Battery Switch Wiring

[Rustic Charm]

Can I get some feed back on 'number' of batteries from others? Do others believe six 200amp batteries is too many? Ted

[Wotname]

Originally Posted by tedsherrin

Can I get some feed back on 'number' of batteries from others? Do others believe six 200amp batteries is too many? Ted

It is not so much as too many but rather how many do you need and how much charging capacity do you have.

If you have a large electrical load, it might only be just enough; on the other hand, if you have a very low load, you have way too much and just carrying excess weight (and dollars!). For instance, I get by with a single 150 AH battery but others do not!

Likewise, if you have a large capacity, you must have some way replacing what you use or you end up with partially discharged batteries - which is a bad thing.

Start off by doing a power budget to determine exactly how much capacity you need.

[slowshoes]

Originally Posted by tedsherrin

Can I get some feed back on 'number' of batteries from others? Do others believe six 200amp batteries is too many? Ted

That is alot of amp hrs for a 35 foot boat. I would cut back to three (which is still plenty of amp hrs) and look for ways to reduce my amp hour usage. Replacing lights with led's would be a good place to start.

[Pete7]

Originally Posted by tedsherrin

When I came down from Adelaide in Sept last year, over ten days, the four batteries (800ah) did run down rather quickly, basically by next morning after running through the night, they were pretty low.
Will not the engine + solar + wind gen (future) replace the power?

Again, I'm here asking because I am a complete novice. Value all your inputs. Love the article by Main Sail that Stu submitted. It's been the easiest thing for me to follow so far. Ted

Ted, yes it will, but like others I am concerned were 800ah disappears over night or even say 50% of it. So you have the fridge/freezer and auto pilot plus lights and radar running but even so that's a lot of power being used. The downside is that this then has to be replaced which will take an awful long time with a standard alternator. You can fit bigger alternators or even a smart widget to boost the existing alternator

Sterling Power Products: Alternator Regulators

However, its all more and more dollars. It would be much better to reduce the power requirements which would mean less battery charging, fewer batteries and possibly a simpler installation.

Like Wotname, we get by with a house bank of 220AH and would be spoilt it we upped this to 330AH.

Pete

[nitpik]

Do you have the 240A to 300A alternator to match that 1200 Ah battery bank?
A smaller alternator will likely burn out sooner because it will always be asked to operate at 100% output. The batteries will never see a 100% state of charge, probably not even 80%, and so they will also not "live long and prosper."
It is not as simple as saying: "You can't have too much battery power." The whole system needs to be balanced.

[Jbaffoh]

800ah overnight??? I couldn't use that if I tried! Do you have a 4000 watt inverter powering a woodworking shop onboard?

My 34 footer has no refer, windless or inverter, but it does have all incandescent lights, radar, plotter, fishfinder, autopilot, television, DC outlets used for charging devices, and a perpetually running stereo. We frequently go out for a week at a time, using lights and watching movies all night, and I never run the motor to charge the batts.

According to my battery monitor history, my maximum discharge has been only 18 percent! I have a 260ah bank maintained by a 50 watt solar panel.

[ka4wja]

Ted,
Bill gave you the straight scoop here....reread all of what he wrote.....

Further.....
1) Like the others I find 1200 A/H to be a fairly high number for a 35' boat, and I have a BIG house battery bank myself (with 1125 A/H on my current 47' sloop)....

Originally Posted by tedsherrin

Can I get some feed back on 'number' of batteries from others? Do others believe six 200amp batteries is too many? Ted

And, allow me to repaet the advice of others....You REALLY need to do an energy budget.....
Without an energy budget (how much energy do you use daily/weekly, and how are you going to generate/replace that energy), it is VERY difficult to determine solar array size, wind gen size, or battery bank size requirements.....

BUT.....





2) But, I wonder if you really do have a 1200 A/H battery bank??? Reading what you wrote here:

Originally Posted by tedsherrin

My boat when I picked it up had four 200ah batteries, but spots for two more. One dead battery that looked like an audinary car battery was still in place and hooked up.. The seller even told me it was dead. Then there was a spot for another battery which battery terminals, but no battery in there. IN addition, there is a pretty decent starter battery.

I'm wondering if you, in actual fact, have a "normal sized" battery bank using some "ordinary car battery"-sized batteries????


Assuming we are speaking about deep-cycle / lighting / house batteries here, "ordinary car battery" size batteries "A/H" ratings WILL be significantly below 200 A/H!!!!
Depending on the exact "ordinary car battery" size and manufacturer, these will have A/H ratings between 65 A/H to 105 A/H.....
Group 24 size ~ 65 - 80 A/H
Group 27 size ~ 85 - 95 A/H
Group 31 size ~ 95 - 105 A/H


You would need to go up to a large 4D or 8D ("truck sized batteries") in order to get to the 200 A/H range.... (with 4D's ~ 180 - 200 A/H, and 8D's 210 - 275 A/H)

If you wish to know exactly what batteries you have, you'll need to LOOK at them, get their manuf and model# and look them up....
But, the figures I give here ARE accurate.....

