Battery charging issues

Maine Sail · Oct 23, 2013

Kordie said:
Anyone here use solar to charge their batteries?

Anyone using the emarine e20 solar and wind regulator?

I can't seem to get my batteries charged above 70%. 12.3 VDC to be exact. Drops down to 11.something by morning just running the fridge.

New batteries. 3 x 4D installed about 6 months ago. Spoke to the emarine folks. They are confident their product is working ok. They suggest it is either my batteries or wiring.

I can't use shore power or I'd use that to charge the batteries and maybe isolate the fault. Problem I have is I am in El Salvador and can't easily get a tradesman in to take a look.

Has anyone experienced something similar or have any suggestions for me?

Thanks team

Simon

Simon,

This sounds like a simple Ah's in vs. Ah;s out situation and it appears as if you are using more than you are putting back in.

We really need a lot more info to help.

# of panels
wattage
panel brand
panel model
Panel location eg: bimini, dodger, on deck etc..
wire size from panels to controller
series or parallel connection of the panels
how are you tracking Ah consumption
How many Ah's per day do you use
what is the peak amperage output you've measured from the panels
where is the controller connected to the battery wiring

Etc.....

waternwaves · Oct 23, 2013

I don't mean to be unenlightened........or cover too much old ground....

But what kind of battery isolator do you have and which side of the isolator (Diode or relay type) is the charging circuit connected to?

And as Maine points out........one really has to know what the real circuit is and all of the components to understand what is going on.

Maine Sail · Oct 23, 2013

Kordie said:
I have two Kyocera 140w panels mounted on my arch. Also have a wind turbine. But not running due to a sheltered spot here.

Standard cable from panels that came with the panels. Series set up. I couldn't tell you the gauge but it isn't big like the #6 wire used to the batteries which is 6 gauge from charger to batteries.

I haven't a record of my consumption. But today I was only running my fridge and seeing up to 17 amps charging voltage for much of the day yet the battery voltage dropped through the day. This makes no sense to me at all. Checking all battery cabling and making sure all terminals are tight as buggery.

If I run my watermaker I see 20amps into my batteries. That is the highest the controller allows. The watermaker uses about this so I can make water during the day.

I am wondering if indeed it is a simple matter of not enough AH in. That means more panels and a new controller as mine is just rated to 300w from the solar panels. I'm really not using much power. Fridge, stereo, and autopilot when under way. Maybe charging an iPad or laptop now and then. Interior and nav lights are all LED.

If you were seeing 17A for most of the day, which would be very stellar performance for two KC140's, even with MPPT, and the battery voltage was dropping, then your loads on the system simply exceed your charging capability. Also panels wired in series, then mounted below a wind gen, can cause lower than optimal charging output because when one panel gets shaded it can drastically affect the output of both panels. Running the panels in parallel might cut down on any shading issues you may be having and actually give you more output per day, if shading is an issue. With a boat swinging on anchor and a wind gen above the panels then it is likely shading will be an issue.

If I had to put a number on it I would say two KC140's can do about 60 to 80Ah's per day on average. If lucky on a very good day you may exceed 90Ah's but this would be stellar performance. I have a single 140 on my own boat so know its capabilities pretty well. In summer our insolation numbers are not far off yours this time of year in Baja.. If your loads exceed this, pretty easy with a water maker and fridge, then you are steadily depleting the batteries.. Remember your loads are 24 hours per day but your solar charging is only about 5-6 good hours of performance.

Do you have a battery monitor or an ammeter to measure your DC loads not just to see what is coming in on the e20??

Also please keep in mind that "loaded" or un-rested voltage readings do not translate to actual SOC unless you've physically graphed it for a given load. have you tried to get a resting voltage reading?

Stu Jackson · Oct 23, 2013

Maine Sail knows what he's talking about when it comes to thsoe panels,. so if you're only getting 60-90 ah per day out of them and you have a fridge, unless it's a super low draw fridge, most folks will budget at least 100 ah per day OUT (fridge, lights, other loads).

