Batteries in parallel - Can I double the CCA?-gctid341037

[Guest]

OK, so I need to replace my start battery but can't get the exact replacement here in Nassau. So I need a new plan!!

The engine specs require a battery with 950 CCA with 160 minutes RC as a minimum.

The best I can get here is 800 CCA with a RC of 120 min

Not good enough!

So, my thought is to buy 2 identical batteries and parallel them.

My question is this: if I use the above mentioned battery specs (800CCA and 120A RC) and have 2 batteries in parallel does this mean I get 1600 CCA and 210 min RC?

Thanks

[johnrupp]

Yes, when you parallel two batteries you double everything but voltage. When you series two batteries you double only voltage.

[Guest]

Correct^^

I do the same on my 3587 as they start both diesel engines.

This way I get the most cranking amps that can fit my battery box.

[seaclusion]

have you considered after you install the new batterys to visit the on board charger aspect .....or maybe you already have . the old chargers do not even come close to todays inventions ... take a look at promariner.com for your size boat a 3 bank c 1240 or c1250 amp charger would fit the bill

http://www.pmariner.com/productFeature.php?ProductNum=63550

good luck

p.s. i could have brought you 2 new battery a few weeks ago as we stoped on a ncl cruise in nassau ......haha

[TimeLess32]

Is it just me? I hear the problems others have with starting batteries, size, etc. While I only have 150 Hinos, they're still diesels and draw a lot to start. However, I only have 1, group 27 battery that starts (one at a time) both engines. This battery has not been changed in 7 years. When I fire off the engines, they start so quickly that you can hardly hear the starter activate. So, I was wondering, do the Cummins and bigger Hinos draw that many more amps to start?

Frank

[Guest]

No, I don't actually have any problems with my start batteries!! What I do have is insufficient house battery capacity. I was using an 8D for my start battery and another for house - this is how it came. But i found I was having to run my generator way too often at anchor.

So I had a choice - increase house battery capacity by buying another 8D or paralleling my two 8Ds into a house bank and adding a new start bank. Here in Nassau, the simplest option was the latter which is what I did. And since my engines (Cummins 220's) need a minimum of 950 CCA I had to parallel two start batteries to give me some reserve as well.

So, now I have about 450 amp-hours in my house and 2000 CCA for my start. Overkill? Maybe, but I don't want to run out of juice somewhere in a deserted anchorage in the Bahamas with the weather deteriorating! Now, hopefully I won't

[Guest]

I use a single blue top optima to start both 250 HP hino's on my 3988. Works great. can alway jumper from gen set battery or cross-swith from house if needed. However, never have needed to in 4 years since the install. Get a smart charger!!!!

[WhiteRockMike]

Dinkytoy wrote:


So, now I have about 450 amp-hours in my house and 2000 CCA for my start. Overkill?

Actually, 450 AH for your house is still a little light considering you'll be anchoring out a lot. We have double that in our 4788. If you get a chance I'd increase your house bank.