numpty solar panel question

[Sammy Lou]

Help needed from anyone who has good knowledge of solar panel specification/installation.

My drying pontoon berth does not have shore power & I don't really need it but I would like to make sure that my batteries are topped up whilst I'm away from the boat during the week.
My intention is to mount a solar panel on the coach roof & more than watts the limiting factor is space - of which I have 800mm x 550mm available. Therefore it appears a 50W panel would be a good fit.

My current set up is two 110ah batteries (domestic/starter) charged via VSR from engine & a sterling charger for shore power (if/when available). All works well but I'd appreciate opinion on weather the following panel and charge controller (1) would work with my set up & (2) are worthless ebay tat that should be avoided at all cost!


Controller - http://www.ebay.co.uk/itm/Solar-Cha...21436836288?pt=UK_Gadgets&hash=item4ad720e1c0

panel - http://www.ebay.co.uk/itm/ECO-50W-1...51067816959?pt=UK_Gadgets&hash=item51bd45c3ff


Many Thanks

 

[VicS]

The controller is a very basic on/off controller. It will disconnect at a specified voltage and reconnect again when the volts have fallen to a lower specified figure

It will prevent overcharging but it will not get the batteries as well charged as a "pulse width modulated" (PWM) controller will. These reduce the effective current as the batteries become charged but do not disconnect altogether.

Read other very recent threads ( last couple of days) and you will find a link to a PWM controller for only a pound more.

http://www.ybw.com/forums/showthread.php?399709-Solar-panel-without-regulator

Cannot comment on the panel.

 

[temptress]

Help needed from anyone who has good knowledge of solar panel specification/installation.

My drying pontoon berth does not have shore power & I don't really need it but I would like to make sure that my batteries are topped up whilst I'm away from the boat during the week.
My intention is to mount a solar panel on the coach roof & more than watts the limiting factor is space - of which I have 800mm x 550mm available. Therefore it appears a 50W panel would be a good fit.

My current set up is two 110ah batteries (domestic/starter) charged via VSR from engine & a sterling charger for shore power (if/when available). All works well but I'd appreciate opinion on weather the following panel and charge controller (1) would work with my set up & (2) are worthless ebay tat that should be avoided at all cost!


Controller - http://www.ebay.co.uk/itm/Solar-Cha...21436836288?pt=UK_Gadgets&hash=item4ad720e1c0

panel - http://www.ebay.co.uk/itm/ECO-50W-1...51067816959?pt=UK_Gadgets&hash=item51bd45c3ff


Many Thanks

I would think that 50w in UK sunshine is not really worthwhile. I would think you need to consider 100w as a minimum. Also cheap pannels and cheap controlers are OK but with this stuff you get what you pay for. If you go for a smaller panel then you need to get a mppt type controller.

 

[Champagne Murphy]

Recently fitted one of these (60w);
http://www.pennygreenfingers.net/60w80w100w-semi-flexible-solar-panels.aspx
and results are very good. Getting 2A+ when sunny. I also have an expensive panel, 69w, which retails at £650! So 6x as much but no more efficient. It MAY be that the longevity on the cheap panel is less but I have no evidence either way although when the expensive panel seemed to have issues the suppliers were very helpful about aftersales. Even so, with the panels improving all the time there is a lot of sense in getting the cheaper panels.

PS I have that much oomph to help power chartplotter, fridge etc etc under sail. If it was just a case of battery top up I'd go along with northwind's view

 

[northwind]

I would think that 50w in UK sunshine is not really worthwhile. I would think you need to consider 100w as a minimum. Also cheap pannels and cheap controlers are OK but with this stuff you get what you pay for. If you go for a smaller panel then you need to get a mppt type controller.

For maintaining a battery 50w is probably overkill, if all you want to do is keep them topped up.

I have an 85AH battery connected to a 20watt panel, no shore power, and a cheap controller, battery is always fully charged when we return the following weekend. I leave the panel connected 365days a year, never had a problem with not enough juice, uk based boat, and no need to charge the batteries at the beginning of the season.

 

[TQA]

50w is fine. Basic controller is fine.

If you went with a smaller panel a better controller would help.

 

[Sammy Lou]

"pulse width modulated" (PWM) controller will. Read other very recent threads ( last couple of days) and you will find a link to a PWM controller for only a pound more.http://www.ybw.com/forums/showthread.php?399709-Solar-panel-without-regulator

Thanks VicS – Ii’ll look for the controller as described

For maintaining a battery 50w is probably overkill, if all you want to do is keep them topped up.

Northwind – I agree with what you say but I may as well optimize on the space available on the coach roof & then anything gained from the extra charging that results in the batteries not draining so quickly will be a bonus.

Thanks everyone.

 

[Stemar]

I would think that 50w in UK sunshine is not really worthwhile. I would think you need to consider 100w as a minimum. Also cheap pannels and cheap controlers are OK but with this stuff you get what you pay for. If you go for a smaller panel then you need to get a mppt type controller.

My experience is different. I fitted 2 20w panels a couple of years ago and we find that, in the summer, they keep up with our usage (lights and a car-type stereo on most of the day, plus water pump, but not the coldbox, which draws about 6A). In winter, my usage over a weekend is replaced by the next one.

I fitted one of these chargers [URL]http://www.solar-store.co.uk/12-24-volt-20-amp-dual-regulator-box.html[/url], wired so it charges the starter battery first, then the domestic one. Unfortunately, both it and the panels have both doubled in price since, but I still think it, or something similar would be worth the extra.

I fitted two smaller panels rather than one big one because the only sensible place is under the boom, and my research suggested that I'd get more out of one shaded panel and one unshaded than from a single bigger panel that's partially shaded.