No t all leis u re batteries are made equal

Leisure battery construction and careW h eth er you cam p on a C lu b site w ith fu ll e lectric h ook-u p or atten d rallies w ith n oW h eth er you cam p on a C lu b site w ith fu ll e lectric h ook-u p or atten d rallies w ith n o

m ain s electric su pply a battery in you r u n it is an essen tial addition . T h is data sh eetm ain s electric su pply a battery in you r u n it is an essen tial addition . T h is data sh eet

explain s th e con stru ction an d provides som e gu idan ce to bu yin g an d m ain tain in g aexplain s th e con stru ction an d provides som e gu idan ce to bu yin g an d m ain tain in g a

leisu re battery to en able a stress free h oliday. G et free h elp an d advice w h en you leisu re battery to en able a stress free h oliday. G et free h elp an d advice w h en you joinjoin

th e C lu bth e C lu b ..

The 12V equ ipm ent in a ca ravan o r mo to rhome

re l ie s on a le is ure ba t te ry. Th is impo rtant item

is no t no rma lly s upp l ie d w ith a new ca ravan

w he rea s m os t new m oto rhomes have one a s

s tanda rd . Ba t te rie s tha t a re de s igned to s ta rt a

veh icle a re m ade d iffe rent ly from ba t te rie s

spe cif ica l ly in tended to run ca ravanning

app l iance s . Th is is be cause the ir ope ra t ing

requ irem ents a re d iffe rent . Fo r ins tance a

veh icle ba t te ry ha s to provide a h igh current

surge to s ta rt an eng ine , but once tha t ha s

been a ch ie ved, a veh icle ’s a lte rna to r immed ia te ly re p len is he s the pow e r it p rovided.

In cont ra s t , a le is ure ba t te ry ha s to provide a s te ady f low o f current ove r a pro longed pe riod and

se ldom ge ts re p len is hed unt i l the use r re cogn is e s tha t it s vo ltage le ve l ha s s ubs tant ia l ly fa l le n.

Tha t ’s w hen a re -cha rge is du ly provided. I f le ft long in a d is cha rged s ta te , a ba t te ry w il l

gene ra l ly no t re ga in it s fo rme r cond it ion. Furthe rmore , manufa cture rs o ften re commend tha t re -

cha rg ing is com menced w hen a ba t te ry drops to 50 pe r cent o f it s fu l l cond it ion.

To a ch ie ve the requ ired pe rfo rmance , a le is ure ba t te ry s hou ld be cons t ructed in a w ay tha t cope s

be t te r w ith a l i fe o f re pea ted s ign if icant d is cha rg ing fo l low ed by re -cha rg ing . Th is is re fe rred to

a s ‘deep cycl ing ’ and o the r products tha t pe rfo rm in th is manne r include ‘s em i-t ra ct ion ’ and

‘t ra ct ion ba t te rie s ’, the se a re used on go lf bugg ie s , d is ab i l i ty w hee lcha irs , and s eve ra l type s o f

w a rehouse veh icle s . The re 's a ls o 'un inte ruptab le pow e r s upp l ie s ' (U PS) ba t te rie s , capab le o f ve ry

deep cycl ing and w iths tand ing a cont inuous cha rge too , the se a re found suppo rt ing s e rve rs ,

s e curity s ys tems and eme rgency med ica l fa ci l i t ie s .

Th is Da ta Shee t fo cuse s on le ad-a cid ba t te rie s w hich a re manufa ctured fo r pa rt icu la r ta s ks but in

re cent yea rs w e 've s een an incre a se in the ava i la b i l i ty o f l i th ium ba t te rie s s o they're now w orth a

ment ion. They a ls o ge t cla s s if ie d us ing va rious names .

T ypes o f conventional lead-acid batteries:Standa rd s ta rte r ba t te rie s (s ome t imes re fe rred to a s ca lcium ba t te rie s , cranking ba t te rie s ,

le ad-a cid ba t te rie s , w e t ba t te rie s ).

Standa rd le is ure ba t te rie s (a ls o re fe rred to a s auxi l ia ry ba t te rie s , deep-cycl ing ba t te rie s , le ad-

a cid ba t te rie s , w e t ba t te rie s ).

