Dead house battery

[SierraHawk]

Thanks porshadpm. The plastic on the positive wire running to the old controller, It was melted. I cut the wires to keep any current from flowing to ground. The 100W panel is putting out over 17amps. That would be enugh to fry something more than the wire. I will get a replaceent controller in the mail tomorrow. I expect to hooki it up (controler wire to the two 12ga wires going to the battery (first) and then the leads to the panel. If there is a beter way let me know.

[1der]

100w solar panel is putting out 17.x volts not amps.

Depending on the length of the wire run from the controller to the batteries, perhaps consider 10 ga or even larger to minimize the voltage drop from the controller to the batteries.

There optimally should be a fuse on the positive wire from the solar panel to the controller. There are in line MC4 connector fuses available. I also like to install a circuit breaker on the positive wire, just before it enters the solar controller, which also acts as a disconnect.

Next, there should be a circuit breaker on the positive wire near where it is exiting the controller going to the battery. There should be a fuse near the positive battery terminal to protect against a short in that positive wire run between the battery and controller.

The idea is to protect for a short but also to have on/off switch points near the controller so connections are not being made “live”.

[SierraHawk]

For now it looks like the battery is defective but since we are parked in the eastern Mojave desert not far from the Utah border it will have to stay that way for another week.

Summary: In 2005 I mounted two 25w panels and one 50w panel (all Fry's Electronics had) on the Penthouse top. They were installed with the only controller that Fry's sold at the time. It was a plug and play setup. Surprisingly the panels and controller have lasted 15 years. Up until the past two months the house battery has been a group size 27 AGM. Tired of paying $300 for batteries that are used only occasionally I replaced the house battery with a Group 54. Only info available is that it puts out 650 ccp. Load on the house battery is very light. It consists of the LED interior lights, water pump, furnace, fridge and occasionally the radio.

Update: Several weeks ago something shorted in the controller. Ungrateful for all of the years of service I cut the wires and tossed the controller. At this time the bare leads from the panels are putting out 17v. Beside the 17v solar panel charge source I am assuming that the alternator is also charging the house battery but my findings are a bit mixed. House battery can be charged through the trailer's battery but it only gets up to 11.5v. That charge dissipates to around 10.5 by the next day. Conclusion is the battery is bad.

The panels are 15 years old but there are no markings that tell me who the manufacturer is/are. Consensus on this forum has favored the Victron SmartSolar 100/20 controller with Bluetooth. Since I have little to do I actually read the instructions. They say that if I don't set the controller up correctly that the battery will meltdown.

On Tuesday I sent a note to Victron asking for a more detailed set of instructions that can help me avoid the destruction of my battery. The short note I got back yesterday said that I need to find out who manufactured the PV panels so that I can pair them with the right controller. Then he/she said that I need to have the work done at the Reno facility that sells the Victron brand. I thought that things got simpler as we advance.

Hoping that I can hook this thing up this weekend I called the installer. They close at 4. I do have a fire extinguisher available and can sleep in the van to watch the battery but am hoping to avoid any further failures in my solar charging system.

[SierraHawk]

BTW, I did read the multi-meter instructions. Simple enough even for me to understand but trying to use it in any meaningful way is my next task.

Thanks Ray. I did find out that it is 17v. The wiring from the panels to the controller are around 8' and 10ga but the wires to the battery are around 3' and look to be 12ga. There were no fuses on the old controller but the new one does have a fuse built in. I will get a breaker as you suggest. I am sure I could cause a lot of damage if I left the bare ends flail around (which is what they are doing right now). Tho I do have the panels covered with a tarp.

[SierraHawk]

Originally Posted by REF

You’ll more want to look at amp hours(ah) number for your house battery, not the cranking amps(CA) or cold cranking amps(CCA). Deep cycle batteries are best for house applications. Many, including myself prefer AGM over flooded or at the very least a sealed or maintenance free flooded, so no spillage or off gassing, especially if placed inside the van.

I have had AGM house batteries up until now. I like the concept but since our plans have changed I really do not need the deep cycle. Fortunately Sportsmobile vented the battery box from below and above. This is the first time I have tried to find the amp hours on a battery. I'm now curious and will see if it has anything more than the CCP or CP. Gotta be somewhere. Last weekend the house battery would not hold a charge. As of Tuesday it is now holding a charge but it is around 10.5v.

I may have bumped something that was causing a leak. That may remain a mystery until we get to a place where I can empty everything out of the van. We have been full timing since 2007. Since we have been parked in the eastern Mojave without any symptoms for a month we can assume that we dodged that bullet. It has been a great adventure but we need a place to settle in while we wait for an immunization.

[1der]

SH - man, you guys lasted longer in the escape pod then we could. Now back in San Francisco after ten weeks on the road including 10 days off grid at Flaming Gorge. Wow, big difference (not all good being in the war zone)

Okay, on to your situation. Couple things come to mind
1. Your panels are mismatched but could be set up so you can maximize the solar contribution. The two 25w panels should be connected in series and then parallel w the 50w. (Scalf77 help ??). This will give you the 100w of solar. (You can check this out later, it is what is now)
2. Light loads on the battery?? Not really. A Group 27 is maybe 90 AH capacity. Overnight: A fridge is 2.5 amps x 14 hrs (this time of year), Lights, other and pretty quickly 45 AH are used every night. Then during the day the solar is tasked with recharging overnight usage plus the needs during the day. The 100w is lucky to contribute 6 to 7 amps for 6 hrs of effective sunlight (I am being VERY optimistic) so 42 Ah goes back in - deficit of 3 for overnight usage plus the fridge alone used 2.5 x 10 during the day. Digging a hole and drawing the battery down nearly 50% every night.

