New battery config for Volvo Penta - advice?

[ChasB]

I've got a 1982 Carver with two petrol Volvo Penta BB225A engines.

I've been having starting problems, and am going to upgrade the batteries and wiring. I'd like to ask here if what I plan will work ok.

There are two alternators - one on each engine. The manual I have is for Volvo Penta AQ225D and states that the alternator output is 490 W (38A) Searching on-line I find the replacement part is Sierra 18-5959 and is rated at 14V/50 AMP. The original alternator is still on the port engine, and a new Sierra was fitted 2 years ago on the starboard.

The boat is not wired as one usually sees on boats. There are two batteries that can be switched A, B, A+B. Whichever is switched on will provide both house power and engine power to both engines. It's not an ideal arrangement, but rewiring it would not be easy.

The battery compartment has two 100Ah lead acid batteries which both need replacing. The compartment is limited in size and will not take more than two of the same type. However it seems to me that if I buy four 80Ah batteries (which are shorter) they should fit if put in sideways. This will then add up to 160Ah for each pair (wired in parallel). I have a Victron Energy Centaur charger which has three outputs delivering 20A charge current for use with batteries rated at 80-200Ah per bank. So, two banks - one charger output to each pair.

(1) this should work, right?

(2) When under way, will the alternators be able to maintain a sufficient charge to the batteries?

I'm looking at using Merlin Powerpack - Deep Cycle / mulit purpose battery 15-1024, rated 86Ah.
http://www.power-store.com/view-item.asp?itemid=1668&id=215&

(3) Is this a good choice, or is there better (bearing in mind that I want to keep costs down where I can) ?

Cheers! /forums/images/graemlins/smirk.gif

 

[mainshiptom]

I would replace baatries first and then test !

Tom

 

[chrisdevonshire]

I have some wiring diags that came with my 1981 carver 3007, they cover the 12v system, the list of wire markers and their designation and the engine instrumentation wiring diag for dual volvo petrols & diesels. unfortunately they dont cover the battery connections but you are welcome to a copy if you think they may be of use.
e-mail chrisdevonshire@btinternet.com

 

[Pete7]

Do you need starter batteries of that size? we had a 70 amp battery on our Sealine 240 with a Volvo V8, and a second 70 amp battery for domestics. There will be a big difference in cost.

Pete

 

[ChasB]

Chris, I think I already have the wiring diagrams you refer to, so you'll appreciate my reluctance to change anything!

But by gad sir - we have the same boat! Is yours the one I saw moored in the Norfolk Broads a few years back? Do you know how they got here?

You may find these pictures I gathered of other similar carvers from off the web interesting -
other carvers
and here's mine -

Pete, Tom, maybe it is just a case of getting fresh batteries and replacing the old wires (25 years!) but I thought that whilst at it I may as well beef it up a bit. It shouldn't cost a lot more. I just want to know if it'll work, in the sense that are the alternators up to the job?

 

[Wiggo]

FIf you can get 4 80Ah batteries in, the I'd put three on domestics and starboard cranking, and 1 to crank port. Junk the 1-2-Both thing. You may want to think about an electronic charge splitter (www.dg2k.co.uk/xsplit.htm) - the XSP60/2/2/BS would fit the bill, as this will spread the load of charging the domestics evenly across both alternators. Whether this is worth it depends on how much you tend to clobber the domestic bank, of course.

As usual, no connection with the company, just a happy customer.

 

[ChasB]

Interesting gadget. Thanks for the heads up. I'll read up on that.

(And I thought boating was going to be all about babes in bikinis!)

 

[Wiggo]

Reason I mention it is that I shoved a load of extra capacity on our domestics and I'm pretty sure the extra load cooked two alternators in succession (in less than a year). Now that we're charging from both we've had no issues.

 

[DavidJ]

I think you need to think through why you need more battery capacity (I use the word capacity and not power) If you want to spend more time at anchor with the fridge etc on then fine but engine starting will not improve (significantly) with more capacity. Starting will improve because you've put new batteries on which will hold the power better whether it be 2 or 4 batteries.
Before someone else mentions it, yes, more battery capacity will reduce the voltage drop during cranking but if the original battery spec doesn't start the engines then you've got another problem.