Sem i t ra ct ion and t ra ct ion ba t te rie s (a ls o re fe rred to a s deep cycl ing ba t te rie s , le ad-a cid

ba t te rie s , w e t ba t te rie s ).

D ATA SH EET#33 A gu id e to le isu re batteries#33 A gu id e to le isu re batteries #33

A cas ing fo r a 12V batteryis manu factu red w ith

s eparate co mpartments

To res is t d is to rt io n fro m repeated deep cycling , leis u rebattery lead o x ide pas te g rid s need to be s tu rdy.

P roducts made d iffe rent ly s uch a s ge l, le ad-crys ta l, l i th ium and AGM ba t te rie s a re ment ioned

la te r in th is Da ta Shee t .

B attery versatilityNot s urpris ing ly, ba t te rie s a re made to be

‘job s pe cif ic’. Fo r ins tance , a convent iona l

ca r ba t te ry s e ldom la s ts long w hen a sked

to provide a 12V supp ly in a ca ravan o r

moto rhom e . Th is is pa rt ly be cause it s le ad

p la te s a re th inne r and it s s epa ra to rs

(de s cribed la te r) a re d iffe rent , too .

In consequence , it canno t cope w ith

repea ted heavy d is cha rge and re cha rge

cycle s . Conve rs e ly, a s tanda rd ‘w e t ’ le is ure

ba t te ry doe sn ’t pe rfo rm w e ll a s a s ta rte r

ba t te ry e ithe r.

So bea r in m ind tha t convent iona l le ad-a cid ba t te rie s a re no t ab le to pe rfo rm bo th s ta rt ing

funct ions and a cce s so ry s upp ly funct ions w ith equa l e ffe ct ivene s s . How eve r, p roducts ca l le d AGM

ba t te rie s , de s cribed la te r, a re be t te r a t pe rfo rm ing bo th ope ra t ions .

Leisure batteries’ tw o-fo ld tasksA lthough a key funct ion o f a le is ure ba t te ry is to run 12V app l iance s , it a ls o pe rfo rms a s e cond

important funct ion. Bea ring in m ind tha t it is pe rmanent ly l inked to a ca ravan o r mo to rhome ’s

bu i lt -in cha rge r, a le is ure ba t te ry is a ls o ab le to smoo th out any irre gu la rit ie s in the s upp ly

re ce ived from th is device .

Th is is w hy a ca ravan ’s 12V a cce s so rie s s hou ld no t be run d ire ct ly from a cha rge r – i .e . w ithout a

ba t te ry ins ta l le d in the s upp ly s ys tem .

B attery anatom yThe s tanda rd (i.e . ‘w e t ’) s ta rte r and le is ure ba t te rie s de s cribed he re usua l ly have a

po lypropylene conta ine r (ava i la b le in s tanda rd is ed s iz e s ) and moulded w ith compa rtments .

Ea ch com pa rtment cre a te s a nom ina l 2.12V , the reby cre a t ing a to ta l o f a round 12.7V fo r a

fu l ly-cha rged ba t te ry.

Ea ch com pa rtment house s a s e rie s o f pos it ive and nega t ive le ad p la te s . The se have a grid

cons t ruct ion s o tha t le ad oxide pa s te can be pre s s ed into a l l the ape rture s .

B o th the po s it ive andnegat ive p lates are co ated

with lead o x ide pas te

Thes e p lates are held in am icro po ro us perfo rated

p las t ic envelo pe

The relief tube wh ichco nveys gas fro m the cellsto the o u tdo o rs mus t no t

get d is lo dged fro m thecas ing

R epeated re- charg ing hascaus ed the pas te in th iss tarter battery to fall awayfro m the p lates

S o me mo to rho mes are no w beingfit ted w ith gel bat teries becaus e

there’s no acid to s p ill

The p la te s in a genu ine le is ure ba t te ry a re th icke r than those

used in s ta rte r ba t te rie s . Ea ch p la te is no rma lly he ld in a

m icropo rous pe rfo ra ted p la s t ic e nve lope ca l le d a s epa ra to r.

Mo reove r, in a genu ine le is ure

ba t te ry, the se enve lope s a ls o

conta in g la s s f ib re s hee ts to

pre s s aga ins t the le ad oxide

pas te he ld in e a ch p la te . Th is

comba ts the tendency during

cons tant re -cha rg ing fo r the

pas te to be come loosened and

then com ple te ly de ta ched from the le ad grid .

