teotwaki
Excelsior!
I kind of figured you regarded this as a must-win situation rather than just a forum discussion where we can all learn and occaisionally get a good laugh.
DC-DC battery charger under hood?
- Thread starter msand1977
- Start date
I kind of figured you regarded this as a must-win situation rather than just a forum discussion where we can all learn and occaisionally get a good laugh.
Good paper. It is quite systematic
Thanks for sharing.
I think I agree 100% with your paper
I strongly advise us all to read this paper. Will maybe take you 5 mins and save you $100( if you are rich, then it's about your IQ
And finally,I think if the alternator is weak, better to upgrade the alternator first.
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Pm me.
This thread is about dc-dc charger.
Thanks
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teotwaki
Excelsior!
Yes it should be a discussion about DC-DC chargers except 25% of the posts are yours with repetitive attacks against DC-DC chargers or snide remarks about anybody who says the chargers were the right solution.
QUOTE"martnH:
The redarc you want to buy is a little baby
……."hobby" dc-dc you want to buy.
And this is all marketing ****************...
Now the little baby dc-dc will not +be able to do that.
So yeah.dc-dc is a waste of money (in most cases But I will give you that their marketing is pretty good
Especially when ppl buy 25amps baby dc-dc.
Get your facts right.
Some very obvious conflict of interest in this thread.
Think about this. $$$guy
What a waste of our time and hard drive
Will maybe take you 5 mins and save you $100( if you are rich, then it's about your IQ
Nothing is more offensive except personal attacks. (especially ironic don't you think?))
This thread was about simply whether or not putting a DC-DC charger under the hood would be OK, but now it's degenerated into a peeing contest and whether or not your pee is the right color and volume.
Seriously, the OP's question was only directly addressed maybe 2-3 times, the bulk of this thread turned into six pages of several of you guys having a argument over who knows more about dc-dc chargers and battery maintenance. Talk about thread jacking. And the OP even came in and said he's trying to boost the charge rate of the ArkPak he has in the rear of his Toyota 4Runner, which more than likely does need a DC-DC charger since he is not only doing this in a Toyota but it's also a fair distance from the alternator so it's seeing even lower voltages. The simple answer that should have just ended this thread was "Put the DC-DC charger as close to the battery being charged as possible and make sure to use a proper sized cable to it to reduce the voltage drop going into the charger/battery." Additional information the OP seems to be missing (if he's even still following all this drivel), which btw I found after taking 10 seconds to do a search since not a single one of you seemed to be able to bother with this since you all wanted to argue about the purpose of DC-DC chargers and how they really work and if they are snake oil or not, is that there are two methods of charging the ArkPak (this is from their website):
In-Vehicle recharging:
There are two ways you can recharge your ArkPak in your vehicle:
(a) Simply by plugging it into the 12V socket in your vehicle, via the optional DC-DC car charger adaptor (sold separately) – giving you 6 amps of charge per driving hour.
(b) Via the ArkPak’s built-in 50 amp Anderson plug, giving you a potential 50amp charge per hour directly off your vehicle’s alternator.
Option A is most likely what he is using, hence the slow charge, when he needs to use Option B and again probably with a DC-DC charger that is close to the battery and fed with properly sized power cables from the alternator/starter battery in order to see charge rates over 6 amps. Having exactly the right voltage doesn't mean squat if you're not also pushing enough amps in to recharge the battery fast enough to make it worthwhile. If he has a Group 31 in that thing with around a 100AH capacity, 6 amps is going to take quite a while to recharge the thing if he drained it overnight or something. And a certain someone going on about charging 3x 100AH batteries with a 25Amp DC-DC charger also is way out in left field for what the OP was even asking about.
All this ridiculous "Fuh fuh fuh I know more about this than you do and you're all fools if you don't listen to me fuh fuh fuh." garbage some of you have been blustering on about and the rest of you that keep responding to those types of posts is just muddying the waters for the poor guy and anyone else trying to figure this stuff out and not really answering their original questions. I can't believe the topic of DC-DC chargers would spark greater debate than a religious or political discussion normally does. Y'all need to go camping and cool off for a while.
Don't get me wrong, there is good information in here from people who do know what they are talking about, but y'all have missed completely the original question the OP asked and the followup info they provided aside from a few terse replies clear back on the first page or two and instead turned this into a mud run. Can we just let this thread die now please since it's way past the point of the OP getting any real help?
