Parallax series 7300 converter question

To add to the discussion---and then there is duration to consider,i.e. my solar charge controller charges, in the Winter, at a higher rate of bulk and float but is only charging during the day, of course. It is charging three small AGM batteries and also two GC2 6 V's. In the Winter, temp compensation and the set charging voltages will be pushing charge at 14.8 V and a float of 14 or so. To date, I don't NOTICE any bad effects to either bank. Since I have AGM's that the mfg suggests to charge at high rates and the 6 V's thrive at near 15 V, a single configuration of set points is working well. I should have tested the AGM's capacity before installation and during their use on an intermittent basis but the battery Gods deemed differently.

I first added water to the 6 V's a few weeks ago. That was over a year with the controller doing the brain work.

BFL13 wrote:
If I lived where it is hot, I would need a lower Float voltage.

The float voltage needed at any given temperature apparently varies by battery design and/or type.

My particular AGM batteries say right on their labels to use a float voltage of 13.5 volts to 13.8 volts, making my 7345 perfectly safe for them from a water vapor loss viewpoint while being floated.

Maybe all wet cell lead acid batteries should be floated at around 13.2 temperature compensated volts - I don't know. It looks like dry cell lead acid (AGM) batteries can be different. For instance, Lifeline recommends a nominal float voltage of 13.2 volts for their AGM batteries. (However, MEX floats his Lifeline AGM battery at somewhat over 13.5 volts, I believe.)

4X4Dodger wrote:

KATOOM wrote:
Thank you. But really if its a signal stage, wouldn't it eventually cook the batteries in a few weeks or so no matter the weather? I guess I'm confused.

The documents that came with my Parallax 7300 clearly state that it will revert to a trickle charge when it senses the batteries are fully charged.

Now this is not to say that the 7300 is as good as most of the new generation of smart chargers that charge batteries in four distinct phases. But I am not sure it is accurate to say that it will fry your batteries.

Parallax has replaced the 7300 (mine is actually a 7345) with the 8345.

That 'trickle charge' is in the amps being reduced. The voltage remains the same at 13.8

The 7300 series has been renumbered but remains the same. No longer made AFAIK. That line was replaced with their newer designs.

Living in a moderate climate, I have no need to replace the 7355 for its Float, but I did have to find a better and faster charger for deep cycle batteries that need up to 15v at times.

If I lived where it is hot, I would need a lower Float voltage. To get that, you can swap to a converter that will do 13.2 which is good at 80F. But some folks see 100F as normal, so what do they do? One way is to not float at all, but let them sit with occasional shots of charging. Or stick with 13.2 and add water often. Or move North! :)

KATOOM wrote:
Thank you. But really if its a signal stage, wouldn't it eventually cook the batteries in a few weeks or so no matter the weather? I guess I'm confused.

The documents that came with my Parallax 7300 clearly state that it will revert to a trickle charge when it senses the batteries are fully charged.

Now this is not to say that the 7300 is as good as most of the new generation of smart chargers that charge batteries in four distinct phases. But I am not sure it is accurate to say that it will fry your batteries.

Parallax has replaced the 7300 (mine is actually a 7345) with the 8345.

BFL13 was abusing the ice cream due to Paramode is a bit weak on voltage.
If normal was 14.8 it would be fine but I think BFL13 was a bit bored at 14.0/14.2 volts.

pnichols wrote:

BFL13 wrote:
We won't talk about how I stuck the Paramode's temp comp wire sensor ring terminal in some ice cream to get the charging voltage higher.

It's good experimental procedure to do that "in a lab" for making measurements ... but probably shouldn't be used when camping .... ESPECIALLY IN WARM WEATHER to make charging voltages even more dangerously higher! :B

I did something similar when testing my first Magnum 1012 inverter's charging function. I used ice cubes and a hair dryer to to ascertain that the unit was faulty. After the RMA I now have a good unit.

HTH;
John

pnichols wrote:
... and just to make sure that it's perfectly clear what "temperature compensation" means with respect to a battery charger
....

Temp-comp for me is with respect to battery temp, not air temp. That is true to my three temp comp chargers. All three have a sensor cable directly attached to a battery terminal and do not measure ambient temps.

The temp comp cables are around 30 ft long although none of the chargers and batteries are more than a few feet apart. Most of the cables lengths are coiled. One of my batteries has two temp comp cables; one from the solar controller and the other from the inverter/charger.

HTH;
John

BFL13 wrote:
We won't talk about how I stuck the Paramode's temp comp wire sensor ring terminal in some ice cream to get the charging voltage higher.

It's good experimental procedure to do that "in a lab" for making measurements ... but probably shouldn't be used when camping .... ESPECIALLY IN WARM WEATHER to make charging voltages even more dangerously higher! :B

The Paramode has the temp comp sensor right at the ring terminal that goes on the battery post at the end of the long wire from the TempAssure part on the converter chassis.

The only difficulty is routing that wire from converter to battery in your rig if there are things in the way. I had a deck- mount up by the batteries, so that was easy. But the units they also make that replace the original converter under the fridge or someplace back in the rig would need that long temp comp wire routed out to the batteries somehow.

Inverter/chargers with temp comp seem to have the wires too. That just leaves some solar controllers with temp comp mounted on the solar controller itself, so unless you have the solar controller in the same ambient temp situation as the batteries it can cause problems. (That becomes easier if yours has a remote display that can be inside the rig while the controller is outside with the batteries (but not in the sun and rain either.)

We won't talk about how I stuck the Paramode's temp comp wire sensor ring terminal in some ice cream to get the charging voltage higher :)

... and just to make sure that it's perfectly clear what "temperature compensation" means with respect to a battery charger (IMHO engineering guesstimate): It means the charger voltage-compensates for the temperature of the air as detected right close to the exterior surface of the battery - NOT the temperature of the air around the charger itself or directly on the surface of the battery.

If my guestimate is correct, this means that it makes no sense to try and use the Paramode charger (or any other temperature compensated charger) as "stand alone" ... or without it's remote temperature detection probe being routed over to, and attached someway very close to, the outer suface of the battery.

Compensating for the air temperature somewhere right close to the battery is the only method that makes any sense with respect to the temperature versus charging voltage charts that seem to imply how to charge a battery, voltage-wise, in the various camping or storage temperatures the battery is sitting in.