The com pa rtments in the ca s ing o f le ad-a cid ba t te rie s a re a ls o f i l le d w ith d i lu ted su lphuric

a cid re fe rred to a s the e le ct ro lyte . The ca s ing a ls o ha s a ga s out le t fo r re le a s ing any

hydrogen cre a ted during re -cha rg ing . Th is mus t no t be a l low ed to be come de ta ched.

The grea te r amount o f le ad in a

genuine le is ure ba t te ry and it s

more e labo ra te s epa ra to rs is

re f le cted in it s h ighe r price and

increa sed w e ight .

N on-w et le isu re batteriesG e l ba tte rie s

Some le is ure veh icle s , s uch a s those used fo r o ff-road quad

b ike s and je t s kis , have a grea te r l ike l ihood o f t ipp ing ove r.

An a ccidenta l inve rs ion m ight a ls o re su lt in the lo s s o f a

ba t te ry’s co rro s ive a cid w hich, in turn, m ight cause pe rs ona l

in jury. In re sponse to th is , ba t te rie s a re ins ta l le d w hich have

a non-sp i l l e le ct ro lyte in the fo rm o f a ge l. U n l ike a ‘w e t ’

ba t te ry, a ge l ba t te ry’s ca s ing is comple te ly s e a le d .

Re cent ly, s ome imported moto rhomes have been f it te d w ith

a ge l ba t te ry ra the r than a le ad-a cid ba t te ry, but th is is fo r

added s a fe ty during a cra sh. From an e le ct rica l pe rspe ct ive ,

ba t te rie s w ith a ge l e le ct ro lyte a re un l ike ly to pe rfo rm any be t te r than w e t-a cid type s . A ls o be

aw a re tha t w hen re cha rg ing a ge l ba t te ry, the cha rge vo ltage mus t no t e xceed 14.2V .

Info rma t ion on cha rg ing requ irements is a s ub je ct in it s ow n right .

Absorbe nt G la ss M a t (AG M ) ba tte rie s

The A G M batteries made by O p t imalo o k like a ‘s ix pack’ o f d rinks

An AGM ba t te ry ha s le ad p la te s in e a ch ce l l and the

manufa cture r us e s a mach ine to add h igh ly compre s sed g la s s

f ib re in to e a ch compa rtment . The f ib re then abso rbs the a cid

e le ct ro lyte . During manufa cture , a ir is a ls o draw n from the

ca s ing and a pre s sure re l ie f va lve is f i t te d . The se proce s se s

rende r the f in is hed product more cos t ly than a convent iona l

‘w e t le ad-a cid ’ le is ure ba t te ry but AGM products can

gene ra l ly a ch ie ve many more re cha rg ing cycle s – the reby

ach ie ving a longe r w o rking l i fe .

Some AGM ba t te rie s , s uch a s the Banne r Running Bu l l range ,

use convent iona l re ctangula r po lypropylene ca se s w he rea s in

O pt ima ba t te rie s the compre s sed g la s s w oo l is f i t te d in a ro l l

configura t ion. Th is g ive s an O pt ima ba t te ry an appea rance

s im ila r to a s ix-pa ck o f d rinks .

As ment ioned ea rl ie r, AGM ba t te rie s a re unusua l in tha t they

can a ct a s s ta rte r ba t te rie s a s w e l l a s le is ure products . Fo r

ins tance , s ome re cent ca rs a re f it te d w ith a s uppo rt ing AGM

second ba t te ry to run the many e le ct ron ic a ids now be ing ins ta l le d . Sim ila rly, the ir no tab le

pe rfo rm ance is re cogn is ed by ca ravanne rs w ant ing a ta s k-spe cif ic s uppo rt ba t te ry to s pe cif ica l ly

run a m o to r m ove r.

W hen re cha rg ing an AGM ba t te ry, the cha rge vo ltage mus t no t e xceed 14.4V but che ck th is w ith

the manufa cture r.

