Ineffective solar charging and upgrades

[fifer]

I was going to replace 2 old solar panels (20 watt) because I thought they were shot! However Henry, at Fox’s (now left) persuaded me to invest in a set of mounts to enable the panels to be directed more effectively towards the sun. In bright sunlight they will input 2 amps when that is done, but only .3/4 amps if off centre. Try alignment first!

Thanks, but I was getting 10% of those low numbers even in bright sunshine

 

[William_H]

The VSR in the link (BEP) is a fine device however it would draw perhaps 5ma continuously and with contacts rated at 140 amps would draw in the coil .25 to .5 amp perhaps more when activated.
OP should look for a cheap 20w panel. If he can find room fit another for the other battery then do so. No controllers.
If you can't afford or fit another panel use 2 diodes to share the one panel output between 2 batteries. Use shotky diodes ratted at 3 amps or more. Anodes together to pos solar wire. cathodes one to each battery pos. If you fit the diodes near the battery post you do not then need 2 fuses. Operate with all isolation switches off. good luck ol'will

 

[ghostlymoron]

If you're on a swinger, the best vertical alignment is almost flat and the horizontal is anything from 0 to 360° so alignment is impossible.

I was going to replace 2 old solar panels (20 watt) because I thought they were shot! However Henry, at Fox’s (now left) persuaded me to invest in a set of mounts to enable the panels to be directed more effectively towards the sun. In bright sunlight they will input 2 amps when that is done, but only .3/4 amps if off centre. Try alignment first!

 

[ghostlymoron]

I've had two boats with BEP VSRs on engine and small solar and AFAIK they worked. However, I now think low loss shotky diodes are a better solution as they give complete separation of the batteries whereas the VSR just parallels them.

 

[Kurrawong_Kid]

If you're on a swinger, the best vertical alignment is almost flat and the horizontal is anything from 0 to 360° so alignment is impossible.

Not quite! On a swinger much of the time will be tide rode one way or the other, especially at springs. With one panel it might be sensible to align it at about 60 degrees from waterline and facing towards the direction from which you estimate the most sun will shine in your situation during daylight hours at the likely tidal situation for the next few days. With 2 panels rather easier. A flat panel will only substantially pick up at midday, whilst at 60 degrees should get energy over a slightly longer time if directed against the sun by tidal swing as suggested above.