Battery Charge Through Car

[HookahGod]

I hope this isn't a silly question, but wanted to check - I'm planning on having a deep cycle battery hooked up via charge controller to some solar panels (the 45w Harbor Freight ones), but figure I'll still have to get a little juice by running the car occasionally. Should I just run jumper cables direct from the car battery to the deep cycle, or do I run the risk of over-charging the deep cycle? I know the car has a built in charge controller, but worried the battery - battery connection is unregulated. Should I run cables from the car to the charge controller instead?

Thank You
-Nova

[FIGJAM]

Did alot of checking on this and my research is showing that the alternator can't overcharge the battery.

[Dr Helix]

Did alot of checking on this and my research is showing that the alternator can't overcharge the battery.

I would be careful with this method though. Since it is unregulated, the battery might be charged too fast and get hot, possibly damaging it. Most chargers put power back till they get to the 80% level then throttle back to top it off.

One 45 watt solar panel should allow you to put back about 4 amps of power per hour of sunlight. My suggestion is to have two deep cycle batteries and rotate them. Also, do you know what your power needs are? You can do some simple calcs and see what you're going to expect from your batteries.

[FIGJAM]

When you jump start a battery for someone who left their lights on, do you realy think that's any different that charging a low battery from an alternator?

It is regulated through the alternator.

If so, why?

In 40 years it has never made a difference in my experience.

[phil]

I have a small gel cell, and it came with a cord that plugs into my cigar lighter to charge the gel cell. The gel cell has whatever electronics it needs built in, so I can' tell you about how the recharging is controlled, but you're running a 12VDC battery to a 12VDC battery, right? Using the car's engine and alternator to keep the car's battery charged while you're charging your deep cycle?

I'd be interested in seeing some calculations on how that would overheat either battery or cause any problems. My mind is open.

[Turnip]

I'm not sure about this method, but what I can tell you is be sure to bring an extra battery and terminals should you have catastrophic melt down.
Also a fire extinguisher. And don't charge it when you're out of camp.

[HookahGod]

When you jump start a battery for someone who left their lights on, do you realy think that's any different that charging a low battery from an alternator?

It is regulated through the alternator.

If so, why?

In 40 years it has never made a difference in my experience.

That makes perfect sense. Thanks for the input everybody!

[motskyroonmatick]

I ran a 12 volt gel cell deep cycle battery with a 1 amp continuous 24 hour a day draw for at least 4 days on the playa being charged by one of those 3 panel harbor freight set ups. Every night before dark the battery was fully charged.

To get the most out of the solar set it up and connect it to the battery immediately when you set up on playa. Have a way to check the voltage of the battery so that you can monitor it's state of charge and plan more aggressive charging means by jumper cables.

There is a reason jumper cables are so thick. They carry a huge amount of power from a charged battery and hard working charging system to a dead battery. People charge batteries all the time with jumper cables but I look at it as a last resort. It is much better for safety and the long life of the battery if it is brought back up to a full state of charge with a regulated charger of some sort.

My understanding is that Jumper cables are meant for short use just to get the disabled vehicle running. Once it is running the cables are disconnected and then it's alternator charges the battery and charging is regulated. I agree it is a quite aggressive charge though.

If it all goes to hell and you need a charge bring it to me on playa and I'll put it on my generator powered charger.

[ygmir]

although a little complicated, and tech heavy, one could get a 110V inverter, hook it to the car, plug a battery charger in, and, have a controlled charge. It'd use more power than direct, but, might accomplish the regulation and/or slow charge you're after

[FIGJAM]

The power from the alternator IS a regulated charge.

Ok, here's the senerio.

You leave your headlights on all night, your battery is dead.

You get a jump from someone and get the car started.

Your alternator is putting max amps in that battery till it get to 80% charge then the alternator regulates the charge down to top off the battery.

My diesel truck has 2 batteries and if I had a trailer with a battery bank of 10 more, it would charge all of them while I'm going down the road.

The alternater will still do the same job.

The jumper cables don't have as much resistance as the plates in the battery.

So hooking jumper cables to a battery outside the truck and idleing for an hour will work the same way, just take less time than a standard 2/6 amp charger that would take 8 hours.

