Solar Charge Setup

[Kokonut]

Hi all, I'm delving into the electronics of the boat and wish to outline what I currently have. I'm not sure if things are working as they should or if it is set up correctly, can anyone offer any word of advice please?

I know ziltch about this topic, and it was even my 1st time using a multimeter. The batteries are BOSCH High Cycle Marine (dated as purchased Sept 2019), and the numbers on them read:

M4
HCM24-600
12V 115RC 65AH
600 CCA (BCI/SAE)

750 MCA (BCI/SAE)
0 092 S47 057 +HHO


1. I have 3 x Solar Panels (A,B, and C).
2. I have 2 x Batteries (X and Y).
3. Panel A connects directly to Battery X.
4. Panel A on a cloudy day has a reading of 15.0v
5. Battery X reads 12.1v

6. Panel B reads 15.0v
7. Panel C reads 19.5v
8. Panels B and C connects to a Solar Regulator that has 20A written on it.
9. The Regulator output wires read 18.2v
10. The Regulator output is connected to Battery Y.
11. Battery Y reads 13.5v.

i. Do these readings look ok, and what one would expect?
ii. Should I connect Solar Panel A to the current Regulator and wire the output to both batteries? or,
iii. Should I buy another Regulator and connect Panel A to it, and then wire this to Battery X.

The Solar Regulator has 2 terminals for input from the Solar Panels (+/-), and 2 output terminals for the battery (+/-).

Do I need to discharge the Batteries at some point and recharge them, or what is the maintenance for these?

Thank you in advance.

[Pete7]

I think you have a bit of steep learning curve ahead over the next couple of weeks but nothing the forum can't help with. Lets start with quick reminder of the boat, this one I presume:

Pete

[Pete7]

So the first thing you need to do is disconnect panel A from battery X, immediately, that's right now.

Why? well until we establish what else is going on there is a very good chance the you will destroy battery X in short order by over charging it at 15v, if it isn't too late. So take the wire off now please.

Turning to the batteries, they look like sealed lead acid (SLA) and a form type of GP24. The only thing "Bosch" about them is probably the stick on label. The words "high cycle marine" on the label is marketing nonsense. They are ordinary engine starting batteries with a total capacity of 80AH and nothing special.

Since they were new in Sep 19, lets roll with what you have for now and perhaps choose a better quality battery next time around in 3 years time. However, you do need to know what the absorption and float voltages are for these batteries, so please ask the supplier and insist he gets it right rather than guessing. This is also urgent!

So some questions need answering before the forum can really help.

1. How do you intend to use these batteries? one for engine starting and one as the house battery for domestics like lights?

2. How are they wired up? are they joined together or separate but with a rotary swith with 1 /2 / both / off type of options?

3. What electrical items do you intend to run from the batteries?

4. What are the max voltage and ampherage of the solar panels? There will be a label on the back, post an image if you can.

5. What is the make and model of the solar controller for panels B and C?

6. Finally you are going to need a book. This will do for a start whilst your waiting for a book to arrive.

https://www.boats.com/resources/12-v...s-for-boaters/

However, This will be invaluable for you, just buy it.

https://www.amazon.co.uk/Boatowners-.../dp/0713672269

[sailorboy1]

Either the way you wrote the info or my understanding of it is way wrong. Seems a LOT of voltage drop going on.

What size are the panels? What size are the wires?

[tkeithlu]

Nigel Calder's "Mechanical and Electrical Manual" is a good starting point for understanding your boat, and is quite readable. But let's start at the real beginning. Never put your multimeter, set for ohms, across a voltage.

[Captain Bill]

It looks tome like you have some serious wiring problems. For instance your regulator output at 18.2 volts and Battery y at 13.5volts indicates a very serious voltage drop. Voltage read at the battery posts should be very close to the regulator output voltage. The regulator output fora 12v charging system should never get to 18.2V. The maximum output voltage should be only around 15.5 and that is if it is in equalize mode. In normal operation it should never exceed 14.8 volts if you have lead acid batteries. Some advanced chargers have voltage sensors attached to the battery posts and will up their output voltage at the regulator posts to achieve the target voltage at the battery. If you have one of these then that indicated you have a very bad wiring problem between the charge regulator and the battery. The difference in Panel B and C could be due to shading. If you are measuring the voltage with the panels disconnected. If there's no difference in shading and you are measuring the voltage with the panels connected you again have a serious wiring problem. Panels connected in parallel should show the same voltage. One may be putting out more amperage based on shading but the voltage should be the same. 19.5 volts on a 12V panel is probably open circuit voltage which it should be if the panel is disconnected from the battery. It is also a reasonable voltage if the regulator is putting out 18.2V. 15V from Panel B would seem to indicate that it is connected to the battery with Panel A rather than the regulator with panel C. As noted before panels connected in parallel should show the same voltage which panels A and B do.



