Rolls Batteries

[BlueSkyNick]

Had a very interesting chat on the Barden stand at LIBs, about replacing our domestic batteries.

Rolls wet batteries seem like good value, ie £160 for a 108Ah, for up to 1000discharges at 50% - allegedly.

In the brochure, I notice they have a 'Reserved Minutes' value, which no other manufacturer states. ie 108AH has 203 Reserved Minutes. What's all that about then?

Anybody used Rolls for a while, and can testify to their endurance?

 

[pvb]

Most battery manufacturers will quote a "reserved minutes" figure, but it's usually qualified by quoting a current too. The Ah capacity of the battery is usually quoted at the 20-hour rate, in other words a 100Ah battery is deemed to deliver 5A for 20 hours. As the discharge current increases, the effective capacity of the battery decreases. I'd guess that the reserved minutes quoted by Rolls are at a 25A discharge current. In this case, 203 minutes = 3.38 hours, which at 25A represents an effective capacity of around 85Ah.

 

[1317]

Rolls Batteries: if they are the same as in NA, then they are made by Surrette in Nova Scotia. Absolute top of the line. Try their web-site and everything you need to know is there. BTW. no connexion.

 

[Bejasus]

we have two Rolls banks of 410AH each. I am not sure how long they have been on the boat, but at least 2 years. I have read that if they are not mistreated, they can last for up to 20 years.

 

[pvb]

[ QUOTE ]
we have two Rolls banks of 410AH each.

[/ QUOTE ]Out of interest, why have two identical banks? If you combine them into one big bank, the efficiency might be better.

 

[roly_voya]

The reserve mim is just the way Rolls express capacity. I.E at a discharge current of 10a a 100a/h battery gives 600min but at 20 amps might only give 250min. Its actualy very useful for checking sizes against demand but a Tigerregis says look at the web site its very good. The only other company I have come accross who seam in the same league are Trojan

 

[pvb]

[ QUOTE ]
I.E at a discharge current of 10a a 100a/h battery gives 600min

[/ QUOTE ]Not so. The normal Ah rating of batteries is given at the 20-hour rate. So a 100Ah battery might give 5A for 20 hours. At 10A discharge, it certainly wouldn't last for 10 hours.

 

[Bejasus]

actually the comment stating that we had two banks was wrong, it is in fact one big bank of 820AH cosisting of 2 x 410AH batteries.

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