Forums » Ask a Question

Use this forum to post your questions to our experts – you need to be logged on to do it (you can register here ), then scroll down to the bottom of this page and click the blue Post Thread words

If you can help answer the question, feel free to post a reply – you need to be logged on to do it (you can register here ), then hit the reply button on the thread.

 

To go back to the experts page click here>>

AuthorMessage
alanclarke
alanclarke

Posted: Thu Oct 22, 2009 9:45pm

Post Subject: alternators

my narrow boat has a b.m.c. engine with only a small out put alternator, i think it's a Lucas 35a or 45a, with out taking it off and checking i'm not to sure but this was what i was told. I would like to replace it with a larger out put one but is it possable to get one of the same physical size with the same type of pulley (v belt type ) so i don't have to go to more expense converting the new alternator to fit. Any advise would be helpful.regards, Alan

Tony-B
Tony-B

Posted: Fri Oct 23, 2009 7:18am

Post Subject: alternators

Dear Alan, can we now assume that you have apparent charging problems? If so have you checked the batteries? Over two or three years batteries on simple holiday boats and many livaboards who do not have shorepower have probably lost over half their capacity. I can not find any references to those alternator models so suspect they are the outputs so it is not possible to positively identify the alternator form them. I suspect its either a 10 or 11AC or an ACR with a big plastic cover over the back. The 10 & 11AC us separate control gear so it would be a very good idea to change it for a modern "all in one" solution. The Lucas A127 range normally fits straight onto the existing brackets but take care when you slide the bush through the rear bracket. I have seen rear brackets snapped when it is forced. There is every chance your existing pulley will fit but if you get a larger alternator you will need a matched cooling fan and whoever supplies that can also supply the pulley. Remember you will also need to upgrade that main charging wires and as you probably already have problems please read the "correct way to wire an alternator" bit on the Smartguage website. As long as you do not require an auxiliary output for things like rev counters and split charge relays a good source is your local car scrap yard - even then the Aux or W terminal may be present on one form a diesel car fitted with a rev counter. Tony Brooks

alanclarke
alanclarke

Posted: Fri Oct 23, 2009 8:55am

Post Subject: alternators

dear tony, thanks for reply. The reason i want to replace my alternator is because over the period of time i have owned the boat my power requiremants have increased so i have increased my battery bank so now i have 3 110ah batteries plus my starter battery, do you not think in your opinion i need to upgrade my alternator to speed up my charging rate. We are not live aboards or cont; cruisers so at this time of year when we use te boat at week ends and stay on our moorings i need to run the engine to charge so i thought a larger out put alternator would speed things up. Would i be waisting my money. Do you have any alternative (no punn intended) ideas. Cheers Alan.

Tony-B
Tony-B

Posted: Fri Oct 23, 2009 4:07pm

Post Subject: alternators

Dear Alan, A higher output alternator would speed up the Bulk charge phase (see answer to the other question) but as the bulk charge typically takes less than 3 hours and the fact that you have a single V belt limits you to 80 to 90 amps output maximum it might not make a significant difference. When I faced just this problem and knowing how important it is to FULLY charge (not the usual 80 odd% most boats like ours achieve) I fitted a 60w solar panel plus controller. Now the batteries are pretty much fully charged each time we return to the boat and normal water heating engine running keeps the system usable over the weekend. I believe the panel extended my battery life by over two years (5+ instead of 3). If you can get a scrap alternator for a few pounds it is worth doing, but if you have to pay full, list price think a bit more about it. It will make a difference, but how much is open to question unless I can see a power audit and voltmeter/ammeter readings for your boat at times throughout the day. Tony Brooks

alanclarke
alanclarke

Posted: Mon Oct 26, 2009 9:43pm

Post Subject: alternators

once again thanks for reply and i think you have answered all my queries on that paticular subject but you have hit on another one that interests me but will hopefuly be easier to answer. having 3 x 110a batteries and 1 x starter battery what size wattage solar panel would you recommend. thanks again Alan.

Tony-B
Tony-B

Posted: Tue Oct 27, 2009 9:31am

Post Subject: alternators

Dear Alan, My advice would be to ignore solar charging for the engine battery because they seem to last far longer than the domestic bank and in an emergency you can always jump start from the domestic bank. It is said that you do not require a controller if the panel is rated at less that 10% of the battery capacity so its seems you could just connect a Watt panel straight to your batteries but I do not think this would give you the best effect. My view is the larger the better especially if you do much winter cruising and if you mount the panel horizontally. I use a 60W panel s a fair compromise between price and performance but would rather like another one to make 120W. I have never seen more than about 4 amps out of the panel and that is at noon during high summer. At noon in winter it is often less than 1 Amp if its cloudy. Now we do not do much winter cruising so a long recharge period is acceptable and cost effective, but not ideal from the sulphation point of view, hence my desire for another panel I can not justify on cost grounds. One you get above perhaps 40W I think the type of controller becomes more important. The most efficient cost a awful lot of money (£500!) but for around the £100 you should get a slightly less efficient one but make sure it does an automatic equalisation charge every so often. This raises the charging voltage for a period which will help combat sulphation to a degree without causing excess gassing. The short answer to your question is "as large as you can afford plus a decent controller". Tony Brooks

wirren
wirren

Posted: Tue Oct 27, 2009 4:38pm

Post Subject: alternators

Tony, I am thinking of getting a 80w or 100w charger when funds allow. Dare I be cheeky & ask what make of controller you purchased. I'm sure you will have done your research before buying ! It might save me making a mistake. ;o) Mark.

Tony-B
Tony-B

Posted: Tue Oct 27, 2009 4:56pm

Post Subject: alternators

I have a Stecca but it and the instructions are on the boat. To be honest as long as it does an equalisation charge and is from a reputable maker I doubt it will matter.

pdscaz
pdscaz

Posted: Tue Oct 27, 2009 6:33pm

Post Subject: alternators

look on ebay new 70 amp lucas replacement alterator with pulley and fan @£50

alanclarke
alanclarke

Posted: Tue Oct 27, 2009 9:43pm

Post Subject: alternators

thanks for that pauldavid i am going to look NOW !

Most Read

Like us on Facebook



Follow us on Twitter

Cache: Disabled for this object  Total Queries: 45.  Total Objects: 164.  Total Unserialized: 5. Total Runtime: 0.89 seconds.