Adding a lithium Ion battery to FWC

Bwht4x4 said:
I'd go with a bigger solar panel than a 100 watt. I went straight for the 160 watt panel and mounted it to my Yakima tracks and it works great. The additional weight from a 100 to 160 is not that great, but you gain a few more amps and a faster battery charge!
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I did. I decided to go whole hog and get 300 Watts (Renology RNG-100DB X3)
 
Ok so after installing one 100 watt panel I was so happy with the performance (5.1amps into the battery at 1PM) that I ordered 2 more priority delivery, which arrived yesterday. I installed those last night and am testing them now.

System is

Renology RNG 100DB Panels (times 3)

Bioenno Power 12V/24V, 30A Solar Controller for LiFePO4 Model SC-122430T[/size]

Each panel is 100 Watts 5.1 amps. I observed 5.1 amps output on the first panel in ideal conditions. Currently array is producing 13.9 amps with all three panels. With engine running total charging rate is 33.7 amps (camper power off), which is more than enough to make me smile. With engine off and Fridge on the draw is a net positive 9 amps.

Photos attached.
 

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That is one awesome looking system! No doubt, 300 watts will do it with some room to spare. At 9 amps net after the draw from the refrigerator, you should be able to recover from the night before with ease.
My only other suggestion is to monitor those MC4 solar connectors. The wind, while driving, may cause the connectors to vibrate and mar your rooftop finish. I clipped all of mines off and simply used crimp butt connectors wrapped in silicone tape. Makes a much smaller bundle. Nice work!
 
Nice job CDBROW1. Do you have panels in series or parallel? If in series, what voltage are you measuring? I have a similar set up with two 100w renogy panels set up in series. I measure between 33 to 39.5v and been up to 9.7A. Best power being seen at the batteries has been 154watts (V x A). With fridge running I am averging +3.5A. I am considering another 100w panel....need another project.
 
Depending on what kind of controller you have will determine whether the panels be in parallel or series. If using a PWM controller, those panels should be in parallel. A MPPT controller can take advantage of the higher voltage, so you can use a series hookup and not lose any power.

A PWM controller will take the panel input voltage and reduce it to the necessary charge voltage and output that voltage at the current it receives from the panel. Any voltage above the needed charge voltage is lost. So if the panel is generating 18v at 5 amps (90 watts), the controller will reduce the voltage to say 14v @ 5A or 70 watts, you have lost 20 watts. By having the panels in parallel will result in less of a lost. Because the voltage presented at the input of PWM controller is less, the net loss in voltage reduction is also less.

A MPPT controller, on the other hand, will still reduce the voltage but not lose the power as a result of the voltage reduction. It has the ability to capture the additional power and convert that to more current flow.
 
Sledawg said:
Nice job CDBROW1. Do you have panels in series or parallel? If in series, what voltage are you measuring? I have a similar set up with two 100w renogy panels set up in series. I measure between 33 to 39.5v and been up to 9.7A. Best power being seen at the batteries has been 154watts (V x A). With fridge running I am averging +3.5A. I am considering another 100w panel....need another project.
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I have them in Parallel
 
Did some testing the last few days - no camping yet (I avoid the 4th since there are just too many people out there).

Saturday night I left the fridge running all night. Battery was down to 70% in the morning (it was a hot night). I drove 100 miles up into the Sierras to do some hiking. My the time I got to the trailhead the batteries were full. Did some hiking and drove a bit to find a good lunch spot.

When I stopped to make lunch (battery at 100%) I opened the back of the camper and the propane alarm was beeping (did that when new but not since). Propane has been turned off for a few weeks. Hit the reset button and turned on the inverter. My inverter gave me an E04 error (over temp shutdown). After I disconnected the solar and restarted the inverter everything was fine. Made lunch - (4 minutes on the microwave) and power dropped to 95%. Reconnected solar and tested inverter and everything was fine. Drove for 20 miles and check again and the battery was full again.

Whenever you have two things go wrong at once you look for any connection between them. The only connection between the inverter and the propane leak detector that I can see is the electrical system. When the battery is full I assume the controller cycles to check the battery SOC and I wonder if that cycling is causing noise or spikes in the electrical system. Anybody have any ideas?

I tried to recreate this in the driveway last night, but the sun was too low in the sky.
 
FYI.

I have the MPPT controller on order. It should be arriving in a few weeks. It will be interesting ot see what kind of improvement that makes in the system.
 
I have confirmed the error messages in my inverter - Over Voltage Shutdown E02 and Over Temp Shutdown E04

This ONLY occur when the battery is full, the controller is connected and the solar array is connected. My voltage do not show a power spike, but they do show the current going up a bit. My guess is the controller is putting out some very quick power spike - likely at the array voltage of ~18 volts as it checks the battery voltage. Not good.