Seriously, the OP's question was only directly addressed maybe 2-3 times, the bulk of this thread turned into six pages of several of you guys having a argument over who knows more about dc-dc chargers and battery maintenance. Talk about thread jacking. And the OP even came in and said he's trying to boost the charge rate of the ArkPak he has in the rear of his Toyota 4Runner, which more than likely does need a DC-DC charger since he is not only doing this in a Toyota but it's also a fair distance from the alternator so it's seeing even lower voltages. The simple answer that should have just ended this thread was "Put the DC-DC charger as close to the battery being charged as possible and make sure to use a proper sized cable to it to reduce the voltage drop going into the charger/battery." Additional information the OP seems to be missing (if he's even still following all this drivel), which btw I found after taking 10 seconds to do a search since not a single one of you seemed to be able to bother with this since you all wanted to argue about the purpose of DC-DC chargers and how they really work and if they are snake oil or not, is that there are two methods of charging the ArkPak (this is from their website):
In-Vehicle recharging:
There are two ways you can recharge your ArkPak in your vehicle:
(a) Simply by plugging it into the 12V socket in your vehicle, via the optional DC-DC car charger adaptor (sold separately) – giving you 6 amps of charge per driving hour.
(b) Via the ArkPak’s built-in 50 amp Anderson plug, giving you a potential 50amp charge per hour directly off your vehicle’s alternator.
Option A is most likely what he is using, hence the slow charge, when he needs to use Option B and again probably with a DC-DC charger that is close to the battery and fed with properly sized power cables from the alternator/starter battery in order to see charge rates over 6 amps. Having exactly the right voltage doesn't mean squat if you're not also pushing enough amps in to recharge the battery fast enough to make it worthwhile. If he has a Group 31 in that thing with around a 100AH capacity, 6 amps is going to take quite a while to recharge the thing if he drained it overnight or something. And a certain someone going on about charging 3x 100AH batteries with a 25Amp DC-DC charger also is way out in left field for what the OP was even asking about.
All this ridiculous "Fuh fuh fuh I know more about this than you do and you're all fools if you don't listen to me fuh fuh fuh." garbage some of you have been blustering on about and the rest of you that keep responding to those types of posts is just muddying the waters for the poor guy and anyone else trying to figure this stuff out and not really answering their original questions. I can't believe the topic of DC-DC chargers would spark greater debate than a religious or political discussion normally does. Y'all need to go camping and cool off for a while.
Don't get me wrong, there is good information in here from people who do know what they are talking about, but y'all have missed completely the original question the OP asked and the followup info they provided aside from a few terse replies clear back on the first page or two and instead turned this into a mud run. Can we just let this thread die now please since it's way past the point of the OP getting any real help?
DiploStrat
Expedition Leader
Touché!
“For what do we live, but to make sport for our neighbors, and laugh at them in our turn?”
-- Jane Austen
“For what do we live, but to make sport for our neighbors, and laugh at them in our turn?”
-- Jane Austen
Yes, there are many. Sterling, Ample, Balmar, I think Mark Grasser.
The commercial ones are hundreds of dollars, an Arduino-based FOSS project as well.
And you need an alt that is convertible to an external VR and an "out of the box" auto electric guy to help in most cases.
But alternator is rarely that significant a source of power anyway.
Most can't put out even half their rated power for any length of time without burning out.
Current limiting to way below what the bank can pull is critical.
Best VR off the shelf is Balmar's MC-614.
Many if not most vehicles these days do not physically have the room.
And then you still have all the same issues.
More is not better, the problem is also precise regulation of the charge profile.
Stock alts are set up for the vehicle's needs. Not big deep cycling banks.
I don't know what that means. Limiting current is very important to protect the alt from burning out
> For example optima battery.
Optimas are not proper deep cycling batts, just robust Starters. Very poor value since Enersys spun them off.
> Anyway maybe you should watch this sterling videos.
I did, and obviously it's all in support of his (very fine) DCDC chargers. Nothing he states is in conflict with my statements, he's talking at an elementary level about the horrifying lack of quality design across the whole RV industry, very valid points but not relevant to the topics here.
Voltage is critical to proper care of the bank, function of the regulator not the alt.
Amps are less so, a given alternator can only put out so many for so long, at a given temperature.
Usually the high temps from trying to pull too many amps for too long result in effect **no more charging** at all.
Bringing the amps demanded down to a temperature level the alt can handle is the critical function required
whether handled by replacing with a quality external VR, Alt-to-battery unit, or if a modern Euro-style catastrophe a batt-to-batt charger is required, able to handle almost all scenarios, much more flexibility.
