Tom Metzger
Sustaining Partner
No
As long as the bank is 12 volts you are OK.
As long as the bank is 12 volts you are OK.
Hi Steven,
I am by no means an expert on this but i have done a bit of reading lately and you should know that the alternator for the A4 (at least the original) was only a 35amp unit. This essentially means it is sufficient to power a bank of 140 amp hours roughly if following the 25% rule as a guideline. I know you can purchase alternators via Moyer Marine with a much higher output and this should probably be done if you are going beyond 2 batteries. If the alternator is not of sufficient amperage it will not charge the batteries properly and the batteries may be dmgd. There are many on this site that know much more than I and hopefully they will chime in and correct me if I am off base here.
I am by no means an expert on this but i have done a bit of reading lately and you should know that the alternator for the A4 (at least the original) was only a 35amp unit. This essentially means it is sufficient to power a bank of 140 amp hours roughly if following the 25% rule as a guideline. I know you can purchase alternators via Moyer Marine with a much higher output and this should probably be done if you are going beyond 2 batteries. If the alternator is not of sufficient amperage it will not charge the batteries properly and the batteries may be dmgd. There are many on this site that know much more than I and hopefully they will chime in and correct me if I am off base here.
Kevin Johnston
Member III
Batteries for an A4 aboard a E27
Before the season starts, I will be in the battery market as well and I may follow your lead. So, let us know what is the best route to go you all.
Thank you,
KJ
Before the season starts, I will be in the battery market as well and I may follow your lead. So, let us know what is the best route to go you all.
Thank you,
KJ
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If you are in a slip and plug into shore power then the size of the alternator is less important provided you have a battery charger that is adequate. The other issue is how you use the boat. If you stay out long enough to deplete your bank and depend on the alternator to recharge then an upgrade is in your future. If you weekend and daysail and the electrical demands are kept in check then plugging in may work well for you.
I did the high output alternator and special regulator which works for me as I am on a mooring.
RT
I did the high output alternator and special regulator which works for me as I am on a mooring.
RT
steven
Sustaining Member
I'm in slip and have access to shore power. Power is through a Newmar ABC 12-8 Charger which is rated 16amps intermittant and 8 amps continuous. It has leads for two isolated banks - but the literature is unclear if the amp rating is total or per channel - total, I suspect. Seems kind of lightweight, but has performed ok so far. Anybody have experience with this unit?
Steve
I have the same boat with an A4 also. I currently have two 12 volt Costco batteries and I keep them charged with a Xantrex True charge plus battery charger. I plan on swapping them out this spring with two new ones because I think I have a dead cell in one of the batteries. I have always wanted to add one more battery as a dedicated starting battery but can’t figure out where the extra battery would go. Is you plan to have more then two batteries and if so how do you have them configured, where are they placed?
I have the same boat with an A4 also. I currently have two 12 volt Costco batteries and I keep them charged with a Xantrex True charge plus battery charger. I plan on swapping them out this spring with two new ones because I think I have a dead cell in one of the batteries. I have always wanted to add one more battery as a dedicated starting battery but can’t figure out where the extra battery would go. Is you plan to have more then two batteries and if so how do you have them configured, where are they placed?
Make the two batteries a dedicated house bank by tying them together. Simple. You can place a single start battery wherever it will fit. Build a shelf/mount for it, put it in a battery box and strap it to the mount. RT
steven
Sustaining Member
Similar to Rob's suggestion. Third battery under the starb settee, wired in parallel with one of the two batteries in the port lazarette, to Bank #2 on the master switch. Both Bank #2 batteries are starter/deep cycle hybrids, so I can use Bank #2 for both house and starting. Bank #1 is a single purely cranking battery reserved for 'emergency' starting. So I've got two ways to get the engine going. I don't have much in the way of appliances, and I'm mostly on shore power, so this works out. Not recommended for everyone.
On the E35-2, I think the third (and fourth?) battery would be better under the (port) quaterberth. Haven't measured but I think there is room. Alternatively, near the other two batteries in the starb. lazarette which would be a shorter cable run to the master switch (but Indigo lists to starb., so I try not to put weight there).
--Steve
On the E35-2, I think the third (and fourth?) battery would be better under the (port) quaterberth. Haven't measured but I think there is room. Alternatively, near the other two batteries in the starb. lazarette which would be a shorter cable run to the master switch (but Indigo lists to starb., so I try not to put weight there).
--Steve