For now I will be running with the solar array unplugged when the battery is full and keeping the camper isolated from the truck.

Once the new inverter arrives I will send this one back for testing.
 
I wonder what the duration of the spike is. I don't imagine a short spike would harm anything but its certainly a disconcerting thing to have happen.
 
craig333 said:
I wonder what the duration of the spike is. I don't imagine a short spike would harm anything but its certainly a disconcerting thing to have happen.
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I don't know. I guess I would need an oscilloscope to find out. I can't see it in total on my handheld volt meter - I can see a rise, but only to 15V or so. It is not enough to trip the BMS on the battery, but that maybe because it is limited in time.

From looking online is seems that spikes (or pulses) are SOP with PWM controllers, in fact it is built into the name (Pulse Width Modulation). This may be something where the lithium ion battery is behaving differently than a Lead Acid battery and is not adequately smoothing the spikes.

One solution might be adding a big capacitor to the system - like the car stereo guys do.

Since I am changing controllers very soon to MPPT I am just going to leave the solar unplugged when the system is charged and see if the problem continues when the new controller arrives.
 
I installed the MPPT controller this morning and observed the same behavior. I have a tech support email in to the Bioenno to see what they have to say. Saw one voltage spike to 17 volts which is CLEARLY unacceptable. For now the solar will remain unplugged unless the battery gets really low - there are no spikes when it is actively charging.
 
You may want to checkout this Kickstarter for Solar/Battery Management device made for Lithium's. His previous version did very well and is available for purchase, or you can get the new one he is developing for release this October.
 
photohc said:
You may want to checkout this Kickstarter for Solar/Battery Management device made for Lithium's. His previous version did very well and is available for purchase, or you can get the new one he is developing for release this October.
Click to expand...
I have looked into that one before and the issue is that I have a battery with an existing BMS so I don't actually need to purchase a controller/BMS - I just need the controller.

I spoke with Bioenno today and run though a ton of diagnostics (it's only 109 outside so it's ok). They believe something in my unit has failed and they are sending a replacement.

The unit reads
18.5 Volts (close circuit) from the panels (aka normal)
Full battery reads 13.5 volts (aka normal)
Charge voltage (absorption) is 14.5 (aka normal)

Everything works fine until the battery reaches a full charge - then things get weird.

Voltages on solar stay at 18.5 (normal) - but cycles between load and no load.
On the battery side voltages vary from 14.4 to as high as 17.0 very quickly.
The "load" connection on the controller - which is unused in my setup - turns on and off in sync with the solar array switching between load and no load.

I even ran only a single panel and received the same results.

Attaching a heavy load to the load side of the controller did not change the results.

A full reset did not change the results.

Finally directly wiring the controller to the battery (bypassing the Xantrax Link shunt) did not change the results.

A new box is on the way.

I am not sure this will be a fix however - my gut tells me the solar controller and my BMS are fighting each other. I hope I am wrong.

If the replacement controller does not solve the problem I plan to install a large capacitor between the solar controller and the battery to "smooth the spikes" or get a different brand of controller.
 
Cdbrow1 thanks for being the beta tester in this arena.
Although I don't have my Grandby yet I am eagerly reading everything I can in order to make myself as self sufficient as possible and extend our off the grid trips.

One little question I had in reading the previous pages, when you switched the wiring from your truck to the camper from 10 gauge to 2 gauge were you able to use the same camper connection? i.e. did the wire fit?

Thanks.
 
That is the one segment that has not been updated because I did not want to pull the camper off the truck at this time. I have 2 gauge from the battery about 1 foot short of the connector and I am working on upgrading the wiring inside as well. Eventually I will pull the camper to do that last piece of wiring and some other projects (improving turnbuckle mounts and perhaps installing greywater tank). I can't picture the wiring actually working in the trolling motor plug so I expect to replace it with an Anderson Connector (http://www.andersonpower.com/). This is a fairly common upgrade.

I hope that helps.
 
Ok so a follow up -

New controller arrived about an hour ago - hooked it up and had the exact same behavior.

I will talk to them in the morning and see if they have any recommendations. If not I will return both and get a Morningstar programmable controller in that case I will have full control over all the charging parameters.

I am off for a 4 day road trip into the Ruby Mountains, Great Basin NP and a few other hidden places in Nevada. I am going to keep the controller in the truck and just turn it on when the battery needs charging since the problems only occur when the battery is full.
 
Sorry to hear of the same problem with the new controller. If you decide to get the Morningstar Sunsaver MPPT, that is what I am currently using until I get my copy of the new Electrodacus SBMS100 Solar/Lithium controller on Kickstarter. I would be happy to share my file setup for the Sunsaver. It works well for me.
 
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