How much cranking power should the starter battery have?

[The_Handier_Man1]

From: Winn_Brave_1980  (Original Message)
Sent: 5/13/2005 4:01 AM

Hi all,

again I need your knowledge!! In my 79 Brave on a Dodge M-400 chassis and a 360-3 Bbl engine with 5,8l and 156 hp I have a funny battery configuration of two 88 Ah batteries and one with around 60 Ah.
To start the engine I have to connect in the current configuration one 88 and the 60 Ah batteries and I guess, the remaining 88 Ah battery is the coach battery.
But if I have a look to the part, where the batteries are installed on, I have the impression, that originally there was one big starter battery and one coach battery.

Am I right with this impression? And, in this case, does one know, how much power the starter battery must have??
Background: I am thinking about, to replace the three exisitng batteries by two AGM batteries!!

Thanks again in advance for your help and greetings from Germany,
Sybille



From: biggrock1
Sent: 5/13/2005 7:36 AM

When I bought my winnie I had 1 big coach battery and 1 smaller chassis battery. they were both toast. Are your batts 6 volt or 12 volt? My guess is if the 2- 88 ah batts were connected together in parallel or series depending on the voltage as the coach batt . and the smaller 1 as the chassis batt or starting battery. I currently have 2 -6 volt batteries connected in series as a coach battery.

biggrock1



From: Winn_Brave_1980
Sent: 5/13/2005 11:40 AM
 
Hmmm, in Germany we know for cars and trucks 12V and 24V systems only!
To get 24V they use two 12V in parallel - if I remember right!!

Anyway - I guess, my Brave has a 12V system, as I connect the 88 and the 60 Ah batteries plus to plus and minus to minus ! If I do not connect them this way, the engine will not start!!
Makes this sense to you??



From: mightybooboo
Sent: 5/13/2005 3:36 PM

Dont know how this translates to German batteries,but I use a single 950 cold cranking amp(950 CCA) for  the engine start battery.For coach you use however much battery power you wish to have available.

BooBoo



From: denison
Sent: 5/13/2005 4:12 PM

Mine originally had a very large battery for the coach, and for the engine it had a battery the same size as a car would have. Both of them 12 volts. The switch to connect them would connect them in parallel - still 12 volts, but more amperage. I believe that was the charge the coach battery while driving. The regular size battery starts the engine very easily, even when it is below freezing. 



From: Winn_Brave_1980
Sent: 5/14/2005 1:32 AM

After a Google I learned:
- the batteries in my Winnie are connected in parallel for keeping the 12V
- 950 CCA might be translated to around 160 - 200 AH depending on the batterie type
- and I know now more about CCA :-) and in future I will take care for it

Thank you a lot for your help!!!
Sybille



From: cooneytunes
Sent: 5/14/2005 11:01 AM

Sybille.......CCA stands for Cold Cranking Amps....for starting a vehicle in extream cold weather the higher the better....now AH stands for Amp hours, that will tell you how many amps you can run for how many hours there is a formular to figure this out....(used for house battery ( deep cycle ) which means it discharges much slower than a starting battery, and can be discharged down to dead many times and recharged up...Higher CCA batteries are for a quick high shot of power (starting)...and the more you dicharge it to dead, It won't recycle (come back up to charge after too many times of doing this...Here's a link  below, that explains all types a batteries, much more clearly than I can.....
Timmy 
...click on the link and then click on: "The 12 volt side of life." (there's are two parts to this) very good reading and very simple....

bart.ccis.com/home/mnemeth/tech.htm



From: Winn_Brave_1980
Sent: 5/16/2005 1:36 PM

Hi Timmy,

sorry, the link didn't worked :-( !!

But nevertheless, in general I understood in the meantime the background of CCA and AH.

But another part of the decision for a battery is the question, what the engine (in german called 'Lichtmaschine', which generates the power into the battery) is able to deliver! Means: if I choose a battery which is to big it might happen, that it is not fully loaded during driving!

And I think, for that it's helpfull to know, how much AH the battery should have!



From: Winn_Brave_1980
Sent: 5/19/2005 9:57 AM

I found a note in the description of Winnebago: the starter battery should have 108 AH!

