Solar Panels On Ebay

[Boatman Al]

Hello all

 

My 55amp alternator is not replenishing the batteries sufficiently when im out on cruises, so im looking at getting a solar panel. I dont want the panel on permanently, id like to only rig it up on cruises and when back in marina use my sterling charger.

 

I have 3 110amp leisures and 1 starter. Running lights, pumps and TV.

 

I found these 2 panels -

 

http://www.ebay.co.uk/itm/150870604139?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1204

 

http://www.ebay.co.uk/itm/160851672817?var=460099490039&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_6235wt_907

 

 

The first one looks like its geared towards being portable. So i can pack down and lock in the boat when not in use.

The second looks like one i need to build fixings and mountings for.

 

Id really appreciate some critique on the panels, and also will they be suffice to work alongside the alternator in keeping my batteries topped up?

 

many thanks

[Ex- Member]

Both panels are pretty portable even the 100w one. The problem is you're not going to get much charge from the panel if you're only going to deploy it when cruising. In fact it would probably be a total waste of time and money for such little return as whilst on the move it will likely be shadowed at times from trees and other structures.

 

Solar panels are better utilised full time flat on the boats roof, they trickle charge batteries over long daylight periods which is very good for batteries and very good for topping batteries to a full SOC and in so doing aids their longevity assuming good maintenance also.

 

If you require more charging whilst cruising, simply fit a higher amp Alternator. 55 amp is probably insufficient anyway for most canal boats as it's likely they are not pullied up to get the best from them at around 5,000 RPM. It's possible your 55 amp alternator is giving you less than 50% of the 55 amp rating it has, and that's why you're having recharging problems.

 

I doesn't seem you're using that much electrical equipment, so deploying 100 watts of solar full time would make much more sense, and upping the alternator to minimum 70 amp or upping the pulley ratio to get mote from the 55 amp alternator if it's currently at a low ratio, low RPM

Edited August 5, 2012 by Julynian

[Chalky]

The panels aren't the solution. You should be able to comfortably charge the batteries off the alternator without problem. I suggest that you look at the charging system first before spending money on solar.

 

Your problem is one or both of the following:-

 

You're not putting enough into the batteries for what you're taking out or you're not storing the power once its been put in.

 

Firstly I'd do a power audit. This is an analysis of how much power you use in a typical day. It can be done on paper buy you'll need to know what parts you've got on the boat so you can work out how much power you use. The methodology has been described on here several times before. This'll tell you how much power you're using in a typical day (allow a bit more just in case) and therefore how big a battery bank you need to cope with it. Battery bank sizing has been discussed on here before - the general view is don't let them go below 50% charge. It may also show that your problem is caused by 1 particular appliance and that it's use should be restricted to reduce the problem.

 

Next bit is your alternator. 55A is what it won't put out - unless you run it at its maximum speed. The chances are it'll be somewhere in the 20A - 30A range on a good day (our 70A domestic alternator with an increased pulley ratio puts out 45A max at typical cruising speed). Provided that you cruise for long enough (and don't use too much power) it will eventually charge. The power audit will tell you (roughly) how much power you've used and give a clue about how long you'll need to charge for to put the power back. It could be that you're not cruising long enough to replace the power in which case you'll need to run the engine for longer. Alternatively you could upgrade the alternator. There are a number of options ranging from pulley size change through to bigger alternators and modified / external regulators on your existing alternator. The options have been frequently discussed on the forum.

 

Thirdly it could be that everything is fine, but your batteries are shot. If they're a few years old or have been allowed to run flat they could be the problem. Once again its a regular topic on here.

 

I put a topic on here a while ago about how you can calculate the power output from a set of solar panels using typical day data from solar observatories. The results aren't brilliant for the UK and the outputs are usually considerably less than people think - especially this year.

 

In summary - sort out the rest before spending money on panels. The info you need is on the forum.

Edited August 5, 2012 by Chalky

[Rebotco]

Agree with others - solar panels are not the solution for the situation you describe. A larger output alternator is most likely your best solution.

Solar would be next to useless whilst out cruising as they could only provide a tiny fraction of the power being generated from the alternator whilst running the engine. And of course they are of no use at all at night.

Solar is really only practical if the boat is not running for long periods.

[bottle]

Agree with posts #2,#3.

 

 

Is this a first, the forum agreeing.

