New to all this 12v power stuff, need advice on these batteries.

[bunce1260]

I'm building a Chevy Astro into an Adventuremobile, I want to be able to run lights, stereo, electric mattress pad, 12v kettle and phone/laptop chargers from the house battery.

Would 2 of these Schumacher SB 12350 '12V' 35Ah AGM Sealed Lead Acid Power Sport Batteries ( http://amzn.to/1MIRJdN )be enough to do the job?

It seems these scooter batteries seem to be a good Ah to $ value as 2 of these would get me 70ah for $124 and free shipping through Amazon Prime.

Your far more experienced thoughts are welcomed.

 

[228B]

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You're looking for a deep-cycle battery setup. There's no reason those Shumacher AGMs can't handle deep-cycle duty, but they're light on capacity. 35 amp hours isn't much.
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Remember too that to preserve a deep-cycle battery (or battery bank)'s lifespan, we don't want to discharge them more than 50%... so you're limited with what you can do between charges. If you were to also invest in a small solar charging setup, you'd have more effective capacity due to the solar charge current available during sunlight hours.
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Still, the electric bedding and the 12V kettle, especially, will eat up battery power. My advice is to invest more money initially on a larger-capacity AGM battery. Also, one must pay attention to how the manufacturer suggests you charge that battery type! If the battery is not charged *correctly* it will never be 100% charged, then you really have far less capacity to run your loads than you thought.
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Those are just some random thoughts on getting started on a good 12V power system. Your battery is it's heart. Pay close attention to it's needs. Good luck.

 

[Big mike]

Get a cpl sear diehard platinums!
They work great on my JKU 50" 40" 20" and two 5" light bars plus arb air compressor arb 50qt fridge winch and electic trailer brakes .
I might be missing something but you get the idea.
Great battery
Mike

 

[bunce1260]

Those die hards are pretty salty. I was seeing if I could get away with doing it a bit cheaper.

So I was looking at doing 2 of those batteries wired together giving a total of 75ah.

I cant do solar at the moment and probably not in the near future. However we wouldnt be stopped in the same spot for more than a couple of days so the alternator should be able to handle the charging?

 

[228B]

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You're not listening. :ylsmoke:
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Whatever battery you buy, you should learn from the manufacturer how it likes to be charged. Often times an engine alternator's output voltage is too low... yes, there may be plenty of charge current/amps, but the voltage needs to be high enough to get the battery completely full.
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This is a great resource for learning more about battery secrets: http://www.batterystuff.com/kb/

 

[228B]

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I should add that Shumacher has not in the past put their name on junk. They have a great reputation. They're smart about chargers, too, because they make smart chargers for other people.
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Your idea of using these particular two 12V 35 Ah batteries in parallel producing 12V and 70 Ah, for this little money, an AGM type, and with Shumacher's name on them is good. Call Shumacher and ask them which charger you should use for this bank of two batteries. You can get by w/ engine alternator charging these, but chances are they won't get fully charged this way so you should at every opportunity when 120V shore power is available plug in the Shumacher charger you should get and top them off if you really need these for the duty you propose in your first post.
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This is only my experienced opinion, earned the hard way. Take it or leave it, and good luck!

 

[workerdrone]

Anything that produces heat (mattress pad, 12v kettle) from electricity is extremely inefficient and hungry. Phone chargers, led lighting, laptop, stereo - nothing in comparison to the heating stuff.

And if you're going to be driving for hours per day then your alternator should handle most of the charging - but it may never get your batteries to 100% actually, which is a nice place to be when you set camp.

I'd go for two 6v golf cart batteries, score 'em cheap on craigslist (test them first) or pay $80-100 each new (and still check that they are fresh mfr) - they are built for deep cycling and vibration and have huge reserves compared to the link you posted.

Keep them above 50% charge and they'll last you a long time.

 

[fog cutter]

.....battery secrets: http://www.batterystuff.com/kb/

good link; thanks

 

[unseenone]

It might be worthwhile to back up, and actually do the math on your power requirements, and not rush off and order those batteries. You also need to know what you are doing to run wiring, etc. unless you want to risk burning down your project vehicle.. So maybe we can start over here..

 

[bunce1260]

Wiring's not too hard, positives, negatives, fuses, switches. I'm not re-inventing the wheel, it's all been done before.