If we assume that Panels A and B are connected together and Battery X is at 12.1 V then the wiring between these panels and the batteries has an issue. The voltage at unregulated solar panels should be just slightly above the battery voltage or around 12.5 V on a battery reading 12.1v. This could be the result of wires that are too small for the length of the run or high resistance connections. Either way your battery isn't getting much of a charge.



Your batteries are not charged. The battery reading 12.1 v is significantly discharged. The 13.5v battery while still being charged has a significant way to go before being fully charged. With a regulator in place the battery will need to be at about 14.6 volts for a couple of hours before being considered fully charged. Given the apparent wiring issues you seem to be manifesting you probably cannot get these batteries to full charge, so there is definitely no need to discharge them, they are already discharged.

[Kokonut]

Wow, that's why I love this forum, and @Pete7 I'm really impressed how you connected the correct boat to me.

It's nearing darkness here, and so I will absorb the valuable feedback and get back with pics and/or answers if one's were asked.

Thank you so much, once again.

@tkeithlu, I had only just purchased "Replacing Your Boat's Electrical System (Adlard Coles Manuals)" by Mike Westin, that I'm hoping will furnish me with some knowledge.

I'm wondering if whoever originally setup the electrics did so, so wrong because almost every wire is cut that is connected to lights, etc. In fact, as far as I can see, only the bilge works (hard wired to the battery), and obviously the starter motor.

[Kokonut]

Just a refresher, and new readings from this morning.


1. I have 3 x Solar Panels (A,B, and C).
2. I have 2 x Batteries (X and Y).

------------------------------------------

3. Panel A connects directly to Battery X.
4. Panel A reads 17.2v
5. Battery X reads 12.0v

Panel A is now no longer connected to Battery X.

------------------------------------------
6. Panel B reads 1 (the meter displays around 12v then almost immediately drops to 1 everytime)
7. Panel C reads 19.9v
8. Panels B and C wires are joined before it is connected to the Solar Regulator that has 20A written on it.
9. The Regulator output wires read 14.5v
10. The Regulator is connected to Battery Y.
11. Battery Y reads 12.8v.



ANSWERS to earlier questions:
1. I'm hoping to use 1 battery for the Engine Starter, and the other for the house battery.
2. I have uploaded a pic that shows how the 2 batteries are connected, along with the Rotary Switch.

3. Intended Electrical items to be used on the boat:

VHF radio, Lights (interior, NAV + Anchor, Search light), Horn, Phone charging, Small Fridge, Fan, 3 x Bilge Pumps, Guages (fuel, power, etc), Laptop (or desktop computer), Electric Winch (maybe), Electric Toilet (maybe).

4. Image of Solar Panels uploaded.
5. Image of Solar Regulator uploaded.
6. Size of Solar Panels 37cm x 40cm. Regarding the size of the wire, do I just measure the thickness of the wire covering?
7. I have sent an inquiry to Bosch to provide the Absorption and Float Voltages for the Battery. Waiting for a reply.



In acquiring the reading for the battery, is it ok to place the Multimeter probes on the terminals that have nothing fixed on them, or do I need to disconnect everything from the battery, for a reading?

[tkeithlu]

Panel B is more than suspect, if connecting it to a multimeter drags it down to one volt. Multimeters use minimal current. That's a lot of house use on one battery being charged by (it appears) one panel. No, you measure the conductor inside the insulation, but with a little practice, you will be able to recognize 12 gauge versus bigger and smaller.

[tkeithlu]

You'll get quite adequate voltage readings by turning off the things that the battery uses. The second level is the battery capacity test. There are very expensive and very sophisticatd tools for this, but a simple resistance battery tester from an auto parts store will do for rough work. You connect it across the battery with big clips like booster cables, apply the resistance for ten seconds, it gets hot, and you see how much the voltage drops. They are conveniently marked with "OK," "Weak," and "Bad."

Putting permanent voltage gauges on your panel for your two batteries is worthwhile; they are cheap and let you keep track of your two batteries, particularly given your having a lot on a single battery and using solar charging. I use analog gauges for batteries and for AC, each with a small rotary switch (NOT the big battery chooser type!) that lets me check each of four batteries/banks, and three sources of AC.

Oh. A separate unused small battery under the panel is a wonderful backup. Batteries are usually mounted low, for obvious reasons. So, you take on water and flood them. BAM! Ouch! No batteries to power the VHF to call for help, or the GPS that powers your MMSI information.

[Pete7]

Originally Posted by tkeithlu

Panel B is more than suspect, if connecting it to a multimeter drags it down to one volt. Multimeters use minimal current. That's a lot of house use on one battery being charged by (it appears) one panel. No, you measure the conductor inside the insulation, but with a little practice, you will be able to recognize 12 gauge versus bigger and smaller.

