Long story short. Machine is 24v, but the diesel heater i installed is 12v. So i mounted a separate battery to run the 12v diesel heater at night so i don't drain down one of the 24v batteries. Every night i disconnect the master switch on the machine as well. What i want to do is when im running the machine during the day, i want the machine's 24v charging system to charge the auxillary 12v battery to run the diesel heater during the night. I don't want to have to take the battery out every day and swap it out with a second battery. I know there are things called buck converters, 24v down to 12v, but what i don't know is if having the 24v system grounded to the chassis, if i also ground the 12v battery to the chassis if that would cause issues if i would use a buck converter from the alternator to the auxillary battery.
Never tried but possibly with 2 separate cables going to the auxillary battery with a disconnect switch on each cable and only turned on when engine running might work. Diesel heater would have to be wired directly to the master switches with main battery master switch off during heating. Think it would work if you are only operator. Otherwise something might cook if one switch left on when not suppose to be. They sell 24 Volt units but not cheap. We preheated a Large D155 Engine 1 week ago off a 12 volt heater with a battery booster helping a small 12 volt Battery. It can be done with no mistakes. Simon C
Could you just hook the added battery to one of the machine batterys in parallel so it will then charge. I've seen people just hook to one battery in a situation like this to use one battery to get 12 volts with out adding one
We use the Vanner 60-10 battery equalizer on our wheel loaders to gain 12v from 24v.
Look up the specs of the heater, it might be max of 18v or if your lucky 32v
You can hook both grounds up even though they're connected already, it will work fine (unless the directions say otherwise). But most buck converters are not meant for charging, check that they output 14V, 12 won't charge the battery, it will run the heater if you want to do it direct off the 24 without a third battery. A solar charge controller would charge the battery off 24V, not the most efficient, but you'll never know unless your alternator is really marginal.
Long story short is not always the best avenue for specific answers. Diesel heater? Would that be a engine block/coolant/oil heater? Or maybe a fuel tank heater? Is this a machine that is remote, not near 110V AC to work a heater? Specific questions require details.
The installation of the heater was all covered HERE Willie. You may have to go back a couple of pages to get the full story.
If you are running a third battery and this third battery is in parallel with one of the two that are in series, you can install a battery "isolator" as they use in boats and campers to charge this third battery, but not discharge the other two starting batteries. These are small, solid state, and maintenance free once installed and protected from the elements. In essence the 24VDC charging system will recharge your 12VDC series interconnected batteries, and the one 12VDC battery will recharge from the same 24VDC alternator. The battery isolator will disallow any discharge of the two series interconnected 12VDC batteries and only draw from the parallel connected 12VDC battery, (in this scenario). When the parallel connected battery reaches the battery isolator cutoff voltage level, it will disallow further discharge by isolating it from the system, (hence the name). This does not have any bearing on your 24VDC, or 12VDC series interconnected batteries at all. When the engine is started, the alternator will recharge all three batteries again. Clear as mud I know but a very easy problem to address.
Why not just get a 24v=>12v converter? That's what I use in my 24v machines when I hook up a 12v radio. Those heaters do not pull a significant load and that would drop out the need for a third battery. The converter will also weigh less than the battery and have less maintenance issues to worry about. One of my other machines also has a 24v equalizer block that puts out a 12v tap to the radio bank.
This is the simplest and best thing to do in my opinion. I've done this before with no issues.
Unless someone leaves a switch on inadvertently so over a weekend or longer......
True dat!
There's a saying that might apply here: "If you make something idiot proof someone will come up with a better idiot!"
Hey there now, I take resemblance to that!!
