| Author | Message | ||
| truthhunter@shaw.ca Rating: |
With the objective of keeping my cost down and simplification ( less to malfunction vs complex redundancy )I am leaning towards just 1 battery bank of 4 or 6 AGM ( Life Line 8D deep cycle or similar ). As long as there are measures to prevent the batteries from being drawn down to low to start the engine, can any one see any reason this might be a bad idea. Is anyone else "doing it this way". I am trying to get away from battery isolators and the concerns of 2 different charging rates for 2 different types of battery banks from the same 270 amp DN50 bus alternator or when parked away from shore power(plugged in 3 stage battery charging) my 24 VDC 140 amp surplus military generator. I could add a smart 3 stage regulator to the bus alternator (although I wounder if it would be worth it given the application involved of being of most of the time);but not to the house generator as it is a real generator not a alternator. see an example at- { http://www.galleria-e.com/cgi-bin/Colemans.storefront/en/product/244901 } that I intend to shoe horn into the spare tire bay and convert to propane and ad a A/C compressor & use recover waste heat (via/air to air heat exchangers form both cooling and exhaust). If I understand correctly the AGM battery can take a high charge rate so the factory regulators should do ok on both the bus alternator and the house generator , and with the claim of very high rates of discharge (I can't find any cold cranking ratings on deep cycle AGMS???) 4 or 6 8D rated at 200+ amp hours should work well at starting the 8V71 or the small 32 CID 4cyl 24 VDC 140 AMP generator engine as long as they are not discharged too low. Will anyone share there related experience on AGM and give there reasons for my ideas strength or weakness. I also would like to hear from anyone that use these 24 VDC military generators and my intentions to convert them dual fuel (propane & gas) as they are low compression at 7:1 (to make use of low grade gas at elevation) I am guessing they should be capable of at least 15 hp and they do run very smooth at even at high rpm, seem to be very rugged and there are lots of these engines around new for cheap to warrant the modification work. Propane is so clean burning and much more appropriate for go-generation and that is why I am intending to go that way, with gasoline for backup only. | ||
| John MC9 Rating: N/A |
"As long as there are measures to prevent the batteries from being drawn down to low to start the engine," It's too, too easy to deplete the battery bank to the point they won't start the engine... and if you're going to use the same bank to start the genset, it will just add to your grief, when (not if) you deplete the battery bank. The RV battery isolators were designed to remove the house battery set from the charging circuit when the engine was off. It was always too easy to run the engine battery down, otherwise. The newer electronic isolators are near foolproof, but the solenoid types are OK.. They just had a bad habit of sticking, and causing the engine battery to go dead where you least expect it to. | ||
| truthhunter@shaw.ca Rating: N/A |
Maybe it would be wiser to add at least a separate small start battery(s)for the 24 VDC generator in addition to it's "rope start" I agree with necessity of adding a low voltage disconnect as they are cheap in both the manual solenoid and electronic forms to augment the inverter's low voltage cutout as some house of the utilities of my system will be strait 24 VDC and not going through the 117 VAC inverter. | ||
| Nick Badame Refrigeration Co. (Dnick85)
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Truthhunter, My concern is your choice of genset, #1- being air cooled and putting it in a small comp, mabe too hot? #2- the gen dosn't say if it is in the 1800rpm range, if not, you could have a loud noise box on your hands if 3400rpm is what it is! Hope this helps! Nick- | ||
| truthhunter@shaw.ca Rating: N/A |
I have several of these impressive and cheap surplus generators and the rpm range is oil pressure governed but very adjustable, but even set at "cruise speed" of 3,000 rpm/belt drive on generator (don't know why they chose to run such a big engine at so high rpm to get a pidley 6 hp or 4.2 kw???) Even running them at 3,000 rpm they are smooth and ultra low vibration, and easy to muffle (due to the opposed 4 cylinder OHV design)so noise is easy to manage. As for the cooling , overkill even by military specs. so putting one in the spare tire compartment on the MC 8 is no problem, even if I need to ad an extra electric blower for the go-generation heating modification (intending to duct the cooling and exhaust heat into a heat exchanger and then into the existing (modified) coach heat duct system in when heating is required , and divert the heat away in the A/C cooing system mode. My biggest concerns of unknown guess work/design is using these AGMs batteries in this configureation ???? and using clean burning propane on these 32 CID "lowered compression" air cooled 4 cyl Chrysler marine engines as propane is surly mopst efficent on higher compression engines(10:1). I could raise the compression by shaving the heads/reducing the head gasket if the efficiency gained would warrant, but then if you are only using 1/3 potential horsepower in generator only mode and 3/4 of the maxiium horsepower in generator/air conditioning mode, then perhaps low compression is of no "efficiency consequence". Any thought on the dual fuel conversion ??? | ||
