridge is in a cabinet without adequate means to ventilate condenser/compressor heat then expect very poor fridge performance excessive battery consumption, and short life.<br><br>One nice feature of my Norcold was that it was an AC/DC fridge. &nbsp;Whenever it was plugged into the grid, it automatically chose 120 volts, and switched to 12 volts dc seamlessly, but it could have been run, much less efficient, off the inverter, if it was plugged into that and I turned it on.<br><br>I hope you can find somebody knowledgeable to look over your system and show you what is what, it kind of sounds like some people completed the work without worrying about the result and ultimate functionality. &nbsp;Even with a 7 cubic foot compressor fridge, your solar should be adequate for your uses if you are in a sunny environment, even in winter.

 

[VanGirl]

Hi Linda, I saw you mentioned that you could install a second alternator. I have never needed to do that. I did upgrade my original Sprinter's 90 amp to a 150 amp alternator. 150 amps at 12 volts is a lot of power.<div id="nuan_ria_plugin"><object id="plugin0" style="position: absolute; z-index: 1000;" type="application/x-dgnria" height="0" width="0"><param name="tabId" value="ff-tab-1"><param name="counter" value="69"></object></div>

 

[sandcastle]

I was referring to the fact that this new all electric Roadtrek which is based off a MB Sprinter Diesel specifically states that those who own one charge their batteries by idling (for 30 min I think it said)....which others have said is a no-no...but if they are specifically saying that's how to charge them, then I wonder why that would not be true for your MB Sprinter Diesel. &nbsp;Of course it wouldn't be the first time that marketing claimed something that just wasn't true, but still....<br><br>Now if you're saying that having a bio-diesel fuel "capability" makes it safe to idle to charge whereas not having that capability makes it a no-no...then that would be a different story. &nbsp;But it's good to know that for future reference if you do know that to be true. &nbsp;I couldn't find any info that connected bio-diesel fuel vs regular diesel fuel with idling to charge batteries, but that doesn't necessarily mean much. &nbsp;I'm probably not using the correct search keywords.

<br><br>What I meant to say is that since that engine accepts bio-diesel it must be a different engine thus have different rules for what you can do with it.<br><br>Linda

 

[bpeck]

I am definitely NOT an expert on power systems, but this url that I got from here..<br><br>http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/<br><br>is very informative and it greatly reassured me that my own power set up was done correctly. &nbsp;I know that I have seen a dramatic decrease in the amount of time it takes to recharge my batteries since I had everything re-done with larger wires and a new charger.

<br>Thank you SO much for that link. &nbsp;Before reading I felt pretty clueless when reading or thinking about anything related to electrical systems and/or solar. &nbsp;Now I feel a lot more knowledgable. &nbsp;Thanks again!

 

[sandcastle]

Here's another really good site for learning about solar:<br><br>http://www.jackdanmayer.com/rv_electrical_and_solar.htm<br><br>Linda