Re: Solar Upgrade Reply #25 – March 05, 2025, 03:31:20 pm I had a question regarding whether the batteries I had installed by Discount Solar were heated or not. The installer invoice stated they were, but the manufacturer literature doesn't mention heaters. After talking to Craig, the owner of Discount Solar, he confirmed that they are indeed the heated variety. Then I received this message from the manufacturer, which gave me a 'warm" feeling. Thank you for purchasing our lithium 12V battery. I am sorry there was no indication of heater on your packaging or battery. We will be looking at adding this to all the labels going forward. Based on the information shared with us, your serial number contains the letters "EV" which indicates there is a heater. We stopped offering non-heated versions about a year ago but they contain "DX" in the serial number. Please let me know if you have any questions.Zack CoxU.S. Battery Mfg. Co.US 12V G24 Lithium-Ion Battery | Essential Li® | U.S. Battery Mfg.
Re: Solar Upgrade Reply #26 – March 30, 2025, 03:50:31 pm No big deal but just curious; the Blue Sky solar controller states that the battery voltage is 13.6V but both the Victron monitor and the battery BMS’s are at 13.3V. Why would it be different?
Re: Solar Upgrade Reply #27 – March 30, 2025, 05:46:06 pm Off the top of my head: unless the Blue Sky controller has a separate voltage sense wire, it's telling you the voltage at the controller's output, whereas the Victron monitor and the battery's BMS are telling you the actual voltage at the battery.Why the difference? My first guess would be voltage drop between the controller and the battery, due to undersized wiring. Measure the length of that cable run, check the wire gauge, and plug those numbers into a voltage drop calculator to see what comes up.What charging voltage does the battery want to see? If you're losing three tenths of a volt in the wiring, then the battery isn't getting a full charge... and that is indeed a big deal.
Re: Solar Upgrade Reply #28 – March 31, 2025, 09:05:56 pm I think the battery may still get a full charge, but slower than it could be. As the battery approaches full charge, the charging current decreases, the voltage drop (which is proportional to current) decreases, and the Blue Sky voltage will increase to approach the battery monitor voltage. 1 Likes
Re: Solar Upgrade Reply #29 – April 02, 2025, 10:25:39 am "the Blue Sky voltage will increase to approach the battery monitor voltage."If the Blue Sky controller doesn't know the actual battery voltage (the voltage shown on the battery monitor), I'm not sure that will be the case. The controller needs to know the true battery voltage if it's to do its job. While three tenths of a volt difference doesn't sound like much, when charging a battery it can be significant.Again, I'd take a look at the wiring gauge and length, and calculate the resulting voltage drop to see whether that's the problem. If it's possible to add a separate voltage sense wire to the controller, that would be a good thing to do.
Re: Solar Upgrade Reply #30 – April 02, 2025, 12:08:43 pm Thanks, Andy. I'll take a look at that. Does anyone know how the wiring is run from the roof to the solar controller in a MidBath?
Re: Solar Upgrade Reply #31 – April 02, 2025, 12:22:21 pm Quote from: Andy Baird - April 02, 2025, 10:25:39 amAgain, I'd take a look at the wiring gauge and length, and calculate the resulting voltage drop to see whether that's the problem. If it's possible to add a separate voltage sense wire to the controller, that would be a good thing to do.Greg, I think I asked before, did the solar installer increase the size of the wires coming down from the solar panels when you upgraded the panels and batteries at Quartzsite?When adding more solar panels to the roof, the wires bringing the power down to the solar controller need to be increased in size to reduce voltage drop.If the wires were not upsized, you are losing charging power, which may explain the voltage differences. Installers probably do not want to do this, as it is a PIA to perform. It is worth doing if you are looking for maximum charging efficiency.Remote electrical troubleshooting is one of the more difficult things to do. Problems that can be found in a few minutes with the use of a voltameter may never be mentioned during discussions on the Forum, there are dozens of potential trouble spots. Your issue may simply be a poor connection....who knows?Larry
Re: Solar Upgrade Reply #32 – April 02, 2025, 01:26:30 pm Hi Greg; Rest easy, there are too many other things more important to worry about. If you boondock for weeks at a time and have to rely on your roof kilowatts of solar, charging your twelve batteries, then highest efficiency is a concern, but just leave your system alone for now. Trust me. RonB
Re: Solar Upgrade Reply #33 – April 02, 2025, 01:42:15 pm Ron, we are not heavy boondockers at this point in our lives so will take a wait and see approach so long as there is no danger of overheating wires.Larry, yes I remember we talked a little about the controller wiring size at Morro Bay the day you and Steve came over to the rig. I pulled the controller out after that conversation to take a peek at the wiring. It appears to be 14 AWG, which is probably factory. The batteries are tracking closely now that we swapped the hook-up cables. Batteries are consistently charging to 99.5% SOC, according to the battery BMS's.
Re: Solar Upgrade Reply #34 – April 02, 2025, 05:54:53 pm Quote from: HiLola - March 30, 2025, 03:50:31 pmNo big deal but just curious; the Blue Sky solar controller states that the battery voltage is 13.6V but both the Victron monitor and the battery BMS’s are at 13.3V. Why would it be different?The Blue Sky controller does not really know what the battery voltage is - it simply is reading out the voltage at ITS output terminals. And, at that voltage, the batteries are likely fully charged. If in the daytime, is there a significant charge current from the Blue Sky? If not, the battery BMS has shut off charging. With no or little charge current, there will be no voltage drop, so likely either the BMS or the Blue Sky calibration is off. A good voltmeter will tell you which.Steve
Re: Solar Upgrade Reply #35 – April 02, 2025, 07:34:09 pm Quote from: Steve - April 02, 2025, 05:54:53 pm With no or little charge current, there will be no voltage drop, so likely either the BMS or the Blue Sky calibration is off. A good voltmeter will tell you which.Learning to use a voltmeter is a necessary skill that owners who work on their own RVs' electrical systems should develop.It can help answer a lot of questions,Larry
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