The machine has two 4D batteries for the 24v system, the battery i've installed in a smaller group24 deep cycle battery from a camper. So the ratings are quite different. I just installed the 4d batteries brand new and i do not want to pull load overnight constantly from one of two batteries. I want to leave them un touched. That Vanner equalizer is quite the expensive unit, for now i'm going to try a cheaper alternative. The heater is 12-22 volt on the fuel pump. If i wanted to change it to run off 24v i would need to replace that, and the glow plug i believe. But as i said before, i want to leave the starter batteries alone and only use the auxiliary battery to power the diesel heater. Delmer you have a good point, i totally forgot about the buck converters not going to a charging voltage. That wouldn't help me at all charging the auxiliary battery. The solar chargers are a good idea, but from what i've seen they can only handle 23-24v, and the alternator puts out 26-28 volts from what i've seen. Not sure if the solar charger would be able to handle that. Willie, the diesel heater is a chinese knock off of a webasto bunk heater. It's a hot air heater that i've installed an EGR cooler inline of the exhaust to scavenge the waste heat to heat the coolant as well. The machine works out in the bush during the winter, miles from any source of electricity. And i'll be starting it in temps down to -20C no colder. I just wont work the machine if it's colder, i don't want to break something and have to fix it in the cold. 1693ta, i didn't know about isolators, looking them up i see that most want them to be installed directly from the alternator, and not from the first battery. Would i instead put a cable from the first battery to the "alternator" post on the isolator, and then hook up the auxillary battery to the correct terminal and then nothing to the "starter battery" post? Treemuncher, i already installed the auxillary battery and really dont want to tie into the starting batteries. I like the idea of having an isolator like 1693ta mentioned. I want to make the system as simple and easy as possible. I put the controller for the heater inside the cab since it is the least bit weatherproof. So it would be nice to make the charging automatic as well so i can easily just set the timer for the next day and then easily hit my master switch and go home. Not having to worry about any connections, or switches.
By paralleling one of the 12V batteries with another 12V battery, you are essentially paralleling 2 different size batteries. I have always been told this is a no-no, as the larger battery is undercharged and the smaller is overcharged. The pair and the single each have to receive the same number of amps current. Or have I been told wrong?
They will both reach the same potential and equalize. Of course the larger battery will have higher capacity as designed, the smaller battery will also charge to it's capacity.
Isolators have a voltage drop, voltage sensing relays don't.
I wouldn't want one of those isolators, they have almost a full volt drop on each side, so the 24V system would never fully charge unless you have a voltage sense and hook it to the 24V battery side of the isolator, and there's no reason to do that, you only need the 12V side isolated from the 24V side, and a solar charge regulator will do that. Having the 12 4d parallel with the 12v 24 size battery with a load on it will kill the 4d that's it's parallel with and over charge the 4d that's in series with the two parallel batteries. All current to charge the two has to go through the single battery, that's what you want to avoid.
Reminds me why I no longer try to jump start my PC200 from my truck batteries. 24v being jumped with 12v to one battery has burned up 2 alternators. At over $600 each, I don't attempt to add juice to just one battery in that system any more. I take both back to the shop to charge them or put 2 different chargers on in the field. Experience can be an expensive educator. The draw on those 4D batteries will be minimal, from my experience with these Chicom air heaters. You could run that heater for well over a week non-stop with one 4D from my experience, with minimal voltage drop on good batteries. I run a similar water-type diesel heater that I can pre-program. I runs off of one 8D battery. I normally program it to run 2 hours in the AM during working days before I arrive on site and if I miss a few days, no battery issues. The water heater is better because it pre-heats the hydraulic oil tank and the engine block. It has the added draw of a small water pump to circulate the coolant. I've got another 24v machine with weak batteries that I rarely use. I recently put 2 12v solar chargers from Ebay on it and keep it pointed to the south. The batteries stay strong enough to start it every time without hesitation. Otherwise, the batteries were dead in 1 month with no drain. It's a cheaper alternative to new batteries and it keeps the system topped off without thinking about it.
I preheat the engine coolant in my dozer with the same method this gent wants to heat his operator compartment, (assumed). I also have two 4D batteries in series and a group 22NF battery paralleled to run the auxiliary heater. The battery isolator is a NOCO brand, and not a bargain basement variety. I want to say it has a 10A charge current rating as it is meant for auxiliary usage. The auxiliary battery is under the seat and the isolator in the battery compartment which is on the side of the dozer and both are out of sight. I have a NOCO solar charger and controller not yet installed for the application also. Sure wished I'd have asked if this would have worked prior to going the expense for the batteries and isolator and the trouble of wiring it all in only to find it all works as I envisioned and performs admirably. This will be the third year this has been installed. Not too bad in my vision for a one year warranty battery to power the heater. A 22NF series battery is Grasshopper diesel zero turn mower battery. Turn that heater on fifteen minutes prior to engine start and it fires off easily in the coldest of weather. It is an open operator station so no need for cab heat although I initially contemplated a small heating coil for a glove warmer as there is physical room, but ruled it out. To be fair, this is a great starting 11000 Allis-Chalmers engine. This will be the third year the system has been installed and although I don't use the machine often, when it's parked at our property, there is no shore power within a 1/4 mile and it is used; hence the reason it was set up this way.
