can I wire new solar panel into 1/2/ both switch.

[Contest1]

New 100 ah batteries and 20w solar panel kit with 5amp controler.
Am trying to devise a simple charging fool(me)proof system.
Idealy I want the solar connected to the leisure.
To extend the service life I plan to rotate duty monthly,ie April 1 starter 2 leisire. May 2 starter 1 leisure via 1/2/both switch.
It ocures to me that if I can make the solar pannel connection at the switch I should be able to use the switch to direct the solar charge to the designated leisure battery, possibly to both for prolonged layups.
Any advice welcome.

 

[VicS]

New 100 ah batteries and 20w solar panel kit with 5amp controler.
Am trying to devise a simple charging fool(me)proof system.
Idealy I want the solar connected to the leisure.
To extend the service life I plan to rotate duty monthly,ie April 1 starter 2 leisire. May 2 starter 1 leisure via 1/2/both switch.
It ocures to me that if I can make the solar pannel connection at the switch I should be able to use the switch to direct the solar charge to the designated leisure battery, possibly to both for prolonged layups.
Any advice welcome.

If you connect to the "common" terminal of the 1,2,both switch you will be able to direct the solar charging to which ever battery you choose .... BUt it means the switch will be ON , defeating its use as an isolating switch.

A dual output solar controller would enable permanent direct connections to both batteries to be made with simultaneous charging of both.

Connecting via a double throw ( change over switch) to the two batteries would enable manual selection of the battery being charged.

A common solution would be to have a smaller battery as a starter battery, charged solely from the engine, and a large domestic battery to which the solar panel is connected to augment the charging from the engine

 

[pvb]

To extend the service life I plan to rotate duty monthly,ie April 1 starter 2 leisire. May 2 starter 1 leisure via 1/2/both switch.

This won't really extend the life at all. Your cheapest solution is just to use one battery for starting and the other for domestic, and wire the solar panel output direct to the domestic battery (with a fuse next to the battery).

 

[jac]

A common solution would be to have a smaller battery as a starter battery, charged solely from the engine, and a large domestic battery to which the solar panel is connected to augment the charging from the engine

Can see the logic of that for someone expecting to spend longish periods at anchor / living aboard. My only concern for that sort of arrangement for someone who just uses the boat at weekends is that although the domestic bank may start the weekend fully charged, you run the risk of the engine start battery becoming fully discharged and being unable to start the engine if the boat hasn't been used for a while. If your domestic bank will start the engine then no problem but if they are truly separate then might be worth wiring a small solar panel up to the engine battery to cope with self discharge and put back any shortfall. 5- 10w should be plenty.

 

[sailinglegend420]

....To extend the service life I plan to rotate duty monthly,ie April 1 starter 2 leisire. May 2 starter 1 leisure via 1/2/both switch.

I agree with pvb that rotating usage will not extend battery life. I would add that there are three good reasons why bigger is better with a leisure bank.

1) Doubling the service bank size means the life cycle is longer as the DoD is unlikely to fall so close to 50% so often.

2) Doubling the service bank size also means the “apparent capacity” is greater. Peukert’s law says that the apparent Ah size of a bank changes depending on the current draw. A lower discharge current gives a higher Ah capacity.

c) Doubling the service bank size also means it will be more efficient and accept more Ah more quickly from all charging sources during the absorption phase up to 80%.

 

[pvb]

I agree with pvb that rotating usage will not extend battery life. I would add that there are three good reasons why bigger is better with a leisure bank.

1) Doubling the service bank size means the life cycle is longer as the DoD is unlikely to fall so close to 50% so often.

2) Doubling the service bank size also means the “apparent capacity” is greater. Peukert’s law says that the apparent Ah size of a bank changes depending on the current draw. A lower discharge current gives a higher Ah capacity.

c) Doubling the service bank size also means it will be more efficient and accept more Ah more quickly from all charging sources during the absorption phase up to 80%.

Whilst all of that is true, the OP wasn't apparently planning to increase his domestic battery capacity.
.

 

[sailinglegend420]

....the OP wasn't apparently planning to increase his domestic battery capacity..

But he said one month he would have 2 starter bats and 1 leisure, and the next month 1 starter and 2 leisure - so every other month he is doubling his domestic battery capacity. Much better to stay all the time with 2 leisure bats and 1 starter.

 

[VicS]

But he said one month he would have 2 starter bats and 1 leisure, and the next month 1 starter and 2 leisure - so every other month he is doubling his domestic battery capacity. Much better to stay all the time with 2 leisure bats and 1 starter.

He'll clarify no doubt but I read his post to mean that he has two new identical batteries, each 100Ah, and that in one month he will use no1 as starter and no2 as domestic then the following month reverse their use so that no2 is the starter battery and no1 is the domestic battery.

 

[halcyon]

Idealy I want the solar connected to the leisure.

Fit a SPDT toggle switch above the 1, 2, both switch, connect bank 1 to one side, bank 2 the other, solar panel to centre, fit label with bank 1 and 2 to suit position.

You now set switch to setting 1, set 1, 2, both switch to position 1, you now charge and use the leisure bank. Next month set switch to position 2, and 1, 2, both to bank 2, the following month set toggle switch back to position 1. Each month change toggle switch and set 1, 2, both to that number.

Brian

 

[ghostlymoron]

As said previously, I would have a dedicated starter battery, this would not need to be an expensive leisure type battery but could be a normal car battery for a small diesel. You could then charge both your 100ah batteries and use them both for lights, instruments etc and charge them with your solar panel. In the unlikely event of your starter battery failing (it should hold it's charge for at least a month) you could always start the engine from the leisures via the 1-2-B switch. Personally, I would ditch the 1-2-both switch an fit an automatic system using a VSR. If you had a dual sensing type VSR, this could also keep your start battery topped up from the solar panel.
There's a good wiring diagram and advice here http://www.tb-training.co.uk/SYES.html#A Small Yacht Electrical System although it doesn't show solar.
Incidentally, i think your worrying un-necessarily about charging the start battery as the alternator will always do that within a few minutes of engine running.