[Chris Pink]

Hello all

 

My 55amp alternator is not replenishing the batteries sufficiently when im out on cruises, so im looking at getting a solar panel. I dont want the panel on permanently, id like to only rig it up on cruises and when back in marina use my sterling charger.

 

I have 3 110amp leisures and 1 starter. Running lights, pumps and TV.

 

I found these 2 panels -

 

http://www.ebay.co.uk/itm/150870604139?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1204

 

http://www.ebay.co.uk/itm/160851672817?var=460099490039&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_6235wt_907

 

 

The first one looks like its geared towards being portable. So i can pack down and lock in the boat when not in use.

The second looks like one i need to build fixings and mountings for.

 

Id really appreciate some critique on the panels, and also will they be suffice to work alongside the alternator in keeping my batteries topped up?

 

many thanks

 

How long are you typically cruising for? your use isn't so high that you should be able to put it back in. Maybe your batteries have had it - how old are they? - or not properly charged before you start?

[nb Innisfree]

OP it's pointless using SP panels while your engine is running, you have 660 watts of potential charging power with your alternator as opposed to 100 watts with solar, why go that route? Alt should give full 55 amps provided it is pulleyed up enough and you are in bulk charging phase. I suspect you go past bulk charge and operate in the absorption phase in which case your alternators charge will gradually reduce. If your batts are not being fully charged then either you're not charging for long enough (to fully recharge takes a min of 8 hours-more like 24) or your batts are buggered up.

 

ETA: OP I think I have misread your post, you probably mean while cruising, not just whe engine is running? If so then SPs would help if used while moored up with engine off.

Edited August 5, 2012 by nb Innisfree

[Boatman Al]

thanks for informative replies

 

Im cruising for 4 hours a day when im out and about. The starter is brand new, as is one of the 3 leisure. The other 2 seemed to be in good state when i got the boat. Ive topped up the water in them.

 

The audit seems like a necessity. Its generally showering and TV that will be me main usage. I could possibly fit lower watt lights as some of them are incredibly bright and appear to resemble car headlight bulbs.

 

Ive noted that the alternator wiring is strange. Its wired into the control panel to a meter that at present doesn't work (but i know its charging) , the panel is then wired back to the batteries. Then the domestic system is also wired onto the terminals of the meter. Surely it would be best to have alternator straight to batteries or my battery selector switch rather than off round the houses to meters? Im getting roughly 13.3 charging voltage when all 4 batteries are on charge.

 

I also think upgrading the alt might be worth it. How simple is a larger pulley to fit? Will that help?

 

Thanks again for the replies. very useful info

 

 

PS - yes im thinking of solars to carry on the charge when im moored up at the end of the crusing for the day.

Edited August 5, 2012 by Boatman Al

[Chris Pink]

If the voltage doesn't rise past 13.3V then you aren't charging your batteries fully. It should go over 14V when charged, probably 14.25 with an old fashioned alternator. It would probably be advisable to take the ammeter out of circuit, again this is an old fashioned way of doing things.

 

It is possible that one of your domestic batteries has a fault causing these symptoms, try and check whether one is getting warm whilst charging and / or isolating each in turn.

Your usage should be fine for your system if it's working properly. Get this as good as you can before adding solar as fault finding will get more difficult as it gets more complicated.

 

If your lights are halogen then yes they are hungry power consumers and would benefit from LEDs

Edited August 5, 2012 by Chris Pink

[Chalky]

 

Im getting roughly 13.3 charging voltage when all 4 batteries are on charge.

 

 

That's very low. If you're only achieving 13.3V then you're going to take ages to charge. The older alternators regulated at 13.8V and the newer ones at 14.6. I would suggest that you change the regulator to a more modern one - 14.2V could be available. I'd also have a serious look at the wiring between the alternator and the batteries. Gibbo's the expert on this - there's lots on the smart gauge website.

[Guest]

Also don't forget some basic stuff like checking that the alternator belt is correctly tensioned -

 

Sorry if it's been mentioned already.

[Chris Pink]

That's very low. If you're only achieving 13.3V then you're going to take ages to charge. The older alternators regulated at 13.8V and the newer ones at 14.6. I would suggest that you change the regulator to a more modern one - 14.2V could be available.

Question; if the regulator is changed will it change the voltage (and hence the current) at the intermediate stage (13.3V in this case) or simply stop the alternator charging at a higher voltage?