Thanks for the link Nige. Very interesting setup. I'm thankful that I don't have to deal with that kind of cold and for that reason haven't really had to rig up something like that. But I agree with fitting a battery isolater to charge the parasite battery.
You would need a 24 to 12 charger something like this https://www.sterling-power-usa.com/24volt-12volt30ampbatterytobatterycharger.aspx
LOL........this thread reminds me of that hydraulic cylinder drift thread.
One way this could work without an extra battery would be to switch the leads from one 4D to the other every week or so.
As I mentioned somewhere, based on the range of ambient temperatures that the OP exeriences in winter, really no sane person should choose to live there .........
You'd have to either switch the 4D's or isolate the heater from ground because it would have 24+v hot and 12+V ground, and short out the original partial discharged battery if the grounds touched.
Inherited insanity from your offspring helps tremendously.....
Couldn't agree more. I always blame my three for how I've ended up....
Well there's no definitive answer for this. The specs on the solar chargers don't state that they can handle over 24 volt like what the alternator can put out. The only solar charger i can find is a 30 amp, which i'm not positive of how many amps the alternator would be trying to push out to try and charge the auxillary battery. The split charger/voltage sensing relay was another option but no one has any locally. And i do not have time to order one and it get to me before time runs out to do my jobs before frost gets bad. My battery is also a group 75 battery, and it is not deep cycle like i thought. It came from my cousins camper and i figured it had to have been a deep cycle. But it's not. so for now i have a 7watt solar panel mounted on the engine compartment to try and trickle charge the battery, it wont be enough, but every morning and night i'll be hooking the booster cables up to the battery from my truck while i warm it up, fuel it up and clean the undercarriage. I do see a local battery place has a group 24 deep cycle battery that should fit with minor modifications to my mounting brackets, but for $100 i'm probably going to buy so i don't completely kill this starting battery since it's still kind of acceptable to start a small tractor/car.
Am I understanding correctly that this way mostly eliminates the problems associated with connecting a 12V load to one battery in a 24V system? I have seen a couple times where a very small load (only a cell phone charger) was placed on one battery, and eventually that battery was undercharged and the first batt was overcharged, and then we have problems. The way you are doing it is disconnecting the parasitic battery while it's in use, and then it becomes connected when the load is removed? Seems like it could still eventually draw down the battery in the 24V system, but it's obviously better than pulling directly from it?
The auxiliary battery cannot discharge through the main batteries because the isolation diodes are reverse biased. When there is current flowing from the alternator, (Delco 26SI series) through the series connection, this is felt as forward bias and the auxiliary battery recharges through a charge limiting circuit internal to the isolator. As far as overcharging one of the two batteries in series, I've not seen or experienced that. The series wired batteries always remain fully charged and even when the auxiliary battery has been purposely depleted, upon starting the engine, all three batteries recharge. You will see the voltage regulator cut back the charge current as the series wired batteries top off and a meter placed onto the auxiliary battery will still show a charge rate which is limited to 10A maximum. I should mention in the series string, I am paralleled across the first battery in this string. I'm certain if you were to parallel across the second battery you would burn the first battery out quickly as the charge current must go through it to reach the auxiliary battery wired in parallel to the second series wired battery. This has worked for me and I've a lot of hours testing it with a barrel of water prior to installing onto the tractor.
It still will overcharge the battery on it's own in the 24V string and undercharge both parallel batteries. The easiest way to avoid that is by charging the extra battery from the full 24V which is easy these days with charge controllers or converters. There are solar charge controllers up to 600V so if you're not comfortable using a cheapo one, there are plenty of any rating you want. There are converters designed for this also, between the $3 and $300 price points somewhere, I'd avoid each end. The problem with the combination series parallel is the one in series has to take all the amperage of the two other batteries, that have used more power and so need more amps, so the single one will reach 15V across it and slow down the amps while the others are still at 13V. Which will kill the batteries if it doesn't run all day to equalize, and will boil if it does run enough to equalize.