I'm considering installing a Harbor Freight 45 watt solar kit on my 5th wheel. I've talked with a friend who uses this on his trailer, but doesn't actually know how it works.I'm concerned about having roof mounted solar panels constantly charging the batteries.I would sure welcome someone holding my hand on this one if someone has experience or thoughts.

Hi,All solar systems should have a charge controller. The Harbor Freight unit is quite expensive per watt. It may be better to look at other more economical systems.

What size and how many batteries? How much will you discharge the batteries?45 watts should be fine for maintaining battery charge but could be hard pressed to recharge one that is much discharged. At 14.4 volts you'll only get about 3 amps.If you just want to keep the battery from discharging during storage you will be fine.An inexpensive PWM controller will keep it from overcharging the batteries.If you think that you might add panels later you might as well make sure the wire that you install now will be adequate for more current.I'm sure you will get a lot more comments here. There are some very knowledgeable people on this board.

I buy some stuff from Harbor Freight but solar gear isn't one of them. If your intention is to have an auxiliary charger for a single (or possibly dual) battery system, when not plugged into the grid, 45-50w is in range. Solar Blvd has this 55w monocrystalline module on sale for $55. You could couple that with an inexpensive PWM controller for around $30. The total system weight would be in the range of 30-40 lbs., easily totable. Shop around for modules that are being sold nearby because shipping the large flat modules can get expensive. Good luck with the solar charger, it is a great way to maintain your batteries.

Thanks guys, for the replies. Have two, 6V Centennial deep cycle batteries (VERY heavy!). Another concern I have is what is the implication when connected to shore power? Seems like maybe there could be a problem with solar panels and the converter charging at the same time. Maybe a switch could be installed to disconnect the solar system when on shore power - ya think??

Hi,Solar charge controllers "play well" with converters. There is no need to disconnect the solar.It sounds as if the battery bank is around 230 amp-hours. For that size, the ball park figure is between 140 and 345 watts of panels. Cost for DIY is about $2.00 per watt.Try these sites:http://rvroadtrip.us/library/12v_system.phphttp://rvroadtrip.us/library/solar_install.phpsilverkid wrote: Another concern I have is what is the implication when connected to shore power? Seems like maybe there could be a problem with solar panels and the converter charging at the same time.

Solar Charger | Good Sam Community

Almot
Explorer III
Jun 03, 2013
RCtime wrote:
pianotuna wrote:
Hi,

The 140 watt is a no brainer from my point of view.

Well it still has 5 days to go on the bidding.

Interesting to see what the final sale price is. Plus shipping.

To the initial question - $190 for HF 45 - it doesn't matter. As others noted, this HF 45 is way too expensive. You can either get a smaller charger for less, or a larger charger for the same $190, from a regular store, not an auction. The question is what exactly you need, i.e. what size panel.
RCtime
Explorer
Jun 02, 2013
Canadian Rainbirds wrote:
pianotuna wrote:
Hi,

The 140 watt is a no brainer from my point of view.

Ditto

Well it still has 5 days to go on the bidding.

Interesting to see what the final sale price is. Plus shipping.
time2roll
Nomad
Jun 02, 2013
Most of these kits come with various do-dads that are not needed or wanted.
HF kit included.
Almot
Explorer III
Jun 02, 2013
What Mex said. 6 amp from that 45W charger is not impressive if you need to charge. BUT if you only need to maintain the existing charge, meaning there are no loads, then 10W is enough.
MEXICOWANDERER
Explorer
Jun 02, 2013
Harbor Freight can be a good value or a poor value. This panel setup is the latter. Take a look at their 6 amp charger. Imagine half of that connected to your batteries five to seven hours a day. It is not impressive. Ten amperes of charging is very very modest, and double+ that of this setup. The folks here on this forum are savvy shoppers. I recommend you give their comments serious consideration.
time2roll
Nomad
Jun 02, 2013
Single panel with controller, no diodes needed.
2oldman
Explorer II
Jun 02, 2013
If you don't care about a warranty, or the fact there's nothing listed about diodes, then yeah, it's a good deal.

Buyer beware.
Canadian_Rainbi
Explorer
Jun 02, 2013
pianotuna wrote:
Hi,

The 140 watt is a no brainer from my point of view.

Ditto
pianotuna
Nomad III
Jun 02, 2013
Hi,

The 140 watt is a no brainer from my point of view.
time2roll
Nomad
Jun 02, 2013
As long as you are drilling holes it is far easier to mount one 140w panel vs three 15w panels.

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