Battery Chg.

bigjim · December 12, 2016

Situation. 2 new 6V golf cart deep cycle from Sam's. 200 Watts of solar panel. 1000W pure sine wave inverter off line. Not happy with the recharging. I only have a basic converter charger. I have 10 amp battery charger I can use at the battery terminals. Can I safely use it to bring the batterys back to full charge while still having the converter/charger and the panels on line in the system.

Does the Inverter draw current when turned off on the inverter but not disconnected from the batterys?

pjstough · December 12, 2016

Yes, you can combine more than one charging source. The inverter will not draw any current when turned off.

dartmouth01 · December 12, 2016

I have a similar set up. 200w of solar won't get that much charging, especially during the winter with low sun angles. It is enough to keep the batteries topped up when storing, or days of light usage. We have to run the generator during the day to supplement, since we work during the day and have multiple computers and monitors and such running. If you don't have one already, install a Trimetric or other battery monitoring system. You will see how much is going in or out of the battery, and what devices are using the most power (and you will be able to confirm if your inverter draws any parasitic drain).

skp51443 · December 12, 2016

Depending on the inverter brand and model it may draw a small amount of power when turned off, usually only a few milliamps that powers the power-on circuitry.

What basic converter do you have? Some can be upgraded (adding a charge wizard device) cheaply to provide much better charging, others can't and you might want to think about upgrading. A modern converter with a charge wizard type setup will manage and preserve your batteries much better than an older converter and it will provide far more charging current. Don't go too big on the ratings for the new converter as your maximum safe charge rate of the GC batteries could be exceeded.

Using multiple dumb chargers together works fairly well but if you have a smart one in the mix it will be confused by the additional charge sources and may switch modes at the wrong charge levels.

bigjim · December 12, 2016

Thanks a bunch. I sort of knew most of what you all have said but just wasn't trusting the memory this AM. (its the medication not the age) :mellow: I had a good converter w/charge wizard for a couple of years but it didn't hold up. Now I have a slightly used take out original install one that I don't recall the details on but will try to sort out. I only have the 10 light set --up showing battery chg. state which of course reads off the panel as 100% when I have sun. I am trying to maintain a basic status qou for now but an not happy that the new batterys are not getting backed up to full charge. I normally don't need them in the winter so getting them back up should get me by until I get back to more sun. Sun is definitly the issue now. Not enough to get the batts to full due to shading a good part of the day and overcast, rain and short days.

skp51443 · December 13, 2016

A old style converter won't get you to a full charge in a reasonable time, it never puts out enough voltage. The battery charger is likely designed for starting batteries and won't be getting you to a completely full state in your deep cycle batteries, but it is likely coming closer than the converter. Give them enough time to do as much good as they can and call it good for now.

When you are ready to upgrade a lot of folks have had converter replacement discussions here on the various brands.

Al F · December 13, 2016

Situation. 2 new 6V golf cart deep cycle from Sam's. 200 Watts of solar panel. 1000W pure sine wave inverter off line. Not happy with the recharging. I only have a basic converter charger. I have 10 amp battery charger I can use at the battery terminals. Can I safely use it to bring the batterys back to full charge while still having the converter/charger and the panels on line in the system.

Does the Inverter draw current when turned off on the inverter but not disconnected from the batterys?

200 watts of solar should keep your batteries charged as long as you don't take the batteries down more than 25% of the capacity (75% full). That would be using about 50 amp hours a day.

In on a nice sunny day from about 10am to 2pm I would expect to see 6 to 12 amps of power coming from the panels. You will start seeing an amp or so coming from the panels as soon as the sun hits the panels. This will increase as the sun rises.

Bottom line: on a nice sunny day I would expect to see 50-70 amp hours (AH) of power (from 8am to 5pm) coming from your panels.

What indications are you seeing which tells you that your batteries are not charged well enough?

A lot of your charging depends on your usage as well as several other things.

-- You have a 1000 watt inverter, so your usage shouldn't be that huge. The inverter won't power the microwave, coffee pot or toaster.

-- What do you power with the inverter?

-- You have 200 watts of solar.

--What size and brand/model panels do you have?

-- Do you have a solar controller or are the panels wired directly to the batteries?

-- What length and size are the wires connecting the solar panels to the controller or battery? This is very critical information. The size and length can really impact the charging.

-- About your PSW 1000 watt inverter

-- Does it have a charger?

-- What brand/model?