Edited August 5, 2012 by Chris Pink

[Chalky]

Question; if the regulator is changed will it change the voltage (and hence the current) at the intermediate stage (13.3V in this case) or simply stop the alternator charging at a higher voltage?

 

It'll stop it achieving the higher voltage, however if it's set to regulate at 13.6 and there's a bad cable installation then he may only be seeing 13.3V. It could be the sign of a number of issues, thus he needs to debug what he's got first.

[Titan]

It'll stop it achieving the higher voltage, however if it's set to regulate at 13.6 and there's a bad cable installation then he may only be seeing 13.3V. It could be the sign of a number of issues, thus he needs to debug what he's got first.

 

I have just purchased a 90amp twin cast pulley alternator as fitted to Caterpiller plant vehicles, a really heavyduty one,advised it pushes max output at slow engine speeds? i appreciate 90amp is not a really powerfull but at £48. i thought quite a bargain!!! supplier has about ten left, if anyone wants to know more pm me regards Martin

[nb Innisfree]

I have just purchased a 90amp twin cast pulley alternator as fitted to Caterpiller plant vehicles, a really heavyduty one,advised it pushes max output at slow engine speeds? i appreciate 90amp is not a really powerfull but at £48. i thought quite a bargain!!! supplier has about ten left, if anyone wants to know more pm me regards Martin

 

We have a large 24v 100A Leece Neville which gives max output at low revs, means we only need to pulley up 2:1 which allows larger alt pulley to improve grip and belt life, only possible downside is less cooling effect from fan, best if an extra electric fan is used to augment it.

Edited August 5, 2012 by nb Innisfree

[pistnbroke]

What you must remember is that a 50 A alternator will not give out 50A to a batttery load .ie charging .

If the batteries are low you will get about 25 A per 100ah battery capacity but this will fall very fast to 15A and then go on the way down as the voltage rises...

 

You need to run it at 6000 rpm + ( max is 12-15 000 rpm)

 

A simple rule is to have 25 A per 100 AH of capacity...

Why not use this alternator for the starting battery and fit another for the house ..go for a 90 A as over 100A the simple v belt will slip

[Boatman Al]

cheers everyone

 

13.3 is the voltage i get when i first start charge, it slowly creeps to 14.2 or so over 15 mins or more.

 

Im interested in fitting a second alternator but im unsure about mountings and fixings, not sure i can squeeze one in as my engine bay is tight in place around the engine. but id like to try if poss.

 

i think i defiantely need to revisit the alternator wiring. This wiring through a meter and back seems like a candidate for voltage drop.

[Chalky]

What engine is it? It may be possible to fit a larger alternator to the existing engine without extra work.

 

You say 1 alternator and you're charging 2 battery banks. How are you managing the split charge? If you're using diodes then you'll loose 0.7V just at the diodes so your 13.3 V at the alternator will be 12.6V at the battery. If you decide to keep the diodes then you need to change the regulator on the alternator from machine (alternator) sensed to battery sensed. For some alternators it's a simple regulator swap and an additional wire to the battery. It's described on the forum.

[Cosmic]

 

13.3 is the voltage i get when i first start charge, it slowly creeps to 14.2 or so over 15 mins or more.

 

It sounds as if your batteries are completely flat before you start charging them. If that's the case, they won't have a lot of life left in them. How long do you charge them for?

[Chris Pink]

cheers everyone

 

13.3 is the voltage i get when i first start charge, it slowly creeps to 14.2 or so over 15 mins or more.

 

Im interested in fitting a second alternator but im unsure about mountings and fixings, not sure i can squeeze one in as my engine bay is tight in place around the engine. but id like to try if poss.

 

i think i defiantely need to revisit the alternator wiring. This wiring through a meter and back seems like a candidate for voltage drop.

 

15 minutes is a bit quick for that voltage rise, implying that your batteries are shot, though, as you say, it would be wiser to replace the ammeter wiring before drawing that conclusion.

 

You should definitely think about isolating each battery and giving it a good charge and assessing its capacity.

 

 

As is a theme in this thread, get everything you have working to its best before thinking about adding more stuff. A larger alternator would be a better first stop than a 2nd alternator.

 

As I said before I think your setup is in line with your usage if everything's working OK though you could get your alternator working better either by fitting a higher voltage regulator or a bigger alternator.