Solar Generator replacement for Kohler gas genny

[GFB]

Hi

My Kohler gas generator (20yrs old) is probably shot. I'm thinking of replacing it next spring with a new solar generator (ie bluetti 200p or Ecoflow Delta pro) with enough power to solve my daily needs at anchor for up to 4 days max (weekend warrior only). I will need it to run my ac 16000btu, plus fridge plus lights and the odd recharging of devices such as phone and laptop on the fly, and electric head/water pump on occasional use. My only charging sources would be Solar array (approx. 600w combined) and main engine alternators. Does anyone have any experience with this type of setup on a boat? My current generator will be taken out and sold off if possible, taking 600lbs (approx) out of the boat not to mention the silly ($$$) maintenance costs. My starter batteries will remain as is. All thoughts appreciated!!!

[km1125]

There are a couple threads on here where some members have put in some solar charging and did nice jobs.

The big difference is going to run at AC/HVAC system. Just running it for about 6 hours is going to take 600 Amp-Hours out of a battery bank. That alone would be a HUGE battery bank (with lead-acid, that would mean you'd want at least a 1200AH battery bank). 600W of solar would take 10 hours (probably much longer) to restore that juice so that would mean multiple days of charging (in good sunlight) just to get that 6 hours of run-time. Now start tacking on all your other loads and it just gets worse from there.

[buster53]

A solar generator will only produce a small fraction of what your generator puts out. Take the AC out of the equation and you might make it happen, but add a couple more batteries just to be safe.

[Phrancus]

The math includes: determine what each device will take from the bank: how much for how long over a typical period of time between charging. That will show your AC as the big 'culprit' and next are fridge(s).

Then figure out if you can reduce that consumption. Insulate your fridge(s) better, change old inefficient devices for more economical ones. Discard stuff you don't really need anyway. Change standby devices to full-off devices (may be a simple switch in the power feed but mind the memory) and so on.

That should give you a number of capital you need in the battery bank for a typical trip.

Then turn to the income: solar is nice but requires...er.... sunlight. So check how much sun you can catch during a typical trip and do the math with the number of panels you can install.
You'll be surprised on how little you can produce during that trip.
Solar is great for long term charging, so the bank will be full when you return to the marina after a work week. But not at quickly delivering a lot of power to fill the bank fast.

Then there is the technology. The bank will consist of some type of battery. Old style with lead-acid is known and lots of info around. Main drawback: big, heavy and cannot handle deep discharge. (i.e.: the bank always needs quite a lot of charge left in it so it will not get damaged) but relatively cheap and simple to charge.
Modern option are deep-cycle batteries with cool abbreviations like LiPo and whatnot. Great stuff as it can hold a lot of charge in less space and can be drawn empty much further. However, also needs some smarter hardware to maintain (to manage the way it is charged, maintained and drawn emtpy). Also much higher investment upfront.

You may want to do a bit of research in the sailing world. They have a typical way of using electricity as they do not generate by engine often. Their importance to weight, usage and generation are much higher than for us, who have lots of space and power at hand. Relatively.

Depending on how far you want to go in rebuilding the electrics, you could set it all up to consume minimally from a battery bank and invest in a modern generator for the AC.

Biggest challenge with panels is the surface: you need quite a lot of it and directed to the sun to get it to produce. And a boat doesn't have much useful surface to put them on. Well, not untill they come in colors and shapes other than blueish-black hard panels. (yes, flexible do exist but still plain ugly on a white boat)

[Midnightsun]

As mentioned by others the units mentioned will only supply a fraction of what you need. The units you pointed to are 2000wh units which is only about 170AH which is not much at all if you want to run AC, Probably need close to 800ah or more just to do a full night assuming AC is running. Remove AC and even then you are looking at maybe only 2 days assuming no sun. IMHO it is not a feasible project due to the cost involved if you want to go big enough to do AC not to mention you would not have enough solar real estate to put the juice back in a reasonable time period.

[Viper]

Ya I'd take a long hard look before going down this road. It sounds great but there are limitations. I suspect there'll be times you'll really wish you had your generator again.

Source of the post.....My Kohler gas generator (20yrs old) is probably shot.....

Why do you say that? What's wrong with it, and what's been done to confirm that it can't be repaired?

[bud37]

Source of the post Hi

My Kohler gas generator (20yrs old) is probably shot. I'm thinking of replacing it next spring with a new solar generator (ie bluetti 200p or Ecoflow Delta pro) with enough power to solve my daily needs at anchor for up to 4 days max (weekend warrior only). I will need it to run my ac 16000btu, plus fridge plus lights and the odd recharging of devices such as phone and laptop on the fly, and electric head/water pump on occasional use. My only charging sources would be Solar array (approx. 600w combined) and main engine alternators. Does anyone have any experience with this type of setup on a boat? My current generator will be taken out and sold off if possible, taking 600lbs (approx) out of the boat not to mention the silly ($$$) maintenance costs. My starter batteries will remain as is. All thoughts appreciated!!!

Welcome to the forum.

I sympathize with you about that noisy hard to work on gen. Removing that would open up a very nice space to install a serious battery bank. Now having said that I , like the others will say that large battery banks are fine but there comes the time when you have to put the power back that you remove.....the batteries are the easy part so to speak.

So with the winter coming you will have time to consider how to do that efficiently......remember there is no free power.......but if you are only doing the two day weekend thing I believe it is possible. The other caveat is in certain areas boats without generators don't sell well, just something else to consider.

How many hours on the Kohler.....is it the 7.3 ??

[Midnightsun]

The other caveat is in certain areas boats without generators don't sell well, just something else to consider.

Good point, a generator on a larger boat is a must have. That being said, I vote for a genny rebuild.

[km1125]

I've always thought the ideal solution for something like this -especially in diesel boats - would be a very small (1000-1500W) DC diesel generator, probably 48 Volt, with a 48 volt battery bank and a large inverter (~3000W).

With an auto-start feature to make sure the batteries never got too depleted and it could provide power when the really big loads were running so the battery bank might never get depleted from those. A generator like this could be as small as a milkcrate, and really sip fuel instead of gulp it.

[Viper]

Unfortunately insurance companies don't like "auto-start" generator controllers on boats anymore because of past incidents and OEMs stopped supporting them for marine applications because of it, but I know what you're saying.