[ygmir]

I'd think the difference, is, that if you have a pretty low battery, and hook jumpers from a hot/good battery, it'll take voltage at (picking random number) maybe 30 amps, at least for a while, and, that might cause heating.
And, the alternator, feeding said good battery, will not change the amount possible through the jumpers (assuming heavy enough wire).
The good battery, acting as a reservoir as such, to allow said surge.

If hooked to a 8 amp (or whatever) charger, the max charge rate will be about 8 amps, taking longer, but, not building heat or possible warping plates.

[FIGJAM]

Yg, I know you are a helpful person.

In your entire life, have you helped out somebody with jumper cables and created the problem you discribe.

One time at a carwash they jumped a car and the battery blew up, because there was no water in it so it was a hydrogen bomb, but other than that I've helped people with dead batteries 100s of time over the years ( and I'll bet you have too) with no such outcome.

Tell me what the difference is.

[ygmir]

Yg, I know you are a helpful person.

In your entire life, have you helped out somebody with jumper cables and created the problem you discribe.

One time at a carwash they jumped a car and the battery blew up, because there was no water in it so it was a hydrogen bomb, but other than that I've helped people with dead batteries 100s of time over the years ( and I'll bet you have too) with no such outcome.

Tell me what the difference is.

totally agree.
I think I'm getting at the fact, that, given a choice, it's (IMHO) preferable to charge a battery at the lower rate.
And, at the potential high rate of jumpers, and doing it every day, it seems it's just taking a chance.
Now, for instance, if the battery is not super low, then, the charge rate will be lower, as well.
Due, to what you correctly point out.

But, Jumping a car, has inherent risks, to be sure.
I did, once, ruin a battery jumping it. warped a plate, was my assesment.
it went dead due to headlights left on, and after jumping, it'd never hold a charge again
Isolated circumstance?
probably.
I'm just sayin, the slower charge rate is safer on the battery.
Not that you're wrong.

But, I do stand by the "really low battery/high capacity jumper cables to hot battery/= high initial charge rate"

[FIGJAM]

I checked with 4 mechanics with 25-40 years experience first.

Then being the suspenders and belt type, I called 3 golf courses and talked to the cart guy's.

They regularly charge those carts at 30 to 50 amps every night.

The other research I did showed that you can charge at the higher rate up to 80%.

That's all I'm shooting for.

A battery won't be hurt by less than a full charge unless you leave it low for more than a month.

So if I can go from 50% to 80%, that give me 30% usable power when I charge with the truck.

That 30% will run the trike about 15 miles.

It makes a big difference on whether the battery is a regular lead acid, gell cell, AGM, and how old it is.

I always check the water level before charging any battery unless it's sealed.

Now from a practical stand point, what would happen if you hooked jumper cables to a steel plate 12"x12"x1/4" and hooked the other end to a power source that could handle that rediculous load?

The cables would be the first thing to fail because of least resistance.

The plates in any decent battery will be similar to that steel plate.

Thats why you don't buy cheap jumper cables.

You can feel how hot they get when you try to jump a car that's hard to start.

This is only my opinion from 40 years life experience and a little double checking, so I could be full of shit, but I feel confident enough to do it my way.

And damnit I do love having this discussion you!

[ygmir]

I checked with 4 mechanics with 25-40 years experience first.

and, again, I don't disagree it will work. I'm just sayin, given the opportunity, there is less risk in the lower charge rate.

Then being the suspenders and belt type, I called 3 golf courses and talked to the cart guy's.

They regularly charge those carts at 30 to 50 amps every night.

Are golf cart batteries plain old car batteries? and, what is their amp rating?



The other research I did showed that you can charge at the higher rate up to 80%.

That's all I'm shooting for.

A battery won't be hurt by less than a full charge unless you leave it low for more than a month.

So if I can go from 50% to 80%, that give me 30% usable power when I charge with the truck.

it would seem you're "deep cycling" said battery that way. As I understand, that's tough on a "regular" battery, hence, "deep cycle" batteries, with different charcteristics.

That 30% will run the trike about 15 miles.

It makes a big difference on whether the battery is a regular lead acid, gell cell, AGM, and how old it is.

again, I agree

I always check the water level before charging any battery unless it's sealed.

Now from a practical stand point, what would happen if you hooked jumper cables to a steel plate 12"x12"x1/4" and hooked the other end to a power source that could handle that rediculous load?

The cables would be the first thing to fail because of least resistance.

