Uninterruptible Power Supply to Protect Electronics

[mackidaddy]

Hello,
Does anyone have experience with a UPS to prevent the drawdown of power when the bow thruster is used?
I worry that the inconsistent power levels may reduce the life of the Raymarine.
Has anyone installed such a thing? Is it a DIY job? Expensive? Worth it?
Thanks,
Eric

[furball]

Eric,
Check this thread, RicM install this on his 28.
viewtopic.php?f=27&t=2136
Doesn't seem like a hard install but I would be interested to hear the details from Ric or someone else on the wiring install. Does the positive lead need to run direct from a battery or can you connect to a switched + power bus already mounted close by. Can I use a local ground bus or ground back to a battery as well. I plan to order mine this week along with a galvanic isolator.
Good luck,
John

[RicM]

The UPS that I installed is to halt electronics blinking out on engine start. It is wired to the start button, and when the start button is pressed the electronic circuit is temporarily switched to the UPS's internal battery. This will not help you with the bowthruster problem. Unless you have very extensive electronics, the bow thruster should not draw the voltage down enough to knock out your gear. Several questions come to mind... Has it always been this way or has the problem been getting worse toward the end of the season? If so, there are several possibilities. 1)The Yanmar has some kind of a electric preheat circuit that comes on when the temp is below a certain point. This draws power from the battery circuit for the first couple of minutes. You can see the drop on the ammeter on the dash. it will pop back up after the engine warms up a bit. 2) The battery is dying. I noticed the problem you described with one of my 2 batteries only. Battery #1, even though on the charger at dockside, has gotten so the thruster will knock out the nav gear, but not the case with #2 or with the switch on 1+2. I'm replacing battery #1 and rewiring as start/house over the winter. 3) The thruster is sucking too much juice. If the problem persists on both batteries singly but not with the switch in the 1+2 postion, or in the 1+2 position as well, the thruster itself might be the issue. Worn brushes, lack of lube in the gears, restriction of the prop in some way, all would cause it to draw more power than when new. Some folks install a dedicated battery for the thruster. This will work as a last resort, but will disguise any thruster issues temporarily. Don't worry about the electronics. The fact that they go down is a protective action in itself. Rather than run at low voltage which would cause overheating, they go off at about 11.5V to protect the components. It's just like turning them off.

[mackidaddy]

Thanks Ric,
The Raymarine usually kicks out when I turn on the engine back on after a while. It only dims when I use the thruster.
With your help, I have a feeling the batteries are to blame. Using the "start simple" rule of thumb, I will consider replacing the batteries first before adding complexity and more circuitry to a boat. Even simpler than that, I suppose, is turning off the machine before using the thruster (a habit I've tried to adopt). If new batteries don't help, then the UPS might become "proportionate response". Thanks again for the insight.

[RicM]

This is the thread from boat diesel.com on the same topic:

Level 1 Member Date: July 25, 2008 - 03:50 PM
If the voltage drop during starting stays above 10.5 volts the battery is good and below 10 volts it is bad. For between 10 and 10.5 volts it is marginal.

Another good test is the 24 hour resting voltage test. Charge the battery up, disconnect the leads, wait 24 hours and measure the voltage with a digital voltmeter.

The capacity for a wet cell is as follows;

100% 12.6 volts or higher
75% 12.4
50% 12.2
25% 12.0
0% 11.8

There must be absolutely no load on the battery for the 24 hours - one auto bilge pump cycle and the test is no good.

mayot


Response #4 from: Ski in NC [email] Level 3 Member Date: July 25, 2008 - 09:34 PM
Lots of boats have the electronics blip off when cranking, even with good batteries. I set up boats so the house battery (the one running the electronics) is isolated from the engine when cranking. That is one of a few ways of avoiding the problem. I use the carolina redneck test for batteries: Crank engine cold on #1. Stop engine. Crank engine cold on #2. If it cranks well on both cold, batteries are good (or good enough!!). Then when running, leave on "all" so both charge. Lots of good ways to manage batteries, but having house and engine share one 1-all-2 switch is not the best.

