Napa 85-5000 battery charger manual

SkiMore wrote:


Step 1) Solar panel.

Step 2) Bring batteries home and hopefully recover them
If the batteries are shot I'll drop down to 2 x 12V * 100A (2400watt) which will give me 1200 usable watts which is still way more than I need. I could probably use 1 battery and get a nice small sinewave inverter and be ok also. On the rare times I need more power I could fire up the generator.

Based on 1200WH(notice the H as it is important)

1) Solar: Have you decided between 12V and 24V battery banks?

The 30A charger is a good match for a 24V 100AH bank. 30% is an optimal rate that balances fuel, charge time and battery life. For a 12V 200AH bank, 60A would be your target. However, with solar, the 30A should be fine. I bulk charge a 110AH bank with a 12A(10+%) charger and then let the solar take over for absorption and float. Together, the charger + solar works very well.

2) Watt-Hours;
a. 2 * 12V 100AH in series is 24V * 100AH = 2400WH
b. 2 * 12V 100AH in parallel is 12V * 200AH = 2400WH

At a rate of 120W you will reach 50% in 10 hours, that is, you have used 1200WH. 120W is approximately the 20hr rating of 10A for 12V, 5A for 24V.

Above or below 120W draws, the AHs taken will vary. In the extreme, you will not get 1200W for an hour, but maybe 30min. Under 120W you will get extra time. This is how batteries work with inverter draws.

This is important to consider because to size solar, you need to know how many bank AHs need to replaced. You can't simply size solar arrays on Watts alone.

Using your 1200WH projection we can SWAG your solar Watts. Do you intend to recharge daily by solar and use the genny for inclement weather? If so, divide 1200 by the daily insolation for you location. Say you get 3.5hrs of daily solar insolation, 1200/3.5 = 360W array. Insolation will vary by season.

HTH;
John

As far as the 120V LED bulbs, get either Philips or Cree. Don't waste your time with the other one's.

MEXICOWANDERER wrote:
Chew on this: At 80% charge when a pair of batteries can digest maybe 20 amps, three pair can digest SIXTY amperes. Double the ampere hours double the SAFE amount of amperes. Works the same for a string of sixty two volt cells for high wattage inverters, (add another bank) or for 2 single 12 volts. When my batteries are almost charged they are accepting over a 100 amps!

I didn't understand this when you wrote it a couple of days ago. I'm trying to chew on it now. Is that the setup you have? Do you run a full home offgrid?

pianotuna wrote:
Hi,

TripLite is a high quality MSW inverter.

Forget the induction cook top--they require pure sine wave.

I would buy one dimable LED 120 volt bulb and try it.

115 minutes is the "reserve capacity". There is an approximate formula for conversion to amp-hours at the 20 hour rate. Check the wobbly wide web.

A good guess may be 200 amp-hours per battery. Since the system is 24 volts that gives you 400 amp-hours X 24 v = 9600 watts. Of which you can use 4800 safely.

In your shoes I'd start by fully charging each individual battery, then equalize and finally desulphate.

Since there are 8 you could keep four "in service" while treating the other four one at a time. The catch will be time as desulphating can take over 24 hours per jar.

In any event, get solar.

Sounds like a winning plan.

I'll buy a couple of different bulbs and see how they work. I'll give tripplite a call. Maybe they know what bulbs I can use.

Step 1) Solar panel.

Step 2) Bring batteries home and hopefully recover them
If the batteries are shot I'll drop down to 2 x 12V * 100A (2400watt) which will give me 1200 usable watts which is still way more than I need. I could probably use 1 battery and get a nice small sinewave inverter and be ok also. On the rare times I need more power I could fire up the generator.

full_mosey wrote:

Yep! You should go ahead and use all your batteries. Then when you run the genny, at least it will have something significant to do and make better use of fuel.

I think the generator+charger+battery setup I have is a loosing inefficient battle.

