Electrical Power Supply Systems Advice

[jack boats]

I've got a 2001 Hunter P420cc with 2 Lifeline AGM 4DL batteries. They are getting to be about 10 years old now. Though they still seem to be running well, I'm preparing to embark on a SURFMEX cruise from San Diego, so I'm considering buying an additional battery or two to add Amp Hours as well as provide a newer backup bank. I know very little about my battery systems and I like to post some of my questions here. I attached a pic of the control panel for the batteries.

1. I get that the top round switch is for the starter battery (interstate deep cycle 750 crank Amps) and either in the off or on position is self explanatory. However, I'd like to know if the on/off position isolates this battery from being charged by the Freedom Marine 20, 2000 watt / 100 amp battery charger monitored by a heart interface. In other words does the starter bat get charged regardless of whether in the on or off position?

2. I believe that the lower round inverter draw selector switch is set-up with one of the AGMs on 1 and the other on 2. I'm one of those people that just leaves it in the both position because I don't understand why I'd want to use one or the other besides just as an isolated backup, but I'd love a brief explanation, also will both batteries always receive charge regardless of the position that switch is in?

3. There are also two toggle switches labeled panel 1 and panel 2. I don't know what these are supposed to do. I need to have at least one set to on to get power to the panel but it doesn't seem to matter which. I thought that they might be wired to the individual house batteries so I could invert from just one of the pair while running DC from the other, but with just one switch in the on position, both batteries seem to drain evenly, as far as I can tell. So why are their two panel switches? and does it matter if 1 or 2 or both are on, and if so why?

4. I don't have much knowledge on heart system either, maybe someone may know what it should be used for in my set-up?

5. Whats the best way to add one or two more batteries to my system? Can I add just another 4D to the system or will I need to add two? or could I add one 8D?

6. I read that the batteries in each bank need to be the same size and age. So does that mean I should take the two old 4D's and run them in series together into the #1 side and then run a third 4d or 8D or possibly another type into the #2 side?

7. Can I use cheaper batteries for the second bank like 6V golf cart batteries?

I know it's a lot to ask but I'm trying to keep it concise so that other battery noobs may benefit as well.

Thanks, J

 

[Don12364]

The Acid Test (Pun intended)

From my experience the only sure way to learn which switch does what is to use a meter. Even the cheapest $5 meter will do.

First make a diagram of your batteries (3?) and switches.

From a standing start - ie. with no charger switched on and not been on for half an hour, measure the voltage across each battery and note it down. If any of them are 14.4 or very close then switch on a few lights (or start the engine and stop it again in the case of the starter battery) just to reduce the voltage a little.

Then switch on the charger and measure the voltage on a battery. Doesn't matter what it is as long as it is not 14.4.
Next operate each of the main isolation switches and note down when the battery voltage on the meter jumps up. This one is then on charge.

Switch it off and repeat for the other batteries.

Now you will know which switch charges which battery.

I leave your other questions regarding additional batteries to those with an inclination to assist.

If you could scan and post the circuit diagram for the boat a picture would help all.

BTW Maine has just posted the best commendation for 'ordinary' batteries you will ever read.

 

[Bill Roosa]

WOW!
Well, I guess we have to make the assumption that a previous owner has NOT been in there and upgraded/changed the system first. Can you confirm that this is a factory supplied solution?
If all you are trying to do is add some storage capacity to the house bank (make it bigger) then that is pretty easy. Just drop the batteries in and wire them to the old ones. This assumes there is nothing odd going on with the inverters, genset (you did not mention one), solar (I saw a solar label on the start batt switch) or other electrical production means you have on board (wind??). A picture of the battery compartment would be of great help.
On a different note, just adding storage may not accomplish what you are trying to accomplish. While cruising you are going to find that you will not be able to buy (or find a place for) enough storage to actually eliminate the need to meet your electrical demand with some means of producing/purchasing electricity. While on the hook you cannot purchase (shore power) electricity as you well know so you are left with producing it for yourself. The basic equation:

energy used = energy produced + energy stored

is still firmly in effect. You can extend your time between charges (once) by buying more storage but after you use up what is in the new storage you HAVE to replace it to get the same time between recharges. Many of us CAN do this over a weekend because we are going to leave the boat on shore power the rest of the week. Start using the boat every day and you quickly run up against a “lack of production means” situation. Basically storage just allows us to concentrate our power production and it does not eliminate the need to produce as much as we are consuming.