Those batteries on the Schumacher website say they can be used in RV's and charged with an alternator so I think they're alright.

With regards to power, I'm not running a fridge, but the electric mattress pad and kettle will admittedly use quite a bit of juice, I just don't know how much.

This mattress pad http://amzn.to/1SLoRWb uses about 7 amps/hr

This kettle http://amzn.to/1DsqEII uses 8 amps/hr but would only be on for about 10 mins at a time.

For a 7 hour sleep and a nice cup of tea in the morning 75ah would work right?

 

[tgreening]

For a 7 hour sleep and a nice cup of tea in the morning 75ah would work right?

Not if you want your batteries to live any length of time. You missed the part mentioned earlier about 50% discharge. Thats as far as you should go in order to keep the batteries healthy. So your 70 amp/ hr of battery bank just became 35 amp/hr.

 

[228B]

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You missed the part mentioned earlier about 50% discharge.

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^ ^ ^ Indeed. Unless, of course, you only want to use these batteries 10 or 12 times then scrap them for another set.
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This mattress pad http://amzn.to/1SLoRWb uses about 7 amps/hr

This kettle http://amzn.to/1DsqEII uses 8 amps/hr but would only be on for about 10 mins at a time.

For a 7 hour sleep and a nice cup of tea in the morning 75ah would work right?

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Forget about the kettle for a minute, forget about Peukert's Law and do some basic math. You have, effectively, 35Ah capacity and ONLY if you've completely charged your battery bank to 100% (not gonna happen with your alternator no matter what you think you heard Shumacher say)... you'd be lucky to achieve a 90% state of charge... and you want to go two days?
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Look, we're really trying to help you here and with experienced advice. Go ahead and do what you think is best, go camping/overlanding/whatever then go buy stuff all over again when you find that this system doesn't meet your demands... or simply toss the nancy heating pad, get a good bag and enjoy your kettle! Do the math...

 

[bunce1260]

The "nancy heating pad" is a requirement to keep the Mrs and dogs happy.

So I can't do this and I cant do that, what should I do?
Bearing in mind this is a budget build and I'm looking to keep it simple with fewer parts to go wrong.

 

[workerdrone]

That kettle takes an HOUR to boil only 20oz of water; if it works at all - lot of reviews claiming DOA, never worked, stopped working after a few times. Propane or gas stove will do it in minutes. I don't wanna wait an hour for my coffee in the morning.

I told you what you should do Tried and true, get golf cart batteries if you want the best bang for the buck, as far as they actually are deep cycle batteries ('marine deep cycle' or 'trolling motor' batteries are NOT), have good capacity, and are tough. Two of them would be about ten times the usable capacity of your little sealed batteries and last for a few years instead of a few trips.

 

[unseenone]

Wiring's not too hard, positives, negatives, fuses, switches. I'm not re-inventing the wheel, it's all been done before.

With regards to power, I'm not running a fridge, but the electric mattress pad and kettle will admittedly use quite a bit of juice, I just don't know how much.

This mattress pad http://amzn.to/1SLoRWb uses about 7 amps/hr

This kettle http://amzn.to/1DsqEII uses 8 amps/hr but would only be on for about 10 mins at a time.

For a 7 hour sleep and a nice cup of tea in the morning 75ah would work right?

Well, the length of the power run, and the amount of Amperage you plan to carry does matter. Indeed, it has been done before correctly, and incorrectly. Put your budget on the side for a moment, and let's spec it out properly, then you can find the right stuff within your budget.

It seems like you are asking the questions, but rejecting anything that does not fit your preconceived ideas.

Here is a picture of a vehicle in South Africa, they lose a couple a month at least due to crappy wiring practices by shops and people who thought they knew what they were doing. The purpose of the questions is to plan to prevent that sort of thing.



So The fridge is the least power hungry item you listed, nothing wrong with factoring it in to run, along with your other goodies. It sounds like you need a minimum of a 30amp power run for (how many feet) to (where will the batteries be) and How you plan to tie it to the vehicle to charge them (stated you did not want solar). and let's begin..

I notice the heating blanket dimensions are 60" x 36" by 1" is that going to be big enough? You could accomidate the Wife needs with quality (think Wiggys) Sleeping bag or blanket, and won't regret it.