I took a look at an old-school Lester ferroresonant golf cart charger under the back bench. Should you have the same, you might want to pack a spare if you're relying on it in a pinch. At least don't leave it on the boat for an extended period. The un-coated laminations in the transformer will slowly swell with rust, eventually shorting the transformer coils. Open crimped un-plated copper wire press-on connectors are sweet too. A heavy coat of dielectric grease will add years, but will eventually need refreshing on hot surfaces. This is an older unit, hopefully later models have improved. Lester's top-of-the-line high frequency model claims more protection on their website, but only the transformer-
The side-draft carb in my jet-powered kayak's Honda general purpose motor fouled a needle valve and flooded the engine compartment with gas. I have not looked into marine generator designs of late, but my '70's era Mercruiser 4L in-line six had a down-draft, as do my vintage Volvo AQ170s (three carbs each). V-8's use down-drafts as well. It makes sense: If the needle valve sticks, the motor runs poorly so you can limp to safety and fix it before you explode. Sure, gas running overboard is "safe", but green? The Honda's are very nice, quiet and powerful. I have never heard of one leaking fuel personally, and have logged many, many hours running power tools from the same. Once in the kayak, however, was enough.
The charger in our Ericson 27 is a DualPro Professional Series PS4. Its not cheap, costing about the same per volt-amp as Lester's published prices, but it is rated as Ignition Protected under the US Coast Guard 33 CFR section 183.410. Underwriters Laboratory also has specs for Marine UL. Alternators, starters, fuel pumps, and carburetors are perfect examples of marine vs automotive levels of enclosure ratings. Please don't advocate un-safe practices to the contrary. The Lester is robust and reliable, and designed for the garage where you store your golf cart. Check the certs their website. No mention of marine application. "On-board" means chassis-mounted in the golf-cart world. Now that I know the cooling requirements of the PS4, the enclosure has a fan and a thermostat. The muffin fan turns on at 130F, and allows the charger full output, even under way. The charger is not a power supply, however, and it does not operate efficiently.
I just found some surplus power supplies. They're 10kw switchers, 0 to 100vdc @ 100a, four of them for $150 each. I located the "obsolete" schematics from the internet (they were built in 2004!), and am considering if they can be marinized. Add a war-surplus 10kw diesel genset, and now you are talking power....For now, a couple in parallel will help make dyno runs very consistent.
Be Well,
Arby
From: Myles Twete <matwete@comcast.
To: electricboats@
Sent: Thu, March 4, 2010 11:15:11 AM
Subject: RE: [Electric Boats] Battery charger limits and the Honda 2000 generator
Arby mentioned: "I've tried running a charger while under way, and found it quickly overheated under the strain. Additionally, as much as I like the Honda3000i genny, it has a side-draft carb, and is not marine rated."
The Honda EUx000i gensets have seen use in a huge variety of environments and while you need to take good care of them, I've never heard anyone say don't use one onboard because it isn't marine rated. Onboard my boat for many years now I have an ETEK brush motor, ALLTRAX controller, LINK10 battery monitor, GE DC/DC converter, onboard LESTER charger and other electrical and electronic equipment NONE of which are marine rated. Sure, get marine rated equipment if you need it, but many of the boaters on this list do not have boats which spend the bulk of their time in salt water or very humid habitat. It's just not an issue for us.
As for charger "overheating under the strain" of running while underway, I have to wonder what kind of cheap charger that is or whether it was provided adequate cooling---I mean, if it can't handle full rated current for the several hours while underway, why would you have confidence in it overnight? I have run my Honda EU2000i while underway for at least 11-hours straight on 2 occasions. In the one instance, I ran with a single 20-amp, 36v Lester charger plugged in, delivering 720watts to my pack. IN the second case, traveling some 35-miles upstream, I ran the Lester along with a home-built Vicor power supply, together delivering a constant 40amps into 36v, for 1440watts continuous, all day long. Neither the chargers nor the genset overheated under the strain. I have nothing but praise for these Honda gensets. Ideally, for charging underway, you would be best to go with a high efficiency, voltage-limited, current-sourcing, current-adjustable power supply. Start the genset, plug in the power supply then slowly increase the current delivered by the supply to your pack. My Vicor power supply current wasn't adjustable by a knob, but I was able to add or remove individual 4-amp modules as needed. So when I had 6 or 7 of these 48v modules mounted, the charger tried to source 24-28amps in addition to the 20-amps from the Lester and when I did this, within a short time the genset would quit. I kept removing modules until the genset could handle the load----that was with 5 of the 4-amp modules plus the 20-amp Lester delivering a total of 40amps at 36v to the batteries--- -1440watts delivered with probably around 1.7kw steady pulled from the genset's AC output ~ 85% efficient. At that rate, my boat can cruise at 4-4.5knots indefinitely, consuming about ¼-1/3gallon/hr- ---I far prefer bringing along this light weight and compact solution for longer cruises than bringing along a "kicker" gas outboard just in case. I do carry extra brushes, fuses, motor controller, generator oil and repair supplies and other supplies just in case.
-Myles Twete, Portland, OR.
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