With all that said if you can cruise right now with the production means currently available then adding some storage will only raise the average state of charge (SOC) of the battery banks.
This is a good thing as maintain a higher average SOC extends battery life. It will not change your recharge cycle at all. You are still going to have to produce what you consume.

Bottom line: what are you trying to accomplish with buying more storage?

 

[jack boats]

Thanks for the response! Donalex, I will try testing the charger with my meter. I saw Maine's explanation and found it very enlightening. To Bills question, there was one previous out of town owner who did not use the boat very often from 2001-2006 when I purchased it. As far as I know everything is factory. There is not a genset but there is a Seaward 11 gallon water heater that I just actually replaced myself. The water heater doesn't appear to wired into the inverter because it only works when on shore power. I don't know if that's a safety feature or a problem or just intended? There is also a small solar panel for trickle charging the starter battery, that appears to be working last check.

The boat has always been in a marina hooked up to shore power since I've owned it. I'm not sure if the batteries are the originals but I haven't replaced them. I have run them down once or twice while on the hook or when the dock breaker flipped while I was out of town and the reefer drew them down, but other than that they have always been kept on the charger. I think I equalized once when I was on the hook a few years ago. Because I've read the bat life is like ~5 years I figure I should have a new set as a backup, but these are still working so I'm not sure the correct way to add more. Should I take the two bats I have now and just connect them together into the #1 pair of cables. Then connect the new bat into the free pair for the #2 position? Picture attached

I'm aware that I've got to put back what power I use regardless of how much storage I have, but I figure I can extend the time I can run the inverter and other systems by adding more bats, right? Currently I can run a couple lights, a TV, laptop, heater, and the reefer for about 4 hours before the charge drops low enough to automatically shutdown the system, at least I guess that's whats happening. I ordered a couple HQRP 45 Watt Monocrystalline Flexible Solar Panels to help decrease motor running for recharges. I'm considering adding wind as well. I'm sure I'll be asking advice about installing the panels later.

My primary concern is that I have capable battery's aboard in case I'm in Mexico and my current batteries begin to fail and I'd like to know what my options are for adding more into the system? Or should I just wait for them to fail and replace them then? If I'm not going to get a longer run between charges I guess it doesn't matter how many I have wired in...

 

[Gunni]

Spend some time tracking down a nearby ABYC cert marine electrician via recommendations and pay her to come aboard, inspect, diagram, load test. Sit at her feet and learn. Respect your instincts on this - you asked the questions because you are concerned and know what you don't know. Very smart. Follow through on that common sense. You don't want to be out there on your own with dead batteries, and no clue. It will be money well spent.

 

[jack boats]

Point taken Gunni. I like to take a hands on approach and learn as much as possible before bringing in the pros so when its just me I'm ready. I've got lots of diagrams from Hunter, but looking at diagrams and actually connecting wires are miles apart on the learning curve. I do have a good Bosun but i don't know if he's ABYC certed.

Thanks,
J

 

[mitiempo]

Water heaters and space heaters should not be run with an inverter as the load will drain the largest battery bank in a few hours. Normal uses for an inverter are 120 volt sockets which can be used for tv's, dvd players, and electrical appliances like microwaves and coffee makers that are not on for longer periods of time.

 

[Ron20324]

The water heater doesn't appear to wired into the inverter because it only works when on shore power.]

If your AC panel has a couple spare breaker postions you can do what I did ( but had to put in a larger panel to get two spares). Wire the inverter to the AC panel, then place a lockout so you can only have shore power OR inverter to feed all the AC breakers. There are those that would suggest a separate DTDT-type selector switch for this same purpose, but they are expensive. The lockout also prevents the battery charger from being on when the inverter is on.

 

[mitiempo]

The best solution I think is to run a sub panel from the inverter with only the loads on it that you would want to power with the inverter - typically 120 volt sockets.

If the inverter is a good quality one it will probably have a bypass so those same 120 volt sockets can be powered by shorepower without any separate switches needed.

 

[LloydB]

I think that Gunni in reply #5 has given you the best recommendation. Your question #4 can't be specificly answered as your set-up hasn't been described and you didn't state the model # version/date you have. #6 No. You probably dont want to connect them together in parallel either, because after a couple years they will have aged differntly even if started identically and that can cause early failure. #7 yes but get the electrical survey first because you may not want to. But wait there's more --

http://forums.sbo.sailboatowners.com/showthread.php?p=878873&highlight=wal%20mart%20battery