Thanks for all the help!!
Sybille



From: denison
Sent: 5/19/2005 10:28 AM

Sybille: The battery for the engine in your winnebago can be large, and it wont matter, but a smaller battery will be OK also. On vacations I use the battery from my small 2.5 liter 4 cylinder car. I put it into the Winnebago, and the V8 motor starts very well. This is in mild or warm weather.
If I wanted to start my Winnebago when it is -10c, then the 108AH battery might be needed.



From: mightybooboo
Sent: 5/19/2005 12:50 PM

The numbers I come up with for a lead acid starting battery is a 108 AH would be the equivalent of 965 CCA or so. So,a 950 CCA is what you want.
Why? Because when its HOT,resistence goes way up,you want the most CCA battery possible that your alternator can reasonably keep charged to overcome that resistence.
These 440 engines run hot,and when you restart the engine(ie,a stop for fuel),they have also heatsinked in the few minutes of being off.
Been there,done that-freeway driving in 37c plus weather you want that big battery.With the price of a smaller battery vrs a larger,get the larger.
I say,the manual  is right on the money in this case.

BooBoo



From: mightybooboo
Sent: 5/19/2005 12:53 PM

My numbers for AH vrs. CCA are for a lead acid starting battery.

BooBoo



From: mightybooboo
Sent: 5/19/2005 12:57 PM

BTW,my last battery was only 800 CCA if I recall correctly(850?),it was marginal at times.Just put in a 950.Havent used it in high heat situation yet,but I felt the 950 was called for.

BooBoo



From: mightybooboo
Sent: 5/19/2005 1:09 PM

Another thought.My battery can sit a month or 2 without being charged,and after 5 years my last battery was toast.In Denisons case,he is using a battery that he keeps fully charged.Which may be part of why his smaller battery performs OK.

I  really need to get a trickle charger solar panel on my start battery.A one amp panel(15 watt or so) should be just about ideal.My MH is stored away from home,so it doesnt get proper maintanence charge.NOT a good thing.

BooBoo



From: Winn_Brave_1980
Sent: 5/19/2005 3:19 PM

I ordered three 108AH AGM battery with around 950 CCA each (1 of them I will use as a starter battery) and I am going to connect them via a Sterling battery charger to the engine power and the generator.
What I learned is, that the charger loads the battery much better as the normal engine-battery-loader (??) can do, as it controls the temparature and knows how to load this kind of batteries in a optimal way!

Hope it works if we have in some month -20 c again :-) !! And may be, we will be then in Switzerland, which means, that it might be much colder than here in Germany (brrrr).

Sybille



From: OldEdBrady
Sent: 5/19/2005 8:19 PM

I picked up one of those small solar panels at Harbor Freight.  The kind you just plug into the cigarette lighter.  I think it cost me about $10 or $10.  Measures something like 4" x 12" (the panel--the frame takes up a bit more space).

It keeps the old Whiny Beggar charged.

'Course, we use her year 'round.



From: mightybooboo
Sent: 5/19/2005 9:11 PM

Sounds pretty good Ed,do you know how many Milliamps it puts out?
A little OT,with all the electronics on my 2001 Jetta,it draws 800 milliamps when  parked and  locked!They ship em with their own solar panel,you see lots of VW panels on  ebay.

BooBoo



From: mightybooboo
Sent: 5/19/2005 9:14 PM

Sybille,sounds like a great battery/smart-charger setup.Im sure you are all set now.

BooBoo



From: OldEdBrady
Sent: 5/19/2005 11:22 PM

The solar panel is 1 1/2 W, 120 mA.



From: mightybooboo
Sent: 5/20/2005 1:13 AM

Ed,thanks.How long does she sit between starts?And it keeps you fully charged?
Sounds good to me,I will get on  ebay next week and get one ordered.

BooBoo



From: OldEdBrady
Sent: 5/20/2005 8:54 AM

There have been a few occasions when she's sat a month without starting.  Then I go out, crank her up, and she's carrying as much charge as if I had used her just the day before.

Prior to getting the panel, I would plug her into shore power (after sitting a considerable amount of time) 24 hours before starting.  I no longer do that, since it isn't necessary.

This thing might take a couple of weeks to charge a battery that was seriously low, but by using the panel at all times while the motor's off, I've had no problems whatsoever.  And, it hasn't ever overcharged the batteries, either.