Anyone here has used alternator to charge battery?

[debit.servus]

I am looking at getting the thickest wires and highest output alternator I can afford, and beefing up the connection between alternator, continous-duty solenoid, starter battery and house batteries. Since I plan to move nearly everyday when I travel the US and CANADA and fulltime this will make for an excellent power source. That and solar if I can afford it.

For those who don't move everyday it's cheaper and more efficient to run a generator to charge the batteries or have solar if one can afford the high upfront cost.

 

[SternWake]

A beefy alternator circuit and alternator are great, when the battery is depleted below 80%, but after this point the battery limits how much it can accept.

It will take about 4 hours of driving to get it to 100% fro 80

Or about 4 hours of Solar.

100% recharges are the key to battery longevity. Quick uto 80% is great, but 80 to 100% is important, and time consuming and there is no way around this.

Alternator quenching in the morning + adequate solar the rest of the day = happy long lived batteries

Alternator only recharges on a deeply cycled battery= premature failure & whining human

 

[New Comer]

Upfront cost is not my main concern. My main concern is about whether or not the van will get very hot in the summer if I park the van under the sun to charge the battery. Secondly, I would like to have stealth, even though I don't live in the van. I only use the van for recreation purpose like traveling to places or park it by the lake.

 

[ascii_man]

Upfront cost is not my main concern. My main concern is about whether or not the van will get very hot in the summer if I park the van under the sun to charge the battery. Secondly, I would like to have stealth, even though I don't live in the van. I only use the van for recreation purpose like traveling to places or park it by the lake.

I was initially anti-solar until I remembered my Hybrid-Electric vehicle / batteries class and yeah, you want solar for the slow top-off. But using an alternator for bulk-charging means that your solar installation can be smaller and thus more stealthy; you won't need a platform covering the entirety of your roof like some people make.

 

[SternWake]

If one is not full timing, and gets to go back to a stick and brick, then one can get away with less recharging sources. When one returns home, plug in an appropriate charger for long enough to actually fully charge the batteries.

it is when one never gets to plug in that one needs to utilize all charging sources possible to get the battery to the highest state of charge possible before that next discharge cycle begins.

A well wired alternator in a morning driven vehicle, when the battery is at its most depleted and able to accept very high charging currents ca replace a lot of power into the battery. But once the battery is brought relatively quickly to 80% charged ir begins to resist the current, and from this point about 4 more hours at absorption voltage are required before the battery can be considered 100% charged.

And this true 100% charge regularly achieved, is how one gets their money's worth out of a battery in deep cycle usage.

Getting only to 95% cycle after cycle and the battery will walk down in capacity much quicker, and if one uses the same amount of battery power that night, they begin cycling their battery deeper and deeper while this walkdown in capacity accellerates.

An equalization charge, on a flooded battery, can restore lost capacity, but not all of it, and not always. This EQ charge requires a charging source which can raise battery voltage 15.5 to 16 volts. Most loads should be disconnected from the battery when applying these higher voltages as they might damage certain accessories.

The more often 100% charges are attained, the less often EQ charges are required, and the less time required during them before Specific gravity returns to their maximum baseline and 'resets' battery capacity to the maximum remaining capacity.

How far you decide to go in attaining a 100% charge is upto you, just know that the 100% charge is key to a good Lead acid battery lifespan, and that batteries dislike being cycled when they never get fully charged. Most of the general public thinks that if a battery is dead, one recharges it and all is fine and dandy, but this only reveals the ignorance of the general public regarding batteries and most things electrical.

When Lifepo4 batteries become mainstream, then one will not need to worry about attaining 100% charge, but as long as lead acid batteries rule the affordable electrical storage medium, then one needs to figure out how to attain a 100% charge regularly, Or they resign themselves to replacing batteries often.

 

[New Comer]

Where is a good place to get Lifepo4 batteries. I heard about it before but never know where to get them. Are they good for the purpose of providing electricity in van? I was told that they were light and had a much larger bank.

 

[SternWake]

Where is a good place to get Lifepo4 batteries. I heard about it before but never know where to get them. Are they good for the purpose of providing electricity in van? I was told that they were light and had a much larger bank.

Lifepo4 batteries are a different animal.  Blars, a member here is using them.  He is the guy to ask.  

They are lighter and one can use more of their total capacity.  80% vs the 50% for lead acid.  

They have special recharge requirements and at this point are not a drop in replacement for lead acid batteries.

I'd not recommend them to a newbie whose grasp of things electrical is limited.

 

[BigT]

After looking for ways to charge my battery, I found that the most practical way for me to charge my battery is through alternator of the car. I found information here on how to do that without draining the car battery. 

As per SternWake's advice, I put a Northstar AGM battery under the hood of my van in place of my OEM starter battery.  
With this set-up I'm automatically connected to car's alternator and electrical system.  I also have 190 Watts of solar, helping with the recharge.  
For me this was the simplest system to install because I didn't have to run a completely separate system for my house-battery power.  
I just dropped the battery in the engine compartment, connected two wires from the CC to the battery, and I was done. 

I'm planning to add another AGM to the system along with an inverter, but when I do, I'll simply connect the second battery to the first with a pair of cables, running under the frame to the terminals.  Done & Done. 

 

[New Comer]

I really like this idea: two AGM batteries, one in the car and the other in the house. But how does having only one AGM battery in the car work for you. Do you run the risk of having no battery to start the car?