-Eric

Response #5 from: RicM [email] Level 1 Member Date: July 26, 2008 - 02:35 AM
Thanks all. Filled with distilled water (6 holes, each took about 6 ounces of water). Ran around today on "both". Checked the voltage drop on cranking tonight and I got 10.8v on the battery in question. 1-2-both-off switch has been working OK and I hate to start a project in the middle of fishing season. Both batteries appear to be oversized deep cycle batteries. The boat is kept in a slip with shore power and we don't overnight on the hook much. Perhaps this coming off season I will add a dedicated battery for the electronics as we do a lot of drift fishing.


Response #6 from: Bill [email] Level 1 Member Date: July 26, 2008 - 10:40 AM
Per Douglas' mesage above, you might not want to wait to replace. The 10.8v battery will continually pull volts from the good battery, shortening the good battery's life. Also, if you have a sensor enabled charging system, the charger will continue to push volts to the battery trying to bring it up to level. Another way to shorten battery life. Even at today's prices, you can buy a lot of batteries for the equivalent of two hours of sea towing.


Response #7 from: RicM [email] Level 1 Member Date: July 26, 2008 - 12:29 PM
Bill:
The battery measured 13V+ just after charging, the voltage dropped to 10.8V during cranking. From what I have read above this would constitute a "good battery" I would think. I don't leave the dock without my towing insurance paid up. In my old boat I got towed in several times, all covered under my BoatUS/TowUS membership, but yes they are hideously expensive events if not covered!


Response #8 from: Bobwire [email] Level 2 Member Date: July 26, 2008 - 04:07 PM
A more definitive battery test is done with a conductance tester.It measures available plate area,which equates to cca's of the battery.If a battery reads 900 cca on meter,and rated on it's manufactering label 1100, its bad.All battery companies use this type meter,I use it,and many repair shops. Ask around you may find someone has one ,very portable,16 oz ,maybe 1 minute to do a test

Bob Johnson Marine Electrician
307 Hall Ave,Pt Pleasant,
New Jersey, 08742,
United States
Tel: 732-814-0735, , Email
Response #9 from: Mike Chi [email] Level 1 Member Date: July 26, 2008 - 09:47 PM
The battery guy i deal with tells me that commercial batteries are only good for 2 years ,he also never punches the the dates that way when you bring it back in to replace, he then punches it to get a better return credit from his supplier. Replace the battery, good luck


Response #10 from: RicM [email] Level 1 Member Date: July 27, 2008 - 02:05 AM
Well I am learning a lot here, thanks to all. I am going to check with my local rental place and see if he has a conductance tester. If not, I see inexpensive models on line for about $120. As I'm going to be moving about in the 12V world for the forseable future, it might be worth it to buy the tool as it will probably cost me $100 to get a mechanic to come down & test it. I realize that you get what you pay for but any opinions on cheap conductance testers?


Response #11 from: RicM [email] Level 1 Member Date: July 27, 2008 - 05:36 AM
OK, some more questions....I looked up Midstate Marine batteries, which is what's in there now.
http://www.midstatebattery.com/marine.htm
and see that the 4D deep cycle does not list CA but AmpHours@20 (225). How do I convert that for a conductance tester? If I do need to replace would I be better off to go to the heavy duty commercial with 1415 CA?


Response #12 from: Bobwire [email] Level 2 Member Date: July 27, 2008 - 08:50 AM
Your 4 d batteries are about 1100 cca's,which is common in a 4d.Not all conductance testers can test high cca's check it's rating before purchasing. Just a short blurp on cca's. As the cca's increase,the plates become thinner to accomadate more plates,hence more surface area increasing cca's, and faster recharge since less density per plate.I really can't see the gain,in high cca's.Depending on your boating,they are less durable in rough service envirnoment.I would recommend a typical cca rating for that particular battery,bumped up a some is ok,and a well know battery specialist,supplier. Some big marine stores don't give you what you pay for in a battery.

