Webasto and low voltage

[Hamster]

This past weekend, I spent a couple of nights out on my R-23 in near freezing temperatures here in the Pacific Northwest. Each night, my Webasto heater (2000 STC) turned off in the middle of the night (usually while in heat mode). The error code was F 03, which was low voltage.

I was not on shore power. The only power that I had going at night was the refrigerator, anchor light and my cell phone. Nothing else was on. The voltage drop was not that radical, but enough to cut the heater off.

I'm curious whether others have experienced this when running the heater all night. What are the solutions? Has anyone added another house battery to their R-23? Could there be other things drawing power? Should I have put my food outside for the night? 🙂

Good thing I brought my long underwear and down sleeping bag.

 

[Chimo]

Your fridge should certainly be on a minimal setting. To avoid this situation I hooked the thruster battery through a switch to the two house batteries. That added 50% capacity. I used a switch though I gather others have not bothered with that step.

 

[j&lgray]

Yes, the issue you described with the Webasto is one that I experienced. The furnace needs about 12.5 volts for its start up sequence of starting the diesel combustion and running the fan. Motors draw a ton of amps. Once the furnace is actively running, the amp demand drops because fan motor and fuel pump are only doing the work. What I do is turn off the Webasto and then turn it on about 20-30 minutes later. Once it starts, it will heat until the thermostat says not too.

On very cold nights, to save amps, we have turned off the refrigerator at night. Nothing bad happens because the door is shut all night.

Yes, there are owners who have wired the house and thruster batteries together and others have replaced the single or two 12 volt batteries with deep cycle 6-volt batteries that are wired in pairs. The solution that works for you is more about the kind and frequency of cruising you do. I do not re-design a system for an occasional or exceptional situation but for a chronic on the new-normal one.

Hope this helpful.

 

[Hamster]

Thank you for the helpful replies.

I have had several trips where low voltage overnight was an issue. The first night I set an anchor overnight I wanted to keep the Garmin running for the anchor watch alarm and also had the refrigerator going. In the morning, I was down below 10.8v and it caused the charger relay needing to be reset - only I didn't know that. Waking up to a fog bank and low voltage, I started the motor and started the radar. The radar then started drawing down the engine battery rather than the house, and soon everything didn't want to run anymore. Luckily, I was able to drop the anchor and figure this out to recharge the batteries.

I do have a solar charger but my experience seems to show that it doesn't do enough to keep up with even limited demand. I do think adding more house storage is the safest thing to do if you want to stay warm, safe and minimal operations during the night. I am curious about wiring the thruster battery to the house, maybe with a switch. My thruster is in a separate lazarette, so don't know if that is an issue. I think I have space to add another house battery next to the other bank. Options to explore, but with my intention of spending more time out on the hook, I would rather have more power in storage - I think.

 

[iggy]

This past weekend, I spent a couple of nights out on my R-23 in near freezing temperatures here in the Pacific Northwest. Each night, my Webasto heater (2000 STC) turned off in the middle of the night (usually while in heat mode). The error code was F 03, which was low voltage.

I was not on shore power. The only power that I had going at night was the refrigerator, anchor light and my cell phone. Nothing else was on. The voltage drop was not that radical, but enough to cut the heater off.

I'm curious whether others have experienced this when running the heater all night. What are the solutions? Has anyone added another house battery to their R-23? Could there be other things drawing power? Should I have put my food outside for the night? 🙂

Good thing I brought my long underwear and down sleeping bag.

Sorry to that. I would look up the specs on the things that you want to leave on for total amps. Than go over the specs on your batteries as to the amp hours. Than do the math to see how much you are falling short. This will tell many things! What can I turn off to go though the night, if anything? How big of a battery or batteries do I need to go though the night. You never want to bring you batteries down below 50% on wet cells and 40% on AGMs as a rule, but I would look that up too. At 12.2 volts on a wet cell is close to the battery being 50% discharged.

 

[Chimo]

Hi Hamster,

I didn't realise that the thruster battery was in the other lazarette. In an R25SC the four batteries are all port side. I could imagine that you can still combine but I would confirm wire gauge. I'm sure a knowledgeable person such as Curt will chip in.

One other thought I had that I'm sure someone can help with. When on the hook and I want to run the inverter for something like the microwave I always start the engine. That maintains my battery voltage nicely. I don't know what the alternator output is at idle but running it's rated at 180A. I believe the Yamaha 200 motor has an alternator output about 50A. Again I don't know what that would be at idle but I expect quite a bit less than the diesel. The point I'm getting to is that we both have to run for quite a while between anchorages to recharge house batteries, you presumably longer.

Hope this helps.

 

[j&lgray]

When we anchor, we completely shut down the chartplotter, all the Garmin pieces and especially the NEMA background because these draw a lot of amps.

 

[Cutwater28GG]

likewise. Im down to fridge and anchor light at night. - making the anchor light LED makes a large difference in Amp usage.

fridge is basically 2.5 amps/hour = 30amps for 12 hours.

chartplotter and NMEA backbone draws I think about another 2.5amps...
...webasto heater another couple
it quickly adds up over night and you get close to your 100amp/H capacity.


also to the original posters scenario; there is a good chance that the batteries were not full the second night as its hard to fully charge the AGMs at anchor. you need a bunch of hours charging at the right voltages to get them to 100% full.

 

[Chimo]

When we anchor, we completely shut down the chartplotter, all the Garmin pieces and especially the NEMA background because these draw a lot of amps.

Did you add a switch for the NEMA backbone? How do you turn it off?

 

[Red Raven]

Hi David,

Our 2014 R27 has breaker panel switches for the NMEA backbone and the Chartplotter. I suspect all the boats of that era had something similar. It is really a nice feature to be able to shut it all off from the panel. I never touch the power buttons on any of the instruments except the VHF radio which does not have a breaker.

Curt

 

[Hamster]

My Webasto has a SmarTemp Control 2.0. One of the options I found, after reading the manual, was to change the point at which the heater disconnects. The control function is labelled "LVD", for Low Voltage Disconnect. The range you can select is between 11 and 12.5v, with 11.4v being the default.

I reset mine to 11.0v for now. I am not typically at anchor more than one night. This last trip, I did fairly long runs at full RPMs, so I'm pretty sure that my house batteries got fully charged. I do think the refrigerator must have been the main culprit and will likely cut that off in the evening if running the heater.