walter
New member
could anybody please advise me if it is possible to split the charge off one 10watt solar panel and charge 2 batteries through one regulator
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solar panel
- Thread starter walter
- Start date
Gunfleet
New member
solar panel supplementary
I don't see why you'd need a regulator at all unless the two batteries were tiny. According to all the stuff I read if the charger output is less that 1.5 per cent of the battery rating in amps you don't need a regulator. I bought a 32W panel on this basis - 2 amps max on a sunny day is less than 1 per cent of my battery rating.
HERE'S THE TRICKY BIT which I can't work out. I have two batteries. Each goes to the one/both/off switch. They have a common negative connection to the engine block. How do I wire the solar panel so that I don't inadvertantly allow each battery to drain into the other? Obviously the panel has to be connected full time, so it needs to be connected to both. Equally obviously if I made the connection to both from the higher potential side of the solar panel I have now made a circuit (because the negative side is already connected). The best compromise I can come up with so far is to connect it to the common on the one both off switch and then take turns leaving the switch made to one or the other battery. As the batteries are 110 amps each and the panel's output is 2 amps max I reckon I'm still unlikely to boil the battery. But I'd really like to connect it to both. Won't some passing electrical expert take pity?
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I don't see why you'd need a regulator at all unless the two batteries were tiny. According to all the stuff I read if the charger output is less that 1.5 per cent of the battery rating in amps you don't need a regulator. I bought a 32W panel on this basis - 2 amps max on a sunny day is less than 1 per cent of my battery rating.
HERE'S THE TRICKY BIT which I can't work out. I have two batteries. Each goes to the one/both/off switch. They have a common negative connection to the engine block. How do I wire the solar panel so that I don't inadvertantly allow each battery to drain into the other? Obviously the panel has to be connected full time, so it needs to be connected to both. Equally obviously if I made the connection to both from the higher potential side of the solar panel I have now made a circuit (because the negative side is already connected). The best compromise I can come up with so far is to connect it to the common on the one both off switch and then take turns leaving the switch made to one or the other battery. As the batteries are 110 amps each and the panel's output is 2 amps max I reckon I'm still unlikely to boil the battery. But I'd really like to connect it to both. Won't some passing electrical expert take pity?
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hylas
New member
Re: Blocking Diodes
The answer is very simple.. you need two different POSITIVE wires comming from the solar pannel: one for each battery and you MUST insert a Blocking diode (connected in the right way) into each wire.. Then the current can flow from the solar pannel to the batteries but NOT from one batterie to the other...
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The answer is very simple.. you need two different POSITIVE wires comming from the solar pannel: one for each battery and you MUST insert a Blocking diode (connected in the right way) into each wire.. Then the current can flow from the solar pannel to the batteries but NOT from one batterie to the other...
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Juggler7823
Member
Re: Blocking Diodes
I do not profess to be an electronics expert but I do not understand this message and thread at all. Surely you can connect the positive wire from the panel onto 2 diodes and split from there onto the 2 batteries.
Besides, aren't the cells in the panels diodes? Sharing charge in the batteries implies current flowing back up the positive wire. This would reverse bias the diodes cells and therefore not happen.
Perhaps an expert out there in cyberland give an opinion.
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I do not profess to be an electronics expert but I do not understand this message and thread at all. Surely you can connect the positive wire from the panel onto 2 diodes and split from there onto the 2 batteries.
Besides, aren't the cells in the panels diodes? Sharing charge in the batteries implies current flowing back up the positive wire. This would reverse bias the diodes cells and therefore not happen.
Perhaps an expert out there in cyberland give an opinion.
<hr width=100% size=1>LOM
vyv_cox
Well-known member
Have a look <A target="_blank" HREF=http://www.sunware.de/US/Products/Regulators/Regulators.htm>here</A>. This is the equipment I have, or actually mine is an older version. It decides which battery needs the charge and directs it there. Not expensive and has been totally reliable for 6-7 years. Keeps all batteries well up (2 x 105 Ah domestic, 1 x 105 Ah starting, 38 W panel.) It also displays voltage per battery and current coming from the panel.
