Sprinter house battery charging

[sandcastle]

I spend my winters living in a converted Sprinter that has two huge batteries to run the systems in the house part. My solar panels are not keeping up with recharging those batteries. I know I can use my alternator to charge them when driving but can I do that when parked by just idling my engine? I've heard that MB doesn't recommend doing that but am not sure that is true.<br><br>Linda

 

[user 2252]

Hi sandcastle, to be brief, at idle the alternator is not spinning fast enough or large enough to push a decent, timely charge to your EXTRA batteries. You could go with a larger alternator or you could raise the engine RPMs while parked, say 1000-1500 rpms ( use a stick or something to hold the gas pedal in place ) but I'm inclined to agree with&nbsp;Mercedes, several factors come to mind:<br><br>1) the carbon monoxide when&nbsp;parked with the engine running<br><br>2) the wear and tear on the alternator ( alternator designed for just the battery used to start the vehicle )<br><br>3) the cost of fuel as well as the repairs on the wear and tear and going no where ( no work being done )<br>&nbsp;

 

[VanGirl]

Hi Linda, I have three options for my house batteries on my sprinter. I can charge as I drive. I have a solar panel and I have a small Honda generator. You are never suppose to idle a sprinter though I break that rule when needed. Night before last I idled all night and the van gave me problems all day yesterday. I'm sure it will keep giving me problems till I take the EGR valve off and clean out the soot caused by the idling. If you idle use an idle stick to keep the RPMs up past 1000 and keep the Espar heater on to keep the engine temperature up to 180. I have 256,000 miles on my Sprinter now, it will keep going if you play by sprinter rules. <br><br>VanGirl<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-2"><param name="counter" value="182"></object></div>

 

[wrcsixeight]

Few alternators do well for very long at idle speeds, and even those that do claim to have high output at low rpm's still do not do a good job once they get up into the 80% charged range. &nbsp;They produce a lot of heat when making a lot of amps, and the hotter they get, the less amps they do produce.<br><br>And they only do a good job at returning the batteries back upto 80% charged if the cabling in the alternator charging circuit is adequate, and that wiring should be at least 1/2 inch thick, insulation included, and preferable thicker.<br><br>You need to get more solar, or a generator, Use less electricity, &nbsp;and it consider it likely your 2 big batteries, due to chronic undercharging and living &nbsp;chronically undercharged, have lost a significant amount of capacity.<br><br>Which is not coming back.<br><br>Many engines intensely dislike excessive idling. &nbsp;If your manufacturer specifically recommends against it, believe them.

 

[VanGirl]

I forgot to mention the <span id="post_message_1276187693">carbon monoxide when&nbsp;parked and idling. I have one of the battery powered carbon monoxide detectors in my Sprinter. I also had my exhaust pipe routed from under the van to under the door and extended out enough to clear the underside. The original pipes exhausted under the van making it dangerous to idle and sleep.<br><br>The small 1000ie Honda generator will sit on the drivers side floor. Keep the fuel cap vent closed and you have no fuel fumes. 3/4 gallon of gas will idle the generator for 6 to 8 hours. I keep a bicycle cable and lock to secure the generator while sleeping. In the summer I use the generator to run the AC. It does not run electric heaters for the winter. The 2000ie will run a small heater, it just weighs too much (42lbs) for me to comfortably lift.<br></span><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-2"><param name="counter" value="203"></object></div>

 

[peacetara]

