I have built a house off grid. Plenty of sun for solar(4kw system) and also 2 home built wind turbines (avg daily 450A) for when the sun isn't out, which is basically night time. I have a small 4 cyl Diesel engine that I have running now on home made bio diesel, cost to make is about 1/4 of bowser price. I want to mount it in a frame and use 4 * 24v truck alternators to supplement the charging of my 12v battery bank (2500AH). Is this possible? And what restrictions would it place upon my system? I am running all 12v lighting, fridge, TV etc the only thing that isn't 12v is the washing machine it's still 240v which I use a seperate generator for.
First answer is no, you won't like the results of charging a 12V bank with 24V generators. Saying that, there is a way, but it is very wasteful of engine power by splitting the charging voltage into a resister bank and just dissipate the excess as heat. That will take some plain and fancy controller circuits. Methinks you might be better off revising everything to 24V. I'll leave it for @BTPost to come up with better ideas for you.
Why in the Heck are you going with 24Vdc Alternators, to charge a 12Vdc Battery bank? That makes No Sense, at all..... If you MUST charge using 24Vdc, then you could put a MPPT Charge Controller, in between the 24Vdc Gen and the 12Vdc Bank, to do the conversion for you.... An 80 Amp Outback (Mx80) will cost you $500US, and for that kind of money you could Buy 12Vdc Alternators for your Diesel Engine.... and just go with that.... Now if you went to a 24Vdc Battery Bank and had minimal 12Vdc loads, and Inverted from 24Vdc to 120Vac for the rest of your loads, it would be a lot more efficient. That is what I do, here... Trace 4024 4Kw Inverter Charger on 1200 AmpHour Battery Bank, twin 20Kw Northern Lights Diesel Gensets. Works great. Then for your 12Vdc Loads, you could get a 24/12 Dc/Dc Converter to make 12 Vdc Power up to 30Amps, easy.... Numar makes them for Marine Uses, and they are BulletProof. Been using them for years, down at my Beach Cabin. Where I have a 36Vdc ForKLift Battery, (900 AmpHours) that I split into a 24 Vdc Bank and a 12Vdc bank. The 3Kw Diesel Genset powers the AC side of my Trace 3624SB Inverter/Charger that runs off the 24Vdc Battery. Then I have a Numar 24/12 30Amp Dc/Dc Converter than also runs of the 24Vdc Battery and charges the 12Vdc Battery. 12 Vdc loads are the Refer, (an Rv ThreeWay Powered Refer (120Vac, 12Vdc, Propane)) the Radios, and the Internet WiFi AccessPoint that looks back to the Network here at the Main Cabin. (2 miles away) The Lights are 120Vac CFLs, and the AC side of the Refer, plus anything that requires 120Vac. Heat is Wood Heater, and Cook Stove is an RV Propane with Oven.
A) I'm not using 24v to charge 12v bank, sorry thought it might have been a given that I would have 24v input and 13.7v out put from charge controller.... Will dumb it down next time. Apologies. B) I did say 240v not 120v...... But then like I said everything is 12v only washing machine is 240v! C) Your reply didn't really answer any of my questions.... Reads more like an advertisement, however thanks for taking the time to respond
You already have the answer to the first question with the charge controller. The second then seems to give the limit as what the controller can handle. The washer at 240V seems to be unrelated to the 12V system, not sure why you mention it at all. Dunno as that helps, but there it is. To tell the truth, I'd like to know more about how well that biodiesel is working out, and a pic or two of the installation if you can do that easily.
