[C320-list] Re: [catalina320] starter battery

[Jeff Hare]

Hi Guys,

     I'm not certain I understand the problem here, but if Bob was 
unsure if paralleled
batteries would be sensed correctly by the charger, then he's either 
not paying attention
to the question or doesn't really understand electronics.

It is not electrically possible to tell whether you have two 
batteries in parallel or
one big battery.   You simply have a plus and minus terminal and it makes no
difference (in this application) whether you attach one charger wire 
to the Plus
post of each paralleled battery, or both to the same postitive 
post.  They're electrically
the same point and will see identical characteristics.

Also, regarding the overcharging,  it may be possible to overcharge 
the starting
battery, but this situation is more likely to happen if you run your main house
batteries down low on a regular basis, because the charger will remain in bulk
charge mode longer than the starting battery needs.  If this happens from time
to time, there shouldn't be any real damage other than the starting 
battery might
not last quite as long as it could.  Batteries are kind of self 
regulating when charging
in that they will only accept as much current as they need, so it's 
not like the starting
battery will be accepting the same amount of charge current as the large bank.

If you're very concerned about overcharging your starting battery 
because you regularly
discharge your house bank, then just move the shore power charger leg 
back over to
one of the house batteries, and install the Blue Sea ACR to trickle 
charge the starting
battery.  I think it's like $80 and seems like a pretty cool 
unit.  (I bought one but haven't
installed it yet).

-JeffH


At 01:51 AM 11/5/2005, you wrote:
>Darrell,
>
>I spoke with Bob at ProMariner again. As expected, his suggestion 
>for using the third post on the charger was wrong. He suggests that 
>you test the charger and if it is defective they will sell you a 
>rebuilt unit. In any case, I think it might be advisable to buy a Xantrex.
>
>I guess I'll hold off on adding a starter battery until I'm ready to 
>upgrade the charger.
>
>JeffC
>
>
>----- Original Message ----- From: "Jeff Church" <jjemail at comcast.net>
>To: "Catalina 320" <catalina320 at list.sailjazz.com>
>Sent: Friday, October 28, 2005 12:30 PM
>Subject: Re: [catalina320] starter battery
>
>
>>Darrell,
>>
>>You aren't wrong. If you follow that procedure you are charging one 
>>bank at a time while you are running the engine.
>>
>>The problem might be that you are overcharging the Group 27 battery 
>>while using the battery charger.  I've been considering installing 
>>a starter battery so I spoke to a customer service person at 
>>ProMariner. I have a 1998 320 with a Flyback charger. I think your 
>>boat has the same.
>>
>>It is very possible that there is too much of a differential 
>>between the capacities of the battery banks, in which case, the 
>>smaller bank will tend to overcharge. I specifically asked if one 
>>Group 27 and two 4D's in parallel is too much of a differential. 
>>The guy practically choked.
>>
>>His advice was to first check the charger. Remove all the DC leads 
>>from the charger. Power on the charger and using a multi-meter, 
>>test voltage at each of the chargers battery connection posts. You 
>>should get 14.6 volts between each positive post and the negative 
>>post. Leave the charger on. After 3 hours it should be in float 
>>mode where you should get 13.3 volts. That will tell you if the 
>>charger is working correctly, but probably won't fix the overcharging problem.
>>
>>After that, he suggested possibly connecting each battery to a 
>>separate charger post. (There are 3 posts on the charger. The 
>>unused one should currently be jumped to one of the others.)  When 
>>I asked if the paralleled batteries would really be sensed 
>>independently, he was not sure. He is going to talk to the 
>>engineers on Monday. I'll call him back next week.
>>
>>Hope that helps a little.
>>
>>JeffC
>>
>>----- Original Message ----- From: "Darrell" <dgray at n-sea.org>
>>To: "Catalina 320" <catalina320 at list.sailjazz.com>
>>Sent: Friday, October 28, 2005 11:18 AM
>>Subject: Re: [catalina320] starter battery
>>
>>
>>>Thanks Jeff and Richard, I also have the starter battery on one 
>>>and the housebank on 2. I typically leave the selector on 1 for 
>>>about 15-20 minutes after starting then switch thru both to 
>>>position 2. At this point I assumed that only 2 is charging, but 
>>>maybe I was wrong. If so , where do I install the isolator? Back 
>>>to the charger , if one positive lead goes to bank 1 and one to 
>>>bank 2 , then it sounds like the charger should be monitoring each 
>>>bank seperately and charging accordingly. Can I check this with a 
>>>multimeter to determine if the charging current or voltage is 
>>>different for each bank? Darrell, Antares, #88
>
>
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