• Looking for a smarter way to manage your heating this winter? We’ve been testing the new Aqara Radiator Thermostat W600 to see how quiet, accurate and easy it is to use around the home. Click here read our review.

Question about solar power

Joined
11 Jun 2024
Messages
69
Reaction score
2
Country
United Kingdom
I've bought a panel that I want to connect to some batteries . My issue is I have 2 x 38Ah batteries and 2 x 65Ah batteries. I know it's not good to wire up batteries with differant Ah ratings. But could I connect 1 solar panel to 2 solar controllers then have 1 for the 38Ah batteries and 1 for the 65Ah batteries?
 
The problem with any lead acid batteries used in parallel is one faulty battery can discharge them all. The blocking diode 1748021627801.png is designed so a number of batteries can be charged from the same source, but if one battery is discharged it will not discharge the others, but it also means each is used independently, which may not be what you want.

As a lead acid discharges it forms sulphur on the plates, as time passes this gets harder and harder, so the aim is every couple of months to ensure every battery is fully recharged, this takes time, and if a battery is in constant use, there are not enough sun light hours in the day to fully recharge it.

So having one battery only charged and not used, in a rotor, can allow them to fully re-charge, but narrow boat users would look for shore power once a month so charge over night as well.

All the batteries can go in parallel if non are faulty, the problem is if one has a fault it can drag the others down. Today we tend to use lithium batteries which don't have the problem of slow charge times.
 
I've bought a panel that I want to connect to some batteries . My issue is I have 2 x 38Ah batteries and 2 x 65Ah batteries. I know it's not good to wire up batteries with differant Ah ratings. But could I connect 1 solar panel to 2 solar controllers then have 1 for the 38Ah batteries and 1 for the 65Ah batteries?

No, don’t do that. Connecting a single panel to multiple controllers in parallel is going to be a mess.

Personally I wouldn’t be too concerned about putting multiple batteries of the same voltage and same chemistry - and ideally the same age - in parallel. You need to make sure they have the same state of charge when you first connect them, so one doesn’t discharge vigorously into the other - and them keep them connected. Are your existing pairs of batteries used together in parallel?

Does anyone make a controller that’s designed for multiple independent batteries? That would be the ideal solution.
 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top