Solar charging and battery question

[shark918v]

Q: Let's say I plan to do a lot of boon dock camping in my pop-up trailer.. And, I currently have a deep cycle battery in use. I keep it on a solar trickle charger when parked. A day before we leave I take it off the trickle charger and let it rest to get an accurate charge reading. It's fully charged. The day we leave I hook up the trailer to the charging alternator of the tow vehicle and off we go. When arrive at the destination I break out the larger 45 watt HF solar panel with the charge controller and hook it up to keep the deep cell battery charged. Also, I did replace all the interior lights with LEDs.



Can I add a small sized 12v gel cell battery in parallel with the deep cycle in order to further extend the battery usage???????



And if so, in your opinion, how is the HF 45 watt solar charger going to work in this overall system???

[pgandw]

If you are going to run batteries in parallel, they should be a matched set. Otherwise, the older/larger one will deplete the newer/smaller one and prevent full charging. If your batteries are not going to be well matched, you need to use one at a time, and not together.

Whether your larger solar panel is going to be enough depends on your usage, and what the real output is. Solar panel output falls off very quickly if shaded, and you will only get near full output if the panel directly faces the sun. The rule of thumb I know says you get about 1/4 the rated output averaged over an 8-10 hour day. This would be 8-10 amp hours per day.

The 45 watt panel will probably be enough if the only load is occasional use of the water pump, and LED lighting. Fans (including the heater fan) will likely suck the battery down faster than the panel can replenish charge. But only experimenting will know for sure.

just my experiences
Fred W

[Witch Doctor]

Originally Posted by pgandw

If you are going to run batteries in parallel, they should be a matched set. Otherwise, the older/larger one will deplete the newer/smaller one and prevent full charging. If your batteries are not going to be well matched, you need to use one at a time, and not together.

Whether your larger solar panel is going to be enough depends on your usage, and what the real output is. Solar panel output falls off very quickly if shaded, and you will only get near full output if the panel directly faces the sun. The rule of thumb I know says you get about 1/4 the rated output averaged over an 8-10 hour day. This would be 8-10 amp hours per day.

The 45 watt panel will probably be enough if the only load is occasional use of the water pump, and LED lighting. Fans (including the heater fan) will likely suck the battery down faster than the panel can replenish charge. But only experimenting will know for sure.

just my experiences
Fred W

X'2 Your battery has to be both the same, and both the same age. If you are within 6mos or so you shouldn't have a problem. But get the same batt. ....