connecting solar charger to 2 12V

[Sceadwian]

rofl, thanks I feel better now.
Well I didn't expect shrouded plugs at ratshack, just hoping. I don't know if I trust the spring rating for good contact on ratshack generic banana plugs. For 'local' I'd suggest a local hobby store that sells RC stuff. The battery disconnects are at 12 volts good for well more than you can put through them, at least from the charger. Their disconnects should be rated for better than 10 amps. Just be wary of where you buy, and make sure you get current rating's directly off the box or in writing from the supplier.

 

[newhillian]

yeah whatever

 

[Sceadwian]

https://www.electro-tech-online.com/custompdfs/2009/05/1140.pdf
Help at all? Those are rated at 10 amps.

I'm a fan of the Deans ultra plugs, but they're not shrouded.
**broken link removed**
good for 100 amps. The RTF airplane plugs are good towards the bottom of the page, 10 amps and shrouded. The Tamya style connectors listed on the same picture as the RTF airplane plugs are common in RC.

 

[newhillian]

OK, my head is starting to hurt! I think I will take this info and visit an RC shop. I just looked one up in town and will stop in to see them. I like the Deans ultra plugs too, they look good and sturdy, but I think I would go with the RTF style just for the shrouding. Will they be gold? Should I ask? Should I just leave you alone?

 

[Willbe]

I might have missed it but you can't charge batteries in parallel unless you have some sophisticated switching going on to equalize the charging.

 

[Sceadwian]

Ask for gold, if they have them, might not, not gonna kill ya if it's not gold. Just check to make sure they're clean every now and then.

 

[newhillian]

Hi Willbe, I was beginning to think this was Sceadwian's personal site! If you've read all the way through our discourse, I covet your input. Sceadwian's head is getting kind of large.

 

[Sceadwian]

How Lead Acid Batteries Work
read for yourself.

For 15 watt charging current from the solar cells no special precautions for pack balancing need to be taken they'll self balance.

 

[newhillian]

well I guess that settles it then. That's a good link! I'm keepin' it.

 

[Sceadwian]

One last note, each battery should be fused independently, so that if there's a catastrophic failure of one or more of the cells from one pack that the other one won't try to dump a lot of current into the suddenly much weaker pack.

 

[bryan1]

I've read thru this post and not seen the amp/hour capacity of those 2 batteries. As far as 15 watts of PV to keep a boats RE system charged is pure folly. Yo give you an idea I'm going to put 10 watts of PV on my electric fence system with a 12 volt 7ah battery.

I have had some experience with RE systems on boats and the current draw for just winding up the winch is close to 100 amps@ 12 volt. Now thats a 1.2Kw draw on the batteries and if your boat is similar would you expect 15 watts of PV to charge the batterybank after a current draw like that.

If you want some help first mention the size of the boat, the appliances thats going to be used and the time frame of use continually.


Cheers Bryan

 

[Sceadwian]

Post #15 according to the numbers he provided the pair should give 85amp hours.

 

[newhillian]

Bryan1,
Post #1 "26 foot Sailboat"

Post #14 " My load is am/fm/cd, a vhf radio, depth/wind/speed sensors and my running lights".

Post #14 "2-3 10 hour sails per month"

Post #15 " That's 87 amp hours"

I think that satisfies all of your requisites for a "proper" post to gain information from the board here. Not to be a jerk, but to me your response comes across as arrogant and impatient. It is also clear that contrary to your claim, you did NOT read the the post(s). If you have advise contrary to that which Sceadwian has supplied or if there is something we missed, please chime in, otherwise save the air. Again my apologies for having been rubbed the wrong way.

Oh, and I have neither an electric winch, nor fence on my vessel.

 

[bryan1]

why bother

 

[newhillian]

precisely what I thought

 

[tcmtech]

I might have missed it but you can't charge batteries in parallel unless you have some sophisticated switching going on to equalize the charging.

Apparently you dont work around big farm equipment, commercial trucks , diesel pickups, bigger boats, or 12 volt based backup power systems.
Typically anything that uses a big engine that starts on standard 12 volts will run two or more batteries in parallel. Everyone of them has a standard 12 volt high amp alternator charging those batteries connected in parallel with nothing between them but big cables!
No fancy switch gear or electronics, Just positive to positive and negative to negative!


And as far as I know a 15 watt solar panel would put out about 1 usable amp while charging. Given a 1 amp trickle charge is low but still an estimated 80 -100 amp hour deep cycle battery will in fact charge at that level.
For a fairly rundown set of batteries it could take 8 -10 days with 12 hours sunper day to do it, but it would do it!

I see nothing wrong with the system design so far. At the worst it will work as a system maintainer and just keep the batteries from discharging any further while sitting.

 

[Nigel Goodwin]

Talking batteries, here's a nice little story you might enjoy

An old friend of mine, who unfortunately died of cancer last year, years ago bought a mini-pickup - for £35 if I recall?.

Instead of the normal little mini sized car battery, it came with two HUGE 6V lorry batteries in the back - and if you were driving along and turned the starter, it went faster

To end the story, he 'obtained' a normal mini battery from work (he worked at a garage), and sold the two lorry batteries for £50.

Nice deal, got a pickup for nothing, and made £15 on the deal!.

There's an even better story about the non-functional heater, but that can wait for another day.

 

[tcmtech]

Hahahaha! I suspect Ford copied that engine design for the escort model!
If you were passing you shifted down one gear. If you need to pass someone fast you also turned off the air conditioning and blower motor! It was a noticeable power increase!

What piece of underpowered sh*t those cars were.

 

[Sceadwian]

New car but a dinky little Kia Rio I used to drive was like that, if I turned the AC off on the highway I could go 5 miles an hour faster at the same revs. That starter bit is hilarious though

 

[Nigel Goodwin]

I'll tell you the rest of the story then.

A mini pickup has a VERY small cab, and my friend Kenny came and picked me up one VERY cold winters night, then we drove to Buxton to pick up another friend (Nog) - Buxton is one of the highest towns in England, and always cold.

Now the heater in this car was completely non-functional, and by the time we got to Buxton we were freezing, but Nog came out and brought a gas bottle and blowtorch (he was a plumber). I slid across to the middle of the car, with the gear lever and handbrake between my legs, Nog got in the passenger seat, turned the gas bottle on and lit it. We had a nice warm car, with a long blue flame across the dashboard

We then drove back to where I came from, Birchover, and went to the Druid Inn for a pint - when we came back out it was even colder, Kenny climbed in the drivers seat, I slid across 'impaled' round the gear lever again, and Nog slid in the passenger seat.

Nog struck a match, held it up, and turned the gas on - but it was so cold it spat liquid propane out of the torch - all over the dash board of the car, igniting as it passed over the match.

Kenny bailed out the drivers side, Nog bailed out the passenger side, and there was me stuck either side of the gear lever going nowhere

Luckily the flames soon went out, with no harm done, and it demisted and defrosted the windscreen faster than anything I've ever seen.