The plates in any decent battery will be similar to that steel plate.

I thought the plates in batteries were lead? well lead acid batteries,anyway.

Thats why you don't buy cheap jumper cables.

I made my 25' jumper cables from 00 welding cable, I agree, again.

You can feel how hot they get when you try to jump a car that's hard to start.

This is only my opinion from 40 years life experience and a little double checking, so I could be full of shit, but I feel confident enough to do it my way.

and, nothing wrong with your way.
I don't even think we are disagreeing. I'm just pointing out what I think is a preferable way and rate to charge.

And damnit I do love having this discussion you!

me too. It's great to exchange ideas and experiences. I always learn from you.

[capjbadger]

And damnit I do love having this discussion you!

me too. It's great to exchange ideas and experiences. I always learn from you.

Caution
Bromance at Work

-Badger

[ygmir]

And damnit I do love having this discussion you!

me too. It's great to exchange ideas and experiences. I always learn from you.

Caution
Bromance at Work

-Badger

I have jumper cables for your nipples there mister smart ass..........

[FIGJAM]

Give us a kiss CB!

[capjbadger]

I have jumper cables for your nipples there mister smart ass..........

Don't threaten me with a good time.
I was that kid that thought pulling 2 inch long arcs off the plasma tube by borrowing wire from a nearby display and wrapping it around the tube (didn't know about induction at the time) was cool as hell even though I left there with many black electrical burns on my fingers.
(SciTrek in GA. Very similar to the Exploritorium in SF)

-Badger

[Sail Man]

Mmmm, the vicarious lives one can lead here

[motskyroonmatick]

Then being the suspenders and belt type, I called 3 golf courses and talked to the cart guy's.

They regularly charge those carts at 30 to 50 amps every night.

Are golf cart batteries plain old car batteries? and, what is their amp rating?

Golf cart batteries are 6 or 8 volt heavy duty deep cycle wired in series to produce 36 or 48 volts. Charging a golf cart is charging 6 heavy duty deep cycle batteries simultaneously. They can take a very large total amperage charge because it is spread out between the batteries. 30 to 50 amps on a 6 battery pack is a 5 to 8.33 amp charge for each battery. The most common golf cart battery is a 6 volt deep cycle and it has a 225 amp hour capacity. These batteries are designed to provide constant power over long periods of time. Vehicle starting batteries are designed for momentary high output to turn the engine over and don't fare well if used like a deep cycle.

There is a wide chasm between factory recommended charging rates and what a battery can be put through occasionally to regularly and still function. The decrease in battery life due to "abuse" is something that rarely shows up immediately and so it is hard to account for in the life cycle. An awful lot has been put in to battery research, technology and design. Batteries are freaking amazing. They take a licking and keep on ticking.

[FIGJAM]

I'm seeing alot of chargers like this.

http://www.boatandrvaccessories.com/VEC-1093DBD.htm

And here's the research on high amp chargers for those that can understand it.

http://atsnm.com/documents/battery_charging_research.pdf

I don't understand all of it, but what I can see is that they are doing very fast initial chargeing at 27 to 99 amps before reducing the charge to top off.

My batteries are 12 volt deka 105 ah AGM deep cycles, so I think I'll be fine.

[much2naughty2]

Using a 200 hp engine to charge a battery may not be the most cost effective charge system, but hey, gotta use what ya got. I spent $200 for a 110 watt solar panel and charge controller on ebay to charge my two RV trailer batteries, Except for the AC, I don't run the generator any more.

[BBadger]

A car charger is a pure "bulk charger" meaning it'll dump as much current as the battery will take, without any regard for the the current profile of your battery. You'll need to rev that engine so that the discharging doesn't hurt your car's battery as well (they don't cycle well). Works well for jumping low battery, as it'll get you to the 80% or so that is needed to send you on your way, but if you want to maintain the life of your deep-cell batteries, you should invest in a dedicated smart charger which will regulate the voltage and current in three stages (bulk, absorption, float) to more optimally charge your batteries especially as they reach full capacity. They also prevent the batteries from discharging into the charger (or solar cells, etc.).

So if you're going to charge your batteries from any source, alternator or solar panel, I would invest in a smart charger. You can even damage your solar cells with overcharging. Here are some smart regulators that could probably get to work from your car alternator. The chargers on that site use wall-power AC, so maybe that could work if you have a generator.