 

[pvb]

He'll clarify no doubt but I read his post to mean that he has two new identical batteries, each 100Ah, and that in one month he will use no1 as starter and no2 as domestic then the following month reverse their use so that no2 is the starter battery and no1 is the domestic battery.

Yes, that's exactly as I read it.

 

[rogerthebodger]

A dual output solar controller would enable permanent direct connections to both batteries to be made with simultaneous charging of both.

I'm with Vic on this. when you come onto the boat all batteries will be charged. The you just select the domestic battery you with to use for the time on the boat.

the most used battery will automatically that the most charge.

No switches no remembering which battery to connect solar panel to no flat batteries.

I have a similar setup but with mush bigger solar panel battery setup

I initially had 3 banks of batteries engine start and 2 domestic as one bank was new and the other 6 years old. last year I replaced to old bank with but now treat then as a single bank thus reducing the depth of charge and thus hopefully a longer battery life

I still have the 1 2 both so when they of off the banks are separate but when in use the switch is in the both position.

Engine battery has it own switch and own solar panel / regulator.

 

[Contest1]

He'll clarify no doubt but I read his post to mean that he has two new identical batteries, each 100Ah, and that in one month he will use no1 as starter and no2 as domestic then the following month reverse their use so that no2 is the starter battery and no1 is the domestic battery.

Correct, sorry if my post misled.
Seems my plan would work but not realy likely to increas battery life.
Back to the drawing board.

 

[William_H]

Ghostly moron suggested using a VSR to connect the domestic battery to starter battery when it is being charged. However a solar panel may not raise the battery voltage enough with 20w panel to activate the VSR. (an engine alternator or battery charger will of course)
What I would do is ditch the regulator and fit diodes from solar panel +ve to all batteries. One diode for each battery. This will ensure all abtteries are charged to the same voltage. 200 AH of batteries are unlikely to be harmed by all the charge from a 20w panel.
Or as said get a duel output regulator. Don't try to use diodes after the regulator as this will just limit regulated voltage. Although that might not matter so much as panel is not likely to go into regulation. (UK sun) good luck olewill

 

[sailinglegend420]

Correct, sorry if my post misled.
Seems my plan would work but not realy likely to increas battery life.
Back to the drawing board.

Sorry I misread your post.

My 140 watt panels sometimes didn't give enough power to close my VSR causing chatter - repeated on/off cycling. My Split Charging solution now is a separate 10 watt solar panel for my 37 Ah Red Flash AGM starter battery which only starts the engine, it never gets any other charging source. The 140 watt panels go directly to the house batteries, as do the alternator and shorepower. An emergency parallel switch will charge the starter battery if it gets low.

 

[Contest1]

Sorry I misread your post.

My 140 watt panels sometimes didn't give enough power to close my VSR causing chatter - repeated on/off cycling. My Split Charging solution now is a separate 10 watt solar panel for my 37 Ah Red Flash AGM starter battery which only starts the engine, it never gets any other charging source. The 140 watt panels go directly to the house batteries, as do the alternator and shorepower. An emergency parallel switch will charge the starter battery if it gets low.

Funnily enough I have a spare battery that I,v used to start the engine when the old batteries began to give trouble.
In hope the 20w panel will match the natural discharge of the leisure, but maybe it will have a positive effect on battery life if I go for the 200ah leisure bank option with the gel as a dedicared starter charged of the engine .
Generaly don,t have access to shore power but plan to use my Ring 16amp smart charget from the Sip generator for charging in general on this years hopefuly longer cruises now I,m free from the 9 to 5.

 

[Stemar]

Another possibility to consider is a dual battery controller. I got one of these: http://www.sunstore.co.uk/EP-Solar-Duo-Battery-Solar-Charge-Controller-12-24v-10A.html and it's set to give 90% of the output from my panels to the starter battery and 10% to the domestic until the starter is full then everything goes to the domestic.

I haven't had the setup long, but it does seem to be doing what it says on the tin. Not bad for change from £30.

 

[ghostlymoron]

Sorry I misread your post.

My 140 watt panels sometimes didn't give enough power to close my VSR causing chatter - repeated on/off cycling. My Split Charging solution now is a separate 10 watt solar panel for my 37 Ah Red Flash AGM starter battery which only starts the engine, it never gets any other charging source. The 140 watt panels go directly to the house batteries, as do the alternator and shorepower. An emergency parallel switch will charge the starter battery if it gets low.

If your Red Flash is connected conventionally to the alternator and starter via a common wire, it'll get some charge back from the alternator every time you start and run the engine unless your alternator is seperated from the starter. Can't tell without knowing your wiring details.

 

[contessaman]

if I read you right you have a total of 2x 100ah batteries and a 20watt panel?

what you need is the K.I.S.S principle!

just split your panels output through a pair of diodes and hardwire to both batteries. dont bother with the regulator. the current will go to the battery with the lowest voltage and the output of that little panel will not do any harm. its absolute maximum output is 1.6 amps. in reality in the uk over a 24hour period you will be very lucky to get half an amp. in reality much less than that. split over 200ah of battery thats never going to boil your batteries. the fact that all '12v' panels actually have an open cct voltage of 16-20v means the voltage drop of the diodes will not be prohibative. If by some miracle we get a summer heatwave and you are concerned about overcharging then just obscure part of the panel or angle it north. of course, if the wx is good you are probably on your boat a lot and using the power anyway. trust me. 2 diodes, 2 fuses, get sailing.