On Fri, 05 May 2006 15:46:52 -0400, Mike Romain <
[email protected]>
wrote:
>SnoMan wrote:
>>
>> On Fri, 05 May 2006 09:17:33 -0400, Mike Romain <[email protected]>
>> wrote:
>>
>> >I ran into mis matched charging with boiling problems all the time when
>> >I tried to charge two batteries in parallel. I would come in in the
>> >morning and one would be just a sizzling away with the other just coming
>> >up to full.
>>
>> This is easy to understand why. When you charge them you did not
>> balance the cyrrent between them. WIth higher charge rates, the lencth
>> of circut from charge to cells can change the effective voltage and
>> current delievered to the cell while charging. When it doubt, use a
>> clamp on current probe to see what circut adjustments need to be
>> made.. On more thing, while it may not be practical sometimes, it is
>> best to use a lower charge rate when possible to recharge deep cycle
>> batteries as it will produce less gassing and extend their service
>> life.
>> -----------------
>> The SnoMan
>> www.thesnoman.com
>
>I was under the impression the RV isolators would balance the current in
>the automotive setting so that wouldn't happen in the vehicle either...
>
>I also have seen some that are designed for the deep cell battery charge
>as the secondary battery.
>
>If I had a second battery I would use the isolator or at least a blade
>switch and do my own isolating....
>
>As it is I have a 7 year old Optima Blue top Marine deep cycle in my CJ7
>which is my daily driver and off road buggy. I haven't been able to
>pull that battery down even running my winch on full load. I do have a
>hand throttle to keep the alternator putting out.
>
>It is the second one in this Jeep in the 7 years though. I broke the
>first one from vibration and took this out of my wife's daily driver
>Jeep 3 or 4 years ago.
>
>Mike
>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>88 Cherokee 235 BFG AT's
>Canadian Off Road Trips Photos: Non members can still view!
>Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
>(More Off Road album links at bottom of the view page)
By its very nature, a isolator cannot balance the current charge rate
between batteries because in order to do so it would have to have the
alt output sent to it directly and then routed to batteries through
isolator and then the isolator would have to have remote sensing at
batteries to be able to balance charge rate. The best way to try to
crudely balance them with a external charge is to place the positive
lead in the correct terminal of one battery and the negative lead on
the correct terminal of the other one as this will split the circuit
resistance between bot batteries some what (moreso than placing the
charger on one battery only). The higher the charge rate, the more of
a problem it is. On my dual battery setups in vehicles, I always run a
extra wire from alt output to second battery so it receives a better
charge rate without the bigger circut loss and it alos takes some of
the load off on main wire charging circuit too abd in theiry increase
rate of charge to both batteris at a give voltage output becaue if you
charge dual batteries at say 40 amps off of altenato. You will have
some drop in feed wire and more in circut to secon battery. With a
parrallel charge circut, the charge leads see less average load and
less voltage drop at a give load fso more power is deleivered to
battery. I also install a fuse in the extrra lead so that there is
some alt short circuit ptotection.
-----------------
The SnoMan
www.thesnoman.com