I don't know anything about sprinters, so I'll skip that part, but what comes below is just general battery/electricity love:<br><br>1) conserve your electricity usage.<br><br>2) Add more incoming electricity.<br><br><br>The easiest, and cheapest method is of course #1, conservation:<br><ul><li>&nbsp; If you are running lots of things off of an inverter and 120V AC,&nbsp; you may want to think about getting adapters for those things that let you run them direct from your batteries at 12V DC, that will save you around 30% right there (inverters are not very efficient).</li><li>If you can change out a device to one that uses less electricity, say regular lightbulbs with LED lightbulbs, for instance.&nbsp; LED lights use a LOT less electricity than traditional lights(of any kind).</li><li>Perhaps change something to use a different energy source, say go from an electric heater&nbsp; to a propane heater.</li><li>Use your devices less, or take a day off from electronics and play in nature once a week.</li><li>Offset your energy uses, and charge from other places: take your laptop into the local library and charge it there, as an example.</li></ul><br>Without knowing what devices you use, and your use patterns, it's hard to list specific things, but above are some examples.<br><br><br>The second big thing is add more incoming electricity.<br><br><ul><li>&nbsp; Clean your solar panel, make sure there is no shadow falling on the panel, etc. all of these things help your panel produce the most amount of electricity your panel can produce.</li><li>Use a generator.&nbsp; Some generators are built for this sort of thing, but they also tend to get noisy apparently.</li><li>Add more solar panels, assuming you have roof space.</li><li>Stop in once a week or so to somewhere you can plug in and charge your batteries, RV parks, friends, etc.</li><li>Use a wind generator, water generator, etc that takes power from wind or water (assuming you have either in abundance).</li><li>Be patient, This is winter season, when solar panels are at their absolute worst, because the sun doesn't come out as much, and doesn't come out as long (I think the other day was the shortest day of the year).</li></ul>Another thing, if your batteries have the caps on them, you should test the water level on the batteries once a month or so, to make sure the batteries are in good shape. <br>Also, Make sure there isn't any gross stuff growing on the posts, etc.&nbsp; Batteries should be clean and not growing weird gross stuff on them (which is a sign that something is wrong).<br><br>Anyways, I wish you lots of success on your winter living!<br><br>With Love,<br>Tara

 

[VanGirl]

Just to comment on the batteries. If you are using batteries inside your Sprinter they should be AGM sealed batteries or be installed in a case that is vented to the outside.<br><br>I have converted everything to LED for lighting. They have some good ones these days. I use a real sine wave 12v to 120v 2000 watt converter for 120 volt appliances. I use an LED (not LCD) TV, and a netbook computer in the van. Think low or no power. I have to have lighting in the van or I get very depressed.<br><br><br><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-2"><param name="counter" value="245"></object></div>

 

[sandcastle]

Thanks for all your input. I'll try to address all the concerns I see in your posts.<br><br>In my conversion process they installed a mount for a second alternator. If I have that alternator installed I think I can charge from it but I don't know what that actually means. It would still mean idling the engine, wouldn't it?<br><br>So far, my batteries are not chronically undercharged. The lowest I have been is 68%. I've been either plugged in or driving every other day to keep them charged. They are AGM truck batteries providing 220 volts each for 440 volts total which means I have 220 volts available. <br><br>I have 4 solar panels of 95 watts each placed so that nothing on my roof shades them. Believe me when I say that's as many as will fit up there. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>The lights I use most are LEDs. My biggest challenge is my 7 cf electric fridge. I run it on 12 volt most of the time but it takes a lot of power. My furnace is diesel. I have no TV but do spend a lot of time on my MacBook Air using my phone as a hot spot. I plug the phone into 12 volt but the computer uses 120.<br><br>The rig is only about 6 weeks old so battery terminals better not need cleaning at this point. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Mostly I am still learning how this rig works but am disappointed that my solar system appears to be undersized for my usage.<br><br>Linda

 

[StarEcho]

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.

 

[sandcastle]

I have a good charger but I cannot crawl around in there to see if they used the proper sized wires. They talked like they would but they did wire one connector on the wrong side of a transfer switch--whatever that means. I did not solve that problem on my own either. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>I suspect I am just more of a power hog than I want to admit. Given that, my challenge becomes how do I add to the recharging of my batteries. The built in diesel generator offered by the conversion place is $8K and I don't have that money right now. I have no propane system at all so getting a propane generator is not an option. To get a portable Honda I would also have to get a rack for the back of the rig and it would have to be one that did not interfere with loading my mobility scooter through the passenger rear door. Such is my challenge.<br><br>Linda

 

[wrcsixeight]

