What is the available AMPS?

[Pgtjs]

Hi folks,

Some two years ago I followed the general advice in the Forum and upgraded to 4 Golf Cart AGM Batteries + a Starter 12 Volt AGM which has been in place for 6-8 years. All works well. I am not a techie and just follow instructions as to electrical matters.

The new 6V AGMs - from West Marine and bought at a big sale for about $260 each - have three amp levels marked on them. Each battery says in big letters they are 6V 190 AH Grp C2.

The sales literature says each has 680 CCA (cold cranking amps) and 900 MCA (marine cramping amps). On the advice of the electrical guy who installed them, I also added a Zantrex Lite meter and can precisely watch the amps in and out. We set the AMP hours at 380 (total) and it fluctuates with that as a base so at 50% used, it shows approx 190 hours accumulated use. I seldom let it get down to less than 70% which occurs whenever I leave the fridge/freezer on overnight and use the diesel heat in the mornings. Around here in the Pacific Northwest, most mornings are 55-60 at this time of the year, so it takes the chill off when we are at anchor which is often.

A yachtie friend around here says I have 760 AH usable capacity and thus twice what I set the Zantrex up with. The other issue is that the Zantrex asks if the batteries are (1) Sealed or (2) GEL or (3) Flooded which I know it is not. I set it at (1) but perhaps it should be (2)? From what the manual says, the difference between 1 and 2 is that the "Boost Charging Voltage" is 14.4V or 14.2V respectively. Should I change it to (2)? Any damage done by leaving it at (1)?

Incidentally I also added two 70W solar panels on the hardtop dodger and am disappointed at the results. Supposedly the best quality panels and made in MA. USA. They work just fine but produce at best 6 Amps and usually 4-5 when no boom shadow is present. Given this is the NW - at 48.00 degrees North, precisely where I am now in Canadian waters, it means at best on a good sunny day it adds about 30amps into the system. Not worth the cost: just run the diesel for an hour!

Look forward to the thoughts and answers,

Cheers all, Geoff, - Taeko 1V C350/392.

[wolfe10]

Geoff,

Answers in SOLID LETTER CAPS

The new 6V AGMs - from West Marine and bought at a big sale for about $260 each - have three amp levels marked on them. Each battery says in big letters they are 6V 190 AH Grp C2. OK, YOU HAVE TWO 190 AMP-HR AT 6 VDC PAIRS IN PARALLEL. SO YOU HAVE 190 AMP-HRS AT 12 VDC PER PAIR. TOGETHER YOU HAVE 380 AMP-HRS AT 12 VDC. USABLE AT 50% STATE OF DISCHARGE= `190 AMP-HRS @ 12 VDC.

The sales literature says each has 680 CCA (cold cranking amps) and 900 MCA (marine cramping amps). CRANKING AMPS ARE NOT REALLY RELEVANT FOR DEEP CYCLE AS IS YOUR APPLICATION.


On the advice of the electrical guy who installed them, I also added a Zantrex Lite meter... SUSPECT THAT IS XANTREX.

A yachtie friend around here says I have 760 AH usable capacity and thus twice what I set the Zantrex up with. DON'T LET HIM PROGRAM YOUR GPS! MAY BE A GREAT SAILOR, BUT NOT 12 VDC ELECTRICIAN.

The other issue is that the Zantrex asks if the batteries are (1) Sealed or (2) GEL or (3) Flooded which I know it is not. IF THERE IS AN AGM SETTING USE THAT. IF NOT, WET CELL CHARGING ALGORITHMS ARE VERY CLOSE.

SOME SMART CHARGERS/MONITORS/VOLTAGE REGULATORS ALSO ASK FOR AMBIENT TEMPERATURE, AS CHARGE VOLTAGE NEEDS TO BE HIGHER AT LOWER BATTERY TEMPERATURES.


Cheers all, Geoff, - Taeko 1V C350/392.

[russp]

Hi Geoff, I suspect your yachtie friend is thinking you have bought Li batteries and not AGMs. If they were lithium you can use most of the available capacity, but for AGMs definitely only about 50%, you should be trying to avoid taking them below 12V or you will shorten their life.''

6A or about 72W from 2 x 70W panels isn't exciting, but placed flat on your dodger is not going to get high efficiency, especially at high latitudes, 30AH/day is better than nothing? and should run your fridge or whatever for 4 or 5 hours at least, still better than another 1/2 hour or more of motor running IMHO if just hanging on the hook.

Regards