How old are your batteries? I know you said they are new, but how many dry camping/boondocking cycles (days of camping) have you gone through? Rough number not an exact figure.

Also consider:

-- If the batteries have not been brought to 100% charge at least every week, or better yet every 4 days or so, they will sulfate and loose capacity. So the usage which used to only bring you down to 70% full is now bringing you down to 50% full or lower.

-- Have you equalized your batteries? Probably not since batteries are new you mention you only have a converter. Many inverters with built in chargers can equalize your batteries.

As someone else mentioned you really need a battery monitor, like the Trimetric to know how much power is going out of and back into your batteries. Especially if you do more than just an occasional overnight w/o hookups.

kinseypw · December 14, 2016

Just a couple of thoughts. A fellow camper here in Yuma is also having problems with charging and asked me to have a look. First problem is his panels are flat on the roof of his RV and so he doesnt get close to 200W. Panels output is strongly affected by the angle to the sun especially in winter when the sun is low. Second problem was the wiring from his charge controller to the batteries - looked to be about 16 gauge wire and a long 15-20ft run. Losses in the wire meant that even tho the charge controller said it was putting out 13.6v he was only measuring about 12.6 at the battery. I use 4 gauge from controller to battery and the run is only 2ft. One other thing I found out the hard way was that the car battery charger has a significant current draw when it is connected to battery but turned off from shore power. I left the battery clamps connected one time on my 420 amphour battery bank and voltage was down to 11.9v 2 days later

bigjim · December 16, 2016

Inverter is Kisae 1000W pure sine w/no chgr. Wire is #4 with a run of about 7ft for positive & 6-7ft for neg. I have the inverter offline now- let's say off but in standby. The batts are about 2 month old now. I used them hard for about a week but not below 50% but was not happy with getting them back up to speed. I have used the old style car charger (1960's) 10amp max twice now for about 5 hours each time a day or 2 apart. I know this has helped and I would have done it longer but I have to work it around the weather. I have 2 100W panels flat that I have used since 9/2001. The only real change is the inverter since it isn't online currently I am fairly certain the issue is standard shading, sunlight, sun angle for now. I just did not want to not get the new batts back up. I think I am good to go now but I am watching it daily.

dartmouth01 · December 16, 2016

My 200W panel is lucky to see 5A back in the battery on a sunny day this time of year. It lays flat on my roof and also is factory spec'd, so the efficiency values already aren't probably very good. My converter (when hooked up to a genny or shore power) puts back upwards of 25A back in the battery if the voltage is low, but trickles down as the battery recharges. Next step will be for me to install and inverter/converter, something that is more efficient for recharging (I have a 1k generator that I run for just this reason, so I don't have to start up the noisy 4k built in one). I love my solar panels during the summer months, but I realize now that I won't be willing to give up a generator to go solar only anytime soon......

Al F · December 16, 2016

Inverter is Kisae 1000W pure sine w/no chgr. Wire is #4 with a run of about 7ft for positive & 6-7ft for neg. I have the inverter offline now- let's say off but in standby. The batts are about 2 month old now. I used them hard for about a week but not below 50% but was not happy with getting them back up to speed. I have used the old style car charger (1960's) 10amp max twice now for about 5 hours each time a day or 2 apart. I know this has helped and I would have done it longer but I have to work it around the weather. I have 2 100W panels flat that I have used since 9/2001. The only real change is the inverter since it isn't online currently I am fairly certain the issue is standard shading, sunlight, sun angle for now. I just did not want to not get the new batts back up. I think I am good to go now but I am watching it daily.

I would guess most of the problem is you don't have a charger which will get your batteries to any wheres near 100% charged in the time the charger has been connected. However w/o a battery monitor like a Trimetric to measure how many amp hours (AH) are going out and being put back in it is very hard to say for sure.

Assuming your car charger puts out 10amps continuously you are attempting to put back 50AH in 5 hours, but since the charger voltage is "probably" about 13.4 volts, you are not getting as much power back in the batteries as you would think. The golf cart batteries need a bulk or absorb charge voltage of about 14.6 to 14.8 volts to do an efficient job of charging the batteries.

bigjim · December 17, 2016

Definitly working with less than optimal equipment at the moment but sometimes you just have to work with the stuff you have until you can get something better. One thing useful to some extent is the Inverer has a digital read out of battey voltage when it is turned on. So I am checking it once or twice a day. Then tuning it back off. Probably wouldn't hurt to leave it on but I don't. The cold here is not helping either.