Solar 'generator' backup battery systems

[goldenstate]

I am curious if anyone has experience with portable solar charging systems. I don't really want to add a fully-fledged solar system if I don't need to.

I started to do a little research on these systems. 'Jackery' (oof) is a prominent manufacturer name on Amazon and seems to get good reviews.

https://www.amazon.com/Jackery-Explorer-Generator-Outdoors-Emergency/dp/B08LDBSGM5/ref=sr_1_9?crid=2J8JE4JOPYUGS&dchild=1&keywords=jackery+portable+power+station&qid=1614202539&sprefix=jackery%2Caps%2C252&sr=8-9

If I need a "Oh no, what if (both of) my alternators fail." This sort of a little 'generator' battery system could keep my podcasts playing and even my AIS and GPS systems on-line. Stow one of these guys and unfold the panels on the dodger or cockpit if I need to in an emergency?

 

[Milagros]

I have one of the jackery units that I use for camping, music fests, etc. to run some lights and play music. I don't remember how I found out (I think someone's youtube video) but I discovered that they have an internal charge controller so you can attach any solar panel (within reason) directly to them. I got a 100w panel for $50 and just did a little wiring to the right connector. The jackery panels are just a bit expensive for my taste. It all works well for that application--remember the watt rating on a solar panel is pretty much what you would get at solar noon in the tropics--my 100w panel will give me 75w at midday in the summer up here. I guess my one reservation is that it isn't marinized at all; you'd definitely want to test it from time to time if you store it on your boat. On the other hand it's a really useful gadget so you may want to use it in other ways.

 

[Kenneth K]

Renogy 50 Watt 12 Volt Monocrystalline Solar Panel (Compact Design)​

Currently $67.50 each on Amazon. I just picked up a pair for a future solar install. Most people seem to like the larger 100W panels, but these are about half the size. At 24" x 20," I figure I can store them below deck when not in use.

https://www.amazon.com/Renogy-Monocrystalline-Efficiency-Charging-Applications/dp/B07GTH79JP/ref=sr_1_3?dchild=1&keywords=renogy+50W&qid=1614536309&sr=8-3

 

[Kenneth K]

Renogy 50 Watt 12 Volt Monocrystalline Solar Panel (Compact Design)​

Fits in bow storage compartment above the water tank. Could probably put 2 in there, even with mounting brackets.

 

[nquigley]

I've mounted 200W of solar panels above my cockpit. Even then, I'm worried that I might not be able to start the engine if I really needed to while cruising off-grid, so I'm thinking of carrying a spare starter battery - probably under the seat in front of the nav station. I'd leave it charged - not wired to the battery bank, but with jumper cables ready to help a dead house battery.

 

[debonAir]

I've mounted 200W of solar panels above my cockpit. Even then, I'm worried that I might not be able to start the engine if I really needed to while cruising off-grid, so I'm thinking of carrying a spare starter battery - probably under the seat in front of the nav station. I'd leave it charged - not wired to the battery bank, but with jumper cables ready to help a dead house battery.

The problem there is that your starter battery will self-discharge and might be dead by the time you really need it. An AGM battery has lower self-discharge but even then you're still looking at needing to charge it back every few months (my AGM will actually start my engine after sitting disconnected over the Winter, but now I have it maintained by solar so dont need to risk it). You could get an echo charger to keep your starter battery topped off from the house bank yet still "disconnected".

Your idea about using jumper cables might not work either. Your starter battery, even fully charged, will be around 12.6V and your dead house battery will be around 11.6V. When you connect the two, the dead battery will take current from the starter battery until they reach a point where they are roughly less-than-half-charged (depending on capacity of each). During most of that time your dead battery will sink so much current that the starter motor on your engine might not get enough juice to turn the engine over. You need about 14.2V to really charge a battery so even a big strong starter battery won't get your house past 1/3 charged or so. Your best bet is to get your engine running first by disconnecting your house bank and attaching your starter battery to the boat directly. Then reconnect the house to charge from alternator, That's why we mostly use off-1-2-both battery switches.