You must have an amp hour counter to say the batteries never have been discharged below 68%. &nbsp;That and a second alternator would indicate whomever set up your RV hopefully did not cut corners on the wiring between alternator and batteries but ultimately the bean counters, not engineers, dictate what goes into a build. &nbsp;One of the best ways to line their pockets, and make the job easier, is to use thinner wiring in the alternator charging circuit.<br><br>Battery monitors cannot be considered 100% accurate. &nbsp;85 to 90% is more realistic. &nbsp;The Percentage remaining is only accurate with new batteries, when the batteries capacity is entered correctly. &nbsp; Occasionally resetting and re zeroing the battery monitor when the batteries are known to be fully charged is wise<br><br>If you used voltage alone to come up with that 68% number, then it is inaccurate.<br><br>You are better off looking at the amp hours from full screen &nbsp;on a battery monitor rather than the percentage remaining.<br><br>Also, capacity is measured in amp hours, not volts.<br><br>Your &nbsp;solar wattage is sufficient, but your electrical consumption is obviously a lot, and this can be blamed on the fridge.<br><br>There are two types of fridges. &nbsp;Compressor fridges and absorption fridges. &nbsp;Compressor fridges, found in stick and brick homes have advantages in that they cool down quickly and can be operated out of level. 120 volt AC compressor fridges run on an inverter use about twice as much electricity as a compressor fridge originally designed to run on 12 volts DC. &nbsp;The latter cost more than twice as much, and thus the bean counter clause must be considered.<br><br>Absorption fridges are meant to run on a fossil fuel. &nbsp;The cooling units on these can usually be run on either propane/ 120vac, or 12vdc. &nbsp;The 12 volt DC function is only meant to be used while underway, and the alternator providing the energy to run it. An Absorption fridge, legally, is not to be run on propane when underway. &nbsp;On 12vdc, the absorption fridge is extremely inefficient.<br><br>if you are not running your absorption fridge on propane, there in lies your problem.<br><br>Idling the engine to recharge the batteries should always be considered the last resort as is does not work well, is extremely inefficient, and increases engine wear. &nbsp;Since they specifically recommend not doing this with yours, don't do it. &nbsp;Replacing a diesel engine is $$,$$$, and if under warranty, they can and will find out if it was idled excessively and deny warranty coverage.<br><br>BTW, batteries hate being below 80% charged, and charging them from 80 to 100%, even AGM batteries, takes a long long time, whatever charging source is used. &nbsp;For best performance, and longevity, they should be brought up to a true 100% once a week at minimum. &nbsp;Anything less is chronically undercharging them and equates to batterycide.<br><br>&nbsp;

 

[sandcastle]

I have a Trimetric that reads in various ways but the percentage is the only one I understand. 12.2 to 12.4 or whatever those numbers are doesn't tell me enough. When I need more detail than that I call my guru who walks me through what I need to do.<br><br>Like I said before, the rig is only about 6 weeks old. My guru set everything before turning me loose. Nothing should need adjusting there yet.<br><br>My fridge is a 12 v/120 v compressor fridge. No propane. No absorption.<br><br>So far, I have been able to bring the batteries up to 100% most days. That 68% was the lowest I have been. Usually only get down to 74-76% overnight when boondocking but can only go 2 nights and 1 day before I feel compelled to drive for recharging. That doesn't make for very good visits with groups like at the RTR. So, I would dearly love to find a solution for recharging by the middle of January. Otherwise I'm going to be driving lots of folks to Parker and back. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Linda

 

[StarEcho]

http://www.roadtrek.com/etrek.aspx<br><br>This is a sprinter engine isn't it? &nbsp;And they say that you recharge by idling the engine.

 

[sandcastle]

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

 

[ZOFCHAK]

Sandcastle, Are you using an MPPT charge controller for your panels? If not, that may give you a little better performance. Also if your panels are fixed in a horizontal position you may want to consider reworking them so that they pivot and can take advantage of the low sun we have this time of year.