Agree with Tkeithlu, so I would take panel B out of the circuit, do one more test completely disconnected and if no improvement and skip it.

Next use panel A after checking it works to fill the space and join up with panel C to charge the house bank of two batteries. Use the other as the engine start battery but it probably doesn't need a solar panel just to start the engine if you use the engine regularly.

Next step then is to trace and draw out the battery wires so that one position on the switch is to the engine start battery and the other position is to the house bank. There will also be an off and both options. Use something so that this is permanently recorded near the switch so you never forget or anyone else on board can see the difference, dymo tape?

The solar control doesn't look up to much and there are better. However more worrying, you only have two small 15w solar panels equaling 30w in good conditions. So that is 2AH tops and won't run your electrical needs without daily engine charging or shore power. At best they will keep the batteries topped up and allow the use of a light.

As Tkeithlu suggested fit a permanent voltmeter (or battery monitor) and don't discharge those batteries much below 12.2 - 12v if you want them to last.

This would be nice if the budget allows:

https://www.12voltplanet.co.uk/victr...tterybank.html

There are cheaper makes on e bay (£22), indeed I have a cheep one just to measure the fridge consumption.

Your solar controller looks like a simple on / off type which isn't great and may not have much adjustment to vary the battery charging voltages. Do a search on CF to learn about the differences particularly with PWM and MPPT solar controllers. That or surf You tube.

[Pete7]

Looking to the future to give you some ideas, we had a similar requirement including fridge, laptops, tv and diesel air heating etc and a similar sized battery bank (170AH in total).

During the UK summer at 50N in good sunny conditions our 150w plus a 30w panel will supply all our daily needs. In partial cloudy conditions we can survive two days okay, but in heavy overcast cloud and rain by day 3, I need to run the engine or plug into shore power. We also have a folding portable 110w panel which we move around the boat during the day to face the sun which is useful in cloudy weather or if we run the slow cooker.

During the depths of winter, no chance of those panels doing much more than keeping the batteries topped up and supplying occasional power for lights.

The 30w has just failed after 2.5 years with delamination, so I removed it last weekend. It looked suspiciously like yours.

I am considering upgrading to 300w of solar to assist with cloudy weather and because we have now fitted a small freezer. These run through MPPT controllers which maximise the power compared to PWM or simple on / off controllers.

Pete

[Kokonut]

Hi all, thank you everyone for the feedback.

Well, given the answers and reading between the line on some replies, I decided to buy a 20A MPPT Solar Charge Controller, and a 100W Solar Panel, to replace the existing system.

I was advised that 200W of Solar Panel would be better, but my budget didn't allow me to extend myself for now. I'm assuming that I can get another 100W panel later and wire this up to the Controller. I may just leave the 2 x 15W Solar Panels connected, so I have 130W.

I'm guessing that I need to join the Solar Panels in a Series, so that only 2 x wires find their way to the Controller.

Also, I have 2 x 12V Bosch Batteries High Cycle Marine HCM24-600 M4, does anyone know if they are Sealed, Gel or Flooded because I can't see that written anywhere on the case?

[Kokonut]

Please refer to the attached diagram.

With everyone's help (big thank you) along with some reading from external sources I think I have the wiring of the batteries (parallel connection) worked out, and also where the Solar Controller connects to, on the batteries.

I am now confused on whether this changes when adding a dual switch to separate the batteries, one battery for the lights, etc, and the other battery for the Starter Engine.


Would someone kindly refer to the diagram and let me know where each circled number connects to the corresponding circled number?

[Pete7]

For now I would suggest you keep it simple (KISS) with both batteries wired in parallel or if they are already connected to the rotary battery switch, great use the "both" option. However, fit something like this to easily monitor the voltage and Ah going in and out of the batteries:

https://www.ebay.co.uk/itm/UK-30A-30...72.m2749.l2649

Now for the reason why I think you should keep the batteries paralleled. Since you don't want to use the batteries below 50% depth of discharge (DoD) or you risk shortening there lives, a single battery for the house and another for the engine will only give you a very small capacity for living on board. If you keep them in parallel they you have twice the capacity (Ah) before reaching 50%. If you dip under 50% then don't panic but do make sure they are fully charged up again quickly.

The down side is if you don't monitor closely then you may discharge to a point the engine won't start. Then your stuffed, hence the cheap battery monitor.

In the future when funds allow, you can add one more battery for engine starting and have the 2 Bosch batteries for a house bank.

Just be aware of one problem with some makes of rotary battery switches. If the engine is running and therefore charging, if you turn that switch there may be a point were neither battery is electrically connected to the alternator for a brief period of time. This is all it will take to destroy the diodes in the alternator, it's instant and fatal requiring an alternator rebuild to fix. So if the engine is running don't touch the battery rotary switch, ever.