[FIGJAM]

Under charge will only hurt the battery if it's not properly charged within a month.

My alternator put out 55amps at idle, and all the researsh sites that I've been reading say that for the BULK charge this is fine.

Going for 50% to 80% with an hours idle will do what I need and will only be needed 2 or 3 times for the whole week.

Google bulk charging.

The spec site for my batteries said the same thing, but then I have deka 105ah agm deep cycle batteries, so they can handle it.

[FIGJAM]

Just a bump to say that I do have a "smart charger" that maintain my deep cycle batteries all year.

Charging from my truck is only for Burning Man.

[EspressoDude]

Then being the suspenders and belt type, I called 3 golf courses and talked to the cart guy's.

They regularly charge those carts at 30 to 50 amps every night.

Are golf cart batteries plain old car batteries? and, what is their amp rating?

Golf cart batteries are 6 or 8 volt heavy duty deep cycle wired in series to produce 36 or 48 volts. Charging a golf cart is charging 6 heavy duty deep cycle batteries simultaneously. They can take a very large total amperage charge because it is spread out between the batteries. 30 to 50 amps on a 6 battery pack is a 5 to 8.33 amp charge for each battery. The most common golf cart battery is a 6 volt deep cycle and it has a 225 amp hour capacity. These batteries are designed to provide constant power over long periods of time. Vehicle starting batteries are designed for momentary high output to turn the engine over and don't fare well if used like a deep cycle.

There is a wide chasm between factory recommended charging rates and what a battery can be put through occasionally to regularly and still function. The decrease in battery life due to "abuse" is something that rarely shows up immediately and so it is hard to account for in the life cycle. An awful lot has been put in to battery research, technology and design. Batteries are freaking amazing. They take a licking and keep on ticking.

not true.
since they are in series, the same current(amps) flows through all batteries. any differences in the batteries will show up as a difference in the voltage across individual batteries or cells

[motskyroonmatick]

Then being the suspenders and belt type, I called 3 golf courses and talked to the cart guy's.

They regularly charge those carts at 30 to 50 amps every night.

Are golf cart batteries plain old car batteries? and, what is their amp rating?

Golf cart batteries are 6 or 8 volt heavy duty deep cycle wired in series to produce 36 or 48 volts. Charging a golf cart is charging 6 heavy duty deep cycle batteries simultaneously. They can take a very large total amperage charge because it is spread out between the batteries. 30 to 50 amps on a 6 battery pack is a 5 to 8.33 amp charge for each battery. The most common golf cart battery is a 6 volt deep cycle and it has a 225 amp hour capacity. These batteries are designed to provide constant power over long periods of time. Vehicle starting batteries are designed for momentary high output to turn the engine over and don't fare well if used like a deep cycle.

There is a wide chasm between factory recommended charging rates and what a battery can be put through occasionally to regularly and still function. The decrease in battery life due to "abuse" is something that rarely shows up immediately and so it is hard to account for in the life cycle. An awful lot has been put in to battery research, technology and design. Batteries are freaking amazing. They take a licking and keep on ticking.

not true.
since they are in series, the same current(amps) flows through all batteries. any differences in the batteries will show up as a difference in the voltage across individual batteries or cells

Although I may not be correct I was trying to show that in a relative way each individual battery is not being charged at a high rate. Golf cart batteries essentially make one big battery just divided out in to easier to handle units. It makes sense that bigger batteries can take bigger charging loads and this is essentially what is going on. To me it seems like what it really comes down to is how much each battery cell can take as a maximum load for safe charging and how many total cells there are to charge simultaneously. If I 'm doing this right 36 volts at 50 amps is 1800 watts. In the 36 volt Golf Cart scenario there are 6 batteries with 3 cells each for a total of 18 cells. Each cell is being charged at 100 watts(in a perfect word of no resistance or differences between batteries). Exactly what this proves. I don't know.

[EspressoDude]

each cell nominally 2.2 volts and at 50 amps is 110 watts. Each cell is charged at 50 amps

[motskyroonmatick]

I give up! I'm now going to don some PPE and charge a battery with my welder to gain hands on understanding of what is going on. I'll be doing it in an argon atmosphere so there will be little chance of fire.

Wait! I'd better label these gifts first!