Thanks for the overview Ray! I’m trying to imagine how you would use 400 plus amp hours of power. You didn’t mention any high amp output appliances. You must have another 300-400 amp hours of power using power stations as well.
Many boats have built-in generators that run on the same diesel tanks as the main engine, but ours doesn't. The best thing is to oversize the battery capacity so we don't have to run a noisy gas generator on deck in a quiet anchorage, which is also dangerous when stationary due to fumes. We draw on average 10 amps per hour I find. In 24 hours that is 240 Amp hours. We have a Nova Kool DC fridge that draws 4.4A when running and in the summer warmth it runs quite a bit, also a Acopower DC fridge/freezer that draws about 3A. Starlink when on most of the day draws about 5A and then there are our laptops 17" HP 3A and Apple 13" 2A and Anne has a 27" computer monitor she sometimes uses for photo editing 6-8A. Then boat lights, water pump, electric toilet, various tool and camera chargers, etc. plus I use a 700W instant pot every few days. It all adds up, if we get socked in with fog, cloud and rain for a few days the batteries can get drained quicker than you think. :) Last night the Xantrex batteries were near full at 92% by morning we were down to 70% and these are the longest days. Good sun today and back to 100% by 3pm. But it only gets worse from here as the days get shorter. Solar harvest can vary when we are at anchor depending on how we swing around. The power stations are Bluetti AC240 and AC70 they have 130AH and 64Ah. The AC70 gets used to charge our phones and a few other small things and the AC240 gets charged by the original solar panels the boat had on it 200W. Then I use that power to heat up our water heater every few days for showers. Water heater uses about 60% of its battery. There is lots of room to conserve power but nice to not have to worry about it. The lead acid bank is my reserve and it has about 220Ah of usable power. Cheers, Ray
Great overview as usual! What's your opinion on having multiple smaller MPPT controllers vs one larger one? I see you have multiple controllers; is that cause "you had them" or is that "the best way" to wire multiple/different wattage panels? Not holding you to it, just want your opinion. Thanks.
Thanks! I used use multiple controllers in this situation because the two solar arrays I'm using have differing voltage/amp ratings and they are located on the boat where one will suffer shading while the other is in full sun. Also the chargers run cooler since they aren't having to work near their max amperage rating. I do the same in my RV where I have a roof that slopes toward the back and front from the middle. I use a different controller for the panels mounted on the back and front as they often see differing sun levels and I can use two smaller sized controllers vs one large one. And another plus is system redundancy. If a controller fails the system can still be made to keep working, which is great when traveling to remote locations like we do on the boat especially. :) Multiple chargers with lead acid can require a lot of setup to get then to charge in sync through various charge phases but with lithium the battery charge curve is very constant almost to full charge. The low internal resistant means that the lithium will easily sop up what ever amps are being produced by both chargers. Cheers, Ray
@@LoveYourRV Excellent points! I didn't think about the redundancy concern that if one controller goes down, charging in some fashion continues on. Also like the point you made about overheating the controller when they are running at their intended max amperage rating. I'll ponder all of your comments in my modifications to my solar system. Thanks a bunch! Safe travels...
Simple by comparison, but I have two 100w Renogy panels each of which comes with a charge controller. If I parallel the two downstream from the charge controllers, they fight each other, one controller seeing the output of the other and thinking the batteries have a greater charge than they do. I have to run both panels thru a single charge controller to achieve full potential. Your system has three inputs (the two PV charge controllers plus the DC to DC charger) all paralleled after these controllers. How do you keep them from conflicting?
Lead acid batteries that charge in multiple phases (bulk, absorption, float) can be an issue unless the chargers are very closely set up for each phase and wiring size and length are closely matched or have a communication data line capability. However, lithium has a much different charging curve. Lithium batteries have very low internal resistance and stay in a bulk charge acceptance mode for over 90% of the charge curve. So basically, they will easily sop up all amps provided. It's not until the lithium battery gets to about 95% charged that the internal resistance will rise, amps drop and the voltage rises enough that the chargers may think they are near a float and conflict. By that time I'm not concerned as the battery bank is nearly full. Comparison between LA and LiFePo4 charge curves www.powerstream.com/z/lfp-la.jpg I usually set my chargers to their lithium preset, usually 14.2 -14.4V and they work well together. It's best to have the charge controllers output wiring near the same lengths and met very close to the battery bank. Cheers, Ray
I'm interested in your setup with two different charge controllers connected to the lithium batteries. Will they each provide full rated charge (on a sunny day) at the same time or will they affect each other? Seems like one controller would sense the output of the other controller and think the batteries are charged. I'm having difficulty understanding how this works.
Lead acid batteries that charge in multiple phases (bulk, absorption, float) can be an issue unless the chargers are very closely set up for each phase and wiring size and length are closely matched or have a communication data line capability. However, lithium has a much different charging curve. Lithium batteries have very low internal resistance and stay in a bulk charge acceptance mode for over 90% of the charge curve. So basically, they will easily sop up all amps provided. It's not until the lithium battery gets to about 95% charged that the internal resistance will rise, amps drop and the voltage rises enough that the chargers may think they are near a float. I usually set my chargers to their lithium preset, and they work well together.
I have to laugh at the names that some Chinese manufacturers give their products. I noticed your amp hour meter is a Junctek, did you buy that or did they send it to you? It looks like you've put together a nice system. Has SRNE put their new products for sale yet that you reviewed quite some time ago?
I bought an identical one called Koolertron, haha ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jFU5Z_GPxmY.html then the Junctek people sent me their updated model for review a while back ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KgjCxIGl7gQ.html So far SRNE hasn't got back to me with a North American purchase option though every time I ask they say it is going to happen. From the Facebook page it appears they have been to trade shows around the world lately including in the USA so likely setting up dealers.