 

[sandcastle]

Yes I have an MPPT charge controller. I pretty much bought the best money could buy until I ran out of money. <br><br>Yes, my panels are fixed. No way I'm going up there to tilt anything. Plus I would have to keep moving the vehicle then to keep them pointed at the sun. This way the sun hits them to some degree or another all day long. Lay a paper flat on your desk and look at the light on the paper from your desk lamp; then tilt the paper towards you and you'll see you lose some light on the paper unless you move it to face the lamp. I know tilting is supposed to be better but like everything it has trade offs. Since I can't climb a ladder tilting doesn't work for me.<br><br>Linda

 

[ZOFCHAK]

<br>&nbsp;&nbsp; Is the vent area on your fridge open enough to allow good air flow? If it is in the sun, or not sufficiently vented the compressor has to work much harder to keep the same temp. Also would it be possible to turn down the settings so that it wouldn't cycle as often, but still keep at a safe temp?

 

[sandcastle]

Nothing blocking the fridge vents and I have no animals so it can't be a pet hair problem although I could probably dust them a little more often. Can't safely turn down the setting any more than it currently is. Sun? It is December, you know. That's a big part of my problem. <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Linda

 

[peacetara]

Hi Linda!<br><br>Your laptop can be run off of 12V DC, you get an adapter from a place like <a href="http://www.ebay.com/sch/i.html?_trk...cbook+auto+adapter&amp;_sacat=0&amp;_from=R40" rel="nofollow">ebay</a>. Just search for 12V or auto car adapter macbook.&nbsp; I have a macbook pro, and have a 12V adapter.&nbsp; (I don't have an inverter).&nbsp; I think I paid $20 with shipping for mine.<br><br>Any alternator will take the engine running to generate electricity.<br><br>Sounds like overall you have a pretty good setup, and based on what you have said, it seems like something isn't quite right...<br><br>68% is actually an ok place to be, you don't really want to get below 50%, but at 440ah of battery, you should be able to go a few days without any sun or driving at all unless that fridge really is a GIANT power hog.<br><br>If you have a good relationship with the people that did all the electrical work (and it sounds like you do), I'd mention the problem you are having, and see what they say.&nbsp; They should be able to do math, and calculate the MAX load for the fridge, your laptop, lights, everything electrical.&nbsp; (In theory they did this BEFORE they did the install, and made sure you never had this problem!).<br><br>Helpful things for them (they might ask):<br><ul><li>How often does the fridge 'turn on', and work (Supposedly people can hear this, but I'm deaf, so don't have this ability)&nbsp; Example answer: It turns on for about 10 minutes, every hour.</li><li>How long do you use the Macbook air plugged in?&nbsp; Example: I run the laptop 12hrs a day, 10 of which is plugged in.</li><li>How long do you run the lights?: Example: I run them for about 3hrs a day.</li><li>If you start the day with a charged battery, without driving, how long does it take to get to 70%?</li></ul>Anyways, to do more troubleshooting, this would be the list of questions (above and now a few more below):<br><ul><li>What is the max power load on the fridge (written on the fridge, usually will say 12V and then something A or something W, usually on a white sticker on the back next to where all the wires are)?</li></ul>My thinking here is, to do some math, and figure out what the numbers SHOULD be, i.e. figure out your electricity usage, and compare that with what the 4 panels should be able to produce.&nbsp; If the math doesn't match with what is actually happening, then it's definitely something with the installation.&nbsp; But it could be that everything is correctly installed and your fridge really is just a GIANT power hog, and the only solution is to replace the fridge with something that takes less power, or figure out how to add more electricity (generator or something).<br><br>If you don't get it figured out before the RTR, I'll be at the RTR, as will Bob and others that are knowledgeable with Solar, perhaps we can figure out what's going on.&nbsp; I can't speak for the others, but I'd be happy to look at it free if you wanted.<br><br>But I really think your best bet, for something this new, is to let your installer people figure it out (since they in theory sized everything, they should be able to show you all the math and let you know what your experiences SHOULD be).<br><br>I.e. they should be able to show you, what your max load should be, and what your panels should be able to bring in. The plus side about Quartzite, it's really good about giving you LOTS of sun to keep your solar panels generating their maximum! <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br><br>Regardless, wishing you lots of success!<br><br>With Love,<br>Tara

 

[wrcsixeight]

What is the make and model of the fridge? &nbsp;How big is it?<br><br>Does it have a door latch?<br><br><br>