I picked up on a 24v pure sine wave inverter today off of a friend of mine that was going to trash it. Without fooling with anything in depth, is there a way to hook up a 24v accessory to our battery configuration to get 24v for that device and leave everything else in tact. I've drawn it out on paper and not sure if it's possible or not.

 

not worth the conversion.

 

You will need p/n PST-SR700-24
http://www.powerstream.com/DC_PC.htm

MikeyB

 

That really shouldn't be that hard. I had 2, 6 volt batteries in a truck I had at one time because I had a FD radio that ran on 6 volts. The 2, 6 volt batteries combined ran the truck, and ONE of them I used to run the radio. I don't remember doing anything special except taking voltage off of just one of the batteries and running a dedicated positive to the radio. Should be the same for your 24 volt application except you'll run a power wire from both batteries to the inverter. Seems like you'll be doing the same thing I did except in reverse.

I may be wrong tho... it happened once before.

chaikwa.

 

You would need to wire your battery in series to get the 24v. The trick would be to do this and still retain your parallel 12v system. I drew the picture below to show how to do it. Finding a diode heavy enough to carry your load might pose a problem but this system would work.


You would leave your batteries wired as they are now only add the wiring shown in the picture. DO NOT do this without a diode unless you like sparks and smoke. Also make sure the diode is wired the correct direction or the same result will happen.

.

 

^^^^thats it right there....some of my old trucks started with 24v starters.

 

Yup, that diagram should work.. Just need to do all the wiring across both batteries.

 

So with the above diagram, what keeps 24v away from the ecm on the truck? What keeps the diode fram blowing when the starter is engaged?

 

How many watts is this inverter? 1000 watts? Unless it was designed for use in military vehicles a 24-volt inverter to me would the type used for off grid applications.

Getting 24-volts is easy, simply add another 12-volt battery in series to get the 24-volts where it gets tricky is to keep them charged, easiest way is to install another 12-volt alternator for the second battery.

You could also install a series/ parallel switch do what the name implies, many transit coaches with Cummins engines use these to start on 24-volts with a 12-volt system also some class-8 tractors use the same system.

Next problem, if it is an inverter of any decent size and since it is 24-volt it will be, it is going to draw a considerable amount of current and if it is using your vehicle as part of the system it can draw it down below starting voltage within a matter of minuets.

My 3000 watt 12-volt inverter can easly draw over 100-amps from my battery under a heavy load but yours being on 24-volts it will draw about half as much.

This is why that I had installed my 160-amp Leece Neville alternator; I can run my inverter off my alternator with the engine idling using the battery for surges.

Military vehicles are mostly all 24-voly systems.
Unless you really needed the inverter for some special application it would be a costly adventure.

Quote:
You will need p/n PST-SR700-24
http://www.powerstream.com/DC_PC.htm

He is going to need one with an output of at least 100-amps.

Jim

 

Oops. I picked the wrong one. Looking through some of my power supply catalogs there are some high wattage (1200w+) inverters for this type of application, but they are expensive. $3-4k range.

MikeyB

 

Need to know more about what your doing , but many / most of the recommendations here so far are going to kill your truck .
More info from you and what you want to run will help , it may be best to sell the one you have & use the money to get a 12v inverter , KISS .

 

To clarify, it's a 300 watt inverter, but it's a pure sine wave inverter, and I actually have two of them. I work in the marine industry, and these are 24v units. All DC electronics, at least 95% of them, on large vessels are 24v. I'm not looking to spend much on this, as the inverters were perfectly good and practically new interters that were going to hit the land fill. I would love to have a nice 1500+ watt sine wave inverter, but it's not practical cost wise for me. Looking at the specs on it, it has a 20 amp input max. If I put them both in it could potentially be a 40 amp load.

Thanks for the ideas thus far. I'm uncertain if I'll do this, but it's worh a though.

 

Hey only 300-watts, I was thinking on a much larger size somewhere in the 3-5Kw range drawing 100-150-amps at load.
This will be an easy one.

I would mount a second battery and then install 2) 175-amp Anderson Connectors observing polarity with short #4 welding cable tails to each battery, next get 2 identical 175-amp Anderson Connectors and wire them (+) to (-) and then the free (+) & (-) leads will connect to the 24-volt input through a fuse to your inverter.

In operation plug in the 2 Andersons from the inverter one into each battery connector, your inverter is now being powered; a 300-watt inverter can run for quite a long time from a static battery. I routinely power a 400-watt inverter off from 4) 17ah AGM batteries powering CFL”s, soldering iron and ventilating blowers I have not yet had the low Battery alarm sound.

Now when the battery gets low you simply disconnect the inverter from the batteries and then connect the 2 battery Andersons together this will connect them in parallel and recharge it using the vehicles system.

An added benefit of doing it this way is after the second battery is recharged you disconnect it. Now if you ever run your battery low all you have to do is reconnect the Anderson Connectors and you have an onboard jumper battery.

The cheapest place that I have found to get Anderson Connectors if at Forklift Repair Shops, they are used on electric lift batteries, my local specialty shop wanted $25.00 for each half = $50.00 but I bought it for $5.00 each side from the repair shop, to them it is just another part.

Also don't forget inverters should be powered from Deep Cycle batteries not starting batteries their discharge characteristics are completely different but something this small should work just fine.

They use Anderson Connectors to connect large battery banks on some of the larger 30Kw 3-phase battery backups.

If you have any questions I could show you how to connect them.

Jim

 

Were getting closer now , put in a deep cycle battery , with an isolator [ allows you to discharge the deep cycle & charge it without affecting the starting batteries ] .
You have not mentioned what you are going to have for a load , drive with the inverter ?

 

300 watt pure sine wave... I understand why you wanted to recycle them for your use! I think I'd have a hard time chunking them too.

But being 24v input you'll either have to purcha$e a 12v-to-24v DC-DC converter for continuou$ u$e or opt to add another 12volt battery in series with your truck's 12V bus for intermittent use (Like Jim mentioned above).

I knew a fellow Ham Radio operator in the Houston area that ran his 24vdc Scandi Marine HF SSB radio (with kilowatt 24v HF linear amp!) in his work vehicle for years using a dedicated pair of big 12v deep cycle batts in the rear. They were connected in series when in use to develop 24v, and he plugged them together in parallel to recharge off his truck's 12v bus.

That got to be rather onerous as he was a rather talkative ham, coupled with his windshield time he was running his batts down quite often, especially after he added that big 24vdc HF Linear Amp.

Eventually, he cobbled the two batts together with a pair of heavy-duty 12VDC DPDT relays to remotely "Operate in Series/Charge-in-Parallel" so he didn't have to pull-over and stop to do it manually.

Your 300watts isn't NEAR anything that drastic a 24v load, but the 12VDC-to-24VDC switchmode converter route could easily be more expensive than purchasing a NEW 12vdc-120vac sinewave inverter..

Too bad you can't trade two good 24v sinewave inverters for one 12volt sinewave unit...

K.