Bill1565 · Oct 24, 2013

Stu Jackson said:
Maine Sail knows what he's talking about when it comes to thsoe panels,. so if you're only getting 60-90 ah per day out of them and you have a fridge, unless it's a super low draw fridge, most folks will budget at least 100 ah per day OUT (fridge, lights, other loads).

I agree with Stu. I budget 125 for fridge and stuff, no water maker. If water maker draws 20 amps, that will mess up the AH Used since the heavy draw far exceeds the 20 hour rating. First thing I think you need is a victron battery monitor.

Maine Sail · Oct 24, 2013

Bill1565 said:
I agree with Stu. I budget 125 for fridge and stuff, no water maker. If water maker draws 20 amps, that will mess up the AH Used since the heavy draw far exceeds the 20 hour rating. First thing I think you need is a victron battery monitor.

With three 4D's he may be okay unless other loads are also running. If we assume 160Ah for each 4D (could be as high as 210 if Lifeline AGM) then he would have 480Ah's..

On the low end:
480 Ah / 20 = 24A @ 20 hour rate
(when you exceed a 24A load on this bank you will get less Ah capacity out of it)

On the high end:
630 Ah / 20 = 31.5A @ 20 hour rate
(when you exceed a 31.5A load on this bank you will get less Ah capacity out of it)

However it seems he only uses the water maker when solar is active, which would keep him well below the 20 hour rate, but when the water maker is on he is no longer "charging" as it likely exceeds the charging the panels can provide. So if he ran the water maker an hour a day at 24A he looses over an hours worth of solar charging...

Course we don't know whether he uses a 12V DC water maker or a 120V AC and inverts it. We also don't know what brand either. Most who run a water maker do so with the engine or genset running as water makers can be LOUD and the current used pretty high.... This can make a big difference in Ah consumption and they rarely if ever match the manufacturers "ideal condition" specs...

Bill1565 · Oct 24, 2013

Maine Sail said:
With three 4D's he may be okay unless other loads are also running. If we assume 160Ah for each 4D (could be as high as 210 if Lifeline AGM) then he would have 480Ah's.. On the low end: 480 Ah / 20 = 24A @ 20 hour rate (when you exceed a 24A load on this bank you will get less Ah capacity out of it) On the high end: 630 Ah / 20 = 31.5A @ 20 hour rate (when you exceed a 31.5A load on this bank you will get less Ah capacity out of it) However it seems he only uses the water maker when solar is active, which would keep him well below the 20 hour rate, but when the water maker is on he is no longer "charging" as it likely exceeds the charging the panels can provide. So if he ran the water maker an hour a day at 24A he looses over an hours worth of solar charging....

Major loss of solar power if he only gets 5 or 6 hours a day at full charging rate

Maine Sail · Oct 24, 2013

Bill1565 said:
Major loss of solar power if he only gets 5 or 6 hours a day at full charging rate

Not at all. I have tracked power output on lots of solar installs on boats. I own & purchased the recording equipment to do this specifically because solar is a huge part of my business and I like to be able to tell my customers exactly what they can expect "on-average".....

I was even able to track the performance of a large Solbian install In Puerto Rico. It averaged about 4.25 to 5.25 hours per day at full output when tracked over 6 days with no bad weather and no shading..

Marine installs are not the same as on land because they can't be permanently oriented at the perfect sun angles. 5-6 hours is tremendous performance, at full output, for a boat with flat mounted panels. If you can manually articulate, then you can get more output, but on anchor this is difficult at best and if not paying constant attention you can lose more than you gain when the boat "sails" at anchor. Here in the Northeast it translates to 3.5-5 hours max per day at full panel output even with MPPT.

This does not mean the panels won't begin producing early and finish off late in the day it just means that when you take the actual Ah's the panels produced during sun up hours, per day, then divide by the panels max potential you wind up at the "average" for your area of what teh panels can produce at "full output"....

On boats this average per day at full output is considerbaly less than land based installations because the panels are mounted in a compromise position.

Different areas of the world have different insolation numbers but I was comparing an insolation number from Baja in late October to what we see here in June which is darn similar.... His performance this time of year should be very similar to ours in June/July...