Battery Going Going Gone

[jv20]

Looks like my napa 7269 8D batteries are headed down hill they provide 1340 CCA and I have 2 on my 42 ocean with twin 471TI detriots. Anyone have any thoughts on multiple batteries of smaller sizes linked together? or throw 2 of these back in? my current charger will only charge wet cells

[nes]

Advantage of multiple smaller batteries in parallel to get the same amphour capacity, is that they are smaller and easier to move, also you will probably experience better voltage control with multiple batteries supplying the current. (I am not absolutely certain of this, but this is what I think would happen, as you would have more plate area to provide the amps). Also, the smaller batteries would probably be less expensive than the 8D's.
On the other hand, do you have room to put in banks of batteries?

[jv20]

Yes plenty of room and I did add a dedicated group 27 for my 7.5kw generator. I would need to get some info on what size batteries (4) to link up? I would want the same 1340 to be avail

[DeepFrz]

What you want are starting batteries with a high CCA. Check out the best place in your area for truck starting batteries. Check the sizes and see if you can fit 2 in your battery box if needed.

The thinking behind having separate batteries to start each engine is in case you ever get a short in your starter that drains your batteries. At least you will have one engine to get home on.

[nes]

BTW here are the ratings for the NAPA 7269 8D batteries. The 1340 rating is for 32 degrees, the CCA rating is 1100. (Minor point, but you do want to compare apples to apples).

Attributes: Battery BCI # : Group 8D
Battery Height : 10"
Battery Length : 20-3/4"
Battery Voltage : 12 Volt
Battery Width : 11"
Battery Cold Cranking Amps @ 0 Degrees F : 1,100
Battery Cranking Amps @ 32 Degrees F : 1,340
Battery Posts Type : Top Post
Battery Reserve Capacity (Minutes) : 325
Battery Weight : 116 lbs
Contents : (1) Battery Assembly
Wet or Dry : Wet

Here is a type 31 battery, that if you put two in parallel, would give you 1400 CCA, and 100 x 2 = 200 Amp Hours. This would require 4 batteries to replace the two 8D's you have.
Each of these batteries weigh 57 lbs, vs 116 for the 8D's. This means that one person could actually move one of the batteries without a crane.

SLI31MDP Xtreme Dual Purpose Battery - BCI Group 31M - Dual Purpose/Hybrid - Marine and Boat - Batteries Plus

Here is a type 24, with 800 CCA, which means with a pair, you would have 1600 CCA. weight of each is 45 lbs, These are meant to be starting batteries, not dual purpose.

SLI24MHP High Power Xtreme Battery - BCI Group 24M - Starting/High Rate - Marine and Boat - Batteries Plus

Here is another type 24 starting battery with 675 CCA (1350 with two) weight is 40 lbs. each.

SLI24MA Premium Xtreme Battery - BCI Group 24M - Starting/High Rate - Marine and Boat - Batteries Plus


BTW I was only looking for batteries with ratings, I do not necessarily recommend these batteries over any others. Only comparing real ratings on batteries.

[jv20]

Thank you for that information I really appreciate it. I think I will go the 4 battery route sounds better to me.

[nes]

You should look at this discussion as well!
http://www.cruisersforum.com/forums/...ies-91529.html

[witzgall]

How about a single LIFEPO4 bank for starting, with a centerfielder alternator regulator feeding the alts from both alternators to the single bank.

Simpler, lighter, and more CCA.

BTW, check out my cells for sale...

Chris

[jaxfishgyd]

I replaced my four 8D's with 12 group 24's as they will fit perfectly into the 8D box. A LOT easier to replace!!!!!I haven't been disappointed at all.
On my Hatteras, I put 6 starting batteries on the port side as they only are used to start the motor, pull the windlass (and at that time) the generator.
On the starboard side I put in six deep cycle batteries as it starts the engine and does all the 12v lights on the boat.
I then installed a 1500 inverter so can use the front box of the deep cycles for 12v boat use and the second box for the inverter only,as I do have a battery switch to keep them separate.
I also put in a group 27 for the generator, with a switch to connect it to the port bank if needed.
I have had no problem starting the starboard engine except when it's cold outside, but have a parallel switch to connect all the batteries.....

[jv20]

Update, I spoke with 2 Exide battery engineers this week and gave them my layout and asked for their input on what to do. Both responded the same, they feel the 8D battery is made with much more lead and is a much different animal than other batteries. For larger diesels boats/trucks they recommend the 8D's.

I asked them about a battery (Exide FEE 850 CCA) its about 4" wide by 21" long made for farm tractors and connecting 2 or 3 together for as much as 2550 CCA in pretty much the same space as 1 8D. They are another heavy duty battery and only about $100 a piece at Tractor Supply.

In their opinion smaller standard battery types are made lighter and will not last as long or give the same power. (Their words not mine) They also prefer the battery type that allows you to add water to it vs the maint free.

I don't quite know what to make of it but it is interesting info from 2 different guys in the engineering dept of a major battery manufacturer.

[witzgall]

I think somebody else a above asked what you were starting? Do you really need that many cranking amps? What does your engine manufacturer recommend?

These are just for starting, no house loads at all, right?

Chris

[jaxfishgyd]

Another important question is... WHERE are your battery box's located at?
Mine are on the outside of either motor... a ROYAL PITA.
I have no problem replacing the 24's by myself.. Cannot do it alone with the 8D's....

[Barnhard_Marine]

You could go with 4 group 31 batteries or stick with the 8D's. The average life of a flooded battery is about three years on a boat or truck. I would not go with AGM or Gel. they bare over priced. Batteries Plus has 8D's for around $150.00 - $180.00 EA Wholesale. Check the date codes on any batteries that you buy and make sure they are all the same. Otherwise you could end up with batteries up to a year old and not even know it. I have a Detroit 6-71 in one of my boats a 24 volt system I use 2 8D's. Semi Trucks with Detroit Diesels use group 31's these days they use to use 8D's. You will have to buy or make up the proper size jumpers for the Group 31's. If you go with 31's go with the stud post they hold up very well, Good Luck