However, a 10 Watt panel seems a little small to be needing this equipment. It seems to be accepted that up to this output there is no need for regulation.
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However, a 10 Watt panel seems a little small to be needing this equipment. It seems to be accepted that up to this output there is no need for regulation.
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Evadne
Active member
Re: Blocking Diodes
I think you'll find if you try and draw it out that you are both talking about the same set-up. Whether you take one one wire and split it or split it at source is irrelevant. It is the presence of the blocking diodes that is important.
It is also easier if you ignore the physics of how the solar panel works and treat it as a current source, and the battery as a current storage device (capacitor).
Some simple folk like me find it easier to explain electrics by an analogue with plumbing: If you replace pressure with voltage, flow with current and resistance with ... well, resistance you have a source with an open valve (solar panel) connected by a pipe to two reservoirs. If one reservoir is fuller than the other then water (current) will flow to the lower one, which is not always desirable. If you connect the source through a one-way valve to each reservoir, than neither can drain the other, even if the pressure in the source drops below the pressure in the reservoir(s). It's amazing just how far you can push this metaphor.
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I think you'll find if you try and draw it out that you are both talking about the same set-up. Whether you take one one wire and split it or split it at source is irrelevant. It is the presence of the blocking diodes that is important.
It is also easier if you ignore the physics of how the solar panel works and treat it as a current source, and the battery as a current storage device (capacitor).
Some simple folk like me find it easier to explain electrics by an analogue with plumbing: If you replace pressure with voltage, flow with current and resistance with ... well, resistance you have a source with an open valve (solar panel) connected by a pipe to two reservoirs. If one reservoir is fuller than the other then water (current) will flow to the lower one, which is not always desirable. If you connect the source through a one-way valve to each reservoir, than neither can drain the other, even if the pressure in the source drops below the pressure in the reservoir(s). It's amazing just how far you can push this metaphor.
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VicS
Well-known member
To my mind the replies to this question so far could be very confusing to someone unsure of whats involved.
Two issues have cropped up
Firstly a regulator. With a panel as small as 10watts a regulator ie a device to control the charging rate and prevent "overcharging" is not necessary (unless you have some exceptionally small batteries)
Secondly a split charge system allowing both batteries to be charged together but without the problems that might result from them being connected together in parallel. This requires a pair of blocking diodes, one in the +ve feed to each battery.
If the panel has been supplied for battery charging it will probably already have a diode fitted to prevent a small discharge back through the panel in 'no light' conditions. I would leave this and add the pair mentioned above in addition because the no-load votage from the panel will be sufficiently high to overcome the effects of the additional voltage drop. Of course if you are desparate to squeeze the maximum out of the system then you can do away with it.
Make the connections directly to the battery +ves (and the -ve) so that the charging continues even when the isolator swich is off but do so via fuses in the +ve connctions as close to the batteries as possible to protect the wiring. Only small fuses are needed, 2amps perhaps.
Finally my only reservation is that 10watts may be a little on the low side especially if you have largish batteries. Consider 2 panels, one for each battery!!
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Two issues have cropped up
Firstly a regulator. With a panel as small as 10watts a regulator ie a device to control the charging rate and prevent "overcharging" is not necessary (unless you have some exceptionally small batteries)
Secondly a split charge system allowing both batteries to be charged together but without the problems that might result from them being connected together in parallel. This requires a pair of blocking diodes, one in the +ve feed to each battery.
If the panel has been supplied for battery charging it will probably already have a diode fitted to prevent a small discharge back through the panel in 'no light' conditions. I would leave this and add the pair mentioned above in addition because the no-load votage from the panel will be sufficiently high to overcome the effects of the additional voltage drop. Of course if you are desparate to squeeze the maximum out of the system then you can do away with it.
Make the connections directly to the battery +ves (and the -ve) so that the charging continues even when the isolator swich is off but do so via fuses in the +ve connctions as close to the batteries as possible to protect the wiring. Only small fuses are needed, 2amps perhaps.
Finally my only reservation is that 10watts may be a little on the low side especially if you have largish batteries. Consider 2 panels, one for each battery!!
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