Adding a battery charger
So it just dawned on me, while re-reading my survey, that the boat we just bought does not have an AC battery charger. It never occured to me that the boat (1984 Sabre 34) would not have one. Here's what it does have:
2 relatively recent deep cycle house batteries, each in a separate bank, standard 1/2/BOTH/OFF Switch, and upgraded Balmar alternator with regulator.
The boat also has a shore power hookup and panel, but it appears this is currently just set up to power the AC outlets on board. No battery charger.
I would like to add a charger. I would also like to avoid going nuts in the process with a ton of new equipment (we have other priorities). However, I would like to do this the smart way--at least make the best of the situation of not having a charger, and add one properly. Any recommendations on how to go about this?
FYI, we're weekend and summer cruisers on the Chesapeake Bay, so the boat will spend most of the week at the marina hooked up to power, but when we're crusing we don't go to marinas much. Also, currently the power demands are relatively low on board--we don't even have refrigeration. Eventually we'll add refrigeration, but we'll also be moving to LED lights, etc. I'm trying to keep power demands reasonable. We don't have a microwave, TV, or coffee maker or any of that stuff and don't plan to.
Please let me know if you have any recommendation on configuration, or if there is a resource I should read myself. Happy to do that of course.
Get yourself an Iota battery charger and either a echo charger (preferred) or battery combiner (less expensive, works, but not as good IMHO). Wire the Iota to a new AC breaker, if you've got space on the shorepower AC panel to do so.
To charge at the dock, plug the shorepower in, turn on the breaker for the Iota Charger, turn the main battery switch OFF. The echo charger/battery combiner will make sure both batteries get topped off.
Would that scenario mean that we would not have DC power (lights, etc.) at the dock though (since the battery switch would be off)?
So Joe...you might have around 200ah's as a house battery bank. Just a small 15-20amp smart charger should suffice well since you are mostly at the dock.
I agree with dawg about adding a breaker. I would NOT go for the echo charge in your case as that is $150 bucks of expense that you just dont need. Instead...I would wire your two house batteries in parallel on Position #1 of your battery switch...then wire your starter into position #2.
Wire the charger into the battery switch and MOST of the time just leave it on #1 but give #2 a chance at a few amps now and then if you have not done a lot of motoring or if you get a low voltage reading (12.2V or less).
I think this will be the least complicated and least expensive setup for you and will work just fine for your particular case. BTW...the IOTA 15amp with smart charging would be a good unit to consider:
The DLS-15/IQ4 features an internal IQ Smart Charge Controller which automatically provides three-stage battery charging for safer charging and longer life for your system's battery.
LOL... if you're on the boat, don't turn off the DC main switch... if you're not on the boat, turn it off. :)
I would buy a charger to meet what you think your needs will be 5 years from now...not just for next year. You should buy one which has multistage charging, and an equilization feature at least, so it helps you batteries last through the many cycle you recharge them. Many people make the mistake of not equalizing their batteries once a month therefore limiting their life.
We bought a Truecharge2 40 amp charger by Xantrex for $280 from sailnet and are very happy with it. It has all the features above plus it is a three bank charger.
Being able to recharge a larger amp hour battery bank in a smaller amount of time is why we went the 40A route as oppposed to 20 or 12 amp charger. The first stage of battery charging will only charge your battery to 80%. usually you do not discharge your batteries under 60%. We have 660 amp house bank. *80% is 528amp, and 60%is 396. So to get from 60% to 80% takes 261 amps or 6.5 hours charging with a 40 amp charger. I am not evebn concerned with the float stage (the next 20% as the charge is dropped down. There will copme times in the next few years you will want to use your boat for longer trips and add refrigeration which will use at least 80 amps a day so you will increase it battery capacity over what you have. You may decide to stay one noght in a marina to charge and need the capacity renewed as quickly as posssible.
Research this well before buying and look ahead to your future uses. It will save you from buying another charger ina couple years.
Thanks everyone. I'm definitely trying to plan for future needs, not just immediate needs. So I did some additional reading (Nigel Calder, etc.) on batteries and chargers, in addition to these posts. I'm also headed to the boat this weekend, where I'll be able to get more specifics on the current wiring.
A couple things to clarify. I don't currently have a separate starting battery. There are just the two single identical batteries, one in each bank. I believe (will verify) that the 1/2/BOTH/OFF switch is currently between the alternator/regulator and the batteries--standard issue for 1984.
So I have a rough plan for the future, which I may revise after using the boat. The future plan is different from my immediate plan. I am limited work at this time to items that I need to do to bring the boat home from new england. Even the battery charger isn't necessary, but I might do it anyway.
- Add a separate battery for starting to bank 2
- Combine the two existing house batteries in parallel to bank 1.
- Wire the alternator/regulator to house bank 1
- Add echo charger between house bank 1 and starter battery (bank 2), as both SD and Nigel Calder recommend if you have one alternator
- Possibly rewire battery charger (see question 4 below)
- Utilize battery config as is, one house battery in each bank, charging determined by 1/2/BOTH/OFF switch
- Add battery charger
So now I have some more specific questions about specifically adding the battery charger:
1. I know you don't know my specific boat, but in general, what are some good locations for the charger? My Sabre 34 layout is out of yacht design 101. Batteries are under the Q-berth, cockpit locker is opposite the Q-berth, nav station next to Q-berth, galley opposite, etc.
2. Does AC power come into the boat, through the MAIN AC breaker, then to the charger? Or does it come into the boat, split to a separate charger breaker, then go to the charger? Or go through both MAIN AC and charger breaker?
3. After the charger, does the charger get wired straight to the batteries, or go through anything else?
4. Future install question only: If I do add a separate starting battery and then combine the 2 house batteries and add an echo charger between, do I just wire the battery charger only to the house bank and let the echo charger handle the starter (the alternator would be set up like this)? Or do I use the multiple outputs on the battery charger to charge them both (not using the echo charger)? If I did the latter, would it mess up the echo charger or alternator/regulator?
Sorry for all the questions, but thanks as always for the help!
Joe...thsanks for the clarifications. On your questions:
2. Do you have ANY switches presently on the boat that turn on and off any AC powered devices or even the AC outlests?? If not, and your shore power is wired directly from the master AC switch only to outlets then you will need to install a small AC breaker panel...with at least one switch for your outlets and one for your charger...I would get a breaker panel with at least a couple of more switches than you need now.
3. Should be answered by 2 above. Shore power, main AC breaker, Individual AC breakers on panel, charger is the order. Charger output to the battery switch for NOW.
4. For your plan...the chargers power SOURCE should be the AC breaker panel...and the destination for the charger DC output should be one of your two house batteries rather than the battery switch. You should not get a charger with multiple outlets since you are planning on charging one bank and using an echo charger for the starter battery.
Here are some answers below...
Here's a pic:
Don't most chargers have multiple outlets? If the one I get has multiple, should I just use one in this scenario?
Joe...the unnamed breaker SHOULD be the water heater. Looks like you have room there to add an additional breaker for a charger.
The reason I suggested going to the battery switch for NOW is that I assume for your future needs you will want to simply wire ONLY to the house bank which requires a charger with ONLY one output. MOST chargers have only one output and it is WRONG to buy one with more outputs than you need especially since many multiple output units will DIVIDE the total amps between the outputs so that one set of batteries will never get the full amperage you paid for. A 20 amp dual output charger may thus only give 10 amps max to each of two banks. Not what YOU want or need.
Thus...if you get a single output unit for your future needs...you must hook it up temporarily to the battery switch to be able to charge both batts you now have until you get the echo charge.
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