Le a d-crysta l ba tte rie s

As it s nam e sugge s ts the re 's b road ly the s ame bas ic chem is t ry go ing w ith a re a ct ion be tw een

le ad and an a cid but w ith the se the a cid is in a crys ta l fo rm . Th is means the re 's ve ry l i t t le l iqu id

content w ith no ris k o f s p i l la ge making them sa fe to t ranspo rt . The un ique chem is t ry enab le s

them to be ve ry deep cycle d w ith l i t t le ris k o f s u lpha t ion. They can be be a round tw ice the price

o f a good qua l ity deep-cycle ba t te ry but a s they w e re o rig ina l ly de s igned fo r U PS use they're

robus t aga ins t cont inuous cha rg ing from a s o la r s upp ly and can to le ra te heavy d is cha rge loads

from an inve rte r fo r e xample .

Lithium ba tte rie s

L ith ium iron phospha te (L iFePO 4) ba t te rie s a re ano the r fo rm o f ve ry deep cycle ba t te ry. They're

s e lf conta ined un it s w ith the ir ow n on-boa rd cha rge manage r. Having e lm ina ted le ad they

typ ica l ly w e igh ha lf a s much a s an equ ive lant output le ad-a cid ba t te ry s o the w e ight s aving is a

bene fit . They can a ls o be fu l ly d is cha rged and re cha rged and during the d is cha rge cycle they can

re ta in a s tab le vo ltage le ve l and they can be rap id ly re cha rged.

Cos t is the is s ue , they can typ ica l ly be more than f ive t imes the price o f a good qua l ity le ad-a cid

ba t te ry.

If the electro lyte level falls in thecells , each o ne s ho u ld be to pped -up w ith de- io n is ed water

M ain tenance-free batteriesConvent iona l le ad-a cid s ta rte r and le is ure ba t te rie s

have inspe ct ion caps s o tha t the le ve l o f a cid can be

inspe cted in e a ch o f the ce l ls . Th is a ls o enab le s the

ce l ls to be topped-up us ing de -ion is ed w a te r (a ls o s o ld

fo r s te am irons ) s o tha t the e le ct ro lyte jus t cove rs the

top o f the le ad p la te s .

In ge l and AGM ba t te rie s , ce l l che cks a re ne ithe r

requ ired no r pos s ib le be cause the ir po lypropylene

ca s ings a re s ea le d . How eve r, s ome convent iona l ‘w e t ’

ba t te rie s e qu ipped w ith removab le ce l l caps a re a ls o be ing ma rke ted a s ‘ma intenance fre e ’

p roducts . Th is is ba sed on the fa ct tha t i f a s ta rte r o r le is ure ba t te ry is no t cha rged a t a

ra te in e xce s s o f 14.6V , it s e ldom needs topp ing-up w ith de -ion is ed w a te r. How eve r, tha t is

no t the ca se w hen pe riod ic boos t cha rge s o f 14.8V o r more a re de s irab le fo r re viving a

f la gg ing ba t te ry. It then be comes ve ry impo rtant to che ck the e le ct ro lyte le ve l and rep len is h

it w ith de -ion is ed w a te r i f ne ce s sa ry.

S afetyA le ad-a cid ba t te ry mus t be s e cure ly mounted and it s ga s e s cape vent f it te d co rre ct ly. Th is

d is cha rge s the m ix o f hydrogen and oxygen cre a ted during h ighe r cha rg ing le ve ls . The ga se s

can e ithe r be s a fe ly ta ken outs ide fo r d is pe rs a l via a p la s t ic tube o r d is cha rged through a

spe cia l ly-vent i la ted ba t te ry-lo cke r doo r. In s ome ca se s the d is cha rge o f ga s m ight be

suff icie nt to a ct iva te a nea rby ga s a la rm such a s a ca rbon-monoxide de te cto r.

Ba t te ry ga s is e xp lo s ive and if i t is ign ite d , the ca s ing o f a ba t te ry can be b low n apa rt and

it s a cid re le a sed, le ad ing to e ye in jury o r f le sh burns . Acco rd ing ly, w hen cha rg ing a ba t te ry

o r d is conne ct ing le ads a fte r a cha rge , ensure the re a re no naked f lames nea rby. Even a

l ighted ciga re t te can ign ite the ga s . A ls o fo l low the se pre caut iona ry measure s w heneve r the

e le ct ro lyte is che cked and w hen a ce l l is topped-up:

W hen inspe ct ing ba t te ry ce l ls , w ea r s a fe ty clo th ing includ ing e ye pro te ct ion and g love s .

