Hi,

I have a question about Renogy 100W kit, which is recommended for batteries with 100AH.
au.renogy.com/new-100-watt-12-volt-solar-premium-kit/

Are there any issues using the same setup for a eg lead-acid battery with lower Amp Hours eg 75AH?

I understand that the battery performance impacts how well the whole solar setup works (eg deep cycle etc.), but I just want to know if the Amp Hours need to be considered in order not to break the battery.

Thank you in advance for your comments and feedback :)

cheers,
Yamaha24ft

I didn't buy the kit but I have 2 of that exact charge controller; one on a boat charging a 120ah lithium and one on my other boat charging a 100ah lead acid. You can change the charging profile on the controller from deep cycle to lead acid to lithium so that should not be a problem.

As for the size of the battery I don't think that is a problem because the controller senses the charge state of the battery (via voltage) and stops charging or slow trickle charges as necessary.

That is my understanding and neither of my boats have burned down yet but I believe Ramona has the same charge controller and he might like to confirm.

One of mine by the way is hooked up to a rigid 120 w panel and the other to a 330 .

oh great :) that sounds reassuring. I assumed you can adjust the battery type on the controller but I have not used it myself.
Thank you for the reply :)

Select to expand quote

Yamaha24ft said..
oh great :) that sounds reassuring. I assumed you can adjust the battery type on the controller but I have not used it myself.
Thank you for the reply :)

You just keep pressing the button till your type of battery appears. I have three of these controllers on my boat and I doubt the controller knows how many amp hours the battery is.

@Ramona awesome thanks ????

Some solar charge controllers will allow you to enter the amp/h capacity of the battery so an approximate percentage of the batteries charge can be displayed.

Gday Yamaha

The charge controllers work by sensing voltage - not amp hours. So your lead acid battery can get up to 15.5 volts when equalizing. The charger will sense the battery voltage and work out whether to allow the solar panels to charge the battery or not. It is a set and forget piece of item, and because a small battery will produce a higher voltage sooner than a bigger one when charging the controller will turn off the panels more quickly than for a larger battery. I like my Renogy charger - although I don't know how to get it to scroll through the parameters like my old one did. I have to click to get it to tell me more data and it is hard to reach (but not to see) the controller.

That being said, I recently installed a little battery monitor with a shunt. It is a great nit of kit and now I can tell how much juice is being drained by all the electronic gear - the AIS transponder takes about 0.4A but the VHF on transmit mode takes about 4 A, and I even got to watch the fridge cycle on and off and work out the total wattage required.

www.google.com/search?q=battery+monitor+junktek&oq=battery+monitor+junktek&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCDU5NDhqMGo0qAIAsAIA&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:19abb7e0,vid:KgjCxIGl7gQ

Thanks @Jolene and @Kankama,
This was helpful. I think I will go for the Renogy setup and will report once installed :)
cheers everyone and thank you for all the feedback.
Yamaha24ft