Points and rebuttle to the diatribe.
Some quotes from this thread and my responses
Drivesafe: As you pointed out, temperature can play a part in charging a battery and temperature is the one thing we CAN NOT control when charging any type batteries from our vehicle’s electrical system ....
Yes you can control the temperature, you just reduce or stop the charging process until the temperature drops.
Dirvesafe: There is nothing more dangerous than running around in a vehicle with an inverter cranking out 240 volts AC.
Nothing more dangerous? A bit of an exageration to say the least. Hydrogen from charged batteries in an enclosed space for one relevent to this thread,not to mention BASE jumping and as far as statistics go just driving the car is infinitely more dangerous.
Drivesafe:
If your vehicle is involved in an accident, there is NO 100% WAY TO GUARANTY THE AC IS SAFELY SHUT DOWN and as such, there is no warning that a vehicle may now be electrified and potentially fatal to not only you but to anybody who may come to your assistance.
There we go with that 100% again. I think the saying goes the only garranteed things in life are death and taxes. And with landrovers that you can't keep the water out or the oil in. There are plenty of ways of shutdown systems from sensors to deadmans handles etc. And to warn others well an illuminated warning sign should do it, Oh and using armoured cable and LEDs so the crash does not break the filaments.
Drivesafe: the amount of advantage is so miniscule that the set up is just not necessary in the first place.
Advantages of transfering energy at higher voltages are reduced current and therefore smaller wires and less loss in the cable run. The other as in the one i installed was to charge 24v batteries in a 12 volt system using off the shelf systems. It also gave an instant state of charge display.
Drivesafe: There is an electronic hydrometer in the states that is immersed in the battery’s electrolyte for a few second and will then give a 100% accurate SoC reading, but the device costs around $2,000 US so not really a device I would expect to see being carried by your average weekend warrior and again, it is only useable with wet cell batteries
Bellaposs works in the battery industry, I would not describe him as a weekend warrior. I am sure his company has plenty of expensive test equipment for testing everything to do with batteries.
Wilbur: Dave, what you say is right, but an additional problem is the alternator. I doubt if the average 85 amp alternator would be very cheerful about pumping out its full output very often.
Absolutely 100% (couldnt help myself) correct. the rating is a maximum short term figure. Trying to get high current like that for any extended period will kill them quickly
Blknight: Actually turning off the inverter after a prang should be quite easy to do...
Yes it is
Drivesafe: Last but not least, trying to protect the live of others is hardly scraping the barrel but thinking you can beat the odds of ever having an accident that could circumvent any so called safe set ups is a tad naive.
I work in an industry that makes products to save lives. I do emergency service work that saves lives. I am Safety officer, first aid officer and fire warden at work. I do volunteer first aid and safety work for several organisations. I assure you my install was safe to all standards, but life is guided by things out of our control. It is not naivety but risk assessment. I implimented all interlocks and exceeded all wiring standards and protective measures. Everything involves risk but we still go about our lives doing risky things. It can't be helped. If your number is up, lights out thanks for coming. I am sure every one thinks they are good drivers, but around 700 people die on our roads every year. Everything I do and everything i design is as safe as is humanly possibe meeting or exceeding all standards and codes of conduct.
Ladas: Sorry but if you have 240v running around whilst moving there has to be a risk, whatever precautions you take, there is a risk.
Risk yes but minimised to negligible levels hen done correctly
Incisor: i have no technical expertise with electrickery but i am dead against their being 240v in moving passenger / non commercial vehicles UNLESS those vehicles are clearly marked, so those that risk their lives saving others have a clue that their MAY be live 240v on the chassis or body.
emergency personnel can then make an informed descision how to help those needing help without risking their own lives IF something untoward does unfortunetly happen.
Great idea lobby your MP, write to all departments and make the workd a safer better place.
Bradtot: have just fitted a dc dc convertor in my rangie to charge my Deep cycle.....
Keep your setup. it overcomes many problems in low voltage systems. I have done this too but don't tell anyone or im sure they will make it into a social threat of the highest order. I used it as the cable run to a caravan was just way too long to practically run big enough cable so a DC/DC was used to bump the voltage back up. Dare i say it was a cheap and successfull solution. My charger design uses one as the front end.
Bradtot: The only disadvantage I have come across so far is when I turn the car off the dc dc convertor is still charging the aux battery till the voltage drops on the starting battery and the sc 40 then disconects which inturn stops the supply to the dc dc convertor therfor stopping the charge to the aux battery
I would have called this an advantage. that is what the SC40 is designed to do so the starting battery is good to go when you decide to head off again.
Tombraider: Guns
Do guns have a purpose other than killing people? What do they have to do with batteries?
Tombraider: Aircraft, Trains etc.. Have specialised wiring and control/emergency systems in place... Nothing like some "home grown" inverter based 4wd installation
As above i assure you it was proffessional in every way and in no way home grown. And i never said it was a 4WD I never even said it was a vehicle.
Tombraider: No Mobile phone has ever set off a fuel pump or caused explosion at a servo, yet we are required to not use them at the bowser... Precedence - None..... Reason... Potential.....
There is always risk with any electrical device that was not designed as intrinsically hazardous area safe. The other reason is so you concentrate on handeling dangerous liquids.
Drivesafe: Tombraider covered that pretty well and I would stress on you that, as Tombraider and Incisor have pointed out, there is no way you can justify your set up by making comparisons to professionally installed commercial use.
As above it was proffessional and for commercial use. Justification was several fold including servicability and leadtime to solution. was mission critical and performed flawlessly. Know who you are talking to before you launch into baseless attacks.
Drivesafe: ....your attitude towards the safety of others is pretty arrogant to say the least.
My attitude to safety is extreme to say the least. Safety is non negotiable. I think it is more of your ignorance than my arrogance!
Drivesafe: Safety has to be paramount in every aspect of our lives and not just something that gets in the way of a good story.
I agree with the safety aspect but it was never just a story
Drivesafe: With a 20 amp converter, batteries over 70 A/H will charge just as quickly off the alternator and batteries of 100 A/H or larger, will actually take longer to be charge via the converter than if they were just connected ( via an isolator ) directly to the vehicles alternator.
Actually true but needs some explanation. Ohms law rules amperage inline with resistance and voltage. No matter how big in amperage your charger is, it is the battery that will determine how much current actually flows. In a normal charge process the current will be at its greatest at the start with a flat battery. this is because the voltage differential between charger and battery is at its greatest. As the battery charges the battery voltage rises and the current reduces. This is true with multistage chargers as well. I have a 20a multistage charger and when charging a flat battety the charger delivers the full 20a in bulk stage for less than an hour, usually for much less than an hour. then the current drops off fairly quicly and the charger switches to absorbtion stage and the current is around 4 to 5 amps. So with your DC/DC it will limit the bulk charge to 20A maximum but would probably only add a short ammount to the total charging time.
Drivesafe: I would suggest using a converter with at least a 50 amp continuos
I think that is overkill unless the battery/s are very large and the alternator etc can deliver that kind of current continiously. It would otherwise kill the main battery as cranking batteries are designed for short term high current drains not extended periods..
Hey look at that a comment relating to batteries?!!!
james