| Stan Rating: N/A |
The main advantage of having fully charged start batteries is to spin the DD starter fast enough. With a bank of partially discharged batteries you will be able to crank for a long time, but not fast enough for cold weather starts. With a common battery, you would have to charge the batteries first. You would have to have almost dead batteries before they would not be able to start a small gas engine. If you have a tow vehicle, you can jump from that or use your rope start. | ||
| David Hartley (Drdave)
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Rope start that Detroit !! I wanna see that !!! Ha ha ha ha ha.. Just kiddling....  | ||
| truthhunter@shaw.ca Rating: N/A |
nah not a even a 2V51 and certainly not my old 8V71, not even with my strength of ten men (and injuries of ten too)Dr.D. The back-up rope start is on the the 32 CID, Opposed 4 cylinder, air cooled Chrysler marine, and it is rope startable down to -47 (due to the opposed configuration and 7:1 comprestion, dual ignition, believe it or not! You know those military specs.? I wouldn't want to see me rope start even a wee Jimie as the consequences take for ever to heal. hahaha just kidding too. | ||
| motorcoach1 Rating: N/A |
when we had low battery banks in the 84ft boat and the engine quit we let it cool off for an hour and put the running one up full throddel- fire walled -and put the downed engine in gear and hit the start button...yep the prop started it lol ...can't do that with your wheels ...lol..well maby down a big hill | ||
| Frank Mooney Rating: N/A |
Use your one Battery for the house,use the air in the tank for the starter......air starter that is....*smiling*....Frank | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
It only takes two 850 CCA Optimas to start my engine. I would go with a separtate system to spare the expensive Lifelines, and the starter. You can interconnect starting and house batteries in an emergency with a solenoid. You will be able to draw down the house batteries further if you are not trying to start the engine with them. But there are folks who have only one battery set and do fine. I will depend on how you camp and how you use your batteries. If you plan on 4 or 6 8Ds you must be planning on some moderately heavy use. | ||
| Bill Glenn
Rating: N/A |
Rope and time or back up batteries, It's your choice my friend. When $#!^ hits the fan! | ||
| truthhunter@shaw.ca Rating: N/A |
Maybe both would be the best comprise, double redundancy like on a "Warthog". There are plenty of battery isolators that could handle the piddly current charge required for the small generator start battery. Thanks for sharing wisdom comrades. Now I just need to deal with charging those start batteries in a acceptable less fragile way than I have been able to surf data on. | ||
| Tom Caffrey (Pvcces)
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truthhunter, I know somebody who uses a single bank of L16 batteries for both purposes. I brought up the subject of starting the engine when it was cold outside, saying that 45 minutes or so with a block heater would get the engine warm enough. He said that was true, but with only the one bank, he wouldn't want to take that much power off of it, and then try to crank the engine. As long as there is plenty of power to start the generator and there are no problems with that part of the system, I suppose that it would work, but it's not my cup of tea. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| FAST FRED Rating: N/A |
Its really just a matter of plate surface. If the house set has ENOUGH golf carts they will start the engine , even when well down. The starters are built to work well at about 9V under cranking loads (12V system) if you can provide that 9v till the engine starts , your'e home free! FAST FRED | ||
| Donald Lee Schwanke (Dontx)
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For what it is worth, I own a high end diesel motorhome that is set up as presented in this thread originator. They made the failsafe key by using a separate battery for the genset, with the anticipation that if you ran down the battery bank too much, you could always start the genset, and recharge the main bank. I did not think too much of this idea when I bought it, but it seems sound in real live use. |