Ba t te ry a cid a ls o damages clo th ing .

W he reas a 12V ba t te ry is un l ike ly to cause e le ct ro cut ion, i f the te rm ina ls o r the ir coup le

cab le s a re s ho rted-out , it can cause a f ire .

Spa rks s om e t imes occur w hen conne ct ing up a ba t te ry and good qua l ity clamps a re

needed. Tempora ry cro cod i le cl ips , o fte n s upp l ie d w ith ba t te ry cha rge rs , a re no t s u itab le

fo r pe rm anent conne ct ions . A ls o no te tha t a s pa rk can cause ign it ion o f re le a s ing ga s o r

re s idua l ga s le ft in a ce l l .

Purchasing gu idanceThe fa ct tha t the re a re d iffe rent type s o f ba t te rie s made in d iffe rent s iz e s and s o ld a t d is s im ila r

price s can confuse anyone w ant ing to purchase a le is ure ba t te ry. Expe rie nce ce rta in ly re vea ls

tha t s ome o f the cheape r and l ighte r p roducts no t on ly lo s e the ir cha rge rema rkab ly qu ickly but

the ir w o rking l i fe is s ho rt a s w e l l . A s a ru le o f thumb the heavie r the ba t te ry the more le ad it

conta ins and the re fo re ha s the ab i l i ty to ho ld a la rge r capacity o f cha rge . I f you w ant a le is ure

ba t te ry to provide pow e r to pe rfo rm deep cycl ing a heavy ba t te ry is a good p la ce to s ta rt .

Due to the a huge va ria t ion in qua l ity, p rice and a ctua l

pe rfo rm ance , the le is ure indus t ry w o rking w ith The Na t iona l

Ca ravan Counci l (NCC) ha s int roduced a Le is ure Ba t te ry

Ve rif ica t ion Scheme to make s e le ct ion o f a s u itab le qua l ity

ba t te ry e a s ie r and provide s confidence tha t the ba t te ry

purchased is f i t fo r purpose and w il l pe rfo rm a s adve rt is ed .

As sum ing a te s ted le is ure ba t te ry pe rfo rms a s requ ired it w i l l

be ca tego ris ed in one o f thre e groups and approva l logo (s ee

RH co lumn) w il l be app l ie d to the ba t te ry.

In s ome ins tance s an inexpens ive ba t te ry m ight mee t the needs o f s ome ca ravan o r mo to rhome

ow ne rs , e spe cia l ly i f you s pend mos t o f your ove rn ight s tops a t s ite s equ ipped w ith 230V ma ins

hook-ups . W hen conne cted to a ma ins s upp ly, a ca ravan ’s ba t te ry is then on ly a ct ing a s a device

tha t ‘smoo the s out ’ the 12V output from the ‘van ’s bu i lt -in cha rge r. Since the ba t te ry is s e ldom

ope ra t ing a s a provide r o f pow e r, an inexpens ive ba t te ry m ight be a s u itab le purchase .

Tha t is no t the ca se i f your ca ravanning and moto rhome t rips ta ke you to Ce rt i f ica ted Site s

w ithout e le ct ric hook-ups o r C lub ra l ly s ite s w he re you have to be fu l ly s e lf-conta ined. In those

s itua t ions , a good qua l ity, h igh capacity ba t te ry is e s s ent ia l fo r runn ing 12V app l iance s . Equa l ly,

i f you enjoy e xtended s tops on a s ite o f your cho ice and ne ithe r tow a ca ravan no r drive a

moto rhom e o ff-s ite fo r s e ve ra l days , your le is ure ba t te ry w on’t ge t re -cha rged from a veh icle

a lte rna to r e ithe r. So a good le is ure ba t te ry is needed in tha t ins tance , too . O n ly buy ba t te rie s

tha t have been m anufa ctured in the la s t 12 months . Ask the s upp l ie r th is que s t ion a s o ld

ba t te rie s cou ld a lre ady be su lpha ted (s ee ba t te ry ca re ).