My charger is only 24V@30A = 720watt
Generator = 7000watt (I'm only using 10% of capacity)
Battery bank is 8 batteries * 200A(approx) x 6V = 9600 watts
I'm not sure how many hours it would take to charge the batteries anywhere near capacity, but I do know that it is way longer than I'm interested in running the generator. And, I don't need 9600 watts (4800 usable) than I need for a weekend.

I think that solar is the answer. Get a 200-300watt system and let it charge the batteries while I'm not there and hopefully not need the generator.

Hi,

TripLite is a high quality MSW inverter.

Forget the induction cook top--they require pure sine wave.

I would buy one dimable LED 120 volt bulb and try it.

115 minutes is the "reserve capacity". There is an approximate formula for conversion to amp-hours at the 20 hour rate. Check the wobbly wide web.

A good guess may be 200 amp-hours per battery. Since the system is 24 volts that gives you 400 amp-hours X 24 v = 9600 watts. Of which you can use 4800 safely.

In your shoes I'd start by fully charging each individual battery, then equalize and finally desulphate.

Since there are 8 you could keep four "in service" while treating the other four one at a time. The catch will be time as desulphating can take over 24 hours per jar.

In any event, get solar.

SkiMore wrote:

So, even with two batteries I wouldn't get past 90% charge unless I burned a lot of gas.

Yep! You should go ahead and use all your batteries. Then when you run the genny, at least it will have something significant to do and make better use of fuel.

SkiMore wrote:
How are people in RVs without solar effectively charging their batteries?

At least once per month you go to an electric RV site and plug in for a day. Or, for the weekend camper, go home.

HTH;
John

That 115 AT 75 goes with a 6v at 226AH more or less. Two of those in series would be a bank of 226AH at 12v.

It would take about 2 hrs to recharge that pair from 50-90% with an 80a smart charger. Add another ten minutes if you start with a 60amper instead of an 80.

If you do several 50-90s in a row on that pair their capacity drops due to "progressive sulfation" until they won't get you through one night. Then you need shore power to get them back to 100% and start over. Two weeks was our max for that.

To go longer with the same daily draw, you need solar. This negates some of your daily draw so you can stay out longer --ie, same number of 50-90s, but with longer times to drop from 90 to 50.

If you have solar but go home every so often, then while you are away with no draw, but with solar coming in, you can catch up. This lets you keep going with a fresh start doing 50-90s.

pianotuna wrote:
Hi SkiMore,

Ah, but...after 85% state of charge acceptance rate drops to about 12.5 amps per 100 amp-hours of storage (at 12 volts). Thus generator run time becomes excessive. At 95% it is about 3 amps per 100 amp-hours.

There are 120 volt led bulbs but I'm not sure if they like inverters. What inverter do you have?

Unfortunately if you wish the battery bank to last, of the 5500 watts only 2750 should be used (i.e. 50%).

You speak of eight batteries. What are they? How many amp-hours?

So, even with two batteries I wouldn't get past 90% charge unless I burned a lot of gas.

How are people in RVs without solar effectively charging their batteries? Are they dumping massive amounts of energy into them while connected to the wall? Do people with TTs or FWs run extra heavy wires from the alternator all the way back?

I forgot about the 50% thing. Even at 2750 watts that is a huge amount of power especially if I had a 300watt panel charging it while I was there. It's more than I would know what to do with at the cabin. I guess I could buy an induction hot plate and save the propane and get a 5000BTU AC unit. Sounds like I won't need so many batteries when it comes time to replace them.

Thanks for mentioning the possible issue with 120V LED bulbs and some inverters. I'd hate to buy a bunch of expensive bulbs and have them not work or fail early. Do CFL bulbs have the same problem?

The inverter is triplite PV-2400 2400watt 24V input.

We have 8 NAPA 8144 batteries. They are probably 5 years old. I'm having a problem finding the AH spec. It says 115MINS@75A on them. Does that mean it is a 144AH?

SkiMore wrote:
This forum is so full of abbreviations there is no way to know them all.

Even this old timer didn't figure out that one. It's usually MW, but the O threw me.