 

[Rocinante33]

I've mounted 200W of solar panels above my cockpit. Even then, I'm worried that I might not be able to start the engine if I really needed to while cruising off-grid, so I'm thinking of carrying a spare starter battery - probably under the seat in front of the nav station. I'd leave it charged - not wired to the battery bank, but with jumper cables ready to help a dead house battery.

You have a great start (pun intended). Add one of these Echo chargers to your circuit and it will keep your separate starter battery charged from the same solar panel output, but the starter battery will not drain or be drained by the house bank. It is my plan to add the separate starter battery and wire it this way. I think a small, relatively light weight starter battery should be adequate fir these small engines of our boats.

Xantrex Heart Echo Charge Charging Panel

Convenient Dual Battery Bank Charging. Xantrex digital echocharge part82012301 is designed to charge auxiliary or starting batteries from an invertercharger or other charging source with limited voltage drop. The Xantrex echocharge detects when...

www.hodgesmarine.com

 

[Kenneth K]

Keith, or others,

I am considering adding an Echo-Charger as part of a solar install. To minimize solar wiring runs, the port solar panel will go to the house bank, and the starboard panel will go to the starting battery.

Do you know if the Echo Charger is dual-sensing? I.e., will it combine the banks if there is a charge voltage on either bank, or does it just look for a charge voltage (voltage sensing) on one bank?

With dual sensing, sufficient output from either panel would always hit both banks, even if the other panel wasn't generating any power.

 

[Bobby Steele]

We bought the 1000 Watt Jackety/100Watt panel last year. It’s worked very well for us on the Hudson River as far as being able to run music, microwave, induction stove, laptop, and phone charger at various times of day/ night. The only caveat is that the panel isn’t waterproof - so we do have to take it in after every use. We’ll eventually get mounted panels, but this works fine until we learn more about solar- charging the house batteries. Since we removed our head/tank and put in a composting head, we’re thinking the added space could eventually hold larger batteries

 

[Rocinante33]

Keith, or others,

I am considering adding an Echo-Charger as part of a solar install. To minimize solar wiring runs, the port solar panel will go to the house bank, and the starboard panel will go to the starting battery.

Do you know if the Echo Charger is dual-sensing? I.e., will it combine the banks if there is a charge voltage on either bank, or does it just look for a charge voltage (voltage sensing) on one bank?

With dual sensing, sufficient output from either panel would always hit both banks, even if the other panel wasn't generating any power.

Ken,

I don’t think that the Echo Charger can be dual sensing but wouldn’t that be more a function of your solar charge controller? I believe Maine Sail has written about it.

 

[Kenneth K]

Keith,

MaineSail did a great writeup about ACRs. From the gist of it, I got that an ACR/Echo-charger doesn't care whether the charging source is the engine, an AC charger, or solar--it just combines the battery banks when there is a charge current above battery voltage.

If this can be done with a solar charge controller (without an ACR), that would be even easier for me. I don't know enough about solar charge controllers to know if they can do that. I'm also assuming that two solar panels (one port, one starboard) requires two separate charge controllers.

 

[nquigley]

Keith,

MaineSail did a great writeup about ACRs. From the gist of it, I got that an ACR/Echo-charger doesn't care whether the charging source is the engine, an AC charger, or solar--it just combines the battery banks when there is a charge current above battery voltage.

If this can be done with a solar charge controller (without an ACR), that would be even easier for me. I don't know enough about solar charge controllers to know if they can do that. I'm also assuming that two solar panels (one port, one starboard) requires two separate charge controllers.

I don't know about ACRs, but I can report that my single Victron charge controller receives power from my two 100W panels, which are wired in parallel to minimize losses due to possible shading of one panel.

 

[Kenneth K]

I don't know about ACRs, but I can report that my single Victron charge controller receives power from my two 100W panels, which are wired in parallel to minimize losses due to possible shading of one panel.

Ok, that's what I need to know. Does the Victron manual describe how to wire it up like that? Did you get a 30A controller for 200W?