T he ca te gorie s a re :

C a te gory A is fo r h ighe r s to rage capacity fo r peop le w ho

frequent ly us e the ir ca ravans o r mo to rhomes aw ay from

e le ct rica l hook-ups

C a te gory B a re a imed a t those w ho fre quent ly us e s ite s w ith

hook-up fa ci l i t ie s , but re qu ire a grea te r ba t te ry capacity to

ope ra te device s s uch a s mo to r move rs

C a te gory C is fo r us e rs tha t re qu ire a low e r capacity ba t te ry to cove r ba s ic ope ra t ion o f the ir

hab ita t ion equ ipm ent fo r s ho rt pe riods aw ay from a hook-up

B attery careTo ge t the be s t out o f a le is ure ba t te ry:

App ly a th in f i lm o f g re a se o r pe t ro le um je l ly, s uch a s Va se l ine ,

to a ba t te ry’s te rm ina ls (s e e right ).

U se good qua l ity ba t te ry clamps and if you pre fe r s pring-loaded

clam ping cl ips , make sure tha t the ir s te e l conta ct s urfa ce s don ’t

s ta rt to rus t

O n a non-s ea le d ba t te ry, pe riod ica l ly confirm tha t the e le ct ro lyte

cove rs the le ad p la te s . Be fo re inspe ct ing the ce l ls , e nsure the re

a re no naked f lam es o r l i t ciga re t te s nea rby. W ea ring s a fe ty

spe cta cle s is a ls o a w is e pre caut ion. Pe riod ica l ly che ck tha t a

ba t te ry’s ga s re l ie f tube (w he re f it te d) is co rre ct ly coup led-up.

Ba t te ry m anufa cture rs o ften s t rong ly advis e tha t a ba t te ry

re ce ive s a re -cha rge w hen it s capacity fa l ls be low 50 pe r cent o f it s fu l l cond it ion. It is a ls o

added tha t you shou ld neve r run a le is ure ba t te ry unt i l i t is virtua l ly ‘f la t ’. Furthe r de ta i ls a re

cove red in the ba t te ry cha rg ing Da ta Shee t (36).

If a ca ravan o r mo to rhome is unused fo r a long s pe l l , p rovis ion mus t be made to keep it s

le is ure ba t te ry cha rged. A t rickle cha rge r is o fte n used to ma inta in the s ta te o f cha rge .

Some ow ne rs remove a ba t te ry and t rans fe r it to a bench w he re it can be ma inta ined – but

don ’t fo rge t tha t th is may d is ab le any e le ct rica l ly-pow e red s e curity a la rms .

K eep it chargedNeve r le ave a ba t te ry in a d is cha rged s ta te . I f

re cha rg ing is de la yed, a s itua t ion know n a s s u lpha t ion

occurs in w hich a w hite depos it fo rms on a ba t te ry’s

p la te s . In gene ra l th is is an incurab le cond it ion, w hich

rende rs a ba t te ry use le s s .

C hecking a battery ’s charge levelMos t ca ravan cont ro l pane ls have a l ight d is p la y o r ba t te ry

cond it ion m e te r, s om e o f w hich don ’t p rovide a pre cis e ind ica t ion o f

it s cha rge le ve l. Mo re a ccura te in fo rma t ion is obta ined by taking a

read ing a cros s a ba t te ry’s te rm ina ls us ing a d ig ita l me te r. W hen

us ing a hand-he ld me te r, no te the fo l low ing po ints :

A l l e le ct rica l app l iance s s hou ld be sw itched o ff. I f you don ’t

w ant to d is conne ct a clo ck, an a la rm tha t runs from the ba t te ry,

a fridge ’s fa s cia cont ro ls o r s im ila r, the re ad ing w il l no t be comple te ly a ccura te . O bvious ly th is

is no t an is s ue i f you ’ve removed a ba t te ry and t rans fe rred it to a w o rk bench.

If you have re cent ly d is conne cted a cha rge r o r have been driving a mo to rhome o r tow ing, a

re ad ing w il l be h ighe r than no rma l. A fte r a ba t te ry ha s been re ce iving a cha rge , it is

re comm ended to le t it s e t t le fo r a t le a s t four hours be fo re ta king a vo ltage re ad ing .