If high amps for long periods is truly required (very rare) then a vehicle that can accommodate a large frame Leece-Neville alt as seen on emergency vehicles is required.
As well as the sophisticated regulation hardware discussed above.
dwh
Tail-End Charlie
Yea sure, true enough. But thread drift is normal and will happen unless some moderator turns full nazi - which isn't going to happen around here.
Besides, it's not all bad. This site has more than 100k subscribing members and gods only know how many lurkers. At any given moment there could be 5k people milling about the place.
Plus all this is being archived and searchable. So whether or not the OP's question ever got answered, it's entirely possible a dozen other people's questions will be answered over the next few years.
restorationrides
Member
It does seem that there are some individuals on here who want to show how much they know about every little detail about batteries, chargers and related. The nuanced details that they go into are just not a factor in the real world. It seems, to me, like they're just trying to push a sales agenda.
I see little value in using the vehicle alternator or any other source to charge the STARTING battery and then use a DC DC (12v to 12v) charger to tap into the STARTING battery and use it to charge the HOUSE bank. As I said before you're not going to get away without losing energy through inefficiencies.
And the idea that most alternators can't even sustain an output when they get hot, is ridiculous. They're rated output is what's listed on them and that is good up through some very high engine compartment temperatures. Quick research has anecdotal results at over 300 degrees before thermal shutdown. Remember that vehicle and equipment manufacturers have designed these alternator to operate in extremes of temperatures in most places that you would ever find a vehicle...
With regards to voltage versus amps...it's the AMPS that create the heat and losses. it is important to remember that INCREASING the VOLTAGE allows us to DECREASE the AMPERAGE required of a particular power transfer scheme.
If you want to use a DC to DC (12v to 12v) charger, put the charger closest to the SOURCE battery which will have an alternator restricted Max voltage of around 13.8 to 14.2v because this is the side of the circuit that's going to require the largest wires and have the largest losses. I say that because no device is 100% efficient. If the device (charger) is going to take in DC power and then transform it into DC power again, it is going to incur internal losses. Those losses must be added to the current draw in considering the input wire size.
Then, with your dc-to-dc charger, drive your voltage SLIGHTLY higher which will allow you to theoretically charge with less amps for the same total power transferred. In theory, you should be able to run a SLIGHTLY smaller wire size this way...
But as I said before, I don't think a DC DC (12v to 12v) charger is a necessity for the cost and scarce real estate available in most vehicles. I think your money would be better spent on an isolator (separating STARTING from HOUSE batteries) and a sophisticated external regulator to drive your alternator. With a sophisticated external regulator, you can create more optimal battery charge profiles for each bank (that some people on this thread think is absolutely necessary in order to protect their battery investment.) without adding power factor losses and unneeded complexity. Of course, this is all IMHO...
Regards,
RestorationRides
BTW, I'm not going to contribute to this thread any further as I run the risk of beating a dead horse over this issue and as someone pointed out tastefully and tactfully, this person is probably already committed to using a DC DC charger and just wants to know where to put it...
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I am sorry that I hurt your feelings baby boy
Why don't you PM me and stop wasting forum space.
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dwh
Tail-End Charlie
That statement is ridiculous. Tell it to the guys who build the things.
Heavy-duty construction: marine alternators operate at sustained high output for much of their lives. This requires high-temperature grease, large cooling passages, large or multiple fans, heavy-duty bearings, high-amperage diodes, etc. Standard automotive-type alternators rarely offer the construction required to meet the demands of large marine charging systems.
...
Temperature ratings are often determined using a military standard of 122°F, measuring the ambient air temperature in the vicinity of the alternator. Sustained operation in hot engine room conditions will reduce alternator output. A “hot” alternator, operating at approximately 180°F -200°F will only supply about 80% of its rated capacity. Large-frame models generally run cooler than their smaller siblings because of their ability to dissipate heat. Small case alternators are not designed for continuous high-output operation.
https://www.westmarine.com/WestAdvisor/Selecting-an-Alternator
In the rating charts the cold Amps rating is for an ambient air temperature of $ 77^\circ $ Fahrenheit, ($ 25^\circ $ C). The hot Amps rating is for an ambient air temperature of $ 200^\circ $ Fahrenheit, ($ 93^\circ $ C). Typical operating temperatures are much less ...expect more than the hot rating.
http://www.amplepower.com/products/alt/
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