And just FYI, that old generality is pretty true...."the heavier the battery, the more A/H's" (and you can approximate it with each pound of weight being equal to about 1.3 to 1.5 A/H, depending on the exact batteries...)






3) Now onto another telling aspect.....what "condition" your batteries are in...even if you had a large battery bank, your writings show that the former owner didn't have much respect for the existing batteries, and I suspect that they don't have a great deal of capacity anymore....

Originally Posted by tedsherrin

My boat when I picked it up had four 200ah batteries, but spots for two more. One dead battery that looked like an audinary car battery was still in place and hooked up.. The seller even told me it was dead. Then there was a spot for another battery which battery terminals, but no battery in there.

My advice is to do some investigating here.....determine exactly what batteries you have, making sure they are deep-cycle / lighting / house batteries, how old they are, and what condition / capacity they currently have!!!

And, then do an energy budget to determine what batteries, what solar, etc. you require/desire....




Fair winds...

John
s/v Annie Laurie

[Jbaffoh]

Originally Posted by ka4wja

Assuming we are speaking about deep-cycle / lighting / house batteries here, "ordinary car battery" size batteries "A/H" ratings WILL be significantly below 200 A/H!!!!
Depending on the exact "ordinary car battery" size and manufacturer, these will have A/H ratings between 65 A/H to 105 A/H.....
Group 24 size ~ 65 - 80 A/H
Group 27 size ~ 85 - 95 A/H
Group 31 size ~ 95 - 105 A/H

You would need to go up to a large 4D or 8D ("truck sized batteries") in order to get to the 200 A/H range.... (with 4D's ~ 180 - 200 A/H, and 8D's 210 - 275 A/H)



Fair winds...

John
s/v Annie Laurie

I agree with everything you said, but there's plenty of room to quibble over the conservative Ah ratings above. For example, Trojan makes a Group 27 with a 20-hour rating of 115, and a 30H rated at 130.

Still, your points are all well taken.

[ka4wja]

jbaffoh,
No worries here....just trying to help Ted!!!
My point, as I wrote above, was that using the words that Ted himself wrote, made me wonder if he really had 200 A/H batteries....
I did NOT write that he didn't, just that I was "wondering".....

Not sure how me using some "generic" figures means we must quibble???

If you wish to quibble, that's fine, but (in my opinion) sort of defeats the purpose of trying to help....yes???
And, yes, my Rolls/Surrettes 8D's are 375 A/H's.....and while the 30H's might be 130 A/H they're taller, etc...but all this diverts from the basic queries here, dosen't it???

Oh, well gotta' go....
Fair winds...

John
s/v Annie Laurie

[btrayfors]

John, K4WJA, is exactly right and on point (post #22 above).

Bottom line: before you do anything else....including asking for more advice...do some investigating to be absolutely sure of what you've got (battery type, size, AH rating, age, condition, and how they're all connected and charged), and what your needs may be (i.e., do an "energy budget").

Bill

[Jbaffoh]

Originally Posted by ka4wja

jbaffoh,
No worries here....just trying to help Ted!!!
My point, as I wrote above, was that using the words that Ted himself wrote, made me wonder if he really had 200 A/H batteries....
I did NOT write that he didn't, just that I was "wondering".....

Not sure how me using some "generic" figures means we must quibble???

If you wish to quibble, that's fine, but (in my opinion) sort of defeats the purpose of trying to help....yes???
And, yes, my Rolls/Surrettes 8D's are 375 A/H's.....and while the 30H's might be 130 A/H they're taller, etc...but all this diverts from the basic queries here, dosen't it???

Oh, well gotta' go....
Fair winds...

John
s/v Annie Laurie

Wow. Re-read the first and last sentences of my comment. Why so verbose and defensive?

[Stu Jackson]

Here's how to do an energy budget

Energy Budget

[Exile]

Originally Posted by ka4wja

jbaffoh,

And, yes, my Rolls/Surrettes 8D's are 375 A/H's.....

John
s/v Annie Laurie

Sorry to go off-topic here for a moment, but was wondering about your 375ah Rolls 8D's. I'm only curious because my LifeLine 8D's are rated at 225ah, and the newer ones at 250ah I think. Are your Rolls flooded vs. AGM & does that account for the difference?

Thanks,
Dan

[btrayfors]

Originally Posted by Exile

Sorry to go off-topic here for a moment, but was wondering about your 375ah Rolls 8D's. I'm only curious because my LifeLine 8D's are rated at 225ah, and the newer ones at 250ah I think. Are your Rolls flooded vs. AGM & does that account for the difference?

Thanks,
Dan

Dan,

Generally, flooded batteries have a slightly higher 20-hour AH rating than do AGMs of the same size.

John probably has the Rolls/Surette 12EHG375M, 375AH (8D)...it's a modular battery with six removable cells which fit the form factor of an 8D.

Bill

[Jbaffoh]

Originally Posted by Exile

Sorry to go off-topic here for a moment, but was wondering about your 375ah Rolls 8D's. I'm only curious because my LifeLine 8D's are rated at 225ah, and the newer ones at 250ah I think. Are your Rolls flooded vs. AGM & does that account for the difference?

Thanks,
Dan

They're not true 8D's. They're modular flooded cells in an 8D sized box.