dual battery searching making me more confused...help!

[liquid-diet]

Ok i have been searching dual battery setups for a week now, and there is so much stuff out there and everything wire up is different. I made this diagram to outline what i think everyone is telling me. Let me know if i am close or way off please.



Also i have heard people talk about stingers and hellroaring and about voltage drop and diode based isolators hurting batteries. My question is i dont want to spend tons of cash, but i do want to do it right. If i use a Borg Warner R3098, is that the same as the higher priced one per Diesel @ MC thread (http://www.tmcowners.com/teamtalk/showthread.php?t=3557) or does it have a voltage drop? and if so can it degrade my batteries?

[kaikane]

RE: dual battery searching making me more confused...help!

They way you have this wired up...your secondary battery will have a constant draw on it. That is ok assuming you will be disconnecting the battery, or installing a cutt off switch. My personal recommendation would be to use one of these, http://www.delcity.net/store/Voltage-Sensing-Relay-!-Single-Sense/p_793848.a_1 or a multi battery isolator to tie your secondary batteries into the system. All that stuff about voltage drop, etc. is not very important unless you are lookign to provide sound to an entire lake. The Isolation relay you have listed there is more of a starter type isolator meaning...it doesn't really have a good way to deal with the heat generated when isolating a current load over a long perion of time. That isolator is meant for short bursts. A true multi-battery isolator (like what you would find in an RV) is the best choice for longer, low amperage current draws like you get form stereos and amps.

In my opinion, easiest thing to do is add a second, true deep cell battery 100Amp Hours or greater to your regular circuit with a properly wired isolator to seperat and or charge the batteries. Don't forget to fuse your main power line as close to the 2nd battery as possible or you might have a major fire hazzard on your hands.

[liquid-diet]

RE: dual battery searching making me more confused...help!

can i run with the Yandina C100 if i dont plan on upgrading my alternator on my 01 SAN?

[kaikane]

Yeah you should be able to. The VSR I linked you is a better quality that the Yandina but it's up to you. Your stock alternator (assuming it's a 60/80 amp) should be fine if you are only adding 1 or 2 batteries. If you end up adding more batteries or ones with high capacity, you will probably need to move up to a 100/120 amp alternator.

The charging rule of thumb for deep cell batteries is your amperage should supply at least 10% of the total amp hour capacity in your battery bank (remember the running gear also has amp draws so factor that into your equation). Example, if you add a 120 AH house battery...you'll need at least 12 amps to charge it properly. a starting battery uses a high initial burst to charge but drops off quickly as well. You should factor a constant 10 amps for the starting battery. Running gear on boat with electronic ignition, injection system, etc. usually takes a constant 20-30 amps if memory serves. That would leave you with roughly 10 additional amps on a 60amp alternator.

[liquid-diet]

ok i think i am going with a Sure Power 1314, fits into my schematic without ignition wire

[inboardsonly]

Have a look at either Blue Sea Systems or BEP Marine

Both of these companies make battery isolators.

I assume that is what you are trying to do.

These units allow the start battery to start the engine, and the house battery to power the stereo.

When starting the engine, the two batteries are disconnected from each other. The start battery starts the engine, then starts to be charged by the alternator. Once it's charged, the relay closes, and the house battery gets charged.
The advantage here is that there are no voltage spikes passed on to your stereo equipment.
When you are stopped, and the engine is off, the house battery powers the stereo, and cant drain the start battery. If either the house or the start battery is dead, you can manually connect the two batteries (emergency parallel)....
The DelCity link supplied above is showing the BEP Marine Voltage Sensitive Relay.
It's a good choice too.... Try getting it from West Marine or if you're in Canada, I can hook you up with what you need....
Safer to use than what you are doing, and it's made for the marine environment.

Pat