Charging golf cart batteries hooked up in series

[john61ct]

Originally Posted by Sunsetrider

Just using diesel to get from A to B, not to charge the batts.

But a big Alt is worth looking at compared to more solar, IF you need more input. But only if you're motoring many hours per day, especially in the mornings. Or a little genny if you already carry petrol.

Originally Posted by Sunsetrider

But bottom line, you think an investment in a 20A charger, for examplle, is worth the cost?

And actually, maybe more.

I don't see it as optional, and 40A is IMO low.

And a good batt monitor, unless you're regularly using a hydrometer.

Originally Posted by Sunsetrider

I know that it can be risky to hook an older battery up to new ones, but this is only one season old and not heavily used.

The bank will perform as good, last as long as the weakest member.

Since a new additional pair is only what $180 I'd say no, but up to you, a stinkpot certainly has less risk than LD cruising at sea.

[CSY Man]

Originally Posted by Sunsetrider

So assuming I had said watts, what then? Or did that error throw everybody else right off the deep end of the pool as well?

99,9 % of the people on this board knew what you meant to say, but probably tempting to play along to see how much you would insist on amp hours rather than watts.

No biggie, we have all had too much brew and or been wrong, many times.
I am th poster boy for all of the above..

[StuM]

Originally Posted by CSY Man

99,9 % of the people on this board knew what you meant to say, but probably tempting to play along to see how much you would insist on amp hours rather than watts.

No biggie, we have all had too much brew and or been wrong, many times.
I am th poster boy for all of the above..

Yep! (He said A (Amps), not Ah (Amp hours)

[CSY Man]

Originally Posted by StuM

Yep! (He said A (Amps), not Ah (Amp hours)

Aye, he did, but he meant amp hours instead of amps and he meant watts instead of amps.

[Pete7]

Originally Posted by StuM

Yep! (He said A (Amps), not Ah (Amp hours)

A hanging offence on CF

Anyway back to Sunsetrider, so alternator, big solar panel and top ups from a battery charger when in a marina, so the question is this enough?

The answer can only be found by trying it for a weekend and monitoring the AH. Does the boat have any form of battery monitoring?

Pete

[StuM]

Originally Posted by CSY Man

Aye, he did, but he meant amp hours instead of amps and he meant watts instead of amps.

You can't rate solar panels in Amp hours! You can rate them in either Amps or Watts.

[Sunsetrider]

OK so we're all good now.

I have a Midnite SOC gauge to hook up. It's basic, shows the percentage of charge, which I expect will tell me whether my usage is overpowering my equipment - at least that is the plan. Certainly, some have told me I should have a bigger alternator, others have said I should have at least 4 GC batts, and everyone says I need a bigger charger. But I can't do it all, I am already spending too much on this 45 year old 25-ft. vessel. So far my tip of the hat to cutting consumption is an LED anchor light ($85), and onboard electricity is used pretty much exclusively for charging the iPad and cell phone - that is, until the arrival of the fridge/freezer (avg 2.7 A p/h average over the course of the day if advertised accurately).

So my idea is to go with what I have and see if it works. I can upgrade the batteries if need be; upgrade the charger if need be. It's kind of why I went for the biggest solar panel I could fit on the boat without getting silly. But I guess my question is - does it make sense to see how this limited plan works before spending more - and trying to figure out where the heck I could fit additional batteries in any case! I need to work out the answer to that while cruising in local waters.

[mitiempo]

Originally Posted by Sunsetrider

But I guess my question is - does it make sense to see how this limited plan works before spending more - and trying to figure out where the heck I could fit additional batteries in any case! I need to work out the answer to that while cruising in local waters.

Yes, try it and see. The unanswered question is your daily AH usage.

Ideally you want a large enough battery bank for 2 to 3 days without charging.

[CSY Man]

Originally Posted by StuM

You can't rate solar panels in Amp hours! You can rate them in either Amps or Watts.

Yeah, I know. Just testing the crowd.

[john61ct]

Without the fridge you should have no problems at all.

With the fridge you will need to make use of that monitor to keep an eye on SoC patterns.

Have a look at Maine Sail's excellent posts on getting as much accuracy out of them as possible.

Getting more insulation around the box, and venting the hot exhaust air away from the compressor, will really help with its efficiency.

[Stu Jackson]

Originally Posted by Sunsetrider

You are right of course. Canada Day and I may have had a beer too many. Your reply might make you feel superior and me like an ass but your "wish" is my command. Watts. I'll eff off now and try another source for answers that add value to questions with obvious errors. Have a nice day.

