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sonnyo916
07-05-2012, 12:51 PM
Greetings,

Newbie from Boston, MA is asking if it is "safe" to daisy chain a deep cycle and a car battery together for a RV? From what I've read, I connect positive-positive and negative-negative, with the deep-cycle being "closer" to the RV connection, since that battery has the smaller, thinner posts to the RV wiring. I've also read that these batteries should *not* be daisy-chained, but don't understand why (I'm no electronics expert). The only components I wish to power in the RV are the refrigerator and lights, however the deep-cycle battery alone only lasts 2-3 days. Sometimes our camping trips last longer.

Also, what type of solar panel would be good enough to trickle power to the battery setup to keep the fridge running and cold between weekend camping trips ?

Thanks in advance for any advice.

RussN9ZP
07-05-2012, 01:07 PM
Greetings,

Newbie from Boston, MA is asking if it is "safe" to daisy chain a deep cycle and a car battery together for a RV? From what I've read, I connect positive-positive and negative-negative, with the deep-cycle being "closer" to the RV connection, since that battery has the smaller, thinner posts to the RV wiring. I've also read that these batteries should *not* be daisy-chained, but don't understand why (I'm no electronics expert). The only components I wish to power in the RV are the refrigerator and lights, however the deep-cycle battery alone only lasts 2-3 days. Sometimes our camping trips last longer.

Also, what type of solar panel would be good enough to trickle power to the battery setup to keep the fridge running and cold between weekend camping trips ?

Thanks in advance for any advice.

They're two different creatures with different charge and discharge properties. I would not do it.

For the refridge you need to figure out how much power it consumes in order to accurately tell how much solar and battery you would need.

billvon
07-05-2012, 01:16 PM
Newbie from Boston, MA is asking if it is "safe" to daisy chain a deep cycle and a car battery together for a RV? From what I've read, I connect positive-positive and negative-negative, with the deep-cycle being "closer" to the RV connection, since that battery has the smaller, thinner posts to the RV wiring. I've also read that these batteries should *not* be daisy-chained, but don't understand why (I'm no electronics expert). The only components I wish to power in the RV are the refrigerator and lights, however the deep-cycle battery alone only lasts 2-3 days. Sometimes our camping trips last longer.

A starter battery won't help you with that; they'll provide power for a while but die very quickly. If you want to extend your operation get another similar battery and put it in parallel. Ideally you should get TWO new batteries and put them in parallel; if your battery "dies" after 2-3 days you've probably already done damage to it.

However it is safe to parallel a starter battery and it won't start a fire or anything.


Also, what type of solar panel would be good enough to trickle power to the battery setup to keep the fridge running and cold between weekend camping trips ?

Trickle charge means maintain the battery. If you are planning on operating loads you are talking a full blown solar power system.

If your refrigerator takes 100 watts on average (I have no idea . . .) then that's 2.4kwhr a day. That means you need about 3800 watt-hours a day of panels, which in turn is 760 watts of panels in a sunny area. (Call it $1000 for very cheap Chinese panels.) Then a charge controller to regulate power to the batteries. Those can be pretty cheap on the order of $150.