 

[SternWake]

There is that risk. Quality AGM batteries however can start an engine when depleted, better than a flooded battery could if depleted to the same low level of discharge.

For example two batteries one flooded and one AGM are both drawn down to 30% charged. The flooded battery might spin the engine once slowly and then the dreaded starter click occurs. The 30% charged AGM battery will likely easily start the vehicle.

My group27 northstar AGM is 90AH capacity and 930 CCA. It has started my engine with 64AH removed from it, and it was not even close to struggling.

The issue with AGM batteries is they require higher amp recharging from their most depleted state, and it is more important that they reach a true 100% recharge compared to a flooded battery.

The le$$er AGM's will list a 30% maximum charge rate, meaning no more than 30 amps per 100AH of capacity, while the higher $$ AGM have basically no upper limits on charging amps, just do not let the voltage climb above a certain level and one can feed them huge charging amps.

The high$$ AGMs are Odyssey, Lifeline, and Northstar Expect to pay ~300$ minimum for a 100Ah group 27.

Lesser $$ AGMS can be had for about 180$$ for the same capacity, but they have more limitations.

While the 30 amps is the maximum on the 100AH lesser AGMS, they still enjoy initial charge rates upto this 30 amps.

As such, they do not make great batteries when deeply cycled and low and slow solar is to be the ONLY recharging source.

But when one combines a well wired capable alternator and adequate solar, one can get excellent service from an AGM.

I used to have a group31 flooded USbattery as my dedicated house battery, and kept the AGM as the starting/emergency capacity battery.

The group31 lived out its cycle life last June, and I've not bothered replacing it, Using only the AGM for engine and house duties.
But I can plug in too and not even cycle the battery.

I am considering getting just a small Odyssey battery for emergency jumpstarting, and placing it where my large flooded battery once resided.

If one only has One battery for house and engine, then I'd recommend carrying a jumper pack such as this example:

http://www.amazon.com/Jump-N-Carry-JNC660-1700-12-Volt-Starter/dp/B000JFJLP6

I recommend not using this except for jumpstarting and promptly recharging it afterwards.

Some choose to use the small battery inside these jumper packs as a house battery, but these batteries do not have much capacity and might not be charged enough to actually jumpstart the vehicle when a jump start is required.

Most jumper packs have just a 12 or 18AH AGM battery inside:
http://www.amazon.com/D5744-Sealed-...e=UTF8&qid=1453170941&sr=1-2&keywords=UB12120

I am thinking about getting this Odyssey as my emergency jumpstarting battery as it is much more powerful than the UB12120 linked above, and can accept huge charging currents:

http://www.amazon.com/Odyssey-PC625..._UL160_SR160,160_&refRID=1AMTG8JH3HC6PM5BXXWD

But the Odyssey battery is expensive. I could get a trojan t-1275 with 150AH capacity for ~175$ so I am waffling on my capacity strategy

One thing to note is that I started out with 345 AH of total capacity, and now am at the other extreme, and down to just 90AH total, but have total confidence in my system. But part of that is my ability to plug in.

 

[BigT]

I really like this idea: two AGM batteries, one in the car and the other in the house. But how does having only one AGM battery in the car work for you. Do you run the risk of having no battery to start the car?

Not yet, but right now my power needs are very low so I don't cycle it very deeply overnight.  I don't have a fridge or other power-robbing appliances, I just run a CPAP machine and charge small electronics, like my iPhone and Mac.  Since I use my van to get to work (& daily driver duties), the alternator is able to quickly replenish whatever I use the night before.  

In the future I would like to be able to run some kind of energy-efficent refrigerator and charge things like my cordless drill, saw and razor, and I'm not sure if my 75 Ah battery, hooked up to an inverter, is up to the task on its own.  Thus the second battery idea.

I also carry a jumper pack, but so far haven't needed it.

 

[SternWake]

the alternator is able to quickly replenish whatever I use the night before.

This is true, upto 80% charged only. from 80% to 100% charged, there is NO quickly recharging a lead acid battery. It takes time, as the battery simply cannot accept much current even at 14.8volts when it is above 80% charged.

AGMS are slightly faster in this regard, from 80% to 100% they can accept slightly higher amperages at the same voltage, but there is no quickly recharging any lead acid battery from 80% to 100%. It is always going to take hours no matter the charging source.

 

[ascii_man]

This is true, upto 80% charged only.  from 80% to 100% charged, there is NO quickly recharging a lead acid battery.  It takes time, as the battery simply cannot accept much current even at 14.8volts when it is above 80% charged.

AGMS are slightly faster in this regard, from 80% to 100% they can accept slightly higher amperages at the same voltage, but there is no quickly recharging any lead acid battery from 80% to 100%.  It is always going to take hours no matter the charging source.

Keep repeating this and people will eventually absorb it. It's just going to take time...much like charging a lead-acid battery from 80% to 100%.

 

[BigT]

Given I'm not using my battery for anything but running the car right now and therefore not depleting anywhere near 80%, I feel confident my alternator alone is doing the job just fine.    In the future, if I do start using more power, I'll rely on my solar panel for the remaining 20%.

 

[blars]

My LiFePO4 resources page, including all places I know of to buy them is here: http://techno-viking.com/posts/lifepo4-resources/
(Actually, I have a third RV installer page to check and add.)

AM solar has a good, long-standing, reputation with RV owners. Their first try with LiFePO4 was a failure, and they did not carry them for a couple of more years.