Now you need to in te rpre t the re ad ing and a lthough w e ta lk about 12V ba t te rie s and

acce s so rie s , th is de s crip t ion is on ly nom ina l. I f a le is ure ba t te ry a ch ie ve s a 12V re ad ing , it is

cons ide red to have re a ched a d is cha rged s ta te .

As a rough guide , w ork to the fo llow ing ta ble :

V o ltmeter read ing A p p ro x state o f charg e

1 2 .7 V o r o ve r 1 0 0 %

1 2 .5 V 7 5 %

1 2 .4 V 5 0 %

1 2 .2 V 2 5 %

1 2 V o r u n d e r D is ch a rg e d

Ba t te ry s pe cia l is t s s ome t imes d iagnose a le ad-a cid ba t te ry’s

cond it ion us ing a hydrome te r to obta in the s pe cif ic g ravity o f the

a cid . A lthough th is me thod ha s s ome advantage s , it canno t be

used on a s ea le d ba t te ry and the procedure is no t d is cus sed

furthe r he re .

Perform ance period betw een chargesThe capacity o f a ba t te ry s hou ld de te rm ine how long a ba t te ry can provide pow e r be fo re it needs

to be re cha rged. Some a re more h igh ly s pe cif ie d than o the rs and the idea o f having grea te r o r

le s s e r capacit ie s is e xpre s sed in Amp hours (Ah). So a 110Ah ba t te ry provide s pow e r fo r a longe r

pe riod than a 65Ah ba t te ry; it a ls o ta ke s longe r to re cha rge comple te ly. How eve r, the re a re many

o the r fa cto rs tha t in f luence w he the r re cha rg ing is needed s oone r o r la te r.

Factors affecting battery perform anceT e mpe ra ture – The s ta ted capacity o f a ba t te ry is e xpre s sed in Amp hours (Ah) but the

quo ted f igure is on ly app l icab le w hen the ambient tempe ra ture is 25C. In re a l ity, the re a re

many occa s ions in the U K w hen it ’s much co lde r than 25C and fo r e ve ry one degree drop in

tempe ra ture , the re ’s an approxima te one pe r cent re duct ion in a ba t te ry’s Ah capacity.

Le t ’s ta ke an e xample . I f a ba t te ry w hich is nom ina l ly ra ted a t 60Ah is ope ra t ing in tempe ra ture s

o f 15C, th is te n degree reduct ion w il l b ring about a 10 pe r cent re duct ion in it s capacity. Th is

now means tha t it e ffe ct ive ly pe rfo rms l ike a 54Ah ba t te ry. The tempe ra ture is s ue can have

adve rs e e ffe cts fo r ca ravan and moto rhome use rs w ho enjoy w inte r s po rts . No t on ly w il l a ba t te ry

fa ce grea te r demands w hen provid ing the ir l ight ing , fan-a s s is te d hea t ing , and e ven ing TV

ente rta inment during long, da rk e ven ings ; it s e ffe ct ive capacity is s ign if icant ly low e r than it

w ould be in w a rme r cond it ions .

Need le s s -to -s ay, i f a ba t te ry box is mounted ins ide , hea t in the l iving a rea w il l he lp to improve

it s pe rfo rmance . How eve r, many ba t te rie s a re mounted e xte rna l ly w he re ambient tempe ra ture s

can be m uch low e r.

Ba tte ry a ge – As a ba t te ry ge ts o lde r, it s pe rfo rmance de te rio ra te s and it needs re -cha rg ing

w ith incre a s ing fre quency, the re fo re , it is un l ike ly to la s t more than f ive yea rs .

Highe r ra te s o f consumption – If nume rous app l iance s a re be ing used s imultaneous ly, a

ba t te ry’s incre a sed d is cha rge ra te a ffe cts it s ab i l i ty to provide pow e r. Th is is no t jus t a ma t te r

o f s aying tha t runn ing app l iance s w ith doub le the w a t tage re su lt s in a ba t te ry be com ing

d is cha rged in ha lf the t ime . In pra ct ice , an e xt ra demand on a ba t te ry ha s an e ven grea te r

e ffe ct on it s pow e r-provid ing po tent ia l. O r to put it ano the r w ay, the fa s te r your ba t te ry is

d is cha rged, the low e r it s capacity w i l l be .

