andybussell
Well-Known Member
My present 10W panel doesn't provide enough ooomph to keep my 2 domestic batteries charged. I want to upgrade to 20W, is there any reason why I should not just add another 10W panel feeding into the same regulator?
Solar panels
- Thread starter andybussell
- Start date
LadyInBed
Well-Known Member
No
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Quite acceptable
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Quite acceptable
vyv_cox
Well-Known Member
For panels as small as 10 W per battery you don't really need a regulator. Usual advice is that 10W counteracts the natural drain of a battery with nothing connected to it. It might be worth bypassing the regulator, which presumably has some drain of its own, and that might just be enough to keep two batteries up to maximum. Of course, if you have any other drain, such as the small connection to your radio that retains its memory, or a sensor on a bilge pump, then it won't.
Otherwise, yes just connect another in parallel.
Otherwise, yes just connect another in parallel.
andybussell
Well-Known Member
TVM, thought so.
andybussell
Well-Known Member
Thanks for the useful tip, as it happens I still will need the regulator because of factors you mention.
MonniotC
Well-Known Member
I have two batteries - one is 85ah leisure type, and the other is a small car battery from Halfords. I have 2 separate 10W panels - one is connected directly to the leisure battery and the other is connected directly to the car battery. I have just returned from checking the boat out for the first time since November. Both the batteries were fully charged and hunky dory. I previously had the panels wired to a regulator and split charger, and it never worked properly - I don't know why, but I do know that since I wired them up directly it is very effective.
My panels are horizontal, as the boat is on a swinging mooring. If you are on a pontoon you could angle the panels to get more output.
My panels are horizontal, as the boat is on a swinging mooring. If you are on a pontoon you could angle the panels to get more output.
saltwater_gypsy
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If you are not going to fit a regulater (re Vyv) it can be useful to fit a diode to prevent leakage from the battery via the solar cell at night. The solar cell is itself a diode but the "reverse current" in some panels can be significant. I know this from Scottish weather conditions where the good work from one day of sunshine was undone by a few dull days of leakage.
MonniotC
Well-Known Member
All the solar panels I have ever bought (all in the 3 to 10 watt range) came with an on-board diode pre-fitted. I agree that they are necessary, but they are usually pre-fitted. If you were to add another diode you would be introducing an unnecessary voltage drop, therefore reducing the usefulness of the set-up.
matelot
Well-Known Member
You're brave. Not checked the boat out since November and its on a swinging mooring!
gavin_lacey
Well-Known Member
Strongly advise bigger panels and regulator. NB Split charge diode will prevent effective charging. The voltage the panels recieve will always be insufficient unless you have a reulator with a separate battery voltage sensing wire, and even then it will not charge as well as if the split charge diode was bypassed.
William_H
Well-Known Member
Hello Andy your response to Vyv-Cox indicates you missed his meaning.
You should try the solar panel you have with no regulator. The reg. will waste a little power in itself while possibly limiting charge under some circumstances. The additional factors like radio memory waste or bilge pump make it more desirable to disconnect the regulator.
My experience is that the radio memory can be significant on a low power system.
But yes just add another panel in parallel with the existing one with or without the regulator. With more solar power especially in bright summer sun there is more reason to have the regulator.
Re splitter diodes. As in alternator regulators if the diodes are fitted between the reg and the batteries then the volt drop will kill proper charge.
Splitter diodes are great without a regulator especially if you can find the built in diode and fit an additional one so only one diode in series with charge for each battery. The one diode does the job of stopping reverse current in darkness and of isolating the batteries.
Other wise you need battery voltage sensing regulator, one with 2 outlets or 2 regulators and isolation diodes between the panel and the regs.
Usually with modest panel size and multiple batteries you won't need a reg. olewill
You should try the solar panel you have with no regulator. The reg. will waste a little power in itself while possibly limiting charge under some circumstances. The additional factors like radio memory waste or bilge pump make it more desirable to disconnect the regulator.
My experience is that the radio memory can be significant on a low power system.
But yes just add another panel in parallel with the existing one with or without the regulator. With more solar power especially in bright summer sun there is more reason to have the regulator.
Re splitter diodes. As in alternator regulators if the diodes are fitted between the reg and the batteries then the volt drop will kill proper charge.
Splitter diodes are great without a regulator especially if you can find the built in diode and fit an additional one so only one diode in series with charge for each battery. The one diode does the job of stopping reverse current in darkness and of isolating the batteries.
Other wise you need battery voltage sensing regulator, one with 2 outlets or 2 regulators and isolation diodes between the panel and the regs.
Usually with modest panel size and multiple batteries you won't need a reg. olewill
andybussell
Well-Known Member
Thanks William, yes I had missed the point, but will keep regulator as I have found that, for example, for my single engine battery (also charged by a 10W panel) I often see the regulator indicating battery fully charged which I suppose must mean that the regulator is doing it's job and protecting the battery from being overcharged?