Solar solution for replacing alternator in vehicle

[ibdnzgr]

I have a 1979 Ford E-350 Econoline ambulance with two batteries and a very large engine. Alternator went out and nobody seems to know how to wire a new one into the system. I've been keeping the batteries charged with a 15w solar panel in the dash and plan to add a 50w panel to the top. The ambulance with its flat roof can handle a lot of these panels if necessary. I need to know about how to add more batteries to my solar system to increase storage capacity while leaving the voltage at 12v output to the vehicle. Do I just wire the batteries in series, in parallel.. do I need any other electronics or devices to help handle this? Maybe similar to an RV application but I am wanting to NOT reinstall an alternator. The vehicle actually starts and runs fine on just the batteries and I have a switch to run one or both batteries. I just need more POWER. The lights are not very bright and my system voltage typically drops to 12.2 or 12.4 while driving instead of the 13.5 I get with system turned off and just charging. Any ideas?

[Mike90250]

The lights are not very bright and my system voltage typically drops to 12.2 or 12.4 while driving instead of the 13.5 I get with system turned off and just charging. Any ideas?

You really need an alternator to be safe, if doing any driving at night. Batteries will only last a few hours. You won't need the 300A ambulance alternator, but a 90A automotive one should be fine.

Days, you need a charge controller, and as many panels as you can afford. Mounting them to be windproof will be desired.
the Trace/Xantrex C40 40 Amp controller is a good rugged one, and would

http://store.solar-electric.com/c40.html

work well with up to 4, 200W panels (you wont get full power because they will not be aimed properly)
a 200W panel will typically produce only 60-70% of its power flat on a roof.

[ibdnzgr]

Charge controller

Thanks. I have one 15w panel with a charge controller and it is charging my very large deep cycle battery. The battery easily starts the engine. I intend to add more panels... Mostly 60w panels on the roof. Not worried about charging so much as storage. I believe many home solar systems actually maintain a bank or cluster of deep cycle batteries to provide more electricity.???

[ibdnzgr]

I am thinking maybe I can put four deep cycle batteries installed in parallel or series to some kind of regulator so they don't charge/discharge each other, and from the regulator, provide enough current to keep my headlights bright and run my A/C blower, my emergency lights, flood lights, etc.

Secondary project here is to install this:

Tripp Lite APS750 750W 12V DC to AC Inverter with Automatic Line-to-Battery 20-Amp Charger. I already have a shoreline outlet. I want this inverter to hook up to my solar panels, to my batteries and to the shore line. My ambulance is already wired for an inverter system but it is very old (1979).

[Mike90250]

a 15watt panel, is little more than a trickle charge. It will maintain a battery, but will be very slow to charge it to a full charge. Undercharged batteries die much sooner. And, as you have noticed, the lights and things dim at night. After a night out, the 15w panel will take several days to recharge the battery. Engines will often start with 10V in the battery, your ability to start is not a good meter for state of charge.

[dslmn]

solar vs. alternator

Is your van a diesel? If so, that explains why the engine runs with low batteries. The early Ford diesels did not have an ECS (computer) and a diesel does not need electricity for the ignition system. No starter will spin an engine, especially a diesel engine, with the battery below 12.3 volts. Ambulances come with giant alternators, but wiring them should be no different than standard engine wiring. The original alternator is rebuildable and the cost is probably less than replacing with a standard alternator. Look for a shop that rebuilds in your local area or one you can ship the alternator to for rebuild. Also, check the batteries by disconnecting them and letting them sit for an hour or so. A dual battery system does not work well with unmatched batteries.

[dslmn]

solar vs. alternator

Is your van a diesel? If so, that explains why the engine runs with low batteries. The early Ford diesels did not have an ECS (computer) and a diesel does not need electricity for the ignition system. No starter will spin an engine, especially a diesel engine, with the battery below 12.3 volts. Ambulances come with giant alternators, but wiring them should be no different than standard engine wiring. The original alternator is rebuildable and the cost is probably less than replacing with a standard alternator. Look for a shop that rebuilds in your local area or one you can ship the alternator to for rebuild. Also, check the batteries by disconnecting them and letting them sit for an hour or so. A dual battery system does not work well with unmatched batteries. I would also bet that the alternator is putting out current when the engine is running. The Zener diode (voltage regulator) is probably fried. Use a voltmeter to check the voltage at the positive terminal with the engine running. A working alternator will put out about 14.5 volts; a bad one or one with a bad diode will put out less and the usual condition with a bad diode allows the batteries to short to ground with the ignition off.