This is why I feel min 300w solar plus a 200Ah battery bank should be the minimum people setup. That way there is a balance between usage and charging plus a cushion for cloudy days and winter (less solar hours) days. Summer is easier as days are longer.

Hooking up the new Victron SC -
The wires coming from the solar panels have pos and neg., using your meter you can confirm which is which. Those go into the appropriate terminals on the SC. Then you have a pos and neg wires going to the battery, connect those to the terminals for the battery. If you have the fuses then put those inline on the positive wires.

Hope this helps.

[SierraHawk]

Thanks 1der. I will rewire the panels. When I say light use I mean that for the past several years we just have not been using the van as much as we had. We actually cheat on the camping. Our SMB is a 2004. It has 300,000 miles on it and I could not imagine living without it. Up until 2007 we would just use the van as a Class B and travel into remote areas but that required some kind of mobile base if we wanted to travel for more than a month or two. By hapenstance I picked up a 29' 1976 Airstream for $5000. Put another $10,000 into it and we had a home. Sold our house in Sacramento and have not gone back. The trailer is our base. We can park it and range wherever we want and then return to the base, do repairs, maintenence and plan for our next trip. Nice thing is that the solar system I installed (single 100w panel) on the trailer and all of the other systems that we have rebuilt work great. We picked up an old Thousand Trails membership. It allows us to travel around the US and have a place to park for free when we need it. We pay TT $500 each year but that doesn't even pay for the electricity we use. Having to sit out the COVID 19 for the last month was no different than the way we have lived for the past 13 years. Since I had a lot of time to assess the van and trailer this past month I dove into the solar system on the van. We have been successfullly living with one sealed lead acid battery in the trailer I thought I would try it with the van. It just happened that the old controller finally gave out and forced me to check everything that is connected to the solar system now. Thank you for the heads up on the panels. In 2005 no one knew any thing about solar so it was a do it yourself project. Guess I am lucky it lasted this long. Hopeffully I can get the solar system seet up right this time and not worry about it for another 15 years.

[SierraHawk]

Thanks porchedpm. The battery box is buried in the back of the van and is well vented. We are headed north to Reno. I will dig the old battery out and drop in a new one when we get there. I will also check for any leaks using the ammeter.

The system in the trailer had a Group 27 AGM in it but the AGMs would die after two or so years. Four years ago the controller in the trailer died but in the process of dying it killed the AGM. We were in the Yukon. I actually found a solar shop and bought a controller for less than $100. But the AGM was closer to $400. The solar shop owner suggested that I try a lead acid battery and switch to an AGM if the wet cell did not work out. Trailer has just a single 100w PV panel on top. That combination has worked OK so I did not get another AGM.

Since we are parked in an area that has no resources and had lots of time I was trying to do a quick repair out here. What stopped me was the notation in the instructions that came with the new controller. It says that if I set up the Victron wrong (all terminals are clearly marked pos/neg for Batt, PV and Load) something bad will happen to a lead acid battery if it does not charge fully. The current battery is not holding a charge. Not sure if it was the old controller that killed the battery or it was just a dud but I do not want to damage any of the components. I am hoping that when I drop a new battery in that magical things will happen and we will live happily for at least another year or two.

[SierraHawk]

Last week I was stressing because I did not know what I was doing. We made it to Carson City safely. Interesting route via Nevada 93 and the Extraterrestrial Highway. I emailed Victron (makes the controller) and asked several questions. Got an answer to one question but was directed to have some techs in Reno install the controller.

In her email Jan told me that the PV panels have to be made by the same manufacturer. The panels are 15 years old and putting out 19V. None of them have the handy label on the backs but I was able to find that they are hooked up in parallel. I am going to bet that Fry's Electronics had one source for PV panels at the time.

I called the Reno shop. No answer. I emailed the shop. No answer.

So...that leaves you and me. I caved and bought a new Group 27 AGM. Fit perfectly in the box. Mounted the Victron controller on a piece of aluminum sheet because Sportsmobile used a fiber board for the wall. Screwed the aluminum sheet to the fiberboard.

Once the controller was mounted I connected the battery leads to the controller. So far so good. It was still light so I had to wait until the PV panel output was "0". At dusk I inserted the pos & neg wires from the PV panels into their respective clamps and waited til morning to see if everything will work.

Next morning. No fire. PV panels putting out 18V in low angle light. Battery is at 13.2V and charging. So, it looks like plug and play is over but if you have panels made by the same company connecting and the controller is built to handle the output of the PV panels you are good to go. Next; connect the controller to the battery. Wait until it is dark enough that you can avoid an electrical surge from the PV panels and check your work in the morning.

Thank you to everyone who commented and provided essential information. Looks like we are ready for the next leg of our trip: Oregon Coast for the summer.