Bob Johnson Marine Electrician
307 Hall Ave,Pt Pleasant,
New Jersey, 08742,
United States
Tel: 732-814-0735, , Email
Response #13 from: RicM [email] Level 1 Member Date: July 27, 2008 - 09:22 AM
Bob:

Thanks for your input. I see that the cheapo testers only go up to 800cca, you have to spend $250 to get one that goes to 1400cca. Ya get's what ya pays for.

What would you recommend for an install like this?
The boat is a 2003 Albin 28, Yanmar 6LP diesel currently with 2 4D's of unknown vintage on a 1-2-all-off switch. Electronics include Furuno 1932 10" GPS chartplotter, 1732(?) 7" GPS & radar networked to the 1932. NavPilot 510, VHF radio, 15 LCD TV, radio & DVD player. 3 direct wire bilge pumps. A small Faria 12V dc clock and a marine alarm (micro amps) are also connected to the #1 battery direct. The Sony AM/FM radio also needs a direct that's not currently hooked up (the radio forgets the presets when off for any length of time). Also an electric 55Kg Vetus bowthruster sucks in the amps in bursts while docking. Small AC/DC refrigerator runs all the time.

Use profile is that the boat sits in a slip 3-4 days at a time with shorepower connected through a Newmar galvanic isolator with battery charger on. Most often we drift fish which involves a run of 15 minutes - 2hours, then on and off with numerous engine restarts for the drift fishing, then a run back to port. We almost never stay on the hook or a mooring, but it does happen. All runs fine with battery switch on both, but I loose the electronics when cranking or using bow thruster on battery #1, Battery #2 is usually OK, "both" is always OK. I don't want to do a rewire job now in the middle of the fishing season, so I'd like to put in a very good storage device that I could maybe use as part of a redesign over the winter.

Thanks for any insights!


Response #14 from: Got Diesel [email] Level 3 Member Date: July 27, 2008 - 04:07 PM
As long as the switch is on ALL only when running the engine or on charger the weaker battery will not shorten the life of the good battery. At the dock switch to #1 or #2. If left on ALL it will not destroy the good battery only shorten it's life by making it go into deeper cycles and store it's self at a lower charge.

Designated Engineer
3401 Dale Place,Fort Pierce ,
Florida, 34947,
United States
Tel: 954-562-7465, , Email
Response #15 from: Got Diesel [email] Level 3 Member Date: July 27, 2008 - 04:10 PM
13.2 volts was 100% last time I checked, I think some one gave you some wrong numbers

Designated Engineer
3401 Dale Place,Fort Pierce ,
Florida, 34947,
United States
Tel: 954-562-7465, , Email
Response #16 from: Got Diesel [email] Level 3 Member Date: July 27, 2008 - 04:37 PM
Mike Chi, from what you said this seems like a battery Dealer you don't want to deal with or take advice! I'm sure his commercial batteries only last two years!

Designated Engineer
3401 Dale Place,Fort Pierce ,
Florida, 34947,
United States
Tel: 954-562-7465, , Email
Response #17 from: Mayot [email] Level 1 Member Date: July 27, 2008 - 06:51 PM
The 24 hour rest test is one of the best and most accurate test but not widely used by boatyards as you have to wait 24 hours. They like the testers as it can be done instantly.

I don't know where Bob got 13.2 but I have never seen that number. With the alternator running you should see just over 14 volts for a wet cell. For the 24 rest test you should get 12.6 volts for a wet cell.

A great reference source is East Penn Manufacturing who make the Deka brand battery. They have a full description of the 24 hour rest test along with the numbers for the resting voltage for wet,AGM and gel cells. Since they make wet cell, AGM and gel cells I find their technical data non-biased as they make all three. East Penn, Enersys and Exide are tied as the second thru fourth largest lead acid manufacturers at just under $1.5 Billion in sales last year.

Mayot