Supercharge Your Solar Charge Controller Settings

[uncle_bob]

Originally Posted by pteck

Sure, if I want only the absolute best for my $90 batteries. For the minor ounces a year my batteries have taken, I'll admit I'm more than happy to compromise on many things and sometimes good enough (and RO is plenty good enough) will do.

We'll see what the new watering needs will be. Depending on that, I'll take your advice and keep a jug of distilled around.

Hi

Last time I noticed a bottle it was a bit over $2 for a gallon jug. No idea if that's normal or the deal of the century. If a gallon doesn't last you a season or two, I'd back off on the charger settings....

Bob

[gcarter]

I have been RVing since 1978 and always had house battery problems dealing with life span. 3 years ago got new golf cart batteries and added Thermoil. This is removing some acid and adding about 3oz per cell. Have added a LITTLE water once in the last three years and that was about a year ago.

[uncle_bob]

Hi

What happens when you crank up your charger settings to the "correct" numbers for a T-105 is that you drive off water as gas. Since it's already in gas form, an evaporation inhibitor isn't going to help. It's just what you get to put up with to get another ten or twenty percent out of your batteries.

Bob

[ROBERT CROSS]

I have used the AS AC drip water, filtered with a Brita in the Ford 6v.

Bob
🇺🇸

[rmkrum]

I carry two gallons of distilled water from the grocery store. Used very little so far.

Solar system does the charging and cooks off very little water in the last six months, maybe 6 ounces total. Not sure it all went into the batteries as I spill some when I disconnect the watering system from the connector. The solar charger does have a temperature sensor in the battery box.

Cheap GC-2 golf cart batteries in series from Sam’s Club. Added a battery watering system to make it super easy to check once a month.

[pteck]

Originally Posted by AirMiles

How much water per month? I typically add two or three full Big Red hydrometers of water per cell each month. You will need to check more frequently with your new higher voltage settings. I do have Temperature and Voltage compensation on my Victron solar controller and also leave my PD4655 converter disconnected except when I need to boost charge the batteries a few hours per year.

After a week, checked the cell water levels again. Each cell was down more water than I've seen checking at 6 month intervals with the default settings. Each one took about 1/2 a big red hydrometer worth of water after a full week at these settings. So not far off from what your suggesting after a month.

I can see why the default settings are so conservative now.

While supercharged voltage settings may maximize battery capacity, I'm not willing to deal with watering on such a regular basis. So I backed down the voltage settings. Closer to default voltages as I like default levels of water usage. I don't really need the more reserve anyhow.

[uncle_bob]

Originally Posted by pteck

After a week, checked the cell water levels again. Each cell was down more water than I've seen checking at 6 month intervals with the default settings. Each one took about 1/2 a big red hydrometer worth of water after a full week at these settings. So not far off from what your suggesting after a month.

I can see why the default settings are so conservative now.

While supercharged voltage settings may maximize battery capacity, I'm not willing to deal with watering on such a regular basis. So I backed down the voltage settings. Closer to default voltages as I like default levels of water usage. I don't really need the more reserve anyhow.

Hi

Keep in mind that the "super charged" settings are what give you the full rated capacity on the batteries. Backing off means you never really will get them completely "full". Equalization between cells also is impacted by the settings. They will equalize better at the higher numbers and that also leads to better performance.

All that said, watering them every few days along with the house plants *is* a real hassle Apparently the golf cart industry likes to water batteries. It's not at all clear what happens with the many thousands of carts you see running around your typical retirement community ....

Bob

[rmkrum]

Many of them have a battery watering system to make it easier.

I installed one. It replaces each of the battery caps with a gadget that has a float in it and tubing to interconnect them. A quick connect fitting on one end connects to a squeeze bulb pump. You simply connect up, put the pump inlet into your jug of distilled water and squeeze the bulb until it gets ‘firm’ which tells you all the floats are shutting off the water coming into the cells. Takes only moments to do.

Then you disconnect the bulb, drain the excess water out of it, and put it away.

I have my rig in storage, and around the first of the month I hit the batteries with some water. So far, maybe an ounce or two each time. The MPPT solar controller is temperature compensated and works well at not cooking the batteries. Came from AMSolar.

Google search should find the gadget. I think it came from camping world a couple years ago.

Possibly is a Pro-Fill System from FlowRite. The picture looks similar. It’s specifically designed for golf cart batteries. The one minor gotcha is that you must use very clean distilled water at all times. Since the cells are interconnected, these systems will fill them all properly, but you cannot tell if one cell is consuming excess water. A hydrometer check is also more difficult as you have 6 individual caps to remove instead of being able to take off three at a time. (My GC-2 batteries had three caps tied together with quick removal bars)

All in all a great way to speed up my battery maintenance, IMHO.

[pteck]

It's easy enough to switch my controller between the default flooded lead acid profile and user profile.

When my trailer is in storage, low maintenance is the priority. So I'll switch to the default profile which uses next to no water.

When active camping, I may switch to my user "semi-supercharged" profile a couple days prior to the trip to maximize capacity performance. Though I have backed the numbers down a bit as that last few percentage points of capacity is really not necessary for me. It's likely the absorption voltages where most of the water loss is happening. I'll leave equalization on the high end as once a month when my controller performs that at a higher voltage won't cause too much water loss.


Truthfully, even the default profile has served very well with 400W of solar.

[uncle_bob]

Hi

If you are in storage, there is no big need for anything other than a "float" voltage. Anything other than that is of doubtful value on the type of batteries you have. Yes, there is always an "if" to any absolute statement like that. If you store for > 6 months it would not be a good idea.

If you just float in storage and it's been months, then indeed some sort of equalization when you come out of storage should be done. You also should check water levels and tire pressure . It's all part of the "get ready to go" process. Let them run up to "full" for a day while the fridge comes down to temperature.

Bob