WADR, he can't read your mind, only what you type. And he's right for pointing it out because if it was a typo it's one thing, if it was an error you might be glad he pointed it out.

Happy Canada Day! 150 - WOW!

[wcapman]

My boat runs 2 banks of GC2 Golf Cart batteries. The system includes 2 solar regulators and 15 amps from panels, a 3 step Balmar regulator coupled to a modified Delco 150A alternator, and a Xantax 40 amp 3 step AC charger. Each bank has a Link 10 for monitoring and the alternator has a separate amp meter. The trick with using any flooded battery is to keep the battery above a 50% charge and to equalize the batteries at least once a month. My total amp draw is about 30 amps with all electronics powered up and a DC refrigerator. This can quickly draw down the batteries while sailing at night. In cooler weather and with no radar my amp draw is about 15A/hr. However at anchor the draw is about 5A/hr, which is quickly replaced by the solar panels. I have found that the 40A charger is more than adequate to fully replace lost amps overnight. The alternator can replace the charge in about 5 hours.

My point being that to properly maintain a set of flooded batteries, whether Golf Cart or not, one needs to have a battery monitor on each bank. Without such, you have no idea how much current you have pulled out and how much you need to put back in. Voltage alone will not tell you what you need to know. For instance, say a bank is down 40%. The resting voltage should be about 12.3, but if there is just a slight load on the battery the voltage reading could drop a few more tenths, depending on how and where the meter is wired into the circuit. Unless you know the total accumulated amps drawn you have no idea when you have reached the 50% level or when you have replaced all the amps drawn. I killed a lot of batteries until I put in the Link 10's. Now my GC2 banks last 5 to 7 years.

[john61ct]

Originally Posted by wcapman

My boat runs 2 banks of GC2 Golf Cart batteries.
...
one needs to have a battery monitor on each bank.

Your batteries will last longer and deliver greater total energy without being discharged as low, if you combined all banks into one big one.

Unless there is a really compelling reason to keep them separate of course. . .

[wcapman]

Originally Posted by john61ct

Your batteries will last longer and deliver greater total energy without being discharged as low, if you combined all banks into one big one.

Unless there is a really compelling reason to keep them separate of course. . .

I respectfully disagree with connecting all batteries in parallel. I am assuming that you mean both banks of GC2 batteries, that is 2 sets in series and paralleling those two banks. In fact paralleling any pair of 12v batteries is only good for starting an engine. My experience when reverting back to house load without a charger (solar, alternator or AC) connected, is that each bank should be operated separately. Battery chemistry being what it is, one bank will discharge into the other. It is far better to OPERATE with isolated banks and charge in COMBINED mode.

When operating 2 GC2's in series, chemistry is not a factor. If one cell goes down, that is no different that a cell going bad in a regular 12v battery.

If all the batteries are replaced at one time with identical batteries thsi is not quite as important, but unless one is diligent about equalization and keeping fluid topped up and only using distilled water, chemistry will change. I've operated two sets of GC2s, but one set is in the cabin under a settee and the other is in the engine compartment. These batteries operate at different temps and that affects chemistry. Evey boat is different. If one is fortunate to have all 4 new batteries located in one cool place there is a better chance of parallel operation, but after the batteries get a few years on them, best to operate as two separate banks, especially if you rely on one or the other for engine starting.

One other issue I've found with Sam's batteries is the date code. This may apply to Trojan's also. There is a round sticker on the batteries that I've bought that indicates the date code. If I recall the letter is the month of manufacture and the number is the year. Make sure that you have all date codes matched and the month is no more that 1 from the present month. It is not common practice to charge these batteries while in storage and the batteries will self discharge and partially sulfate. If you mix an older battery with a newer one, the battery bank will never perform as well because the sulfated battery will keep the other battery from charging fully even during equalization.

[slowpoker]

What if the original poster guy that is wondering what to do with his existing charger and worried about buying an expensive, bigger charger; just gets another 20 Amp or 30 Amp charger and uses both chargers at the same time to charge the same bank of batteries?
Meaning charging with the original 20 Amps which is already installed and all, plus put another 20 Amps from a newer, different charger to pump additional Amps, both at the same time? Then he would basically have about 40 Amps charging and if the old one quits, he still has some way to charge his batteries.
Just an idea to beat around the forum for opinions.