Also, where did you physically locate the controller (I have the same boat)?

 

[nquigley]

This is the controller I installed:

Amazon.com: Victron Energy SmartSolar MPPT 75V 15 amp 12/24-Volt Solar Charge Controller (Bluetooth): Industrial & Scientific

Buy Victron Energy SmartSolar MPPT 75V 15 amp 12/24-Volt Solar Charge Controller (Bluetooth): Energy Controllers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

My two 100W panels both feed into it.

This is the battery monitor I got (the next size up is is only needed for significantly larger panels and I don't have room for that much solar panel real estate - plus, the next size up has heat dissipation fins underneath it, which make it stand about a 1/2" off the mounting surface - I didn't want that 'look'):

https://www.amazon.com/Victron-BMV-712-Battery-Monitor-Black/dp/B07F3C7ZV7/ref=sr_1_3?dchild=1&keywords=victron%2Bbattery%2Bmonitor&qid=1615322301&s=industrial&sr=1-3&th=1

- it comes with the shunt (the temp probe is an additional, optional, item).

You have to think a little about how to wire the shunt in so that all outgoing power gets 'measured' by the shunt, but the monitor's handbook has good instructions. I was able to do this for everything except the windlass, but that's not a slow & steady drain on the batteries, which, I think, is what you most want to monitor.

Attached is a pic of where I mounted both units beside the DC distribution panel.
The solar panel wires came in through a waterproof gland on the outside of the port cockpit combing (which you can barely see in the stern view pic below), over the little bulkhead back there and above the zippered headlining into the top of the open cubby hole ... you can actually see a bit of them (red & black) in that cubby hole. From there, they went down into the space behind the little hinged cover I mounted the controller into.
The battery monitor's wiring goes down, though a 1" hole cut in the little ledge in the fiberglass liner, to the side of the battery box (you can reach this area from the inspection port at front-left of the battery box).
- the battery box pic below is a bit busy, but you can see where I mounted the shunt: the upper hole in the side of the battery box is for the windlass cables, but the hard-to-see hole below it is for the shunt<-->monitor wires (and the temp probe wires - which have the blue heat-shrink at the terminus seen near top left).

 

[Kenneth K]

Great pics Neil. A big help--thank you.

Just downloaded the 96 page Victron 75/15 manual (good thing the last 81 pages are all foreign-language).

Nice looking boat !

 

[Kenneth K]

Neil,

Where'd you get that great looking brass lamp in your first picture? Is it LED? I assume it's a straight-forward swap-out. As you probably know, the original Ericson ones are kind of flimsy. Several of mine will no longer hold the screws that screw into the sides.

 

[Geoff W.]

My solar charge controller, same boat, went on the aft bulkhead at the bottom of the port-aft lazarette, or right behind the bulkhead if you climb into the back of the quarterberth. It's up high enough that it doesn't encounter any water, and is pretty well protected from things in the lazarette itself by a canvas cover. This kept the wire run from the panels pretty short, and is nicely out of the way.

 

[Kenneth K]

My solar charge controller, same boat, went on the aft bulkhead at the bottom of the port-aft lazarette, or right behind the bulkhead if you climb into the back of the quarterberth. It's up high enough that it doesn't encounter any water, and is pretty well protected from things in the lazarette itself by a canvas cover. This kept the wire run from the panels pretty short, and is nicely out of the way.

Thanks. I'm finally taking on my solar installation. Had a long conversation with Renogy today about charge-controller/panel hook-up options. I think I'll post that in a separate blog. Wanted to talk to Victron, too, but can't find a US number--their Netherlands number would be 9 hours ahead time-wise, so I missed them.

Has anyone used or looked into Renogy's charge controllers?

 

[Filkee]

I have a Renogy Rover and two 160 watt panels.

 

[Kenneth K]

2×160 is a lot of Watts. Nice. Have Any pictures of where you put the controller? I like the display on the Renogy controllers.

Also, does the Bluetooth module add much when you can just read it off the display?