W ha t size le isure ba tte ry do I ne e d? – Y ou w il l f irs t need to w o rk out w ha t your

consum pt ion is go ing to be on the 12V equ ipment you use and fo r how long it is us ed then, i f

re qu ired , fa cto r in w ha t s e a sons you go aw ay. An e xample is s how n be low :

E q u ip ment(T yp ical

examp le) C urrent(A mp s) M u ltip ly Ho urs o f use =

A mp ho ur

rating (A H)

O n e flu o re s ce n t tu b e 0 .7 5 x 5 = 3 .7 5

2 h a lo g e n lig h ts 1 .5 0 x 3 = 4 .5 0

2 h a lo g e n lig h ts 1 .5 0 x 3 = 4 .5 0

LC D TV 2 .5 x 4 = 1 0 .0 0

TV b o o s te r 0 .0 5 x 4 = 0 .2 0

W a te r p u mp 0 .7 x 0 .5 = 0 .3 5

M o to r mo ve r 3 0 (Ave ra g e ) x 0 .3 = 9 .0 0

S ub Tota l = 2 7 .8

(Fo r w in te r u s e a d d a n e xtra

1 0 % )Ad d 2 0 % s a fe ty ma rg in = 5 .5 6

Tota l Ampere H ours

required per day= 3 3 .3 6

This g ive s your typ ica l da i ly consumpt ion. It is s urpris ing how much pow e r is re qu ired and how

w e take it fo r g ranted . Heavy consumpt ion equ ipment l ike mo to r move rs w il l have a de t rimenta l

e ffe ct on the ba t te ry pe rfo rmance fo r the re a sons e xp la ined be low .

From th is in fo rma t ion de cide w ha t s iz e ba t te ry w il l l ike ly be needed depend ing on how long you

a re aw ay from a cha rg ing s ource . It is l ike ly tha t th is is no t enough to mee t your needs and w il l

have to cons ide r a top up cha rge . Th is w i l l be cove red in more depth in the Ba t te ry Cha rg ing

Da ta Shee t (36).

R a te o f d ischa rge – Fo l low ing on from the above po int , a ba t te ry’s ab i l i ty to provide pow e r

w il l depend on the ra te o f d is cha rge . T ime p la ys a key pa rt and

tha t is w hy ba t te rie s bu i lt to mee t EU 50342 s tanda rds have

tw o o r s om e t im es thre e Ah capacit ie s ma rked on the ir la be ls .

No rma lly a m anufa cture r’s quo ted Ah capacity o f a ba t te ry is

ba sed on a d is cha rge t ime o f 20 hours – re fe rred to a s ‘the 20

hour ra te ’. Fo r ins tance , a ba t te ry de s igna ted a s 95Ah a t the 20

hour ra te m ight on ly a ch ie ve 80Ah a t a f ive hour ra te – o r a s

much a s 105Ah if e duced demand extends ove r a 100-hour pe riod .

U nfo rtuna te ly the re a re s o many d iffe rent fa cto rs invo lved in a ba t te ry’s a ctua l pe rfo rmance , it s

Ah capacity can on ly be taken a s a gu ide . The type o f ba t te ry de s ign and cons t ruct ion, ambient

tempe ra ture , ba t te ry age , and consumpt ion le ve ls have a lre ady been ment ioned. In pra ct ica l

te rms , nea rly a l l ca ravanne rs f ind the ir ba t te ry s e ems to need re cha rg ing fa r s oone r than they

expe cted .

For fu rther in form ationSee Da ta Shee t (36) Cha rg ing a le is ure ba t te ry a t

ht tps ://w w w .campingandca ravanningclub .co .uk/da ta shee ts /

Thank you to John W icke rsham (w w w .w ickyw orld .co .uk) and Banne r

Ba t te rie s (w w w .banne rba t te rie n.com) fo r the ir kind he lp producing th is da ta shee t .

If you ha ve fe e dba ck on our ne w forma t Da ta she e t, p le a se le t us know , using our short

Fe e dba ck Form.

W eb :W eb : The Camping and Ca ravanning C lub

Greenf ie lds House , W estw ood W ay , Covent ry CV4 8JH

Tel:Te l: 024 7647 5442

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